Imaging device, reference light data acquisition method, light wave reproduction method, wavefront aberration data acquisition method, noise reduction method, and device manufactured using said device or methods

Abstract

The present invention makes it possible to effectively utilize reference light in an imaging device in digital holography, a reference light data acquisition method, a light wave reproduction method, a wavefront aberration data acquisition method, a noise reduction method, and a device manufactured using said device or methods. An imaging device 1 comprises: an illumination light source SQ that emits illumination light Q for illuminating an object 4 to be imaged; a reference light source SR that emits reference light R for generating interference fringes with object light O radiated from the object 4 illuminated by the illumination light Q; an imaging element 5 that acquires, as an object light hologram IOR, data of the interference fringes of the object light O and the reference light R; and reference light data RD that is data of the reference light R used when an image of the object 4 is reproduced from the object light hologram IOR. The reference light data RD is accurately acquired and provided without approximation or ambiguity by a reference light data acquisition method. The imaging device 1 can accurately reproduce an object light wave using the reference light data RD.

Description

Imaging device, reference light data acquisition method, light wave reproduction method, wavefront aberration data acquisition method, noise reduction method, and device manufactured using these devices or methods The present invention relates to an imaging device, a reference light data acquisition method, a light wave reproduction method, a wavefront aberration data acquisition method, a noise reduction method, and a device manufactured using these devices or methods. Conventionally, in the technology of analyzing light waves such as reflected light and transmitted light, there is holography in which data on the intensity and phase of light are recorded and analyzed on a recording medium such as a photographic plate called a hologram. In recent years, holography has been performed by using an imaging device and a semiconductor memory to acquire the intensity and phase of light waves as digital data, or by generating a hologram on a computer and then analyzing it. Such holography is called digital holography (hereinafter also referred to as DH). Various methods and devices for measuring the shape of a subject with higher accuracy using the above-mentioned DH have been proposed and put into practical use, and the following prior arts are known as typical ones. For example, an in-line hologram recording method and a light wave reproduction method from an in-line hologram are known. In this method, the same light is used for the illumination light and the reference light, and since the conjugate images are not separated but superimposed, there is a problem that accurate object light cannot be obtained. Also known is a phase shift method in which holograms of interference fringes are recorded for each of a plurality of reference lights that have undergone phase shift, and one object light hologram is extracted from the plurality of recorded holograms. The phase shift method requires a mechanism for shifting the phase of the reference light, and there is a problem that the accuracy of recording the object light depends on the phase shift mechanism. In addition, in order to obtain one object light hologram, sequential recording of a plurality of holograms is required instead of one-shot recording, so it is difficult to capture a three-dimensional image of an imaging target object that moves or deforms. Also known is a practical DH that realizes both a reflection type and a transmission type. This method has a configuration using an imaging optical system, and therefore, there is a problem that the object light cannot be accurately recorded because it is affected by the aberration generated in the imaging optical system. In addition to the above prior art, as DH technologies enabling one-shot recording, various technologies for achieving higher speed and higher precision in acquiring and processing hologram data have been proposed and applied to imaging. For example, there is known a DH technology that applies spatial frequency filtering and spatial frequency modulation to off-axis hologram data recorded in one shot to generate a complex amplitude in-line hologram for object image reproduction quickly and accurately. To solve the problems of conventional optical microscopes, by using DH technology, there are known a method of accurately recording object light with a large numerical aperture (NA) without using an imaging lens, a method of accurately computer-reproducing a high-resolution three-dimensional image by plane-wave expansion of the recorded object light, and a technology of a lensless three-dimensional microscope for recording and reproducing an undistorted high-resolution three-dimensional moving image. According to this method, a lensless three-dimensional microscope capable of recording and reproducing an undistorted high-resolution three-dimensional moving image is realized. Since such a microscope does not use an imaging lens, it can solve the problem that conventional optical microscopes are affected by the medium and the imaging lens. In addition, to observe and measure the internal structure of cells and biological tissues in a culture solution at a high resolution at the cell level, by developing the technology of a lensless three-dimensional microscope, a reflection-type lensless holographic microscope and a high-resolution tomography method using wavelength-swept laser light are known. In addition, there is known a method of recording object light with a large numerical aperture emitted from an object irradiated with illumination light having different incident directions as hologram data for each incident direction of the illumination light, and synthesizing these multiple large numerical aperture holograms into one hologram to reproduce the object light under a synthetic aperture number exceeding 1. According to this method, an ultra-high-resolution three-dimensional microscope having a resolution exceeding the normal diffraction limit can be realized. There are known holographic imaging devices with a long operating distance and a wide field of view, and holographic imaging devices that realize an ultra-high resolution transmission type or reflection type microscope having a large numerical aperture or a synthetic aperture exceeding 1. This imaging device includes an optical system having a beam combiner composed of a cube beam splitter in front of an image sensor, and realizes high-precision light wave reproduction by performing calculations of light wave reproduction in consideration of the refractive index of the cube beam splitter. As an application to optical measurement, a holographic ellipsometer using accurate recording of light waves by DH and plane wave expansion of the recorded light waves is known. According to this ellipsometer, since a large number of incident lights having different incident angles included in non-parallel illumination light can be used to record data of a large number of reflected lights in a hologram at once, ellipsometric angles Ψ and Δ can be obtained for each of a large number of wave vectors corresponding to the incident angles, and the measurement efficiency is dramatically improved. There is known a technique for accurately acquiring data on the phase distribution of the regenerated object light on the surface of an object using DH and performing surface shape measurement from the data. The above-mentioned DH for one-shot recording uses the same off-axis reference light (R) for object light (O) and in-line spherical wave light (L) in-line with the object light (O), and records them as two off-axis holograms (I ＯＲ and I ＬＲ ), and a method is used to remove the information of the off-axis reference light (R) from the two recording holograms (I ＯＲ and I ＬＲ ) to obtain a complex amplitude in-line hologram (J ＯＬ ) representing the relationship between the object light and the in-line spherical wave light. Information on the object light (O) is extracted from the complex amplitude in-line hologram (J ＯＬ ). Such DH for one-shot recording is different from general DH by the phase shift method. Since only one off-axis hologram (I ＯＲ ) is required as the hologram of the object light (O) necessary for light wave reproduction of the object light (O), one-shot DH is realized. Therefore, one off-axis hologram (I ＬＲ), and a plurality of one-shot off-axis holograms (I ＯＲ ) of the object light (O) facilitate video imaging of the object. Further, Patent Document 1 discloses a method of calculating information on the light wave distribution of the reference light using a calibration unit including an optical system that generates a known light wave distribution. Japanese Unexamined Patent Application Publication No. 2023-70071 As described above, from the two recording holograms (I ＯＲ and I ＬＲ ), the DH using a technique of removing information on the off-axis reference light (R) to obtain a complex amplitude in-line hologram (J ＯＬ ) has the advantage that only one-shot hologram recording is required to obtain a hologram of the object light (O). Since the above-described complex amplitude in-line hologram (J ＯＬ ) records the phase difference distribution between the object light and the in-line spherical wave light at the position of the imaging device, in order to extract the object light (O) from the complex amplitude in-line hologram (J ＯＬ ), an accurate phase distribution of the in-line spherical wave light at the position of the imaging device is required. For this purpose, accurate position coordinate data of the focus point of the in-line spherical wave light with respect to the position of the imaging device may be obtained. When the position coordinates of the focus point are obtained, the required phase distribution of the in-line spherical wave light can be obtained by analytical calculation of the spherical wave light. In the DH in which the hologram of the above-described object light (O) can be recorded by one-shot hologram recording, for example, the position coordinates of the focus point of the spherical wave light can be obtained by repeating light wave reproduction so that a reproduced image such as a test pattern of known dimensions is undistorted and the size of the reproduced image is equal to the size of the subject. However, the method of obtaining the position coordinates of the above-mentioned light-gathering point searches for and determines the position of the light-gathering point based on the presence or absence of distortion in the reproduced image and the coincidence of the known image size. Therefore, it is difficult to say that it is easy to obtain the position coordinates with high precision. In addition, since it is necessary to repeat the light-wave reproduction, there is a problem that it is time-consuming. Further, the method shown in Patent Document 1 described above requires a mechanical operation for moving a light source having a known light-wave distribution in a three-dimensional space, and there is a problem that the accuracy of the light-wave distribution of the reference light to be calculated greatly depends on the mechanical operation accuracy of the calibration unit. In digital holography (DH), when recording the interference fringes formed by the object light and the reference light with an image sensor, the spatial frequency bandwidth of the recordable interference fringes (or the field of view angle of the subject) is determined by the pixel pitch of the image sensor. In order to accurately record the object light, it is necessary to adjust the distance between the image sensor and the subject according to the size of the subject so that the spatial frequency bandwidth of the interference fringes is below the bandwidth determined by the pixel pitch. When recording an image of a large subject, the subject is placed far from the image sensor, so the size of the optical system for recording becomes large. In addition, when recording the object light in one shot by off-axis holography, it is necessary to adjust the spatial distribution and irradiation angle of the reference light according to the position and size of the object. The size of the measurement surface that can be recorded without using a lens or mirror for light collection is limited by the pixel pitch of the image sensor, the size of the light-receiving surface, the size of the recording optical system, and the like. Although methods using a lens for light collection and an imaging lens or a mirror for light collection and an imaging lens for measuring a large-area flat plate have also been proposed, measurement errors occur due to the aberration of the lens or mirror, so there is a limit to obtaining high measurement accuracy. Therefore, on the premise of using a wavefront conversion element such as a lens or a mirror, it is necessary to develop a device that can remove measurement errors by providing wavefront aberration data that can be used for accurate reproduction of the object light wave in response to an unwanted phase change such as aberration caused by the wavefront conversion element and a deviation from a desired phase change. In addition, it is necessary to develop a method for efficiently and accurately acquiring the above-mentioned wavefront aberration data as data representing the characteristics of individual wavefront conversion elements. In object light recording by an imaging device, since there is a limit to the number of electrons or holes that can be accumulated in each pixel, random noise such as shot noise occurs. This random noise causes errors in precise measurement by DH. In order to promote fine shape measurement and achieve more precise measurement, it is necessary to develop a technique that can accurately and efficiently remove the influence of such noise. The present invention solves the above problems, and an object thereof is to provide an imaging device, a reference light data acquisition method, a light wave reproduction method, and a device manufactured using these devices or methods. In order to achieve the above object, the imaging device of the present invention is In an imaging device using holography, An illumination light source (S Ｑ ) that emits illumination light (Q) for illuminating an object (4) to be imaged, A reference light source (S Ｒ ) that emits reference light (R) for generating interference fringes between the object light (O) radiated from the object (4) illuminated by the illumination light (Q), An imaging element (5) that acquires data of interference fringes between the object light (O) and the reference light (R) as an object light hologram (I ＯＲ ), Reference light data (RD) that is data of the reference light (R) used when reproducing an image of the object (4) from the object light hologram (I ＯＲ ), and is characterized by comprising The reference light data acquisition method of the present invention is In a reference light data acquisition method for acquiring reference light data (RD) representing reference light (R) used in holography using an imaging element (5), Coherent auxiliary light (L) and intermediate light (R ３ ) are prepared for the reference light (R), The auxiliary light (L) is made incident on the imaging element (5) perpendicularly as parallel light, and data of interference fringes between the auxiliary light (L) and the intermediate light (R ３ ) is recorded as an intermediate light hologram (I ＬＲ３ ) using the imaging element (5), The interference fringe data between the reference light (R) and the intermediate light (R ３ ) is recorded as a reference light hologram (I ＲＲ３ ) using the image sensor (5), Based on the fact that the auxiliary light (L) is parallel light that perpendicularly enters the image sensor (5), using the intermediate light hologram (I ＬＲ３ ), reference light wave data (RD) representing the reference light (R) is obtained from the reference light hologram (I ＲＲ３ ). This is the gist of the invention. Another reference light data acquisition method of the present invention is In a reference light data acquisition method for acquiring reference light data (RD) representing reference light (R) used in holography, The interference fringe data between the reference light (R) and the auxiliary light (L) that is coherent with the reference light (R) and can be analytically expressed using known parameters (PA) is recorded as a reference light hologram (I ＲＬ ) using the image sensor (5), Using the parameters (PA), auxiliary light data (LD) obtained as an analytical expression of the auxiliary light (L) is calculated on the hologram plane set on the light-receiving surface (50) of the image sensor (5), Using the auxiliary light data (LD), the component of the auxiliary light (L) is deleted from the reference light hologram (I ＲＬ ), and data of the reference light wave (g Ｒ ) representing the reference light (R) is obtained as reference light wave information (RI) that is the light wave information of the reference light (R) on the hologram plane, The reference light wave information (RI) is used as the reference light data (RD). This is the gist of the invention. The light wave reproduction method of the present invention is In a light wave reproduction method for reproducing object light (O) from an object light hologram (I ＯＲ ), The object light hologram (I ＯＲ)(0) is a hologram recorded by the off-axis method, and is obtained by an imaging device that includes data of a reference light (R) used for recording object light (O) emitted by an object (4) to be imaged as reference light data (RD). The object light hologram (I ＯＲ ) is subjected to spatial frequency filtering and inverse Fourier transform on the data obtained by Fourier-transforming the object light hologram (I ＯＲ ) to extract a complex amplitude object light hologram (J The complex amplitude object light hologram (J ＯＲ ) is multiplied by a reference light phase component (exp[iφ Ｒ (x, y)]) based on the reference light data (RD) on the hologram plane to remove the component of the reference light (R) and calculate an object light wave (g) representing the object light (O). An optical wave propagation calculation by plane wave expansion is performed on the object light wave (g) to reproduce an object light wave (h) at the position of the object (4). This is the gist of the invention. In the imaging device according to the present invention, the imaging device includes A wavefront conversion element (E Ｘ ) disposed on the optical path from the object (4) to the imaging element (5) to cause a predetermined deformation in the wavefront of the object light (O), When reproducing the light wave of the object light (O) from the object light hologram (I ＯＲ ), the wavefront aberration data (WD) representing the characteristics of the wavefront conversion element (E Ｘ ) is used to remove the influence of the wavefront aberration added to the predetermined deformation due to the imperfection of the wavefront conversion element (E Ｘ ) and reproduce an accurate object light wave. It may be provided with In the wavefront aberration data acquisition method of the present invention for acquiring the wavefront aberration data (WD), The wavefront conversion element (E Ｘ ) is a collimating element (E Ｐ ) having a focal point (F ｃｏｌｌ ) that converts spherical light waves into parallel light waves and also converts retrograde parallel light waves into spherical light waves. The wavefront aberration data (WD) is the collimating element (Eｃｏｌｌ ), and the information of the focus (F Ｐ ), the focal position (z = z Ｐ ), the principal plane position (z = z Ｅ ) defined as the switching boundary plane between the spherical wave and the plane wave, and the data acquisition position (z = z Ｍ ) of the wavefront aberration, which is the data application position (z = z Ｍ ) serving as the post - processing position. Further, the information of the phase aberration distribution function (A(x, y, z ｃｏｌｌ )) which is the measured value of the wavefront aberration generated in the phase distribution of the light wave passing through the collimating element (E Ｍ ). It has The wavefront aberration data acquisition method includes the following steps: The illumination light (Q) emitted as a spherical light wave from the illumination light source (S ｃｏｌｌ ) arranged off - axis near the focus (F Ｐ ) of the collimating element (E Ｐ ), or arranged at the position of the focus (F Ｑ ), is made incident on the collimating element (E ｃｏｌｌ ) to generate parallel light. The parallel light is reflected and reversed by a plane mirror (FM) arranged at the data acquisition position (z = z ｃｏｌｌ ) which is a position close to the collimating element (E Ｍ ), and the measurement light (Lc) with an outer diameter smaller than that of the parallel light is made incident on the imaging element (5) by the collimating element (E ｃｏｌｌ ). The data of the interference fringes between the measurement light (Lc) and the reference light (R) is recorded as a measurement light hologram (I ＣＲ ). Using the reference light data (RD), the measurement light wave (c ＣＲ ) of the measurement light (L Ｃ ), which is the light wave of (z = 0), is reproduced from the measurement light hologram (I Ｓ ). The plane mirror (FM) is replaced with an object (4) having a plane pattern of known dimensions, and the illumination light (Q) is applied to the collimating element (E ｃｏｌｌIlluminating the object (4) with parallel light generated by making it incident on (), Object light (O), which is the reflected light from the object (4), is made to travel backward through the collimating element (E ｃｏｌｌ ), is made incident on the imaging element (5), and data of interference fringes between the object light (O) and the reference light (R) is recorded as an object light hologram (I ＯＲ ). Using the reference light data (RD), an object light wave (g), which is the light wave of the object light, is reproduced from the object light hologram (I ＯＲ ), optical propagation calculation is performed on the object light wave (g), and a position where the read value of the dimension of the plane pattern obtained at a plurality of propagation positions becomes the known dimension is determined as the main surface position (z = z ｃｏｌｌ ) of the collimating element (E Ｅ ). Based on the data of the known focal position (z = z ｃｏｌｌ ) of the collimating element (E Ｐ ), an ideal spherical light wave (b Ｅ ) at the main surface position (z = z Ｓ ) is calculated, and a phase conversion function (T(z Ｓ )) for removing the phase component related to the analytically calculated spherical wave is multiplied by the ideal spherical light wave (b Ｅ ) to generate an ideal parallel light wave (b Ｐ = b Ｓ ·T). Regarding the phase aberration distribution function (A(x, y, z ｃｏｌｌ )) acquired at the data acquisition position (z = z Ｍ ) due to the incompleteness of the collimating element (E Ｍ ) as an unknown function, by multiplying it by the ideal parallel light wave (b Ｐ ), a mathematical expression of the plane wave incident on and reflected by the plane mirror (FM) is represented as a reflected light wave (b ＰＡ = b Ｓ ·T·A). Multiplying the reflected light wave (b Ｓ ·T·A) by the inverse phase conversion function (T －１ ) of the phase conversion function (T) and further multiplying it by the phase aberration distribution function (A), the collimating element (E ｃｏｌｌretrograde the measurement light hologram (I ＣＲ ), and generate a mathematical expression (b Ｓ ·T·A·T Ｅ ·A) corresponding to the light wave at the principal plane position (z = z Ｓ ·T·A·T －１ ·A) of the measurement light wave (c propagate the measurement light wave (c Ｓ ) to the principal plane position (z = z Ｅ ) by light propagation calculation, and make the propagated measurement light wave (c Ｓ (x, y, z Ｅ )) equivalent to the mathematical expression (b Ｓ ·T·A·T －１ ·A) to obtain the phase aberration distribution function (A = (c Ｓ / b Ｓ )) as an unknown function, which is characterized by this. １／２ ), which is characterized by this. The noise reduction method of the present invention is a method of reducing image noise by calculating and processing the data of the object light hologram (I ＯＲ ) obtained by using the imaging element (5) in the imaging device according to the present invention by a statistical method, repeating the acquisition of the object light hologram (I ＯＲ ) by the imaging element (5) while keeping the imaging conditions constant to obtain a plurality of object light holograms (I ｊ ＯＲ , j = 1,..., m), using the reference light data (RD), removing the component of the reference light (R) from the object light hologram (I ｊ ＯＲ , j = 1,..., m) to reproduce the light wave of the object light (O), and calculating the phase value distribution (φ ｊ , j = 1,..., m) at the position of the object (4), performing an unwrapping process on each of the phase value distributions (φ ｊ , j = 1,..., m) with respect to the phase value, setting a plurality of reference points (a ｊ , i = 1,..., k) at common coordinate points between the distributions in each of the phase value distributions (φ ｉ , i = 1,..., k), From the phase value distribution (φ ｊ , j = 1, ···, m), select a reference phase value distribution (φ α ), and between it and other phase value distributions (φ ｊ , j ≠ α), perform global alignment by rotating and phase-adjusting the light wave in three-dimensional real space so that the calculated value of the cross-correlation regarding the phase values at the plurality of reference points (a ｉ , i = 1, ···, k) becomes minimum. By performing an averaging process on the data of the phase value distribution (φ ｊ , j = 1, ···, m) after the alignment, obtain a phase value distribution with reduced noise (<φ> = Σφ ｊ / m). This is the gist of the invention. The imaging device of the present invention In an imaging device (1) by holography that images an object (4) so that the light wave can be reproduced, An illumination light source (S Ｑ ) that emits illumination light (Q), A reference light source (S Ｒ ) that emits reference light (R) for generating interference fringes between the object light (O) radiated from the object (4) illuminated by the illumination light (Q), An image sensor (5) that acquires data of the interference fringes as an object light hologram (I ＯＲ ), And an aperture (Ap) that restricts the azimuth angle distribution of the object light (O) incident on the image sensor (5). This is the gist of the invention. The device of the present invention is characterized in that it is manufactured using at least one of the above imaging device, reference light data acquisition method, and light wave reproduction method of the present invention. According to the imaging device of the present invention, since it has reference light data (RD) used when reproducing the light wave of the object (4) from the object light hologram (I ＯＲ ), a process of reproducing the light wave from the data of the object light hologram (I ＯＲ ) and the reference light data (RD) can be executed. According to the reference light data acquisition method of the present invention, auxiliary light (L) which is parallel light perpendicularly incident on the image sensor (5) is used to obtain intermediate light (R ３), and obtain the data of the reference light (R) using the intermediate light (R ３ ). By using a two-step acquisition method of obtaining the data of the reference light (R) using the intermediate light (R ３ ), it is possible to accurately obtain the reference light data (RD), which is the light wave information of the reference light (R) with an arbitrary beam shape, by the intermediate light (R ). According to the reference light data acquisition method of the present invention, the reference light (R) is recorded as a reference light hologram (I ＲＬ ) using the auxiliary light (L) that can be analytically expressed using known parameters (PA). Therefore, the reference light data (RD), which is the light wave information of the reference light (R), can be accurately obtained using the auxiliary light data (LD) obtained as the analytical expression of the auxiliary light (L). . According to the light wave reproduction method of the present invention, only the real image component can be easily extracted from the object light hologram (I ＯＲ ) obtained by the off-axis method as a complex amplitude object light hologram (J ＯＲ ) due to the effect of the off-axis method. Further, by using the reference light data (RD), the object light wave (g) on the hologram plane can be easily calculated from the complex amplitude object light hologram (J ＯＲ ). The object light wave (g) can be propagated by performing a light wave propagation calculation, and the object light wave (h) at the position of the object (4) can be reproduced. . According to the imaging device of the present invention, for example, by using a collimating element as a wavefront conversion element (E Ｘ ), a large-diameter object light (O) can be recorded on a small-diameter hologram, and by using the wavefront aberration data (WD), the wavefront aberration caused by the collimating element can be removed, and an accurate object light wave can be reproduced. Therefore, a large-area flat plate or the like can be imaged without being limited to the size of the light receiving surface of the imaging element, and an object light wave with less aberration can be reproduced. . According to the wavefront aberration data acquisition method of the present invention, based on the fact that the incident and outgoing light of the collimating element (E ｃｏｌｌ ) can be made into spherical light waves and plane light waves, and the object light is propagated by performing a light wave propagation calculation, the collimating element (Eｃｏｌｌ The wavefront aberration data (WD), which is the information of (), can be accurately acquired. According to the noise reduction method of the present invention, global alignment is performed by rotation and phase adjustment of a plurality of phase value distributions obtained from a plurality of samples (a plurality of holograms imaged under the same conditions of the same imaging object), and statistical processing based on averaging between the distributions is performed. Therefore, random noise can be effectively reduced. According to the imaging device of the present invention including an aperture (Ap), since the azimuth angle distribution of object light (O) incident on the imaging element (5) is restricted, only the object light from an object visible through the aperture (Ap) can be recorded, and imaging can be performed under the condition of the same resolution regardless of the distance of the object. A new device according to the present invention, which is a device manufactured using at least one of the above imaging device, reference light data acquisition method, light wave reproduction method, wavefront aberration data acquisition method, and noise reduction method of the present invention, is a device that exhibits the effects derived from the performance and functions of the above device and method of the present invention used for manufacturing it. (a) is a schematic configuration diagram of an imaging device according to the first embodiment, and (b) is a diagram showing the configuration of reference light data included in the imaging device. A schematic diagram showing the relationship between the aperture and the reference light focus point provided in the imaging device. (a) is a side view for explaining the setting of vertically incident parallel light in the reference light data acquisition method according to the second embodiment, and (b) is a side view for explaining the state of recording a hologram of reference light using the vertically incident parallel light set in (a). A flowchart showing the procedure of the reference light data acquisition method. A flowchart showing the procedure for acquiring the focus point information of the reference light in the reference light data acquisition method. A flowchart showing the procedure of spatial frequency modulation and filtering according to the third embodiment used in the reference light data acquisition method. A side view showing the state of imaging by an imaging device according to the fourth embodiment including the reference light data acquired by the reference light data acquisition method shown in FIG. 3. (a) is a side view for explaining the setting of vertically incident parallel light in the reference light data acquisition method according to the fifth embodiment, and (b) is a side view for explaining the state of recording a hologram of reference light using the vertically incident parallel light set in (a). A side view showing the state of imaging by an imaging device according to the sixth embodiment including the reference light data acquired by the reference light data acquisition method shown in FIG. 8. (a) is a side view showing an example in which the end of an optical fiber is used as a light source of spherical wave reference light, and (b) is a side view showing an example in which a pinhole is used as a light source of spherical wave reference light. A block diagram schematically showing the procedure of the reference light data acquisition method according to the seventh embodiment. A flowchart showing the procedure of the light wave reproduction method according to the ninth embodiment. An overall view of the hologram to be processed by the light wave reproduction method and a partial enlarged view thereof. (a) is a conceptual diagram of the spectrum in the spatial frequency space obtained by Fourier transform, (b) is a conceptual diagram for explaining the enlargement of the calculation target of the spectrum in the same space, and (c) is a conceptual diagram of the hologram obtained by inverse Fourier transforming the spectrum in (b). An overall view of the hologram obtained in FIG. 14(c) and a partial enlarged view thereof. (a) is a diagram showing the calculation of the light wave of the object light from the hologram obtained in FIG. 14(c), and (b) is a conceptual diagram for explaining the enlargement of the calculation space of the light wave obtained in (a). A flowchart showing a method for removing the diffracted light component generated at the aperture and included in the object light according to the tenth embodiment. A schematic configuration diagram of an imaging device according to the eleventh embodiment. A schematic configuration diagram of an imaging device according to the twelfth embodiment.A flowchart showing the procedure of surface shape measurement according to the 13th embodiment. A diagram showing the relationship between the optical system and the coordinate system for explaining the method of obtaining lens data according to the 14th embodiment. A flowchart showing the procedure of obtaining lens data. A schematic configuration diagram of an imaging device according to the 15th embodiment. A schematic configuration diagram of an imaging device according to the 16th embodiment. A flowchart showing the procedure of noise reduction processing according to the 17th embodiment. A reference light hologram I in which interference fringes between the reference light and the auxiliary light are recorded using the optical system of FIG. 3(b). ＲＬ Partial enlarged image of (the first example). An object light hologram I obtained by imaging the transmitted light of the USAF test target as object light using the imaging device of FIG. 7 ＯＲ Reproduced from, the light intensity image of the object light at the position of the USAF test target (the second example). A hologram I obtained by imaging the transmitted light of a large USAF test target as object light using the imaging device of FIG. 18 ＯＲ Image of (the third example). Hologram I of FIG. 28 ＯＲ Image of the spatial frequency spectrum of. Hologram I of FIG. 28 ＯＲAn intensity image of object light at the position of a large USAF test target reproduced from. A diagram (fourth embodiment) showing the intensity distribution of reflected light from a plane mirror of illumination light imaged using the imaging device of FIG. 21 and an explanation of the region near the axis. A diagram showing the measurement result of the phase difference distribution representing the wavefront aberration generated by the collimating lens in the imaging device of FIG. 21. A diagram (fifth embodiment) showing the measurement result of the phase difference distribution reflecting the surface shape obtained by using the object light wave on the wafer surface and the illumination light wave on the wafer surface generated in consideration of the wavefront aberration by the collimating lens, which are reproduced and propagated from the hologram on the wafer surface imaged using the imaging device of FIG. 19. A diagram (sixth embodiment) showing the intensity image and partial enlarged view of the wafer surface obtained by calculating the influence of the wavefront aberration by the collimating lens on the light wave reproduced from the hologram on the wafer surface after resist exposure imaged using the imaging device of FIG. 19. A diagram showing the measurement result of the phase difference distribution on the wafer surface obtained from the light wave from which the intensity image of FIG. 34 was obtained. A diagram showing an example of the optical phase difference distribution obtained considering the wavefront aberration by the collimating lens from a plurality of object light holograms on the plane mirror surface imaged while keeping the imaging conditions constant using the imaging device of FIG. 19, with three reference points and a noise evaluation axis (white line). A diagram showing the height error due to shot noise along the noise evaluation axis (white line) in the height distribution of the plane mirror surface obtained from the optical phase difference distribution of FIG. 36. A diagram showing the height error in the noise-reduced optical phase difference distribution obtained by performing a process of narrowing the band of the spatial frequency of the object light wave to one-third (1 / n times, n = 3) when calculating the object light wave from the object light hologram used to obtain the optical phase difference distribution of FIG. 36. A diagram showing the height error in the noise-reduced optical phase difference distribution obtained by calculating the optical phase difference distribution from each of nine (m = 9) object light holograms and processing the phase value data by a statistical method based on the setting of the three reference points in FIG. 36. A diagram showing the height error in the noise-reduced optical phase difference distribution obtained by combining the process of narrowing the band in FIG. 38 (n = 3) with the statistical process in FIG. 39 (m = 9). Hereinafter, an imaging device, a reference light data acquisition method, a light wave reproduction method, a wavefront aberration data acquisition method, a noise reduction method, and a device manufactured using these devices or methods according to an embodiment of the present invention will be described with reference to the drawings. Hereinafter, an embodiment mainly using off-axis holography will be described. However, the basic configuration of the embodiment is not limited to off-axis holography, and can be applied to, for example, phase-shift holography and in-line holography. In the following description, imaging an object as a hologram by a holographic imaging device is also expressed as recording on a hologram in the same meaning as imaging. In this embodiment, in digital holography, an imaging device and a light wave reproduction method capable of imaging an imaging target object having a wide range of sizes from an extremely small size to an extremely large size compared to the size of an imaging element under an optical system having a simple configuration can be provided. (First Embodiment: Imaging Device) With reference to FIGS. 1(a), 1(b), and 2, the imaging device 1 according to the first embodiment will be described. The imaging device 1 is an imaging device using off-axis holography, and includes a coherent light source 9, an optical system 2, an illumination light source S Ｑ , a reference light source S Ｒ , an imaging element 5, a dark box 6, reference light data RD, and a control unit 10. The reference light source S Ｒ and the imaging element 5 are provided in the dark box 6, and the reference light data RD is provided in the control unit 10. The coherent light source 9 emits coherent light. The optical system 2 guides the coherent light emitted from the coherent light source 9 to the illumination light source S Ｑ and the reference light source S Ｒ by optical fibers 22 and 21, respectively. The illumination light source S Ｑ emits the light from the coherent light source 9 as illumination light Q for illuminating the object 4 that is the imaging target. The illumination light source S Ｑ usually only needs to be able to illuminate the object 4, and in one embodiment, emits parallel light having a beam cross section necessary for irradiating the object 4 or light spread in a conical shape. The reference light source SＲ The light from the coherent light source 9 is emitted as reference light R toward the light receiving surface 50 of the image sensor 5. The reference light R, together with the object light O radiated from the object 4 illuminated by the illumination light Q, generates interference fringes on the light receiving surface 50. In this embodiment, the reference light R is spherical wave light having a reference light focus point P that is the focus point of the reference light R. Ｒ The reference light source S Ｒ is the end of the optical fiber 21 in this embodiment. The reference light source S Ｒ is arranged at the reference light focus point P. Ｒ Actually, after the arrangement of the reference light source S, Ｒ the position of the reference light focus point P Ｒ is determined by measurement. The determination is performed using a reference light data measurement method (see FIGS. 3(a)(b) to FIG. 6, FIGS. 8(a)(b)). The image sensor 5 acquires and records the data of the interference fringes between the object light O and the reference light R as the light intensity distribution of the interference fringes. This recording becomes the imaging of the object 4. The data of the light intensity distribution of the interference fringes is the data of the object light hologram I. ＯＲ The image sensor 5 is, for example, a light receiving element of a CMOS camera. If the coherent light is monochromatic, the object light hologram I ＯＲ is monochromatic data. Also, for example, if the coherent light is three primary color lights and the image sensor 5 is color-compatible, color-compatible hologram data can be obtained. The dark box 6 has an aperture Ap and is a housing that houses the reference light source S Ｒ and the image sensor 5 and blocks external light from outside the aperture Ap. The dark box 6, as a housing, has a function of fixing the mutual positional relationship among the aperture Ap, the reference light source S Ｒ and the image sensor 5. The aperture Ap opens in the center front of the image sensor 5 and restricts the azimuth angle distribution of the object light O incident on the image sensor 5. The aperture Ap is not limited to a circular aperture and may be a rectangular aperture. The control unit 10 includes a storage unit 11 and an object light reproduction unit 12. The control unit 10 is configured using, for example, a dedicated, general-purpose, or arbitrary computer. The control unit 10 controls the imaging element 5 and the coherent light source 9 during imaging, and operates the storage unit 11 and the object light reproduction unit 12 during light wave reproduction. The reference light data RD is stored in the storage unit 11 of the control unit 10 in the form of reference light wave information RI and focus point information PI. The reference light data RD is data used to reproduce the image of the object 4, and is used to reproduce the light wave of the object light from the object light hologram I ＯＲ when reproducing the light wave of the object light. The reference light data RD is data that reproduces the reference light R used to generate the interference fringes for recording the object light O on a computer. The reference light wave information RI is data representing the light wave of the reference light R on the hologram surface, which is the light receiving surface 50 of the imaging element 5, and is data representing the phase distribution of the reference light R. The reference light R is not limited to a spherical light wave in general holography, and may be a reference light R with an arbitrary phase distribution. As long as the reference light data RD can be used as data of such a reference light R, the light wave of the object light can be reproduced, and the image of the object 4 can be reproduced. By providing either such reference light wave information RI or the focus point information PI described below, the light wave of the object light, and thus the image of the object 4, can be reproduced from the object light hologram I ＯＲ (see FIG. 12). Note that the image of the object 4 is the intensity distribution and phase distribution of the light wave of the object light. Here, reproducing the image of the object 4 is not limited to simply reproducing the image of the object 4 itself, and may include, for example, reproducing other images based on the image of the object 4. The focus point information PI is information that exists and is obtained when the reference light R is a spherical wave having the reference light focus point P Ｒ in this embodiment. The focus point information PI is the data of the position coordinates (x Ｒ , y Ｒ , z Ｒ , Ｒ ) of the reference light focus point P with respect to the imaging element 5. This is three real-valued data, and becomes four when including the information of the wavelength λ. The reference light focus point P​Ｒ If there is information representing the position coordinates, the phase distribution of the spherical wave on the hologram plane, that is, the reference light wave information RI, can be obtained by calculation. The reference light data RD is information unique to the imaging device 1. The reference light data RD can include data unique to the imaging device 1 that is necessary for reproducing the object light, such as the distance between the light receiving surface 50 and the aperture Ap, the specifications of the imaging element 5, and the like. Such data may be provided in the object light reproduction unit 12. Also, the imaging device 1 can perform imaging without including the object light reproduction unit 12. However, since the object light reproduction unit 12 as a separate device cannot reproduce the light wave without the reference light data RD, it is necessary to pass the reference light data RD together with the imaging data. The object light reproduction unit 12 is ＯＲ configured using software that reproduces the object light wave g representing the object light O from the object light hologram I which is the imaging data in the computer, and is provided as a program in the control unit 10. When the object light wave g is reproduced, an image of the object can be reproduced from the object light wave g. The object light reproduction unit 12 includes a diffracted light component processing unit 12a. Since the imaging device 1 includes the aperture Ap, the object light O may diffract at the edge of the aperture Ap to generate diffracted light, which may be mixed into the object light O as a diffracted light component. This becomes noise light. The diffracted light component processing unit 12a is configured using software that removes the diffracted light component from the data of the object light hologram I during light wave reproduction (see FIG. 17). ＯＲ As described above, the imaging device 1 includes, as an imaging optical system for recording the object light O formed by the illumination light Q being reflected or scattered from a large imaging target object, a reference light R which is a spherical wave for off-axis holography, and an aperture Ap that restricts the azimuth angle distribution of the object light O incident on the imaging element. As the spherical wave reference light R, the emitted light from the end of the optical fiber or the light passing through the pinhole can be used (see FIGS. 10(a) and 10(b)). The focus point P of the reference light R Ｒ , and thus the reference light source S Ｒis located on the same plane as the plane formed by the aperture Ap or on a plane close to the front and back, and is disposed at a position deviated from the aperture Ap (see Fig. 2). The reference light source S Ｒ is disposed inside the camera obscura 6 so that the reference light R irradiates the light receiving surface of the imaging device 5. (Regarding the aperture Ap) Fig. 2 shows the positional relationship between the aperture in the x-y plane and the focus point P of the off-axis reference light. As the aperture, in addition to the rectangular aperture shown in Fig. 2, a circular aperture can also be used. The interference fringes formed by the reference light R of the spherical wave and the object light O passing through the aperture Ap are the off-axis hologram I ＯＲ is recorded in one shot, and only the object light O passing through the aperture Ap is recorded. This situation is replaced by a situation where there is a planar light source of the object light O on the entire surface of the aperture Ap. That is, equivalently, the object light 0 emitted by an object having the same size as the aperture width a of the aperture Ap is recorded. Even for an object with a wide size, it is possible to image an object within the range visible to the imaging device 5 through the aperture Ap. (Design of the imaging optical system) The design of the imaging optical system of the imaging device 1 will be described. An orthogonal xyz coordinate system is set with the center of the light receiving surface 50 (also called the hologram surface) of the imaging device 5 as the origin. The x-axis, y-axis, and the direction of the z-axis are set in the direction of the object 4 within the light receiving surface 50. The aperture Ap is formed in a plane, and the aperture surface, which is the plane formed by the aperture Ap, and the light receiving surface 50 are parallel planes to each other. The imaging optical system is related to the light wavelength λ, the hologram width D, the numerical aperture NA, and the distance z from the imaging device 5 to the aperture Ap ａ The light wavelength λ is the common light wavelength of the illumination light Q, the object light O, and the reference light R emitted from the same coherent light source 9. The hologram width D is each width in the xy direction determined by the product of the pixel pitch and the number of pixels, and is the width in the real space of the recorded hologram. The hologram width is the effective pixel distribution width of the imaging device 5, the effective width of the light receiving surface 50, and more practically, the spread width of a large number of pixels that receive the adopted data. The numerical aperture NA is the numerical aperture of the hologram on the light receiving surface 50 as seen from the aperture Ap. The distance z ａis the distance between the light-receiving surface 50 (hologram surface) and the aperture surface formed by the aperture Ap, that is, the perpendicular distance. The distance z, which is the z-position of the aperture Ap with respect to the light-receiving surface 50 of the imaging device 5 ａ is given by the following equation (1). (Determination of the arrangement position of the reference light focus point P Ｒ ) Next, the reference light source S of the reference light R, which is spherical wave light Ｒ , and thus the coordinates P Ｒ representing the position of the reference light focus point P Ｒ (x Ｒ , y Ｒ , z Ｒ ) will be described. The guideline for setting the arrangement position of the reference light focus point P Ｒ is, for example, to determine the position of the reference light focus point P Ｒ so as to generate interference fringes that can effectively utilize the light-receiving surface 50. This guideline is based on (a) the fact that the area occupied by the spatial frequency spectrum of the object light hologram I ＯＲ in the spatial frequency space is determined by the hologram width D, which is the size of the light-receiving surface 50, and (b) the fact that the positions of the object light component OR Ｒ and its conjugate component O ＊ R in the spatial frequency spectrum change depending on the arrangement position of the reference light focus point P ＊ . The distribution of the spatial frequency spectrum of the object light hologram I ＯＲ such that it effectively utilizes the available spatial frequency space means, for example, a distribution with a smaller distribution area of the zero value of the spectrum. In this case, the light-receiving surface 50 can be effectively utilized. The determination of the arrangement position of the reference light focus point P Ｒ involves the pixel pitch p of the imaging device 5 and the aperture width a of the rectangular aperture Ap. Also, the z-position coordinate z Ｒ of the reference light focus point P Ｒ is the same as the z-coordinate z ａ of the aperture Ap, z Ｒ = z ａ . Based on the above guideline, the pixel pitch p, the aperture width a, the light wavelength λ, and the distance z ａUsing this, the position coordinates (x Ｒ , y Ｒ ) of the reference light focusing point P Ｒ are given by the following formula (2). In the case of a circular aperture with diameter a, the diameter a may be used instead of the aperture width a. Here, the coefficients 3 / 8, 1 / 2, and 1 / 4 for a, x Ｒ , y Ｒ are appropriate adjustment parameters related to the spread and position of the spectra of the respective components appearing in the spatial frequency space. FIG. 29 described later shows the spatial frequency spectrum in the case of a circular aperture with diameter a. In FIG. 29, the components OR ＊ of the object light appear on the upper left and right, and the conjugate components O ＊ R of the object light appear on the lower left and right. The arrangement position of the reference light focusing point P Ｒ is selected and determined so that this is the case. If such selection and determination are not made, for example, the component OR ＊ of the object light appears on the upper right, the conjugate component O ＊ R of the object light appears on the lower left at the diagonal position, and the upper left and lower right have a zero-value distribution. When the width D of the hologram, the numerical aperture NA, and the pixel pitch p are given, the imaging optical system can be designed regardless of the size of the object, and imaging of objects of a wide range of sizes from extremely small to extremely large can be supported using the same set optical system. Also, the distance z ａ from the imaging element 5 to the aperture Ap and the coordinates (x Ｒ , y Ｒ ) of the reference light focusing point P Ｒ can be fixed, and as shown in FIG. 1, the imaging optical system can be covered with a light-tight box 6. Since the light-tight box 6 can shield light other than the light passing through the aperture Ap, accurate and high-speed imaging is possible even in a normal illumination environment. (Resolution of the Reconstructed Image) In the optical system shown in FIG. 1, two different numerical apertures NA and NAa can be defined. They are the numerical aperture NA of the hologram as seen from the reference light focusing point P Ｒ and the numerical aperture NAa of the aperture Ap as seen from the object 4. When both the hologram and the aperture Ap are quadrilateral, for an object 4 located at a position close in the z direction from the aperture Ap, the theoretical resolution δ of the reproduced image is δ = λ / 2NA. For an object 4 arranged at a position far from the aperture Ap in the z direction, δa = λ / 2NAa. When both the hologram and the aperture Ap are circular, for an object 4 located at a position close in the z direction from the aperture Ap, δ = 0.61λ / NA, and for an object 4 arranged at a position far from the aperture Ap in the z direction, δa = 0.61λ / NA Ａ is obtained. (Features of the imaging device 1) According to the imaging device 1 of the present embodiment, compared with a conventional imaging device using digital holography, the following effects are achieved. In a conventional device, it is necessary to adjust the distance between the imaging element and the object according to the size of the object to be imaged in order to suppress the spatial frequency bandwidth of the interference fringes to be recorded to be smaller than the bandwidth determined by the pixel pitch of the imaging element. However, the imaging device 1 does not require such an operation. This is because when the object light is reproduced, the imaging device 1 has an aperture Ap and uses digital holography imaging, so it can be handled by post-processing in a computer. When the imaging device 1 images a large object, it is not necessary to place the object far from the imaging element, and it is not necessary to increase the size of the optical system for recording. Also, when generating and recording the interference fringes of the object light using the reference light, it is not necessary to adjust the spatial distribution and irradiation angle of the reference light according to the size and position of the object so that the spatial frequency bandwidth of the interference fringes is equal to or less than the bandwidth limited by the pixel pitch of the imaging element. The imaging device 1 can accurately record the object light in one shot for objects with a wide range of sizes from extremely small to extremely large compared to the imaging element. The imaging device 1 does not require adjustment of the positions of the components and has a simple structure. The imaging device 1 can accurately and quickly image the object to be imaged under a normal illumination environment. The imaging device 1 can remove the influence of diffracted light generated at the aperture edge and reproduce only the object light that has passed through the aperture. By providing the imaging device 1 with a camera obscura 6 and an aperture Ap, the spatial frequency bandwidth of the recorded hologram, which is imaging data, can be set to be equal to or less than the bandwidth determined by the pixel pitch of the imaging element. That is, a part or most of the reflected light or transmitted light emitted from the subject, which is the object light, can be blocked by the peripheral portion forming the aperture, and only the object light that passes through and enters the imaging element can be recorded by the aperture. The imaging device 1 is a lensless imaging device, and by using an off-axis spherical wave reference light, it can accurately record in one shot. When the light wavelength λ of the reference light R, the numerical aperture NA, the pixel pitch p of the imaging element 5, and the number of pixels are given, the imaging device 1 Ｒ can optimally determine the positional relationship among the three elements of the aperture Ap, the reference light focus point P, and the imaging element 5, as well as the size of the aperture Ap (see Equations (1) and (2)). The imaging device 1 is an imaging device with a simple structure composed of four elements: the imaging element 1, the reference light focus point P Ｒ , the aperture Ap, and the camera obscura 6 for light shielding. The imaging device 1 has two types of removal methods for removing diffracted light generated at the edge of the aperture Ap according to the situation. One method is to apply Fourier transform and spatial frequency filtering to the recorded hologram to remove the diffracted light component. The other method is to reproduce the object light including the diffracted light at the position of the aperture Ap, which is the generation position of the diffracted light, and separate only the focused diffracted light component and remove it from the reproduced object light (see FIG. 17, which will be described later). According to the imaging device 1 of the present embodiment, the following effects can be obtained. When the light wavelength λ of the reference light R, the numerical aperture NA, the pixel pitch p of the imaging element 5, and the number of pixels are given, the positional relationship between the aperture Ap and the reference light focus point P Ｒ , and the imaging element 5, as well as the aperture size (aperture width a, diameter a), can be determined. The reference light focus point P ＲUsing the same optical system designed according to the parameters of the aperture Ap and the imaging device 5 respectively, it is possible to correspond to objects 4 of a wide range of sizes from the minimum size to the maximum size. Since the light other than the light passing through the aperture Ap can be completely shielded by the dark box 6, accurate and high-speed imaging can be performed even in a normal lighting environment. By removing the diffracted light generated at the aperture edge, the object light O passing through the aperture Ap can be accurately reproduced. The imaging device 1 has an aperture Ap, so it is close to the form of a camera and can image any perspective and is portable (no film, so no shutter is required). The imaging device 1 is provided with a display device, an image data output terminal, etc., so that it can image while confirming the reproduced image on the spot. The imaging device 1 may be configured as a remote control system by being separated from the control unit 10, and for example, it may be used as a surveillance camera regardless of indoors or outdoors. (Modification example of the imaging device 1) The imaging device 1 of the first embodiment uses a spherical wave light as the reference light R for recording and reproducing the hologram of the object light O, and the reference light R is arranged off-axis. However, the imaging device of the present invention is not limited to the device for off-axis holography, and for example, it can also be configured as an imaging device by phase-shifting holography or in-line holography. In phase-shifting holography, the phase of the reference light R is shifted to sequentially record a plurality of holograms, and a plurality of recorded holograms I ＯＲ are used to obtain the complex amplitude hologram J ＯＲ . Therefore, by shifting the phase of the reference light R in the imaging device 1 of the first embodiment and sequentially recording a plurality of holograms, imaging can be performed as an imaging device 1 by phase-shifting holography. When reproducing the accurate object light wave g from the complex amplitude hologram J ＯＲ , the reference light data RD, that is, the reference light wave RI or the focus point information PI representing the light wave of the reference light R may be used. In in-line holography, an in-line state is formed in which the object and the reference light source S Ｒ are arranged on the optical axis of the imaging device, and the interference fringes formed by the object light O and the reference light R are used as the in-line hologram IＯＲ is recorded as. Therefore, in the imaging device 1 of the first embodiment, by arranging the reference light source S Ｒ on the optical axis of the imaging element, imaging can be performed as the imaging device 1 by in-line holography. In this case, the reference light data RD may be acquired as the data of the in-line reference light R. When reproducing the object image from the in-line hologram I ＯＲ , the reference light data RD, that is, the reference light wave RI representing the light wave of the in-line reference light R or the condensing point information PI may be used. (Second Embodiment: Method for Acquiring Reference Light Data) With reference to FIGS. 3(a)(b), 4, and 5, a method for acquiring reference light data according to the second embodiment will be described. This method for acquiring reference light data is a method for acquiring the reference light data RD (reference light wave information RI, condensing point information PI) included in the imaging device 1 according to the first embodiment. In this data acquisition method, data of the reference light (R), which is a spherical wave having a reference light condensing point (P Ｒ ), is acquired using the auxiliary light L, which is parallel light perpendicularly incident on the imaging element 5. As shown in FIGS. 3(a)(b), with respect to the imaging element 5, the reference light source S of the reference light R Ｒ , and thus the position of the reference light condensing point P Ｒ being fixed, the reference light data RD is acquired. After the reference light data RD is acquired, the imaging element 5 and the reference light source S Ｒ are assembled as the imaging device 1 so that their relative positional relationship is maintained even during use of the device. (Angle Adjustment of Cube-Type Beam Splitter and Imaging Element) In order to set the auxiliary light L to be perpendicularly incident on the imaging element 5, a cube-type beam splitter 3 (also referred to as a cube-type BS) is disposed on the front surface of the imaging element 5 as an optical coupler and as a mirror M for the auxiliary light L. The auxiliary light L is incident on the mirror M from a direction parallel to the light receiving surface 50, and is reflected there and perpendicularly incident on the imaging element 5. In order to realize the state where the auxiliary light L is perpendicularly incident on the imaging element 5, the auxiliary light L which is parallel light is blocked by the mask 9a having the pinhole 9b, and is made into a thin parallel light beam L1 by the pinhole 9b. The parallel light beam L1 passes through the beam splitter 3 and is incident on the light receiving surface 50 of the imaging element 5. A part of the parallel light beam L1 is reflected by the surface BS1 of the beam splitter 3 to become the reflected light L2 and heads toward the mask 9a. The rest of the parallel light beam L1 is reflected after reaching the light receiving surface 50 to become the reflected light L3, and is further reflected by the reflecting mirror M and heads toward the mask 9a. For example, by visual confirmation, the arrangement state (arrangement angle) of the beam splitter 3 and the imaging element 5 is adjusted and set so that both the reflected lights L2 and L3 converge on the pinhole 9b of the mask 9a. By this setting operation, the positions of the auxiliary light L, the beam splitter 3, and the light receiving surface 50 (imaging element 5) are adjusted, and the state where the auxiliary light L is perpendicularly incident on the light receiving surface 50 is realized. Other methods may be used instead of this visual confirmation and position adjustment to realize the state where the auxiliary light L is perpendicularly incident. After the state where the auxiliary light L is perpendicularly incident on the light receiving surface 50 is realized, the mask 9a is removed and the auxiliary light L is made to be perpendicularly incident on the imaging element 5. The reference light R is incident on the imaging element 5 through the cube type beam splitter 3 from above the light receiving surface 50. The reference light R Ｒ is a spherical wave light having the reference light focus point P Ｒ and the reference light source S Ｒ which emits the reference light R as a spherical wave at the position of the reference light focus point P Ｒ is arranged. The reference light focus point P Ｒ , and thus the reference light source S Ｒ is arranged at a position deviated from the central axis of the light receiving surface 50 in order to be off-axis arranged (note that if the reference light focus point P is arranged on the central axis of the light receiving surface 50, it becomes the reference light R2 of the in-line spherical wave, but this is not used here). ＲＬ The data of the interference fringes formed by the auxiliary light L and the reference light R on the light receiving surface 50 is stored and recorded in the computer 7 connected to the imaging element 5 as the reference light hologram I The recorded reference light hologram I ＲＬUsing the arithmetic processing unit 71 provided in the computer 7 and the high-frequency component processing unit 71a included in the arithmetic processing unit 71, etc., processing is performed to calculate the optical wave information of the reference light R, and reference light data RD is obtained. The processing in the reference light data acquisition method is performed in a preparation step #1, a recording step #2, and a calculation step #3, as shown in the flowchart of FIG. 4. The preparation step #1 is a step of realizing a state of perpendicular incidence of the auxiliary light L on the light receiving surface 50 using the mask 9a and the beam splitter 3. The recording step #2 is a step of creating an interference fringe of the reference light R using the auxiliary light L, and recording the reference light R as interference fringe data in the reference light hologram I ＲＬ is a step of recording in. The calculation step #3 is a step of calculating reference light wave information RI representing the light wave of the reference light R from the reference light hologram I ＲＬ and using the result as the reference light data RD. The reference light wave information RI is data such as the phase distribution data of the light wave of the reference light R on the hologram plane. The processing of the calculation step #3 is a process of dealing with light waves having a much higher frequency compared to the spatial frequency of the interference fringes of about the pixel pitch p of the imaging element 5. Therefore, special processing is required (see FIG. 6 described later). The reference light data acquisition method may further include a light wave propagation step #4 and a position coordinate search step #5, as shown in FIG. 5. The light wave propagation step #4 is a step of performing a light wave propagation calculation to reverse the light wave of the reference light R represented by the reference light wave information RI on the hologram plane to the position of the reference light focusing point P Ｒ The coordinate search step #5 is a step of obtaining the position coordinates (x Ｒ , y Ｒ , z Ｒ ) of the reference light focusing point P Ｒ and using the obtained coordinate values as the focusing point information PI. The process of performing a light wave propagation calculation on the light wave of the reference light R to obtain the position coordinates of the reference light focusing point P Ｒ can be performed by the same calculation as the light wave propagation calculation in the process of reproducing the light wave of the object light O obtained from the object light hologram I ＯＲ . This step #5 is when the reference light R reaches the reference light focusing point PＲ Since it is a spherical wave having [the above], it is a step that can be performed. In other embodiments, there are also imaging devices that do not use a spherical wave as the reference light R. The reference light data RD of such an imaging device is only the reference light wave information RI and does not include the condensing point information PI. According to the reference light data acquisition method of the present embodiment, under a lensless optical system, the phase information of the reference light R can be accurately recorded by the interference fringes formed by the auxiliary light L which is perpendicularly incident parallel light and the reference light R which is a spherical wave light. Since perpendicularly incident parallel light is used as the auxiliary light L, the auxiliary light L can be expressed by a mathematical formula without depending on uncertain information, and the recorded reference light hologram I ＲＬ From this, the reference light data RD (reference light wave information RI and condensing point information PI), which is the light wave information of the reference light R, can be accurately acquired and can be used for light wave reproduction. Perpendicularly incident parallel light is light whose light source position is determined to be at infinity, whose direction is perpendicular to the imaging element, and can realize an auxiliary light L that does not include uncertain elements in terms of mathematics. By the light wave propagation calculation of the reference light R, the coordinates of the reference light condensing point P Ｒ can be obtained with high accuracy below the light wavelength and used as the condensing point information PI which is the reference light data RD. (Spherical wave reference light R, perpendicularly incident parallel light auxiliary light L, interference fringes by mathematical expression) Regarding the interference fringes generated by the reference light R and the auxiliary light L, an explanation will be given using a mathematical formula. The plane z = 0 at the position of the light receiving surface 50 of the imaging element 5 is the surface on which the interference fringes are generated and recorded as a hologram (also referred to as a hologram surface). On this hologram surface (z = 0), the reference light R(x, y, t) which is a spherical wave with an angular frequency ω and the auxiliary light L(t) which is a perpendicularly incident parallel light with a uniform amplitude are generally expressed by the following formulas (3) and (4) respectively. The constant φ in the above formula (4) Ｌ０ represents the initial phase of the auxiliary light L which is perpendicularly incident parallel light on the light receiving surface 50. Hereinafter, for the sake of simplicity, the notation of this constant initial phase φ Ｌ０ will be omitted. Note that the amplitude L of the auxiliary light L ０ is also a real number with a constant value. Interference fringes I of the reference light R and the auxiliary light L on the plane z = 0 of the light-receiving surface 50 ＲＬ (x, y) is represented by the following formula (5). Here, I ＲＬ is the light intensity (square of the absolute value) of the interference fringes formed by the overlapping (addition) of the two lights R and L, and I ＲＬ = |R + L| ２ is calculated by The interference fringes I ＲＬ (x, y) form a collection of Newton's rings (cross-sections of a large number of concentric spheres nested at regular intervals) as shown in FIG. 19. The position of the center of the concentric circles in the interference fringes is the reference light focus point P of the reference light R in the spherical wave optical state before entering the cube beam splitter 3 Ｒ of the position (x Ｒ , y Ｒ ). In formula (5), the first term on the right side is the low-frequency component of the light intensity distribution of the reference light R and the auxiliary light L respectively, the second term is the reference light component, and the third term is the conjugate component of the second term (Calculation of the focus point coordinates using light wave propagation calculation) The coordinates of the reference light focus point P shown in FIG. 3(b) Ｒ can be calculated by performing light wave propagation calculations on the spherical wave light in the air and the spherical wave light in the cube beam splitter 3. This propagation calculation is performed considering the refractive index of the cube beam splitter 3. The reference light R is recorded, holograms are divided and overlapped to synthesize the reference light R, and light wave propagation calculations are performed on the plane wave expansion of the synthesized reference light to obtain the coordinates of the point where the intensity of the focused light is maximized as the reference light focus point P Ｒ (x Ｒ , y Ｒ , z Ｒ ). This process is the same as the reproduction process of the light wave of the object light (see FIG. 12 described later) (Phase of the spherical wave reference light on the hologram surface) In FIGS. 3(a) and 3(b), the cube beam splitter 3 is used to reflect the auxiliary light L, so the imaging element 5 and the reference light source S ＲIn the case of an imaging apparatus using an optical system composed of [components], since auxiliary light L is not used, the beam splitter 3 is unnecessary. That is, after the condensing point information PI, which is the reference light data RD of the reference light R, is obtained, it is not always necessary for imaging the object 4 to be imaged and can be removed (for example, refer to the imaging apparatus 1 in FIGS. 1 and 7). In the imaging apparatus 1 not provided with the cube type beam splitter 3, the phase φ of the reference light R on the hologram plane z = 0 Ｒ (x, y) is expressed by the following equation (6) using the analytical solution expressing the spherical wave and the condensing point coordinates (x Ｒ , y Ｒ , z Ｒ ). In the following equation (6), the light wavelength λ and the initial phase φ of the reference light at the condensing point (z = z Ｒ ) are involved. Ｒ０ This phase φ of the reference light R Ｒ (x, y, z) is reproduced by the above equation (6), which is a pure analytical solution, because there are no optical elements such as a lens or a cube type beam splitter 3 on the optical path from the reference light condensing point P Ｒ to the hologram plane z = 0 (light receiving surface 50). Using such phase φ Ｒ (x, y, z) data, the light wave of the object light O is accurately reproduced. (Third Embodiment: Processing for High Numerical Aperture) The calculation method of the reference light data RD in the reference light data acquisition method when the numerical aperture NA of the reference light hologram I ＲＬ is large will be described. When the size of the light receiving surface (actual size of the hologram) is the same, the numerical aperture NA is small for imaging a distant object, but the numerical aperture NA becomes large for imaging a near object. For the same distance, the larger the light receiving surface (actual size of the hologram), the larger the numerical aperture NA. When the numerical aperture NA of the hologram and the light wavelength λ are given, the maximum spatial frequency fM that can be recorded on the hologram (in other words, the maximum spatial frequency that can be supplied to the light receiving surface) is determined, and fM = NA / λ. When the numerical aperture NA becomes large, the recordable maximum spatial frequency fM becomes high. However, it can be recorded under the limitation that fM is equal to or less than the following fmax. When recording interference fringes as a hologram using the image sensor 5 with a pixel pitch p, the maximum spatial frequency fmax of the recordable interference fringes is fmax = 1 / 2p from the sampling theorem. That is, it shows that changes finer than the pixel pitch p cannot be recorded, and the maximum spatial frequency fmax is limited by the pixel pitch p. Consider the case where the numerical aperture NA of the hologram becomes large and NA > (2p / λ). From this equation, fM = NA / λ < 1 / 2p = fmax, that is, fM < fmax is obtained. This means that although the pixel pitch p is dense enough to record up to fmax, the recordable spatial frequency is limited to fM, that is, the lower maximum frequency, due to the relationship between the size of the hologram and the imaging distance, that is, the numerical aperture NA. When the maximum spatial frequency of the recorded image, such as interference fringes, exceeds the recordable spatial frequency fM determined by the numerical aperture NA, the spatial frequency spectra of the image component of interest (reference light component) and its conjugate component are distributed over the entire area in a folded state between -fM and +fM in the spatial frequency space. Therefore, even if the hologram is directly Fourier-transformed to generate the spatial frequency spectrum in the spatial frequency space and spatial frequency filtering is applied, it becomes difficult to separate and extract the spectral component of interest (reference light component). To solve this problem, a process for performing a conversion to lower the spatial frequency of the recorded reference light hologram I ＲＬ is introduced. This process is a post-recording process of the hologram and is a process showing the advantage of digital holography. Specifically, based on the fact that the reference light R is a spherical wave, another spherical wave light close to the reference light R (referred to as a proximity spherical wave light) is introduced, and a new interference fringe (referred to as a conversion interference fringe) between the interference fringe of the reference light R and the proximity spherical wave light is generated on a computer. By bringing the focal points of the reference light R and the proximity spherical wave light close to each other, a conversion interference fringe with a lower spatial frequency is generated. The coordinates (x １ , y １ ) of the center of the concentric circles are obtained from the interference fringes of the hologram. A proximity spherical wave light R １Considering the proximity spherical wave light R １ The proximity point light source P which is the light source of １ １ The coordinate z on the z-axis of １ １ is set. From these, the coordinate (x １ of the proximity point light source P of the proximity spherical wave light R １ , y １ , z １ ) is determined. １ ) In practical applications, for example, by using the calculation of the correlation function between the interference fringes of the reference light R on the hologram surface and the Newton's ring pattern formed by the proximity spherical wave light R １ , the proximity point light source coordinates (x １ , y １ , z １ ) of the proximity spherical wave light R １ are obtained. The proximity spherical wave light R １ is represented by the following formula (7) at the hologram surface z = 0 and time t = 0. Here, when both sides of formula (5) are divided by the phase component exp[iφ Ｒ１ in formula (7), the following formula (8) is obtained (arguments such as x and y are omitted for display, and the same applies hereinafter). Here, since the phase distributions of R and R １ are almost the same, φ Ｒ１ ≈φ Ｒ , φ Ｒ −φ Ｒ１ ≈0, φ Ｒ +φ Ｒ１ ≈2φ Ｒ . The first term of formula (8) is the spherical wave light component, the second term is the low-frequency light component, and the third term is converted into a spherical wave-like light component. When formula (8) is Fourier-transformed, the second term becomes a low-frequency component having a spatial frequency spectrum that is narrowly distributed in a dot-like manner near the origin in the spatial frequency space. This is due to setting the proximity spherical wave light R １ so that the phase distribution is almost the same as that of the reference light R. In other words, the proximity spherical wave light R １ is set so that a spatial frequency spectrum that is narrowly distributed in a dot-like manner near the origin can be obtained in the spatial frequency space. On the other hand, the first term and the third term of Equation (8) are converted into components having a spatial frequency spectrum that is widely distributed in a state of being folded over the entire spatial frequency space. Next, after the Fourier transform of Equation (8), spatial frequency filtering is performed to separate and extract the low-frequency components of the second term. The extracted low-frequency components of the second term are subjected to an inverse Fourier transform, and further, the phase component exp[iφ Ｒ１ of Equation (7) is multiplied. By this multiplication, the phase component that was initially captured by division is removed. Through this series of processes, the second term of Equation (5), that is, the reference light component RL ０ L ０ exp[iφ Ｒ is obtained. The above processing will be described with reference to the flowchart of FIG. 6. In step S1, the point light source coordinates (x １ , y １ , z １ , z １ ) of the proximity spherical light R whose phase distribution is almost the same as that of the reference light R are uniquely determined from the reference light hologram (I ＲＬ ) by correlation function calculation, for example, by the maximum value of the correlation value. In step S2, low-frequency modulation is performed by dividing the hologram I １ by the phase component exp[iφ Ｒ１ calculated from the proximity spherical light R ＲＬ . As a result, the spherical light component can be moved to the low-frequency region. In step S3, in order to obtain the spatial frequency spectrum, the division result I ＲＬ / exp[iφ Ｒ１ is Fourier-transformed F<I ＲＬ / exp[iφ Ｒ１ >. In step S4, the low-frequency component LFC is extracted by spatial frequency filtering. This LFC corresponds to the component R ０ L ０ exp[i(φ Ｒ - φ Ｒ１ )]. In step S5, the low-frequency component LFC is inverse Fourier-transformed F－１ Perform <LFC>. Use the result as the complex amplitude reference light hologram J ＲＲ１ = F －１ Perform <LFC>. In step S6, multiply the complex amplitude reference light hologram J ＲＲ１ by the phase component exp[iφ Ｒ１ (J ＲＲ１ × exp[iφ Ｒ１ ) to perform high-frequency modulation. This removes the phase component introduced during low-frequency modulation. In step S7, as reference light data RD, which is data representing the light wave of the reference light R, obtain the spherical light wave component R ０ L ０ exp[iφ Ｒ , that is, the phase distribution on the light-receiving surface 50. When the numerical aperture NA of the hologram is large, such a method for obtaining reference light data that uses a method of moving the spherical light wave component to the low-frequency region, performing filtering processing, and then returning it to the high-frequency region can be similarly applied regardless of whether the cube beam splitter 3 is used or not on the optical path of the reference light R. According to the processing method of the present embodiment, even when the numerical aperture NA of the hologram is large, the phase distribution on the light-receiving surface 50 of the imaging element 5 of the reference light R, which is a spherical wave for object light recording, can be accurately obtained. (Fourth Embodiment: Imaging Device) With reference to FIG. 7, an imaging device 1 including reference light data obtained by the reference light data acquisition method shown in FIG. 3 will be described. This imaging device 1 is configured by removing the beam splitter 3 used in FIGS. 3(a) and 3(b). Also, the imaging device 1 is configured with the mutual arrangement relationship between the imaging element 5 and the reference light source S Ｒ in FIG. 3(b) maintained as it is. Further, the imaging device 1 includes the reference light data RD obtained using the configuration of FIGS. 3(a) and 3(b) in the storage unit 11. Therefore, the wavelength of the coherent light emitted by the coherent light source 9 is the wavelength at the time when the reference light data RD was obtained. Such an imaging device 1 can record an object light O emitted from an object 4 illuminated by illumination light Q as a hologram in one shot using a reference light R. In the embodiment of FIG. 7, an illumination light source S that is a point light source Ｑ irradiates the flat object 4 with the illumination light Q and records the object light O, which is transmitted light emitted from inside the object 4. The illumination light Q is not limited to the light from the point light source, and light of any shape such as parallel light, spreading light, and converging light can be used. Further, the object light O is not limited to transmitted light, and reflected light can also be the recording target. An example of imaging using the imaging device 1 of FIG. 7 and reproducing an image will be described in Example 2 described later (see FIG. 20). (Fifth Embodiment: Another Method for Obtaining Reference Light Data) With reference to FIGS. 8(a) and 8(b), a method for obtaining reference light data according to the fifth embodiment will be described. In this embodiment, the auxiliary light L travels straight through the beam splitter 3 from the front of the imaging element 5 and enters the imaging element 5, and the reference light R flies in from a direction parallel to the light receiving surface 50 of the imaging element 5 and is reflected by the reflecting mirror M of the beam splitter 3 and enters the imaging element 5. The method for obtaining reference light data of this second embodiment corresponds to a configuration in which the auxiliary light L and the reference light R incident on the cube-shaped beam splitter 3 in the second embodiment are interchanged with each other, and the rest is the same as that of the second embodiment. (Sixth Embodiment: Imaging Device for Large Aperture Ratio) With reference to FIGS. 9, 10(a), and 10(b), the imaging device 1 according to the sixth embodiment will be described. This imaging device 1 uses the same optical system configuration including the beam splitter 3 as that used in FIGS. 8(a) and 8(b). The beam splitter 3 is an essential optical element for reflecting the reference light R. Further, the imaging device 1 of this sixth embodiment has the same configuration as that of the imaging device 1 of the fourth embodiment except for using the beam splitter 3. This imaging device 1 also has advantages due to the use of the beam splitter 3. For example, the reference light R can be made to enter the beam splitter 3 from the space on the side of the imaging element 5. Since various optical systems can be arranged in this side space, the reference light source S ＲThat is, it is not limited to the end of the optical fiber 21 shown in Fig. 10(a). A reference light source S composed of a condenser lens 23 and a pinhole of a mask as shown in Fig. 10(b) Ｒ can be adopted. The advantage of using the pinhole transmitted light as the reference light R is that the numerical aperture NA can be increased to a value close to 1.0. In this case, since a condenser lens such as an objective lens is also required in addition to the pinhole, when using the pinhole transmitted light, an optical system using the cube type beam splitter 3 as shown in Fig. 9 as the recording optical system becomes effective. The problem when recording the object light O using the cube type beam splitter 3 is that the accuracy of the optical phase measurement is limited by the surface accuracy of the cube because the object light O is affected by the surfaces of the beam splitter 3 and the internal mirror M. In order to avoid this problem and perform high-precision optical phase measurement, it is necessary to use an optical system in which the cube type beam splitter 3 is removed. When using the spherical wave light emitted from the optical fiber end shown in Fig. 10(a), the optical fiber can be bent and no accessory parts such as a lens are required. Since no accessory parts such as a lens are required, an optical system in which the cube type BS shown in Fig. 7 is removed can be adopted as the hologram recording optical system. That is, a great advantage of using the optical fiber end as the reference light source S Ｒ is that the reference light source S Ｒ can be easily arranged in a narrow space. Therefore, as the hologram recording optical system, as shown in Fig. 7 of the fourth embodiment, an optical system in which the reference light source S Ｒ is arranged near the object 4 can be used. (Seventh Embodiment: Yet Another Method for Obtaining Reference Light Data) Referring to Fig. 11, yet another method for obtaining reference light will be described. The method for obtaining reference light in this seventh embodiment is the same as the methods of the second and fifth embodiments in that the perpendicularly incident parallel light to the imaging device 5 is used as the auxiliary light L. The differences are that the intermediate light R ３ is used as additional auxiliary light, and two holograms are recorded and the reference light data RD is obtained by two processes. The advantage of the reference light data acquisition method of this embodiment is that it is not necessary to use the cube beam splitter 3. Since there is no optical element on the optical path of the reference light R, the reference light data RD can be accurately obtained. Another advantage is that the medium light R ３ and the reference light R are not limited to parallel light or spherical wave light, and may be light of any beam shape. Furthermore, the reference light R is not limited to the off-axis reference light R, and the reference light data RD can be obtained as the in-line reference light R. The differences from the second and fifth embodiments will be mainly described. The method of recording the hologram and obtaining the reference light data RD from the hologram is the same as that of the second and fifth embodiments. The steps (#10 - #12, #20 - #21) in the following description can be appropriately rearranged. First, in step (#10), the auxiliary light L is made incident perpendicularly on the imaging device 5 as parallel light, and the interference fringe data between the auxiliary light L and the medium light R ３ is recorded as the medium light hologram I ＬＲ３ using the imaging device 5. In step (#11), a series of processes including Fourier transform, spatial frequency filtering, and inverse Fourier transform are performed on the medium light hologram I ＬＲ３ to remove the first-order term and the conjugate term, and the complex amplitude medium light hologram J ＬＲ３ is calculated. In step (#12), using the auxiliary light data LD, which is known information about the auxiliary light L obtained based on the fact that the auxiliary light L is perpendicular parallel incident light, a light wave reproduction process is performed on the complex amplitude medium light hologram J ＬＲ３ to obtain the light wave g ３ representing the medium light R. More specifically, the process here is that since the phase distribution of the perpendicular parallel incident light is a constant value distribution on the hologram plane, the calculation process related to the light wave reproduction process is unnecessary, and it is only necessary to rephrase it from the complex amplitude medium light hologram J ３ to the light wave g ＬＲ３ ３ . Next, in step (#20), the reference light R and the medium light R ３ ​Using the image sensor 5, record the interference fringe data with the reference light hologram I ＲＲ３ as. In step (#21), a series of processes including Fourier transform, spatial frequency filtering, and inverse Fourier transform are performed on the reference light hologram I ＲＲ３ to remove the linear term and the conjugate term, and calculate the complex amplitude reference light hologram J ＲＲ３ . Next, in step (#31), using the light wave g ３ representing the intermediate light L ３ , perform a light wave reproduction process on the complex amplitude reference light hologram J ＲＲ３ to remove the component of the intermediate light R ＲＲ３ from the complex amplitude reference light hologram J ３ and obtain the light wave g Ｒ representing the reference light R. The obtained light wave g Ｒ representing the reference light R is the reference light data RD and is the reference light wave information RI representing the phase component of the reference light R on the hologram plane. Next, when the reference light R is a spherical wave having the reference light focusing point P Ｒ , proceed to step (#32), perform a light wave propagation calculation on the reference light wave information RI, and obtain the coordinates (x Ｒ , y Ｒ , z Ｒ , z Ｒ ) of the reference light focusing point P (Eighth Embodiment: Another Method for Obtaining Reference Light Data) Another method for obtaining reference light data will be described. The reference light data acquisition methods described in the second embodiment (Figs. 3(a)(b)) and the fifth embodiment (Figs. 8(a)(b)) can be more generally described as the eighth embodiment as follows. In this case, the reference light R can be assumed not to be limited to a spherical wave reference light. The reference light data acquisition method for acquiring the reference light data RD representing the reference light R used in holography is as follows: (a) Using the image sensor 5, record the interference fringe data of the reference light R and the auxiliary light L that is coherent with the reference light R and can be analytically expressed using the known parameter PA, as the reference light hologram I ＲＬRecord it as, (b) Using parameter PA, on the hologram plane set on the light-receiving surface 50 of the imaging device 5, calculate auxiliary light data LD obtained as an analytical expression of the auxiliary light L, (c) Using the auxiliary light data LD, from the reference light hologram I ＲＬ delete the component of the auxiliary light L, and obtain the data of the reference light wave g Ｒ representing the reference light R as reference light wave information RI which is the light wave information of the reference light R on the hologram plane, and (d) This can be implemented by using the reference light wave information RI as the reference light data RD. Also, when the reference light R is a spherical wave having the reference light focus point P Ｒ in the case of, (e) Perform a light wave propagation calculation to reverse the reference light wave g Ｒ acquired as the reference light wave information RI, and acquire the data of the focus point information PI representing the position of the reference light focus point P Ｒ as the reference light data RD, and (f) The focus point information PI can be used as the reference light data RD. In this generalized reference light data acquisition method, the auxiliary light L can be analytically expressed using known parameter PA, and using that parameter PA, the light wave of the auxiliary light L can be reproduced on a computer. As light waves that can be analytically expressed using known parameter PA, for example, there are parallel light and spherical light waves. For parallel light, if the azimuth angle in the three-dimensional space of the incident parallel light with respect to the light-receiving surface 50 of the imaging device 5 where the coordinate system is set is given, it can be analytically expressed. The position of the light source of the parallel light can be set as an infinite point, and in terms of calculation processing, the infinite point can be processed as a known point without problem. When the parallel light is used as the auxiliary light L, if the parallel light is perpendicular incident light, the phase becomes constant within the light-receiving surface 50. Embodiments using this perpendicular incident parallel light as the auxiliary light are the second and fifth embodiments. In the second and fifth embodiments, the reference light R is a spherical light wave having the reference light focus point P Ｒ However, the reference light data acquisition method using the perpendicular incident parallel light L is not originally limited to a spherical light wave for the reference light R, and can target a reference light R with an arbitrary beam shape. The azimuth angle in the three-dimensional space of the obliquely incident parallel light can be determined using the perpendicularly incident parallel light on the light-receiving surface 50. Therefore, when using the obliquely incident parallel light as the auxiliary light L, since the process of determining this auxiliary light L is necessary, the acquisition of the reference light data RD is performed in two steps, which, for example, is included in the reference light data acquisition method of the seventh embodiment. The spherical wave can reproduce the light wave of the spherical wave light as the auxiliary light L on a computer if the position of the point light source, which is its light source, is given as a parameter. However, it is necessary to separately obtain the position of the point light source of the spherical wave light, which can be obtained, for example, using the perpendicularly incident parallel light on the light-receiving surface 50. However, this is the same as obtaining the reference light focus point P of the reference light R of the spherical wave using the auxiliary light L that is the perpendicularly incident parallel light. Ｒ be obtained. Even when using the spherical wave light as the auxiliary light L, since the process of determining this auxiliary light L is necessary, the acquisition of the reference light data RD is performed in two steps, which, for example, is included in the reference light data acquisition method of the seventh embodiment. (Ninth Embodiment: Light Wave Reproduction Method) With reference to FIGS. 12 to 16(a)(b), the light wave reproduction method according to the ninth embodiment of the present invention will be described. First, the outline of the light wave reproduction method will be described. The light wave reproduction method in holography is a method of reproducing the light wave of the object light O from the object light hologram I. ＯＲ In this embodiment, the object light hologram I recorded by the off-axis method will be described. Further, the object light hologram I ＯＲ is assumed to be recorded, for example, by the imaging device 1 according to the first embodiment of the present invention. This imaging device 1 includes data of the reference light R, which is an off-axis spherical wave light used for recording the object light O emitted by the object 4 to be imaged, that is, the reference light data RD. By using this reference light data RD, light wave reproduction can be performed on a computer. The reference light data RD is data of the reference light R necessary for light wave reproduction on the hologram surface, which is the light-receiving surface of the imaging element, for example, the reference light phase component exp[iφ ＯＲ (x, y)]. Ｒ (x, y)]. Object light hologram I ＯＲ Perform spatial frequency filtering and inverse Fourier transform on the data obtained by Fourier-transforming the object light hologram I, to obtain a complex amplitude object light hologram J ＯＲ Next, the complex amplitude object light hologram J ＯＲ is multiplied by a reference light phase component exp[iφ Ｒ (x, y)] based on the reference light data RD on the hologram plane, to remove the phase component of the reference light R from the complex amplitude object light hologram J ＯＲ As a result, the object light wave g representing the object light O is extracted, that is, the light wave of the object light is reproduced. The object light wave g at this stage is a light wave on the hologram plane. Even if the light intensity distribution is obtained from the square of the absolute value |g| of this object light wave g ２ it is not possible to visually recognize the shape of the object 4 that is normally observed. To obtain a visible image of the object 4, it is necessary to calculate the object light h at the object position by retropropagating the object light wave g on the hologram plane to the position of the object 4, that is, the light source of the object light O. To calculate the object light h at the object position, a light wave propagation calculation by plane wave expansion is performed on the object light wave g, and the object light wave h at the object position is obtained. The square of the absolute value |h| of the object light wave h ２ makes the image of the object 4 visible. The above-described light wave reproduction process has limitations in the applicable range. To obtain an image with a large numerical aperture or a high-resolution image, it is necessary to add a new technique to the light wave reproduction process. The reason is that in the reproduction of the hologram, it is necessary to reproduce at a pitch finer than the pixel pitch p of the image sensor, that is, at a larger number of sampling points. The interference fringes recorded by the image sensor become a fringe pattern that changes at intervals much larger than the wavelength of the light wave by using the interference phenomenon. The spatial frequency band of the fringe pattern can be recorded (i.e., sampled) at the pixel pitch p of the image sensor. Conversely, only such things can be recorded. In digital holography (DH), the object light wave g processed in the computer and extracted from the interference fringes becomes high-frequency data in the wavelength region of the light wave, and it is necessary to process it under a sampling interval finer than the pixel pitch p. Hereinafter, data obtained under the size in the real space of the imaging device will be described for processing in a high-frequency region exceeding the frequency limited by the pixel pitch p in the space of spatial frequency. By returning the processed data to the real space, data sampled at a small pitch, which is subdivided narrower than the pixel pitch p, can be obtained. By increasing the number of pixels in this way so as to handle high-frequency data, it becomes possible to cope with high resolution and a large numerical aperture. As shown in the flowchart of FIG. 12, in step S11, from the object light hologram I ＯＲ through Fourier transform, spatial frequency filtering, and inverse Fourier transform, the complex amplitude object light hologram J ＯＲ is extracted. In step S12, the complex amplitude object light hologram J ＯＲ is converted into an in-line complex amplitude object light hologram J ＯＲ２ . This conversion is realized by replacing the reference light R, which is the off-axis light contained in the hologram J ＯＲ , with the component of the newly introduced in-line reference light R ２ . FIG. 13 shows an in-line complex amplitude object light hologram J ＯＲ２ having a pixel pitch p and a square shape with a side length D. The specific process of in-line conversion will be described. First, the phase component exp[iφ Ｒ of the reference light R is obtained from the reference light data RD. Next, an in-line reference light R Ｒ having a point light source is set at a point formed by moving the reference light focusing point P ２ on the optical axis in the xy plane. The phase component exp[iφ ２ of the in-line reference light R Ｒ２ emitted from the point light source is calculated on the hologram plane. Further, the phase difference component exp[i(φ Ｒ２ - φ Ｒ )] is multiplied by the complex amplitude object light hologram J ＯＲ . By this multiplication, the component of the off-axis reference light R is replaced with the component of the in-line reference light R ２ , and the in-line complex amplitude object light hologram JＯＲ２ is obtained. In step S13, the in-line complex amplitude object light hologram J ＯＲ２ is Fourier-transformed to generate a spectrum F<J ＯＲ２ > = G. Further, around the spectrum G obtained in the two-dimensional spatial frequency space, a zero-value space G ０ with a spectrum intensity of 0 (zero) is added to expand the space to be calculated by m × m times. The original spectrum G and the zero-value space G ０ are combined to obtain an expanded spectrum G ＥＸ = G + G ０ (see FIGS. 14(a), (b), and (c)). Note that the hologram is considered to be a square hologram. Therefore, it is assumed that the spectrum, which is the result of Fourier-transforming the hologram, also has a square distribution. However, in the present invention, not only squares but also rectangular holograms and spectra can be treated in the same manner. In step S14, the expanded spectrum G ＥＸ is inverse Fourier-transformed F -１ <G ＥＸ > to obtain a pixel-increased complex amplitude object light hologram K ＯＲ２ having a subdivided pixel pitch p / m obtained by dividing the original pixel pitch p by m (see FIG. 15). In step S15, the phase component exp[iφ ＯＲ２ of the in-line reference light R ２ is multiplied by the pixel-increased complex amplitude object light hologram K Ｒ２ to remove the phase component exp[iφ ２ of the in-line reference light R Ｒ２ . As a result, a light wave representing the object light O itself can be obtained as a pixel-increased object light wave g on the hologram plane z = 0. This pixel-increased object light wave g is, as its name implies, a light wave represented by data with a number of pixels increased from the number of pixels of the imaging device, that is, the number of sampling points. After extracting the above-described complex amplitude object light hologram J ＯＲ , the steps from step S12 to step S14 for calculating the object light wave g ＯＲA pixel-increased complex amplitude object light hologram K formed by increasing the number of data points ＯＲ２ can be referred to as a pixel number increasing step for generating it. Also, the process of step S15 can be referred to as a reproduction step of obtaining a pixel image object light wave g on the hologram plane from the pixel-increased complex amplitude object light hologram K ＯＲ２ . Next, in step S16, around the pixel-increased object light wave g, a zero-value space g ０ with a light intensity of 0 (zero) is added to expand the calculation space by n×n times. The original pixel-increased object light wave g and the zero-value space g ０ are combined to form an expanded object light wave g ＥＸ = g + g ０ . This is a process for preparing a so-called large projection screen for reproducing an image with a size larger than that of the imaging device 5 (see FIGS. 16(a) and 16(b)). In step S17, after the expanded object light wave g ＥＸ is subjected to plane wave expansion, light wave propagation calculation is performed to reproduce the object light wave h at the object position. The steps of S16 and S17 for generating the expanded object light wave g ＥＸ on the above-mentioned hologram plane and calculating the object light wave h at the position of the object 4 can be referred to as an expanded wave propagation reproduction step. According to the light wave reproduction method of the present embodiment, light wave reproduction can be performed at a pitch of a light wavelength size finer than the pixel pitch of the imaging device, and an object light wave with a size larger than the size of the imaging device can be easily and accurately reproduced. In other words, an object with a size larger than the size of the imaging device can be imaged. (Tenth Embodiment: Removal of Diffraction Light Component and Light Wave Reproduction) With reference to the flowchart of FIG. 17 and FIG. 22, light wave reproduction including a process of removing a diffraction light component according to the tenth embodiment will be described. This process is a process of removing the diffraction light component included in the object light hologram recorded by the imaging device 1 having an aperture Ap through which the object light O passes in front of the imaging device 5 when the diffraction light component generated at the aperture edge (edge) is included. When a part of the object light is blocked by an aperture, diffracted light is generated at the aperture edge, and this diffracted light overlaps with the object light passing through the aperture and is recorded on the hologram. Since the diffracted light is weak for recording bright-field object light, the influence of the diffracted light on the reconstructed image is not significant. However, when performing precise optical measurement using the phase of the reconstructed object light, even weak diffracted light changes the phase of the object light, so it is necessary to remove the influence of the diffracted light. Also, for recording dark-field object light, since the object light itself to be recorded is weak, the influence of the diffracted light on the reconstructed image cannot be ignored. Also, when obtaining a high-quality dark-field image, it is necessary to remove the diffracted light from the recorded object light. Diffracted light is generated at the aperture edge. By utilizing this fact, the diffracted light can be completely removed by the following method. (Method of removing using spatial frequency filtering) When recording a hologram using spherical-wave reference light, a intensity distribution similar to the reconstructed object light at the reference light focus point P Ｒ in the intensity distribution of the spatial frequency spectrum of the hologram may appear (for example, in the case of an imaging optical system where the paraxial approximation holds in imaging). In such a case, when the reference light focus point P Ｒ and the aperture Ap are close to each other, a spectral intensity distribution similar to the shape of the aperture Ap appears in the intensity distribution of the spatial frequency spectrum. That is, if the aperture Ap is circular, a circular spectral intensity distribution corresponding to the aperture appears, and if the aperture Ap is square, a square spectral intensity distribution corresponding to the aperture appears. Since diffracted light is generated at the aperture edge of the aperture Ap, the spectral intensity distribution of the diffracted light component appears at the position of the spectral intensity distribution corresponding to the aperture Ap. FIG. 22 shows an example of the intensity distribution of the spatial frequency spectrum of a hologram recorded using an imaging device when the aperture Ap is circular, and an intensity distribution similar to the reconstructed object light appears. The aperture Ap, and thus the spectrum corresponding to the diffracted light component, is shown as the aperture edge 81 in the figure. Inside this aperture edge 81, there is an object light component OR ＊ existing. Therefore, by extracting the data inside the filtering circle 82 shown inside the opening edge 81, an object light component OR that does not include a diffracted light component ＊ can be extracted to obtain a complex amplitude object light J ＯＲ . (Method for removing diffracted light component from object light of reconstructed object at opening position) The process in the case where the diffracted light component and the object light component OR ＊ cannot be separated in the spectral space will be described. When the numerical aperture NA of the reference light R is large, or when the reference light focus point P Ｒ of the reference light R is not close to the plane formed by the aperture Ap, when recording a hologram with such an imaging optical system, it becomes difficult to separate the diffracted light component and the object light component using the spectral intensity distribution in the spatial frequency space. This is because, for example, the spectral intensity distribution of the diffracted light component does not become a spectral intensity distribution similar to the opening edge. In this case, first, spatial frequency filtering is performed so as to include the object light component and the diffracted light component, optical wave reproduction is performed on both extracted components, and the reproduced optical wave is propagated to the position of the aperture Ap. The diffracted light component becomes an in-focus image at the opening edge, and since the object light component is out of focus, the diffracted light component can be completely removed by removing the in-focus image at the opening edge. The flowchart of FIG. 17 will be described. The object light hologram I ＯＲ to be processed will be described as being imaged by the imaging device 1 of the first embodiment using the off-axis method. However, the method for removing this diffracted light component is not limited to the off-axis method, and the method of this embodiment can be appropriately modified and applied to object light holograms recorded by other methods. First, the object light hologram I ＯＲ is Fourier-transformed F <I ＯＲ > to shift to the spatial frequency space (spectral space) (S21). Based on an overall judgment from the image of the spectral intensity distribution in the spatial frequency space and the imaging optical system, etc., it is determined whether the component of the object light O and the diffracted light component can be separated (S22). When separable in the spatial frequency domain (Yes in S22), the diffracted light component, DC light component, and conjugate term component are removed by spatial frequency filtering, and inverse Fourier transform is performed on the obtained data to obtain a complex amplitude object light hologram J without the diffracted light component. ＯＲ This is done in step S23. Next, using the reference light data RD, the object light wave g is reproduced from the complex amplitude object light hologram J. ＯＲ This object light wave g is a light wave that does not contain the diffracted light component. By performing a plane wave expansion on the object light wave g and propagating the light wave, the object light wave h at the object position can be obtained (S25). On the other hand, when not separable in the spatial frequency domain (No in S22), the DC light component and conjugate term component are removed by spatial frequency filtering, and the object light component is extracted while including the diffracted light component. Inverse Fourier transform is performed on the extracted data to generate a complex amplitude object light hologram J that includes the diffracted light component. ＯＲ This is done in step S26. Next, using the reference light data RD, the object light wave g is reproduced from the complex amplitude object light hologram I. ＯＲ This object light wave g is a light wave that contains the diffracted light component. By performing a plane wave expansion on the object light wave g and propagating the light wave to the position z = z of the aperture Ap, the light wave at the position of the aperture Ap is obtained. Since the light wave obtained at the position of the aperture Ap is focused on the aperture edge, an image of the diffracted light component is obtained in the image obtained by image reproduction from the light wave (S28). ａ The image component focused on the aperture edge position is removed to obtain the object light wave g at the position of the aperture Ap, that is, at the position z = z of the aperture edge. This object light wave g is a light wave that does not contain the diffracted light component. ａ By performing a plane wave expansion on the object light wave g and propagating the light wave, the object light wave h without the diffracted light component at the object position can be obtained (S30). ａ This object light wave g is a light wave that does not contain the diffracted light component. ａ This object light wave g is a light wave that does not contain the diffracted light component. The object light wave g ａ By performing a plane wave expansion on the object light wave g and propagating the light wave, the object light wave h without the diffracted light component at the object position can be obtained (S30). According to the method for removing diffracted light components of this embodiment, the diffracted light components generated at the aperture edge can be completely removed, and the object light O passing through the aperture Ap can be accurately reproduced. (11th Embodiment: Imaging Device) Referring to FIG. 18, an imaging device according to the 11th embodiment will be described. The imaging device 1 includes a lens 24 as an optical element for imaging object light O that has passed through an object 4, which is a large sample to be imaged. The illumination light source S distributed over the surface of the lens 24 Ｑ When considered as Ｑ is configured to emit illumination light Q so as to have an illumination light focusing point P Ｑ (not shown) between the object 4 and the imaging element 5. In the case of imaging a transmissive object with transmitted light from the object 4 irradiated by such illumination light Q as object light O, bright-field object light can be recorded by illuminating with the illumination light Q focused on the aperture Ap. This illumination light source S Ｑ (not shown) is configured such that the illumination light Q is incident on the imaging element 5. Also, the illumination light source S Ｑ can be configured such that the illumination light Q is not incident on the imaging element 5. In this case, by moving the focusing point of the illumination light Q at the position of the aperture Ap outside the aperture Ap, dark-field object light can be easily recorded. (Other Modification Examples) In the optical systems of FIG. 18 and FIG. 1(a) described above, a focusing point P of the spherical wave reference light R is arranged near the aperture Ap. Ｒ When it is difficult to assemble an optical system for forming the reference light R in the space near the aperture Ap, as shown in FIG. 9, this problem can be solved by using the cube-type beam splitter 3 as an optical coupler. As the structure of the illumination light Q, as described above, illumination light Q with various structures and arrangements can be used to obtain a bright-field image or a dark-field image. For example, beam light transmitted through an object may be used as the illumination light Q. (12th Embodiment: Imaging Device for Large Area) Referring to FIG. 19, an imaging device according to the twelfth embodiment will be described. The imaging device 1 of the present embodiment is a device that enables large-aperture object light O to be recorded on a small-aperture hologram and reduces the wavefront aberration caused by the collimating lens 25 to reproduce the object light wave. Further, by using the collimating lens 25, the imaging device 1 can be an optical system for creating large-aperture parallel illumination light and condensing and recording large-aperture reflected light. The imaging device 1 has a part of the configuration of the first embodiment (see FIG. 1) changed, and the other configurations are the same as those of the first embodiment. The configuration related to the change is a configuration for enabling imaging of a large-area flat plate or the like without being limited by the size of the light-receiving surface 50 of the imaging element 5. The content of the change includes adding the collimating lens 25, wavefront aberration data WD, and the wavefront correction unit 12b, and further changing the illumination light source S so that the illumination light Q is emitted as spherical wave light. Ｑ And other changes. The imaging device 1 illuminates the object 4 to be imaged with the illumination light Q that has become parallel light through the collimating lens 25. The object light O radiated from the object 4 travels backward through the collimating lens 25, becomes object light O with a reduced outer diameter, and enters the imaging element 5, and is acquired as the object light hologram I. ＯＲ The following is a detailed description. The collimating lens 25 is a lens that converts spreading spherical wave light into parallel light and converts backward-traveling parallel light into converging spherical wave light, and has a focal point F. Ｐ The focal point F Ｐ is arranged between the collimating lens 25 and the imaging element 5. The collimating lens 25 itself is arranged on the optical path from the object 4 to the imaging element 5 for the purpose of causing a predetermined deformation in the wavefront of the object light O. If the collimating lens 25 is an ideal lens without aberration, the spherical wave light Q is converted into parallel illumination light Q by the collimating lens 25 that is at a focal length away from the illumination light source S, and is reflected by the plane mirror FM arranged near the collimating lens 25. The reflected parallel light O is converted into spherical waves after passing through the lens 25 again, and the illumination light source S Ｑ ... Ｑis focused on a point on the x-y plane, passes through the aperture Ap, and then enters the imaging device 5. The illumination light source S Ｑ constitutes a point light source. The collimating lens 25 is, in a broad sense, a collimating element E ｃｏｌｌ and, in an even broader sense, a wavefront conversion element E Ｘ . The collimating element E ｃｏｌｌ includes, for example, a lens type and a parabolic mirror type (see Fig. 23). The collimating lens 25 of the present embodiment is a single plano-convex lens type collimating element E ｃｏｌｌ . The wavefront conversion element E Ｘ is an optical element that acts on the wavefront of incident light to convert the wavefront and emits the emitted light having the converted wavefront. The wavefront conversion element E Ｘ is designed and manufactured to convert light having a predetermined wavefront (for example, diverging spherical wave light) into light having another predetermined wavefront (for example, plane wave light), but it is not possible to manufacture it exactly as designed. Therefore, the converted wavefront includes wavefront aberration (phase distortion, phase aberration) that occurs as a deviation from a predetermined deformation (design deformation, desired deformation) due to the incompleteness of the wavefront conversion element E Ｘ . The light wave of the object light O recorded on the object light hologram I ＯＲ passes through the collimating lens 25 (wavefront conversion element E Ｘ ), so due to the influence of this wavefront aberration, it is not the light wave of the true object light but a light wave distorted by the influence of aberration. Thus, the actual collimating lens has aberration, and due to this aberration, the reflected light O does not converge to a single point but becomes light having a spread at the position of the converging point. By recording and reproducing the reflected light O affected by the aberration, it is possible to obtain, as data of wavefront aberration distributed on the x-y plane, the aberration using the reproduced reflected light O and the spherical wave illumination light Q. The wavefront aberration data WD is data used to remove or reduce, by data processing by calculation, the wavefront aberration received when passing through the collimating lens 25 (wavefront conversion element E Ｘ ), and is data obtained by measuring the characteristics of the collimating lens 25. The illumination light source SＱ is a point light source that emits illumination light Q as spherical wave light, and is off-axis arranged near the focal point F of the collimating lens 25 Ｐ . With this configuration, the object 4 is illuminated by the illumination light Q that is parallel light with distortion. The object light O, which is reflected light, converges with spreading around the focal point F Ｐ and then diverges. The optical axis of the imaging element 5 (the z-axis having the origin at the center of the light receiving surface 50) coincides with the optical axis of the collimating lens 25 and is arranged to pass through the center of the aperture Ap. Also, the focal point F of the collimating lens 25 Ｐ is arranged at the center of the aperture Ap. The wavefront correction unit 12b performs data processing for reducing the influence of wavefront aberration generated due to the imperfection of the collimating lens 25 when reproducing the light wave of the object light O from the object light hologram I ＯＲ . The wavefront aberration data WD performs data processing necessary for the wavefront correction unit 12b and includes data related to the optical system, for example, the position coordinate value of the focal point F Ｐ , the position coordinate value of the principal plane of the collimating lens 25, the position coordinate value of the illumination light source S Ｑ and so on. According to the imaging device 1 of the present embodiment, by using the collimating lens 25 as the wavefront conversion element E Ｘ , a large-diameter object light O can be recorded on a small-diameter hologram, and by using the wavefront aberration data WD, the influence of the wavefront aberration caused by the collimating lens 25 can be removed, and an accurate object light wave can be reproduced. Therefore, a large-area flat plate or the like can be imaged without being limited by the pixel pitch of the imaging element 5, the size of the light receiving surface 50, the size of the recording optical system, etc., and an object light wave with little distortion can be reproduced. In the present embodiment, the influence of the wavefront aberration generated due to the imperfection of the collimating lens is removed, but the target optical element is not necessarily limited to the collimating lens. For example, it can be widely applied to an optical element for which aberration is to be removed from the optical system. (13th Embodiment: Measurement of Surface Shape of Large Area) Referring to FIG. 20, a surface shape measurement method according to the 13th embodiment will be described. This surface shape measurement method can be performed using the imaging device 1 of FIG. 19, and FIG. 19 will also be referred to subsequently. (Premise Conditions) The imaging device 1 has an orthogonal xyz coordinate system in which the origin and the z-axis are set at the center of the light receiving surface 50 and the optical axis. The wavefront aberration data WD is information regarding the phase aberration distribution function A(x, y, z Ｍ ) which is a measured value of the wavefront aberration generated in the phase distribution of the light wave passing through the collimating lens 25. This phase aberration distribution function A is called by an appropriate expression such as a phase aberration function or an aberration distribution, for example. Further, the wavefront aberration data WD is information of the collimating lens 25, and the focal position z = z Ｐ at the position of the focus F Ｐ , the principal plane position z = z Ｅ defined as the switching boundary plane between the spherical wave and the plane wave, and the data acquisition position z = z Ｍ and the data application position z = z Ｍ which is the calculation position for post-processing. The data acquisition position and the data application position z = z Ｍ are the positions of the reflecting surface of the plane mirror FM in FIG. 21 described later. Usually, the shape measurement surface of the object 4 to be measured is arranged so as to be close to this reflecting surface z = z Ｍ . Since the reflecting surface of the plane mirror FM is the incident surface of the perpendicularly incident light, strict accuracy is not required for the numerical value of this z Ｍ , and it is acceptable with an accuracy of, for example, several millimeters. Further, the spatial change of the phase aberration distribution function A is sufficiently smaller than the spatial change of the wavefront conversion function T of the collimating lens 25, and can be considered as a perturbation element with respect to the function T. In the optical system shown in FIG. 19 and FIG. 21 described later, the phase aberration at z = z Ｅ of the light transmitted through the collimating lens 25 in the forward direction from z = z Ｍ is the same as the phase aberration at z = z Ｍ of the light transmitted through the collimating lens 25 in the reverse direction from z = z ＥIt can be regarded as being equal to the phase aberration in. From this, for the collimating lens 25, the phase aberration distribution function A in each case where parallel light is emitted and incident from the forward direction and the reverse direction can be regarded as being equal to each other. (Shape measurement procedure) In step S31, the illumination light Q is passed through the collimating lens 25 and the object 4 is illuminated as parallel light. The object light O, which is the reflected light of the illumination light Q from the surface of the object 4, is made to travel backward through the collimating lens 25, and the object light hologram I ＯＲ is recorded by the imaging device 5. After this, the object light wave g, which is the light wave of the object light O, is calculated on the hologram surface z = 0, which is the light receiving surface 50, and the object light wave g(0) is finally propagated to the position z Ｅ through the lens position (principal plane position z = z Ｏ ) to the position z Ｅ which is the surface shape measurement position on the object 4. The principal plane position z = z position is the position defined as the switching boundary plane between the spherical wave and the plane wave. In step S32, a plurality of processes are performed. First, the object light wave g calculated on the hologram surface z = 0 is propagated by light wave propagation calculation to obtain the object light wave g(z Ｅ ) in the state of being propagated to the principal plane position z = z Ｅ . Looking at the state of propagation from z = 0 to z = z Ｅ along the optical path, the light wave starting from the hologram surface converges toward the focal point F Ｐ and then spreads in a spherical wave shape and reaches the principal plane position z = z Ｅ . The propagation calculation is performed using the plane wave expansion method, and the wavefront at the principal plane position z = z Ｅ is calculated without performing calculations on the intermediate optical path. Next, a plane wave state object light wave is generated by removing the phase component as a spherical wave from the object light wave g(z Ｅ ). This represents the original action of the collimating lens 25 on the light wave g. Mathematically, a phase conversion function T(z Ｅ ), which is a predetermined operator, is applied to the object light wave g(z Ｅ) is performed by multiplying. As a result, an object light wave g(z Ｅ )·T(z Ｅ ) that is parallel light is obtained. The phase conversion function T(z Ｅ ) is a function for removing the phase component (distributed in xy) from a spherical light wave analytically calculated at the main surface position z = z Ｅ . The function T is obtained from the position z = z Ｐ of the focus F and the main surface position z = z Ｐ . Note that the off-axis arrangement of the illumination light source S Ｅ can be ignored in approximate calculations. Ｑ In step S33, the object light wave g·T that has been made parallel light at the main surface position z Ｅ is divided by the phase aberration distribution function A(x, y, z Ｍ ). As a result, the object light wave g·T / A(z Ｍ ) at the data application position z Ｍ is obtained. In step S34, the object light wave g·T / A(z Ｍ ) is propagated as a light wave to the object position z Ｏ , and the object light wave h(x, y, z Ｏ ) of the object light O at the object position z Ｏ is calculated, and the phase distribution φ Ｏ (x, y, z Ｏ ) is obtained. This object light wave h is a light wave that is affected by the wavefront aberration function A(z Ｍ ) when the object light O travels back through the collimating lens 25 and heads toward the imaging element. The processing regarding the object light O ends here. Next, processing for obtaining the light wave of the illumination light Q at the object position z Ｏ is performed. (Calculation of illumination light wave) In step S35, in order to obtain the light wave of the illumination light Q at the object position z Ｏ , first, the ideal spherical light wave b Ｅ of the illumination light Q at the main surface position z Ｓ (x, y, z Ｅ ) is analytically set. Next, the ideal spherical light wave b Ｓ (x, y, zＥ ), the phase conversion function T(z Ｅ ) and the wavefront aberration function A(z Ｍ ) are multiplied to obtain the ideal parallel illumination light wave b Ｍ distorted by the influence of aberration at the data application position z ＰＡ (z Ｍ ) = b Ｓ ·T(z Ｅ )·A(z Ｍ ) is generated. In step S36, for the illumination light wave b Ｍ at the data application position z ＰＡ (z Ｍ ) = b Ｓ ·T·A, light wave propagation calculation is performed to obtain the parallel light wave b Ｏ of the illumination light Q at the object position z ＰＡ (x, y, z Ｏ ) and the phase distribution φ Ｑ (x, y, z Ｏ ) are generated. (Calculation of phase difference distribution) In step S37, the phase difference distribution obtained from the phase distribution φ Ｏ (x, y, z Ｏ ) in the object light wave h(x, y, z Ｏ ) of the object light O and the phase distribution φ ＰＡ (x, y, z Ｏ ) in the illumination light wave b Ｑ (x, y, z Ｏ ) of the illumination light Q distorted from the ideal parallel light wave is obtained. When obtaining the phase difference distribution, for the phase distribution φ Ｏ of the object light O at the object position z Ｏ (x, y), the phase distribution φ Ｑ (x, y) of the parallel illumination light Q, at the origin on the x - y plane, φ Ｏ (0, 0) = φ Ｑ (0, 0) is set. Thus, the height distribution t(x, y, z Ｏ ) of the surface to be measured with the origin as the reference is obtained by the following formula (9). For a height t exceeding the light wavelength λ, the phase difference distribution φ Ｏ (x, y, z Ｏ ) - φ Ｑ (x, y, z ＯUnwrapping processing may be performed on it. According to the surface shape measurement method of the present embodiment, the optical wave h of the regenerated object light O and the wavefront aberration function A(z Ｍ ) calculated using the optical wave b of the regenerated collimated illumination light Q ＰＡ By obtaining the phase difference distribution between the object surface flatness and the height distribution of the surface shape can be measured. This surface shape measurement method uses the collimating lens 25 and, in consideration of the influence of the wavefront aberration generated due to the imperfection of the collimating lens 25, data processing can be performed, so that the flatness and surface shape of a large area substrate or the like can be accurately measured. (14th Embodiment: Optical System Parameters, Method for Obtaining Wavefront Aberration Data WD) Referring to FIGS. 21 and 22, a method for obtaining wavefront aberration data according to the 14th embodiment will be described. This wavefront aberration data acquisition method can be performed using the imaging device 1 of FIG. 19, and FIG. 19 will also be referred to subsequently. In addition, the descriptions of the 12th and 13th embodiments are also applicable to the present embodiment. In FIG. 21, the plane mirror FM is arranged such that the focal point F of the collimating lens 25 is located at the center of the aperture Ap. The center of the aperture Ap and the focal point F Ｐ Are on the z-axis (optical axis). Also, the focal point F Ｐ , aperture Ap, illumination light source S Ｐ The z coordinate values of are the same as each other (z Ｑ = z Ｐ = z Ａ = z Ｑ ). The illumination light source S, which is a spherical light source Ｑ Is indicated by the position of the illumination light focus point P Ｑ . The plane mirror FM and the object 4 can be replaced with each other. In the wavefront aberration data acquisition method, setting conditions (z Ｐ , z Ａ , z Ｑ , z Ｅ , z ＭData such as ( ) are set or measured. These data are integrated as wavefront aberration data WD together with the information of the phase aberration distribution function A(x, y, z Ｍ ) of the wavefront aberration generated by the collimating lens 25. First, the settings made when measuring the phase aberration distribution function A will be described. (Determination of distance z Ａ ) Prior to measuring the phase aberration distribution function A(x, y, z Ｍ ), the distance z from the imaging element 5 to the aperture Ap is measured. First, in order to identify the aperture Ap, the peripheral edge (aperture edge) of the aperture Ap is illuminated by the reflected light of the illumination light Q from the plane mirror FM, and then the diffracted light generated at the aperture edge is recorded on the hologram, reproduced, and light wave propagation calculation is performed to search for and determine the aperture edge position. Note that the position z Ｑ of the illumination light source S Ｑ is separately set to the position z Ａ of the aperture Ap. Ａ Specifically, in the optical system of FIG. 21, (1) The plane mirror FM is tilted by a minute angle so that a part of the reflected light is blocked by the aperture edge, and the diffracted light generated at the aperture edge is recorded on the hologram as the object light O. Next, (2) The light wave of the recorded object light O is propagated by propagation calculation, the z coordinate value that focuses on the aperture edge, which is the generation position of the object light O, is determined, and that z coordinate value is taken as the measured value of the distance z Ｐ from the light receiving surface 50 of the imaging element 5 to the aperture Ap. (Position adjustment of the collimating lens 25, setting of the position of the focus F Ｐ ) Using the reflected light from the plane mirror FM (the reflected light of the illumination light Q), the position of the collimating lens 25 is adjusted according to the following procedure. In the optical system shown in FIG. 21, (1) After finely adjusting the inclination of the plane mirror FM so that the reflected light O passes through the central part of the aperture Ap, the reflected light O is recorded on the hologram. (2) The component close to the optical axis among the recorded reflected light O is cut out, and propagation calculation is performed on this component near the axis to obtain the light focusing point. (3) While moving the collimating lens 25 along the optical axis direction, repeat the above procedures (1) and (2), and the position (x, y, z Ｐ ) of the focusing point of the component near the axis (paraxial light component) is made to coincide with the center (0, 0, z Ａ ) of the aperture Ap. When this coincidence (z Ｐ = z Ａ ) occurs, the focusing point is defined as the focal point F Ｐ . As a result, the distance from the illumination light source S Ｑ to the collimating lens 25 and the distance from the focal point F Ｐ to the collimating lens 25 become equal, and at least the component near the axis of the spherical wave light emitted from the illumination light source S Ｑ is converted into parallel light after passing through the collimating lens 25. (Explanation of the procedure along the flowchart) After the above settings, the phase aberration distribution function A is measured by the procedure shown in the flowchart of FIG. 22. Steps S41 to S43 are measurements using the plane mirror FM, S44 to S46 are measurements using the object 4, and S47 to S50 are post-processing by a computer. (Processing using the plane mirror FM) In step S41, spherical wave illumination light Q from the illumination light source S Ｑ is incident on the collimating lens 25, and it is a process of converting the spherical wave Q into parallel light. The illumination light source S Ｑ (illumination point light source) is arranged off-axis near the focal point F ｃｏｌｌ of the collimating lens 25 (collimating element E Ｐ ). When the illumination point light source is arranged at the focal point F Ｐ without off-axis arrangement, a cube type beam splitter or the like may be used, but additional calculation processing is required. In step S42, the parallel light is reflected by the plane mirror FM, retro-injected into the lens 25, and the measurement light Lc emitted from the lens 25 is recorded on the hologram I ＣＲ . The plane mirror FM is at the data acquisition position z = z Ｍ which is a position close to the collimating lens 25.It is installed and adjusted perpendicular to the optical axis. The measurement light Lc is made into measurement light Lc having an outer diameter smaller than that of the parallel light by the collimating lens 25 and is incident on the imaging device 5. Data of interference fringes between the measurement light Lc and the reference light R are recorded as the measurement light hologram I ＣＲ is recorded In step S43, the light wave c Ｓ of the measurement light Lc is reproduced from the hologram I ＣＲ . For this reproduction, reference light data RD is used. The light wave c Ｓ (z = 0) reproduced on the hologram plane (z = 0) is propagated to the principal plane position z Ｅ after the principal plane position z Ｅ is determined by light wave propagation calculation, and becomes the light wave c Ｓ (z Ｅ ). (Determination of the principal plane position z Ｅ : Irradiation of a plane pattern with known dimensions) In step S44, the plane mirror FM is replaced with an object 4 having a plane pattern with known dimensions. This object 4 is illuminated by illumination light Q that has become parallel light through the collimating lens 25, similarly to the case of the plane mirror FM In step S45, object light O including reflected light from the plane pattern is recorded in the object light hologram I ＯＲ . In step S46, using the reference light data RD, the object light wave g (z = 0) that is the light wave of the object light O is reproduced from the object light hologram I ＯＲ . Optical propagation calculation is performed on the object light wave g, and the position z Ｅ where the read value of the dimension of the plane pattern obtained at a plurality of propagation positions becomes the known dimension is determined as the principal plane position z = z Ｅ of the collimating lens 25. This will be explained The pattern image of the object 4 is reproduced with the image reproduction position z as a parameter. In the region in front of the principal plane z Ｅ of the collimating lens 25 (z Ｐ < z < z Ｅ ), the illumination light Q is spherical wave light, and the reproduced image becomes larger in proportion to the distance (z - z Ｐ ). On the other hand, in the region after passing through the lens (z > zＥ ), the illumination light Q becomes parallel light, and the reproduced pattern image has a constant value regardless of the change in distance (z - z Ｅ ). The value of the parameter z when the size of the reproduced pattern image first becomes equal to the size of a known dimension is determined as the principal plane z Ｅ position (obtained as the z coordinate of the intersection of two straight lines on the graph of the dimensional change). (Derivation of the phase aberration distribution A: post - processing by computer) In step S47, the functional formula of the ideal spherical wave b Ｐ emitted from and spreading out from the focal position z Ｓ is obtained at the principal plane position z Ｅ . The phase conversion function T(z Ｓ ) that converts the ideal spherical wave b Ｅ into an ideal plane wave light is used to obtain the ideal parallel light wave b Ｅ = b Ｐ · T at the principal plane position z Ｓ . Specific function examples of each function b Ｓ , T are shown below. Coordinates (x Ｑ , y Ｑ , z Ｑ ) of the illumination light source S Ｑ (which is a point light source and is also referred to as the point light source S Ｑ ), the light wave b Ｓ (x, y, z) of the spherical wave illumination light Q emitted from it is represented by the following formula (10). Since the point light source S Ｑ is arranged near the z - axis, x Ｑ and y Ｑ are sufficiently small compared to z Ｅ . For simplicity, in the following, x Ｑ = y Ｑ = 0 is used for explanation. The ideal lens that converts this spherical light wave into parallel light propagating in the positive direction of the z - axis can be represented using the phase conversion function T(x, y, z Ｅ ) of the following formula (11). Similarly, when converting a parallel light wave propagating in the negative direction of the z - axis into a spherical light wave, the phase inverse conversion function T －１ (x, y, z Ｅ ) is used. (Introduce the phase aberration distribution function A(x, y, z as an unknown function Ｍ )) In step S48, it is assumed that the wavefront aberration generated due to the imperfection of the collimating lens 25 is acquired at the data acquisition position z = z, which is the reflection surface position of the plane mirror FM. Ｍ Set the phase aberration distribution function A(x, y, z Ｍ ) in the functional form of the wavefront aberration to be obtained, and use it as an unknown function. After passing through the collimating lens 25, the parallel light wave b Ｍ that has received the aberration after passing through the lens at the position z Ｍ ) using the phase aberration distribution A(x, y, z ＰＡ (x, y, z Ｍ ) is given by the following equation (13). From the above equations (10) and (11), the ideal parallel light b Ｐ (z Ｅ ) at the principal plane position is given by the following equation (14). Therefore, the parallel light wave b Ｍ affected by the aberration at the position z ＰＡ (x, y, z Ｍ ) is expressed by the following equation (15). (Setting of the equation) In step S49, multiply the reflected light wave b ＰＡ = b Ｓ · T · A (at z Ｍ ) by the inverse phase conversion function T －１ and the wavefront aberration A, and consider the resulting mathematical expression b Ｓ · T · A · T －１ · A (at z Ｅ ) to be the mathematical expression corresponding to the light wave when the measurement light wave c Ｓ (z = 0) exists at the principal plane position z Ｅ . Set the light wave of this mathematical expression b Ｓ · T · A · T －１ · A (at z Ｅ ) to pass from the principal plane position z Ｅ through the focal point F Ｐ to the imaging element 5, and be the recording hologram I of the measurement light Lc ＣＲis a light wave (reflected light wave) that is assumed to be the result. (Derivation of phase difference distribution A) In step S50, the mathematical expression b Ｓ · T · A · T －１ · A and the measurement light wave c Ｓ (x, y, 0) is propagated to the principal plane position z = z Ｅ of the measurement light wave c propagated by light propagation calculation Ｓ (x, y, z Ｅ ) and, by equating them, the phase difference distribution A = (c Ｓ / b Ｓ ) １／２ is derived. This is included in the wavefront aberration data WD together with other data regarding the collimator lens 25. Using the optical system of FIG. 21, the reflected light O (measurement light Lc) from the plane mirror FM is recorded, and when light wave propagation calculation is performed on the light wave of the reflected light O, the light wave c Ｅ of the spherical light wave at the principal plane position z Ｓ (x, y, z Ｅ ) can be reproduced. On the other hand, the measurement light wave c Ｓ (x, y, z Ｅ ) is a spherical light wave after the distorted parallel light wave b ＰＡ (x, y, z Ｍ ) is reflected by the plane mirror FM and then transmitted backward through the collimator lens 25. Assuming that this spherical light wave is an ideal plane mirror without bending for the plane mirror FM, the inverse conversion function T －１ (x, y, z Ｅ ) and the phase difference distribution A (x, y, z Ｍ ) can be expressed by the following equation (16). From equations (14), (15), and (16), the phase difference distribution A (x, y, z Ｍ ) of the following equation (17) is obtained. In this way, using the light wave b Ｅ of the spherical wave illumination light Q at the position z Ｓ (x, y, z Ｅ ) and the light wave c Ｓ (x, y, z Ｅ ) of the reflected light O (measurement light Lc), the phase difference distribution A (x, y, z Ｅ) can be represented. According to the wavefront aberration data acquisition method of this embodiment, the incident and outgoing light of the collimating lens 25 (collimating element E ｃｏｌｌ ) can be made into spherical wave light and plane wave light, and based on propagating the object light by light wave propagation calculation, the wavefront aberration data (WD) which is the information of the collimating lens 25 can be accurately acquired. (15th Embodiment: Parabolic mirror type collimating element, wavefront conversion element) Referring to FIG. 23, the imaging device according to the 15th embodiment will be described. The imaging device 1 of this embodiment uses a parabolic concave mirror 26 as the collimating element E ｃｏｌｌ instead of the plano-convex lens type collimating lens 25 in the imaging device 1 of FIG. 19. The collimating lens 25 is a transmissive optical element, and the parabolic concave mirror 26 is a reflective optical element. By using the parabolic concave mirror 26, an optical system for creating large-aperture parallel illumination light and condensing and recording large-aperture reflected light can be configured. The imaging device 1 of this embodiment includes a reflecting mirror M on the optical path connecting the parabolic concave mirror 26 and the focal point F Ｐ . In this imaging device 1, the optical paths regarding the illumination light Q, the object light O, and the reference light R are, from an optical point of view, equivalent to the optical paths in the imaging device 1 using the collimating lens 25. Also, both imaging devices 1 have equivalent optical systems except that they include a reflecting mirror M on the optical path connecting the parabolic concave mirror 26 and the focal point F Ｐ . Therefore, the wavefront aberration data acquisition method in the imaging device 1 of this embodiment can be executed by the same method as in the case of the imaging device 1 of FIG. 19, and the wavefront aberration data WD can be acquired. However, in imaging the object 4, that is, acquiring the hologram and surface shape measurement, it is necessary to consider that a shadow portion that is not imaged is generated due to the presence of the reflecting mirror M. To image the shadow portion, the object 4 may be shifted in the plane and imaged. According to the imaging device 1 of this embodiment, the parabolic concave mirror 26 is used as the wavefront conversion element E ＸIt can be used to record large-diameter object light O on a small-diameter hologram, and by using wavefront aberration data WD, it can remove the influence of wavefront aberration caused by the parabolic concave mirror 26 and reproduce an accurate object light wave. Therefore, a large-area flat plate or the like can be imaged without being limited to the size of the light-receiving surface 50 of the imaging element 5, and an object light wave with less aberration can be reproduced. In addition, the parabolic concave mirror 26 that condenses light by reflection is different from a lens that transmits a medium having a refractive index different from that of the outside sandwiched between two boundary surfaces and condenses light, and it is easy to make it lightweight and large-sized, enabling imaging and surface shape measurement of larger objects. (16th Embodiment: Imaging Apparatus with Noise Processing Unit) An imaging apparatus according to the 16th embodiment will be described with reference to FIG. 24. The imaging apparatus 1 of this embodiment includes a noise processing unit 13 in the control unit 10 of the imaging apparatus 1 in FIG. 19. The noise processing unit 13 includes an imaging processing unit 13a and a statistical processing unit 13b. The imaging processing unit 13a has a configuration for facilitating imaging and storage of a plurality of object light holograms I using the imaging element 5 while keeping imaging conditions constant. For example, it realizes imaging in the continuous shooting mode of a normal camera. ＯＲ The statistical processing unit 13b has a configuration for generating one object light hologram with reduced image noise or a reproduced object light wave by calculating and processing the data of the plurality of imaged object light holograms I by a statistical method. According to the imaging apparatus 1 of this embodiment, noise that can be reduced by a statistical method, such as shot noise, can be efficiently reduced. ＯＲ In addition, changes and deformations of an object over time can be measured. (17th Embodiment: Object Light Synthesis and Noise Reduction Method) Referring to FIG. 25, a noise reduction method according to the seventeenth embodiment will be described. This noise reduction method can be applied to the imaging device 1 of FIG. 24, and reference is made in conjunction with FIG. 24. Shot noise is the main noise generated in the imaging element 5 and is the main cause of reducing the measurement accuracy in surface shape measurement. This shot noise is random noise, and the spatial frequency components of the noise are uniformly distributed over a wide band. As a method for reducing shot noise, since it is random noise, a statistical method of synthesizing a plurality of object light waves, and since it is noise uniformly distributed over a wide band, a method of narrowing the spatial frequency bandwidth of the distributed light wave are effective. Here, noise reduction by a statistical method will be described along the flowchart of FIG. 25. Random noise can be reduced by averaging a large number of samples, that is, by a statistical method. In step S51, the imaging conditions are kept constant, and the object light hologram I ＯＲ is repeatedly acquired by the imaging element 5 to obtain object light holograms I ｊ ＯＲ , j = 1, ···, m. In step S52, using the reference light data RD, the component of the reference light R is removed from the object light holograms I ｊ ＯＲ , j = 1, ···, m to reproduce the light wave of the object light O, and the phase value distribution φ ｊ , j = 1, ···, m at the position of the object 4 is calculated. In step S53, for each of the phase value distributions φ ｊ , j = 1, ···, m, an unwrapping process for the phase value is performed. In step S54, a plurality of reference points a ｊ , j = 1, ···, m are set at common coordinate points between the distributions. The m object lights obtained by recording and reproducing the same measurement target surface m times are at the position z = z of the object ｉ , i = 1, ···, k. ＯWhen synthesizing, it is necessary to match the global inclination of each measurement surface and match the optical phase of the reference points common to each object light. If at least three points (n = 3) of reference points are set, a plane can be set. When the number of reference points is more than 3, a virtual surface including each reference point a ｉ is set. The virtual surfaces set for each phase value distribution φ ｊ are superposed on each other to perform averaging processing of the phase values. For each of the plurality of reference points a ｉ , i = 1, ···, k, the phase value is preferably the average value of the phase values of a plurality of points (N points) in the vicinity of each reference point a ｉ . The plurality of points (N points) preferably have a value larger than the number of samples m, that is, N > m. That is, the average value of the optical phases at N sampling points in the vicinity of each reference point is obtained, and this value is used as the optical phase value at each fixed point. When the number of points N and the number of sheets m satisfy N > m, this averaging process can greatly suppress the influence of noise at each reference point, eliminate the influence of random noise, and enable more reasonable and stable processing. In step S55, the reference phase value distribution φ ｊ , j = 1, ···, m selected from and other phase value distributions φ α , j ≠ α, calculate the cross-correlation regarding the phase values at the plurality of reference points a ｊ , i = 1, ···, k. ｉ In step S56, in the three-dimensional phase coordinate space, rotate and phase-adjust (phase shift) the phase value distribution φ ｊ , j ≠ α so that the calculated value of the cross-correlation is minimized, and align the global inclination between each phase value distribution. The rotation is performed by rotational transformation of the light wave distribution around the x-axis and the y-axis. This rotation makes the inclination of the virtual plane with respect to each reproduction surface coincide. In step S57, by performing averaging processing between the data of the phase value distribution φ ｊ , j = 1, ···, m after rotational alignment, a phase value distribution <φ> = Σφ ｊ / m with reduced noise can be obtained. (Other noise reduction methods) As another method for reducing shot noise, which is the main noise generated in an image sensor, a method of reducing noise by narrowing the spatial frequency bandwidth of light waves in the spatial frequency space when deriving the light wave distribution will be described. Object light hologram I ｊ ＯＲ , j = 1, ···, m to object light wave g ｊ , j = 1, ···, m, perform band-pass filtering processing in the spatial frequency space to narrow the band of the spatial frequency used for reproducing the object light wave. This can reduce the noise contained in the reproduced light wave. This method can enhance the effect by combining it with the noise reduction method based on the statistical method of synthesizing and averaging a plurality of the above-described object light waves. Here, let the number of holograms used for synthesis be m. Also, using the expression that the bandwidth of the spatial frequency filter is reduced to 1 / n times (reduction ratio 1 / n), the degree of narrowing the band is represented by the index n. For such (m, n), the amplitude of random noise is (m × n ２ ) －１／２ times, and the noise amplitude decreases. Therefore, for example, if (m = 1, n = 2) or (m = 4, n = 1), the noise amplitude is reduced to 1 / 2 (see the examples described later). According to the noise reduction method of the present embodiment, since global alignment is performed by rotation and phase adjustment of a plurality of phase value distributions obtained from a plurality of samples and statistical processing based on averaging between the distributions, random noise can be effectively reduced. Also, in combination with the noise reduction method by narrowing the spatial frequency bandwidth, noise can be reduced more efficiently. (18th Embodiment: Imaging Device with Aperture) The imaging device 1 according to the 18th embodiment of the present invention is an imaging device by holography that images an object 4 so that light waves can be reproduced, and includes an illumination light source S that emits illumination light Q Ｑ and a reference light source S that emits reference light R that generates interference fringes with object light O radiated from an object illuminated by the illumination light Q Ｒ and an object light hologram I for data of the interference fringesＯＲ An apparatus comprising an imaging device 5 acquired as such, and an aperture Ap that restricts the azimuthal angle distribution of object light O incident on the imaging device 5. The imaging device 1 can reproduce and image an image of the object 4 by any one of the phase shift method, off-axis method, in-line method, or a method combining these in holography, from the object light hologram I. ＯＲ It is a device that can reproduce and image an image of the object 4 from the object light hologram I. (19th Embodiment: Imaging Device According to the Present Application, Device Manufactured Using the Method) The device according to the 19th embodiment of the present invention is a device manufactured using at least one of the above-described imaging device 1, reference light data acquisition method, and light wave reproduction method. The present invention includes a program used by the imaging device, reference light data acquisition method, and light wave reproduction method according to the present application described above, an electronic medium recording the program, and a device that executes the program. Further, the present invention includes a configuration in which the imaging device, reference light data acquisition method, and light wave reproduction method according to the present application described above are connected by a wired connection, wireless connection, proximity integration configuration, or remote connection to form a system. (Example 1: Reference Light Data Acquisition Method, Reference Light Hologram) With reference to FIGS. 26 and 3(a)(b), an example of the reference light data acquisition method will be described. FIG. 26 shows a partially enlarged image of a hologram I of interference fringes of the reference light R and the auxiliary light L recorded using the optical system of FIG. 3(b). ＲＬ shows a partially enlarged image of. The angle between the cube beam splitter 3 and the imaging device 5 was adjusted by the optical system of FIG. 3(a), and the interference fringes I formed by the auxiliary light L and the reference light R were recorded, that is, imaged, by the optical system of FIG. 3(b). This imaging is for acquiring data of the reference light R and records the reference light R using the auxiliary light L. ＲＬ is recorded, that is, imaged. This imaging is for acquiring data of the reference light R and records the reference light R using the auxiliary light L. The auxiliary light L is a vertically incident parallel light, and the reference light R is a spherical wave light. A red semiconductor laser (light wavelength 638 nm, output 40 mW) was used as the laser light source. The auxiliary light L was a parallel light obtained by expanding the beam system of the spherical wave light emitted from the end of the optical fiber using an appropriate optical element. The reference light R was a spherical wave light emitted from the end of the optical fiber as an off-axis reference light. The imaging element 5 for hologram recording was a monochrome CMOS camera with a pixel count of 4096 x 4096 and a pixel pitch of 6.4 μm. In the optical system of FIG. 3B, a fiber end is disposed at a position about 90 mm in front of the image sensor 5, and a reference light source S Ｒ The interference fringes created by the auxiliary light L and the reference light R are called the reference light hologram I ＲＬ FIG. 26 is a partially enlarged view of the recorded interference fringe hologram. Concentric Newton's rings can be seen, and the reference light focusing point P Ｒ The three coordinates (x Ｒ , y Ｒ , z Ｒ ) of two coordinates (x Ｒ , y Ｒ ) are the x and y coordinates of the center point of Newton's ring. In the optical system of this embodiment, the numerical aperture NA of the hologram with 4096×4096 pixels is 0.131, the theoretical resolution δ determined by the light wavelength and the numerical aperture NA is 2.43 μm, and the focal depth is 18.5 μm. In such an optical system, the phase information of the reference light R, which is spherical wave light, is stored as a reference light hologram I as a large amount of accurate hologram data. ＲＬ will be recorded. Recorded reference beam hologram I ＲＬ The reference light data RD was obtained by performing a predetermined process on the hologram I. ＲＬ The nearby spherical wave R １ The recorded spherical wave-like light R component is moved to a low frequency range by dividing it by the phase component of the reference light R, and then spatial frequency filtering is performed to extract the reference light R component. １The reference light data RD was obtained by multiplying the phase component. Specifically, the reference light data RD is the light wave information of the reference light R and is the data of the phase distribution of the reference light R on the hologram plane z = 0. Using the obtained reference light data RD, the light wave propagation calculation of the reference light R was performed, and the position coordinates of the reference light focus point P Ｒ which is the focus point of the reference light R were calculated. By using the light wave propagation calculation, the coordinates (x Ｒ of the reference light focus point P Ｒ , y Ｒ ) could be obtained with an accuracy of 1 / 10 or less of the resolution δ, and the z coordinate (z Ｒ ) could be obtained with an accuracy of 1 / 10 or less of the depth of focus. (Example 2: Imaging device, imaging and reproduction of USAF target) Referring to FIG. 27, an embodiment of the imaging device will be described. FIG. 27 is an intensity image of the object light at the position of the USAF target reproduced from the hologram I ＯＲ obtained by imaging and recording the transmitted light of the USAF target as the object light using the imaging device 1 of FIG. 7. The imaging device 1 is an optical system in which the cube beam splitter 3 is removed from the optical system shown in FIG. 3(b). The reference light data RD in the optical system of this imaging device has already been acquired by the optical systems of FIGS. 3(a) and 3(b). A USAF test target was placed as the object 4 to be imaged at a position about 90 mm in front of the imaging element 5 using a CMOS camera, and the interference fringes formed by the object light O which is the transmitted light of the object 4 and the reference light R were recorded as the off-axis object light hologram I ＯＲ . For the recorded object light hologram I ＯＲ , a predetermined process was performed to reproduce the object light on the target surface. That is, from the hologram I ＯＲ , the complex amplitude object light hologram J ＯＲ was extracted through spatial frequency filtering, and using the reference light data RD, the complex amplitude object light hologram J ＯＲThe phase component of the reference light R was subtracted from the phase distribution to obtain the light wave g of the object light O. Light wave propagation calculation was performed on the obtained light wave g to propagate the light wave g to the target surface position to reproduce the object light, and the light intensity image of FIG. 27 was obtained. In reproducing the object light, by the processes of steps S11 to S15 in FIG. 12, the object light hologram J ＯＲ was processed to obtain a pixel-increased object light wave g with an increased number of pixels. In order to perform accurate light wave propagation calculation, it is necessary to set the sampling interval to a theoretical resolution δ = 2.43 μm or less. Therefore, the sampling interval in the light wave propagation calculation was set to 1 / 4 of the pixel pitch p = 6.4 μm. This corresponds to the case where m in FIG. 15 is m = 4. Thereafter, using plane wave expansion, the pixel-increased object light wave g was propagated to the object position to obtain the object light wave h at the object position. In this case, the light wave propagation calculation was performed with n in FIG. 16 being n = 1. A light intensity image was obtained from the reproduced object light wave h, and the following could be confirmed. (1) The focus is in place over the entire target. (2) The square overwritten in the center of the left image and the outline of the image pattern within the square match, resulting in a distortion-free reproduced image. (3) The actually measured dimension of 556.8 μm of the upper side pattern of the left image matches the known target pattern dimension. (4) Inside the right image cut out and enlarged from the center of the left image, the pattern surrounded by the horizontal rectangle shows a pattern close to the resolvable limit. The known line width of 2.46 μm of these patterns is almost equal to the theoretical resolution of 2.43 μm. The above-confirmed facts indicate that the recording and reproduction of the object light were accurately performed by both the imaging device 1 having the configuration of FIG. 7 used for imaging and the reference light data RD used for reproduction. In particular, the excellent result of object light reproduction supports the fact that the reference light data measurement method in the present technology can accurately acquire the reference light data RD including the reference light wave information RI and the reference light focus point information PI. (Example 3: Recording and reproduction of a large USAF test target) Referring to FIGS. 28, 29, 30, and 18, an embodiment of the imaging device will be described. FIG. 28 is an image of hologram I obtained by imaging the transmitted light of a large USAF target as object light using the imaging device of FIG. 18. ＯＲ FIG. 29 is an image of the spatial frequency spectrum of hologram I of FIG. 28. ＯＲ FIG. 30 is an image of the light intensity of the object light at the position of the large USAF target reproduced from hologram I of FIG. 29. ＯＲ Using the optical system of the imaging device shown in FIG. 18, interference fringes I formed by the reference light R of an off-axis spherical wave and the object light O were recorded. A red semiconductor laser (light wavelength λ = 643 nm, output 40 mW) was used as the laser light source. As the illumination light Q and the reference light R, spherical light waves radiated with the end of an optical fiber connected to the laser light source as the light source were used. ＯＲ For the image sensor 5 for hologram recording, an interference fringe with a pixel number of 2048×2048 was recorded using a monochrome CMOS camera with a pixel number of 4096×4096 and a pixel pitch of 6.4 μm. At a position about 100 mm in front of the image sensor 5, a circular aperture Ap with a diameter of 5 mm and the end of the optical fiber that is the light source of the off-axis reference light R were arranged. As the object 4, a large USAF test target was placed at a position about 600 mm from the circular aperture Ap, and the object 4 was illuminated so as to be transmitted by the illumination light Q condensed by the lens 24. The numerical aperture NA of the recorded hologram I as seen from the position of the aperture Ap ＯＲ is calculated to be NA = 0.0655. The theoretical resolution δ is δ = 4.91 μm, which is calculated from the light wavelength λ and the numerical aperture NA. Also, the numerical aperture NAa of the circular aperture Ap as seen from the test target position is calculated to be NAa = 0.0042. The theoretical resolution δa in this case is δa = 94.1 μm, which is calculated from the light wavelength λ and the numerical aperture NAa. FIGS. 28 and 29 are respectively of the recorded interference fringes I with a pixel number of 2048×2048. ＯＲIt is an image of the spatial frequency spectrum G. The outer circular broken line 81 in FIG. 29 indicates the position of the diffracted light component generated at the opening edge (edge) of the circular aperture Ap. The inner circular broken line 82 indicates the region containing the object light component. Circular spatial frequency filtering was performed to extract only the data inside this circular broken line 82. As a result, the low-frequency component, the conjugate component, and the diffracted light component generated at the aperture edge can be removed from the recorded hologram, and the complex amplitude object light hologram J ＯＲ containing only the object light that has passed through the aperture Ap was extracted. Next, among the phase components of the extracted complex amplitude object light hologram J ＯＲ the phase component of the reference light R was subtracted to obtain the object light for light wave reproduction. The phase component of the reference light R is obtained from the reference light data RD acquired in advance. FIG. 30 shows an image of a large USAF test target reproduced by propagating the object light wave to the position of the object 4 by light wave propagation calculation and reproducing it at the position of the object 4. In order to perform accurate light wave propagation calculation, it is necessary to set the sampling interval to the theoretical resolution δ = 4.91 μm or less. Therefore, the sampling interval in the light wave propagation calculation was set to 1 / 2 of the pixel pitch p = 6.4 μm. This corresponds to the case where m = 2 in FIG. 15. Also, since the size of the hologram is 13.1 mm and the size of the test target is 76.2 mm, it is necessary to reproduce an image approximately 6 times larger. Therefore, light propagation calculation was performed using a calculation region with a vertical × horizontal size 16 × 16 times larger and a pixel number of 32768 × 32768 than the hologram pixel number. This corresponds to the case where n = 8 in FIG. 16. Therefore, m × n = 2 × 8 = 16 times. From the reproduced light intensity image shown in FIG. 30, the following could be confirmed. (1) The entire target is in focus. (2) The large square overwritten with a broken line in the center of the left image and the outlines of each pattern close to the square inside are in contact and match, resulting in a distortion-free reproduced image. (3) The dimension of 10.0 mm of the reproduced image indicating the space between the three-pattern outer walls in the image with double arrows matches the known dimension of the USAF test target of the imaging object. (4) In the image shown on the right as the enlarged image, the image within the horizontally long rectangle formed by the solid line indicates a pattern close to the resolvable limit. The line width of this pattern, 99.2 μm, is approximately equal to the theoretical resolution δa = 94.1 μm. These facts show that the hologram recording and the reproduced image are accurately performed by a series of techniques according to the present invention, in which the light from the optical fiber end is used as the reference light R of the spherical wave, an imaging device having an aperture Ap is used to image the USAF test target, which is an object larger than the imaging element 5, and the light wave is reproduced using the reference light data RD acquired separately. (Example 4: Measurement of the optical phase aberration caused by the collimating lens) Referring to FIGS. 31 and 32, an embodiment of the imaging device will be described. FIG. 31 shows the light intensity distribution reproduced by imaging the reflected light from the plane mirror FM of the illumination light Q using the imaging device 1 of FIG. 21, that is, by arranging the plane mirror 25 as the object 4 in the optical system of the imaging device 1 of FIG. 19. Using the light wave of the component near the axis in the central part, the focal position z of the collimating lens 25 in the 14th embodiment was determined. Ｐ was determined. FIG. 32 shows the measurement result of the light wave phase distribution generated by the collimating lens 25 with a diameter of 150 mm using the optical system of FIG. 21. The laser light source for measurement used a solid-state laser with a light wavelength of 532 nm. The phase difference distribution was obtained with reference to the center of the lens. As shown in the figure, it has an axisymmetric phase difference distribution. In the optical system as shown in FIG. 21, it is not very difficult to make the spherical wave Q emitted from the illumination light source S an ideal spherical wave by the current technology. However, it is difficult to create an ideal collimating lens 25 with a large diameter. Ｑ from becoming an ideal spherical wave. However, it is difficult to create an ideal collimating lens 25 with a large diameter. If the collimating lens 25 were a perfectly ideal lens, the phase difference distribution in Fig. 32 would be a distribution of the same phase difference on the front surface of the field of view, resulting in a uniform figure without an annular pattern or the like. The measurement results reflect the imperfection of the collimating lens 25. In the central part, the change in phase aberration is small, and as it approaches the periphery, the change in phase aberration becomes large and dense. (Example 5: Measurement of Wafer Flatness) Referring to Fig. 33, an embodiment of the imaging device will be described. Fig. 33 shows the result of measuring the flatness of a 4-inch Si wafer using the optical system of the imaging device in Fig. 19. The height distribution of the measurement surface is indicated by the phase difference distribution of light waves. As the laser light source for measurement, a semiconductor laser with a light wavelength of 643 nm was used. This measurement result is a phase difference image between the reproduced illumination light and the reproduced reflected light. It corresponds to the formula (9), t(x, y, z Ｏ ) representing the height distribution in the 13th embodiment. The phase difference image in Fig. 33 shows that the surface is curved, and it can be seen that the PV (peak to valley) value regarding height is about 10λ. Also, a height change of about λ / 2 can be confirmed at the peripheral part of the Si wafer. (Example 6: Measurement of Baked Wafer Surface Shape) Referring to Figs. 34 and 35, an embodiment of surface shape measurement will be described. Fig. 34 is an intensity image of the wafer surface obtained by imaging a hologram with a semiconductor laser beam having a light wavelength of 643 nm using the imaging device 1 in Fig. 19. The wafer surface is the surface of a 4-inch Si wafer that has been pattern-baked by resist exposure. The intensity image is created by reproducing light waves from the hologram and calculating the influence of the wavefront aberration by the collimating lens 25 on the light waves. Fig. 35 shows the measurement result of the phase difference distribution calculated from the phase distributions of the reproduced illumination light and the reproduced reflected light on the wafer surface, obtained from the light waves from which the intensity image in Fig. 34 was obtained. It can be seen from the light intensity image and its partial enlarged image that the baked pattern on the wafer is reproduced with high resolution. Also, from the phase difference image, it can be confirmed that the wafer surface is curved by about 10λ. In addition, apart from the results shown in FIGS. 34 and 35, as a result of performing surface shape measurement using two laser lights with different wavelengths, it has been found that the thickness of the baked pattern is about 7 μm. (Example 7: Object Photosynthesis and Noise Reduction) Referring to FIGS. 36 to 40, an example of a noise reduction method by statistical processing (m = maximum 9) and processing for narrowing the band (n = maximum 3) will be described. FIG. 36 is an example among a plurality (m = 9) of optical phase difference distributions obtained by processing a plurality of object light holograms on the surface of an optical flat (object 4) imaged while keeping the imaging conditions constant using the imaging device of FIG. 19, taking into account the wavefront aberration by the collimating lens 25. In the figure, a plurality (k = 3) of reference points a １ , a ２ , a ３ and the noise evaluation axis (white line) are shown. Object 4 uses an optical flat with a flatness specification of λ / 20 or less with respect to light with a wavelength of 633 nm. The laser light source for measurement used a semiconductor laser with a light wavelength of 785 nm. The object light (reflected light) from the optical flat was continuously recorded on the hologram (number of samples m = 9 times). Also, the frequency bandwidth of the object light was narrowed by spatial frequency filtering (reduction ratio 1 / n, n = 1, 3). The value of the resolution of the reproduced image changes inversely proportional to the spatial frequency bandwidth. In noise reduction by statistical processing, when there are three reference points a ｉ , a plane (curvature zero) is determined as the virtual surface. Therefore, rotational conversion of the light wave was performed around the x-axis and y-axis so that the integrated value of the optical phase became 0 by integrating the unwrapped optical phase distribution on the line connecting each fixed point. By this rotation, after making the inclination of the virtual plane with respect to each reproduced surface coincide, averaging processing was performed to reduce the noise. In this embodiment, the distribution of errors due to noise was evaluated by the distribution of optical phase differences. Here, the distribution of optical phase differences is the distribution of the phase differences between two reconstructed object lights or the distribution of the phase differences between two synthesized object lights. FIGS. 37 to 40 show the height error Δt (nm) generated due to noise on the noise evaluation axis (white line) shown in FIG. 36. The deviation δ of the error decreases as the parameters m and n increase, indicating that both object light wave synthesis (statistical noise processing) and spatial frequency filtering (noise processing by frequency band reduction) are effective in reducing noise. As the novelty and superiority of the imaging device, reference light data acquisition method, and light wave reproduction method of the present invention with respect to conventional digital holography, the following points can be particularly mentioned. (1) An imaging device including pre-acquired reference light data necessary for reproducing a light wave from an imaged object light hologram can realize a simple and miniaturizable imaging device in which a reference light source, an imaging element, and reference light data are integrated. (2) The imaging device of (1) above incorporates a reference light source and an imaging element, and includes a dark box having an aperture that restricts the azimuthal angle distribution of the object light, so that it is portable and has excellent operability, and can be used in the same way as a camera. (3) The reference light data acquisition method using auxiliary light that can be analytically expressed can acquire definite reference light data without ambiguity, and the configuration of the reference light source and the imaging element for implementing this acquisition method can be used in the imaging device. (4) The reference light data acquisition method of (3) above can acquire reference light data when assembling the imaging device or after the start of use of the imaging device. (5) The light wave reproduction method that reproduces an object light wave without using approximate calculation or iterative calculation from a hologram acquired by an optical system in which the object light does not include an optical element that causes aberrations such as a lens can accurately reproduce a light wave without distortion or ambiguity. (6) An imaging device that includes an aperture that restricts the azimuthal angle distribution of the object light and images the object so that the light wave can be reproduced can be imaged by a reference light source and an aperture whose positions are fixed with respect to the imaging element regardless of the distance from the imaging device. Therefore, the present invention can be applied to a wide range of uses that take advantage of these advantages in the fields of optics, digital holography, optical measurement, interferometry, and fine shape measurement. From the perspective of technological applications, it can be widely applied to uses in fields such as indoor, outdoor, and space, including precision measurement, nanotechnology, substrate shape measurement, semiconductor substrate inspection, optical component inspection, environmental monitoring, defense, and crime prevention. Devices and methods using a wavefront conversion element such as a collimating lens can be widely applied to uses such as flatness and surface shape measurement, detection of scratches, impurities, dust, etc. of various large-area semiconductor substrates, liquid crystal substrates, photomasks, high-precision machined parts, optical components, etc., and can be applied to the incorporation of measurement and detection devices into the manufacturing line. In addition, for example, it can be applied to uses for inspecting the situation in time series when bonding substrates. In addition, for example, it can be applied to uses for inspecting the polishing situation on the surface of polished metal or the like. In addition, it can also be applied to an object that does not transmit at least a part of light. 1 Imaging device 2 Optical system 21, 22 Optical fibers 25 Collimating lens, convex lens 26 Parabolic concave mirror 3 Beam splitter (BS) 4 Object (imaging target) 5 Image sensor 50 Light receiving surface (hologram surface) 6 Dark box (housing) 7 Computer 71 Arithmetic processing unit 71a High-frequency component processing unit 9 Coherent light source 9a Mask 9b Pinhole 10 Control unit 11 Storage unit 12 Object light reproduction unit 12a Diffracted light component removal unit 13 Noise processing unit 13a Imaging processing unit 13b Statistical processing unit A, A(z, y, z Ｍ ) Phase aberration distribution function Ap Aperture E ｃｏｌｌ Collimating element E Ｘ Wavefront conversion element FM Plane mirror F Ｐ Focus G Spectrum G ＥＸ Expanded spectrum G ０ Zero-value space I ＣＲ Measurement light hologram I ＯＲ Object light hologram I ＲＬ , I ＬＲ Reference light hologram I ＬＲ３ Medium light hologram I ＲＲ３ Reference light hologram J ＯＲ Complex amplitude object light hologram J ＲＲ１ Complex amplitude reference light hologram J ＲＲ２ In-line complex amplitude reference light hologram K ＯＲ２ Pixel-increased complex amplitude object light hologram L Auxiliary light Lc Measurement light LD Auxiliary light data M Mirror N Number of samples from near the reference point O Object light P Ｑ Illumination light focus point P Ｒ Reference light focus point PA Parameter PI Focus point information P １ Near contact point light source Q Illumination light R reference light R １ Proximity spherical wave light R ２ Inline reference light (spherical wave light) R ３ Medium light (off-axis reference light) RD reference light data RI reference light wave information (phase distribution) S Ｑ Illumination light source S Ｒ Reference light source T, T(z Ｅ ), Phase conversion function WD wavefront correction data b Ｐ Ideal parallel light wave b ＰＡ Ideal parallel light wave affected by aberration b Ｓ Ideal spherical light wave c Ｓ Measured light wave (spherical wave state) g object light wave, pixel-increased object light wave g ＥＸ Magnified object light wave g Ｒ Reference light wave g ０ Zero-value space h object light wave m number of samples x Ｒ ,y Ｒ ,z Ｒ Coordinates of reference light focus point z ａ z coordinate of aperture z Ｅ Principal plane position z Ｍ Plane mirror position, data acquisition position, data application position z Ｏ Object position z Ｐ Focus position

Claims

1. In an imaging apparatus using holography, an illumination light source that emits illumination light for illuminating an object to be imaged, a reference light source that emits reference light for generating interference fringes between the object light radiated from the object illuminated by the illumination light, and an imaging element that acquires data of the interference fringes between the object light and the reference light as an object light hologram, and reference light data that is data of the reference light used when reproducing the light wave of the object light from the object light hologram. An imaging apparatus characterized by comprising:

2. The reference light data is data of reference light wave information representing the light wave of the reference light on a hologram surface that is the light receiving surface of the imaging element, or the reference light is a spherical wave, the reference light source is disposed at a reference light focus point that is the focus point of the reference light, and the reference light data is data of focus point information representing the position of the reference light focus point with respect to the imaging element. The imaging apparatus according to claim 1, characterized in that:

3. A coherent light source that emits coherent light, and an optical system that guides the light emitted from the coherent light source to the illumination light source and the reference light source. The reference light is a spherical wave, and the reference light source is disposed at a reference light focus point that becomes the focus point of the reference light. The imaging apparatus according to claim 1, characterized in that:

4. The reference light data is data of reference light wave information representing the light wave of the reference light on a hologram surface that is the light receiving surface of the imaging element, or data of focus point information representing the position of the reference light focus point with respect to the imaging element. The imaging apparatus according to claim 3, characterized in that:

5. The reference light source is an end portion of an optical fiber. The imaging apparatus according to claim 1, characterized in that:

6. The reference light source is a pinhole. The imaging apparatus according to claim 1, characterized in that:

7. A cube-shaped beam splitter through which the reference light and the object light combined with each other pass is provided in front of the imaging element. The imaging apparatus according to claim 1, characterized in that:

8. An aperture that restricts the azimuth angle distribution of the object light incident on the imaging element is provided. The imaging apparatus according to claim 1, characterized in that:

9. A dark box that houses the reference light source and the imaging element and blocks external light from outside the aperture is provided. The imaging apparatus according to claim 8, characterized in that:

10. The imaging device according to claim 8, wherein the illumination light source is configured to emit the illumination light so as to have an illumination light focusing point between the object and the imaging element.

11. The imaging device according to claim 8, wherein the illumination light source is configured such that the illumination light is incident on the imaging element.

12. The imaging device according to claim 8, wherein the illumination light source is configured such that the illumination light is not incident on the imaging element.

13. The imaging device according to any one of claims 1 to 12, further comprising an object light reproduction unit that calculates an object light wave representing the object light from the data of the object light hologram using the reference light data.

14. The imaging device according to any one of claims 8 to 12, further comprising an object light reproduction unit that calculates an object light wave representing the object light from the data of the object light hologram using the reference light data, and the object light reproduction unit includes a diffracted light component processing unit that removes a diffracted light component generated by an edge portion of the aperture from the data of the object light hologram.

15. The imaging device according to any one of claims 1 to 12, wherein the data of the object light hologram is acquired so that the object light can be reproduced by off-axis holography or phase-shift holography or in-line holography.

16. A method for acquiring reference light data including information on reference light used in holography using an imaging element, comprising: providing an auxiliary light and a medium light that are coherent with the reference light; making the auxiliary light incident perpendicularly to at least a part of the imaging element as parallel light; recording data of interference fringes between the auxiliary light and the medium light as a medium light hologram using the imaging element; recording data of interference fringes between the reference light and the medium light as a reference light hologram using the imaging element; and obtaining reference light wave data including information on the reference light based on the medium light hologram and the reference light hologram.

17. In a reference light data acquisition method for acquiring reference light data including information on reference light used in holography, data on interference fringes between the reference light and auxiliary light that is coherent with the reference light and can be analytically expressed using known parameters is recorded as a reference light hologram using an image sensor. Using the parameters, auxiliary light data obtained as an analytical expression of the auxiliary light is calculated on a hologram plane set on the light-receiving surface of the image sensor. Based on the auxiliary light data, reference light wave information including the light wave information of the reference light on the hologram plane is obtained, and the reference light data is acquired based on the reference light wave information.

18. The reference light data acquisition method according to claim 17, wherein the auxiliary light is parallel light that is incident perpendicularly to at least a part of the image sensor.

19. The reference light is a spherical wave having a reference light focus point. A light wave propagation calculation is performed to reverse the reference light wave obtained as the reference light wave information, and data on focus point information representing the position of the reference light focus point is acquired as the reference light data. The focus point information is used as the reference light data. The reference light data acquisition method according to claim 17 or 18, characterized in that.

20. The calculation of the reference light data includes performing low-frequency conversion modulation to move the spherical light wave component of the reference light hologram to the low-frequency region, performing spatial frequency filtering to extract the spherical light wave component moved to the low-frequency region by the low-frequency conversion modulation, thereby deleting components other than the spherical light wave component included in the data of the reference light hologram, performing high-frequency conversion modulation to move the spherical light wave component extracted by the spatial frequency filtering back to the original frequency region, and using the spherical light wave component obtained by the high-frequency conversion modulation as the reference light data. The reference light data acquisition method according to claim 19, characterized in that.

21. The low-frequency modulation is performed by dividing the reference light hologram by the phase component of the proximity spherical wave light emitted by a proximity point light source set at a position assumed as the position of the reference light focus point on the hologram surface, and the high-frequency modulation is performed by multiplying the complex amplitude reference light hologram obtained by the spatial frequency filtering by the phase component. The reference light data acquisition method according to claim 20, characterized in that.

22. The proximity point light source of the proximity spherical wave light is set based on the calculation of the correlation function between the proximity spherical wave light and the reference light hologram. The reference light data acquisition method according to claim 21, characterized in that.

23. In a light wave reproduction method for reproducing a light wave of object light from an object light hologram, the object light hologram is a hologram recorded by an off-axis method, and the data of the reference light used for recording the object light emitted by an object to be imaged is obtained by an imaging device provided as reference light data on a hologram surface which is a light receiving surface of an imaging element. The data obtained by Fourier-transforming the object light hologram is subjected to spatial frequency filtering and inverse Fourier-transforming to extract a complex amplitude object light hologram. By multiplying the complex amplitude object light hologram by a reference light phase component based on the reference light data on the hologram surface, the phase component of the reference light is removed to calculate an object light wave representing the object light. A light wave propagation calculation by plane wave expansion is performed on the object light wave to reproduce the object light wave at the position of the object. A light wave reproduction method, characterized in that.

24. The reference light is spherical wave light emitted from a reference light focus point. After extracting the complex amplitude object light hologram, the steps until calculating the object light wave include a pixel number increasing step of generating a pixel number increased complex amplitude object light hologram by increasing the number of data points in the complex amplitude object light hologram, and a reproduction step of obtaining the object light wave on the hologram plane from the pixel number increased complex amplitude object light hologram. The pixel number increasing step includes obtaining data of the phase component of the reference light and the position coordinates of the reference light focus point from the reference light data, calculating the phase component of the in-line reference light having a point light source formed by moving the reference light focus point on the optical axis of the image sensor in a plane parallel to the hologram plane, generating an in-line complex amplitude object light hologram formed by in-lining by removing the phase component of the reference light and applying the phase component of the in-line reference light to the complex amplitude object light hologram, generating a spectrum formed by Fourier-transforming the in-line complex amplitude object light hologram, expanding the calculation target space by adding a zero value space with a spectrum intensity of 0 around the spectrum obtained in the two-dimensional spatial frequency space, and using the combined spectrum of the spectrum and the zero value space as an expanded spectrum, and generating the pixel number increased complex amplitude object light hologram by performing inverse Fourier transform on the expanded spectrum. The reproduction step includes a step of multiplying the pixel number increased complex amplitude object light hologram by the phase component of the in-line reference light to remove the phase component of the in-line reference light and calculate the object light wave representing the object light. The light wave reproduction method according to claim 23, characterized in that.

25. The reference light is spherical wave light emitted from a reference light focus point. The propagation reproduction step of calculating the object light wave at the position of the object from the object light wave on the hologram plane includes expanding the calculation target space by adding a zero value space with a light intensity of 0 around the object light wave, and using the combined expanded object light wave of the object light wave and the zero value space, and after performing plane wave expansion on the expanded object light wave, performing light wave propagation calculation to reproduce the object light wave at the position of the object. The light wave reproduction method according to claim 23, characterized in that.

26. In removing the diffracted light component due to the aperture recorded in the object light hologram together with the object light that has passed through the aperture of the imaging device, an image focused on the edge of the aperture is generated, and the diffracted light image component is removed from the image, thereby obtaining an object light wave representing the object light in a state not including the diffracted light component. The light wave reproduction method according to any one of claims 23 to 25, characterized in that.

27. In the imaging device according to claim 1, the imaging device includes a wavefront conversion element disposed on the optical path from the object to the imaging element to cause a predetermined deformation in the wavefront of the object light, and when reproducing the light wave of the object light from the object light hologram, wavefront aberration data including information on the wavefront conversion element, which is used to remove the influence of aberration by the wavefront conversion element and reproduce a desired object light wave. The imaging device according to claim 1, characterized in that.

28. The wavefront conversion element is a collimating element having a focus that converts spherical light waves into parallel light waves and also converts parallel light waves into spherical light waves. The focus is disposed between the collimating element and the imaging element. The illumination light source is a light source that emits the illumination light as spherical light waves and is disposed off-axis near the focus of the collimating element or at the position of the focus. The imaging device is configured such that the object to be imaged is illuminated by the illumination light that has become parallel light through the collimating element, and the object light radiated from the object travels backward through the collimating element, becomes object light, and enters the imaging element, and is acquired as the object light hologram. When reproducing the light wave of the object light from the object light hologram, the imaging device includes a wavefront correction unit that performs a process of removing the influence of the aberration of the collimating element using the wavefront aberration data. The imaging device according to claim 27, characterized in that.

29. The collimating element includes a convex lens or a parabolic concave mirror, and the parabolic concave mirror includes a reflecting mirror on the optical path connecting the parabolic concave mirror and the focus. The imaging device according to claim 28, characterized in that.

30. In the method for measuring the surface shape of an object using the object light hologram recorded by the imaging device according to claim 28, a coordinate system with the origin and the z-axis set on the light-receiving surface of the image sensor and the optical axis, the wavefront aberration data is information of the collimating element, the focal position which is the position of the focus, the principal plane position defined as the switching boundary plane between the spherical wave and the plane wave, and the information of the data application position which is the position for obtaining data and becomes the post-processing position, and further information of the phase aberration distribution function which is the measured value of the wavefront aberration generated in the phase distribution of the light wave passing through the collimating element, the wavefront correction unit removes the component of the reference light from the object light hologram using the reference light data, thereby calculating the object light wave which is the light wave of the object light on the hologram surface which is the light-receiving surface, in order to propagate the object light wave to the position of the object, first it is propagated by light wave propagation calculation to the principal plane position, in order to remove the phase component related to the analytically calculated spherical wave from the object light wave, it is multiplied by the phase conversion function to be parallel light, the object light wave made parallel light at the principal plane position is divided by the phase aberration distribution function to be the object light wave at the data application position passed through the collimating element, light wave propagation calculation is performed on the object light wave at the data application position to calculate the light wave of the object light at the position of the object, in order to obtain the light wave of the illumination light at the position of the object, the ideal spherical light wave analytically set as the spherical light wave of the illumination light at the principal plane position is multiplied by the phase conversion function and the wavefront aberration distribution function to generate a parallel light wave which is the illumination light wave at the data application position, light wave propagation calculation is performed on the illumination light wave to generate the parallel light wave of the illumination light at the position of the object, from the phase difference distribution obtained from the phase distribution in the light wave of the object light and the phase distribution in the parallel light wave of the illumination light, a height distribution which is the measurement result with respect to a predetermined reference point set on the surface to be measured of the object is obtained.

31. In a wavefront aberration data acquisition method for acquiring the wavefront aberration data according to claim 27, the wavefront conversion element is a collimating element having a focus that converts spherical light into parallel light and also converts parallel light into spherical light. The wavefront aberration data is information of the collimating element, including the focal position which is the position of the focus, the principal plane position defined as the switching boundary plane between the spherical wave and the plane wave, and the information of the data application position which is the data acquisition position and becomes the post-processing position. Further, it includes the information of the phase aberration distribution function which is the measured value of the wavefront aberration generated in the phase distribution of the light wave passing through the collimating element. The wavefront aberration data acquisition method comprises the following steps: Incident the illumination light emitted as spherical light from the illumination light source arranged off-axis near the focus of the collimating element or at the position which is the focus position of the collimating element into the collimating element to generate parallel light. Reflect and reverse the parallel light by a plane mirror arranged at the data acquisition position which is a position close to the collimating element, and incident the parallel light as measurement light with an outer diameter smaller than the outer diameter of the parallel light into the image sensor through the collimating element, and record the data of the interference fringes between the measurement light and the reference light as a measurement light hologram. Use the reference light data to reproduce the measurement light wave which is the light wave of the measurement light from the measurement light hologram. Replace the plane mirror with an object having a plane pattern with known dimensions, and illuminate the object with the parallel light generated by incident the illumination light into the collimating element. Reverse the object light which is the reflected light from the object through the collimating element and incident it into the image sensor, and record the data of the interference fringes between the object light and the reference light as an object light hologram. Use the reference light data to reproduce the object light wave which is the light wave of the object light from the object light hologram, perform optical propagation calculation on the object light wave, and determine the position where the read value of the dimension of the plane pattern obtained at a plurality of propagation positions is the known dimension as the principal plane position of the collimating element. Calculate the ideal spherical light wave at the principal plane position based on the data of the known focal position of the collimating element, and multiply the ideal spherical light wave by a phase conversion function for removing the phase component related to the analytically calculated spherical wave to generate an ideal parallel light wave.Taking the phase aberration distribution function acquired at the data acquisition position due to the imperfection of the collimating element as an unknown function, multiplying it by the ideal parallel light wave, the mathematical expression of the plane wave incident on and reflected by the plane mirror is taken as the reflected light wave. Multiplying the reflected light wave by the inverse phase conversion function of the phase conversion function and further multiplying by the phase aberration distribution function, a mathematical expression corresponding to the light wave at the principal plane position of the measurement light wave recorded as the measurement optical hologram after traveling back through the collimating element is generated. Equating the measurement light wave propagated to the principal plane position by optical propagation calculation with the measurement light wave to the mathematical expression, the phase aberration distribution function taken as the unknown function is obtained.

32. The imaging device according to claim 1, further comprising a noise processing unit that reduces image noise by statistically calculating and processing the data of a plurality of the object light holograms acquired using the image sensor under predetermined imaging conditions.

33. In a noise reduction method for reducing image noise by calculating and processing data of the object light hologram obtained using the imaging device according to claim 1 by a statistical method, the acquisition of the object light hologram by the imaging device is repeated under predetermined imaging conditions to obtain a plurality of object light holograms, using the reference light data, the component of the reference light is removed from the object light hologram to reproduce the light wave of the object light, and the phase value distribution at the position of the object is calculated, for each of the phase value distributions, an unwrapping process regarding the phase value is performed, a plurality of reference points are set at common coordinate points among the distributions in each of the phase value distributions, a global alignment is performed by rotating and phase-adjusting the light wave in the three-dimensional real space so that the calculated value of the cross-correlation regarding the phase value at the plurality of reference points becomes minimum between the reference phase value distribution selected from the phase value distribution and another phase value distribution, and an averaging process is performed between the data of the phase value distributions after the alignment to obtain a phase value distribution with reduced noise.

34. The noise reduction method according to claim 33, wherein the phase value at each of the plurality of reference points used for the calculation of the cross-correlation is the average value of the phase values of a plurality of points in the vicinity of each of the reference points, and the plurality of points is larger than the number of samples of the object light hologram.

35. In the imaging device according to claim 1, when reproducing the light wave of the object light from the object light hologram, a band-pass filtering process is performed in the spatial frequency space to narrow the band of the spatial frequency of the light wave of the object light.

36. An imaging device by holography for imaging an object so that the light wave can be reproduced, comprising: an illumination light source that emits illumination light; a reference light source that emits reference light for generating an interference fringe with the object light radiated from the object illuminated by the illumination light; an imaging device that acquires data of the interference fringe as an object light hologram; and an aperture that restricts the azimuth angle distribution of the object light incident on the imaging device.

37. The imaging device according to claim 36, wherein the light wave of the object is reproducibly imaged from the object light hologram by any one of a phase shift method, an off-axis method, an in-line method, or a method combining these in the holography.

38. An apparatus manufactured using at least one of the imaging device according to any one of claims 1 to 15, claims 27 to 29, and claim 32, the reference light data acquisition method according to any one of claims 16 to 22, the light wave reproduction method according to any one of claims 23 to 26, the surface shape measurement method according to claim 30, the wavefront aberration data acquisition method according to claim 31, the noise reduction method according to claims 33 to 35, and the imaging device according to claim 36 or 37.

Images