Processing device for optical device, optical device, optical object information acquisition method, and optical object information acquisition program

Abstract

To provide a processing device of an optical device capable of acquiring information related to an object, for example.SOLUTION: According to an embodiment, the processing device of the optical device comprises a processor. A plurality of light reception signals of a first light receiver capable of receiving, when at least a plurality of projection light beams having spatial intensity distributions different from each other are projected toward an object, light from the object based on the plurality of projection light beams; Information on the object is acquired based on a first reconstructed image corresponding to a plurality of light reception signals of the first light receiver and a second reconstructed image corresponding to a plurality of light reception signals of the second light receiver, the first and second reconstructed images being obtained by performing imaging processing using a plurality of light reception signals of the second light receiver capable of receiving light from the object based on the plurality of projection light beams.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a processing device for an optical device, an optical device, an optical object information acquisition method, and an optical object information acquisition program. [Background technology]

[0002] Methods for acquiring (estimating) information about objects, such as their shape, are becoming increasingly important. In optically acquiring information about such objects, the BRDF (Bidirectional Reflectance Distribution Function), which represents the light intensity in each reflection direction, as well as the angular and spatial distributions of transmitted and reflected light from a light source, play an important role. For example, methods for measuring BRDF include measuring the intensity of reflected light from an object while spatially scanning a photodetector, and spatially arranging multiple photodetectors. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5624714 [Patent Document 2] Patent No. 6109357 Summary of the Invention [Problem to be solved by the invention]

[0004] The problem that the present invention aims to solve is to provide a processing device for an optical device (optical object information acquisition device) capable of acquiring information related to an object, an optical device, an optical object information acquisition method (optical measurement method), and an optical object information acquisition program (optical measurement program). [Means for solving the problem]

[0005] According to an embodiment, a processing device of an optical device includes a processor that, when a plurality of projection lights having different spatial intensity distributions are projected toward an object, performs imaging processing using a plurality of light reception signals from a first light receiver that can receive light from the object based on the plurality of projection lights and a plurality of light reception signals from a second light receiver that has a spatial arrangement different from that of the first light receiver and can receive light from the object based on the plurality of projection lights, and acquires information about the object based on a first reconstructed image corresponding to the plurality of light reception signals from the first light receiver and a second reconstructed image corresponding to the plurality of light reception signals from the second light receiver. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram showing an optical device according to a first embodiment. [Figure 2] A diagram showing the sample in Figure 1. [Figure 3] FIG. 1 is a diagram showing an example of the configuration of single pixel imaging (ghost imaging) as an optical system and processing device for performing general single pixel imaging processing. [Figure 4] FIG. 2 is a schematic block diagram of a processing device of the optical device according to the first embodiment. [Figure 5] FIG. 3 is a diagram showing a processing flow for acquiring object information using the optical device according to the first embodiment. [Figure 6] 1. Images captured by the cameras at positions A, B, and C when ordinary cameras are placed at positions A, B, and C of the optical device according to the first embodiment and white light is irradiated onto the sample from appropriate positions. [Figure 7] A light receiving unit is placed at positions A, B, and C of the optical device according to the first embodiment, and a reconstructed image at positions A, B, and C is obtained using the received light signals at positions A, B, and C when patterned light is irradiated onto a sample from an appropriate position. [Figure 8] FIG. 10 is a schematic diagram showing an optical device according to a modified example of the first embodiment. [Figure 9] 10 is a schematic diagram showing an optical device according to a second embodiment and a flow for acquiring information about an object using the optical device. [Figure 10]10 is a schematic diagram showing an optical device according to a second embodiment and illustrating a flow for acquiring information about an object using a sample in a state different from that in FIG. 9. [Figure 11] 10 is a schematic diagram showing an optical device according to a third embodiment and a flow for acquiring information about an object using the optical device. [Figure 12] 12 is a schematic diagram showing the spatial distribution of the BRDF of a sample when using the optical setup shown in FIG. 11. [Figure 13] 13 is a schematic diagram showing the spatial distribution of the BRDF of a sample different from the sample shown in FIG. 12 when using the optical device shown in FIG. 11 . DETAILED DESCRIPTION OF THE INVENTION

[0007] An optical device (optical object information acquisition device) 10 according to this embodiment will be described below with reference to the drawings.

[0008] The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc. are not necessarily the same as those in reality. Furthermore, even when the same part is shown, the dimensions and ratios may be different depending on the drawing. Detailed explanations of the content already mentioned will be omitted as appropriate.

[0009] In this embodiment, light is defined as electromagnetic waves. Examples of light include visible light, X-rays, ultraviolet light, infrared light, near-infrared light, far-infrared light, and microwaves. The light source 22, which will be described later, may emit any of visible light, ultraviolet light, and infrared light. Visible light is light having a wavelength of, for example, 420 nm or more and 760 nm or less.

[0010] (First embodiment) An optical device 10 according to a first embodiment will be described with reference to FIGS.

[0011] Fig. 1 is a schematic diagram of an optical device 10 according to a first embodiment. Fig. 2 is a diagram showing a sample 100 in Fig. 1.

[0012] As shown in FIG. 1, an optical device 10 sets up a substantially hemispherical space. A sample 100 shown in FIG. 2 is placed in an appropriate orientation at the center of the substantially hemispherical space shown in FIG. 1. The sample 100 used here is assumed to be paper. The paper used here is, for example, high-quality paper used in copiers, but any suitable paper is acceptable, such as coated paper, matte paper, or kraft paper. A line resembling, for example, the number "7" is drawn in black ink on the paper (white paper) of the sample 100. In general, the BRDF of paper can be treated as being almost isotropic in all directions.

[0013] The optical device 10 sets three different positions A, B, and C that are spaced apart from one another in the substantially hemispherical space shown in Fig. 1. The three positions A, B, and C are set in different directions from the center of the substantially hemispherical space (the position where the sample 100 is placed). Note that the positions A, B, and C may be placed at the same distance from the center of the substantially hemispherical space, but here they are placed at different distances from one another.

[0014] As shown in FIG. 1, the optical device 10 includes an optical system 12 and a processing device 14 .

[0015] The optical system 12 has a light source 22, a first light receiving unit 24, a second light receiving unit 26, and a third light receiving unit 28. The light source 22, the first light receiving unit 24, the second light receiving unit 26, and the third light receiving unit 28 are controlled by the processing device 14 (a processor 61 described below).

[0016] The light source 22 may be, for example, a light-emitting diode (LED). Alternatively, the light source 22 may be a projector.

[0017] The light source 22 shown in FIG. 1 can emit multiple light beams (two-dimensional pattern light shown in FIG. 3) having different wavelengths in a predetermined direction and project at least multiple projection light beams having different spatial intensity distributions toward an object. In this embodiment, the light source 22 can emit light beams having at least two wavelengths (e.g., a first light beam having a first wavelength W1, a second light beam having a second wavelength W2, and a third light beam having a third wavelength W3). In one example, the first wavelength W1 is, for example, 450 nm (blue light), the second wavelength W2 is, for example, 650 nm (red light), and the third wavelength W3 is, for example, 550 nm (green light). In this embodiment, the light source 22 can simultaneously project illumination light including three wavelengths (first wavelength W1, second wavelength W2, and third wavelength W3) onto the sample 100 shown in FIG. 2. The illumination light projected by the light source 22 is pattern light having a two-dimensional pattern. Here, the two-dimensional pattern of illumination light (pattern light) refers to light having an intensity distribution in which the light intensity varies depending on the position in a cross section perpendicular or substantially perpendicular to the propagation direction of the illumination light. That is, the two-dimensional pattern of illumination light has a spatial intensity distribution. The pattern light projected by the light source 22 includes at least two light beams having different wavelengths, namely, a first wavelength W1, a second wavelength W2, and a third wavelength W3, and has different patterns from each other. That is, the multiple projected light beams are at least multiple light beams having different wavelengths from each other.

[0018] The light source 22 sequentially projects, for example, two or more two-dimensional pattern light beams onto the sample 100. After projecting a first pattern light beam PR1 onto the sample 100, the light source 22 sequentially projects a second pattern light beam PR2, a third pattern light beam PR3, ..., an n-th pattern light beam PRn (n is a natural number equal to or greater than 2 and can be set appropriately) onto the sample 100. It is preferable that the first pattern light beam PR1 to the n-th pattern light beam PRn are uncorrelated with each other. Note that it is preferable that n here be equal to or greater than 2.

[0019] The light source 22 irradiates the surface of the sample 100 with two-dimensional pattern light PR1, . . . , PRn (see FIGS. 3 and 9 to 11) at an appropriate refresh rate.

[0020] Of the three positions A, B, and C shown in Fig. 1, the light receiver 24a of the first light receiving unit 24 is disposed at position A. The light receiver 26a of the second light receiving unit 26 is disposed at position B. The light receiver 28a of the third light receiving unit 28 is disposed at position C. Note that the optical element 42 shown in Fig. 3 is not shown in Fig. 1.

[0021] Fig. 3 shows an example of the configuration of ghost imaging as an optical system and a processing device 14 for performing single pixel imaging processing as imaging processing. The example shown in Fig. 3 is a conceptual diagram for explaining the concept of ghost imaging. Fig. 3 illustrates an example in which the first patterned light PR1, ..., n-th patterned light PRn (n is an integer of 2 or more) transmits through the sample 100, but in the present embodiment shown in Fig. 1, the first patterned light PR1, ..., n-th patterned light PRn are reflected from the sample 100.

[0022] 3, a light receiving section having a configuration similar to that of the light receiving sections 24, 26, and 28 shown in FIG.

[0023] The light receiving point of the light receiver 44 is located at the focal position of the optical element 42. The center of the light receiving surface of the light receiver 44 is the light receiving point, and the axis that is perpendicular to the light receiving surface and passes through the light receiving point is the light receiving axis. Light reflected from or transmitted through the sample 100 passes through the optical element 42 and is collected at the light receiving point of the light receiver 44, and is received by the light receiver 44.

[0024] Here, the photoreceiver 44 used in this embodiment is a device (single photoreceiver) that, when light of two or more wavelengths, for example, red and blue, enters, can contribute one or both of the red and blue light as a received light signal, does not have spatial resolution, and measures the light intensity in only one region, and examples of such a device include a photodetector (PD), a photomultiplier tube (PMT), an optical power meter, etc. Furthermore, even if a general image sensor (area sensor) has multiple light receiving elements internally, it can be used as a type of photoreceiver 44 as long as it does not have information about the position at the stage of processing the detection signal. Furthermore, a device that measures the light intensity in a certain region, such as a spectrometer, can also be used as a type of photoreceiver 44.

[0025] A typical spectrometer has multiple detectors arranged inside it. The spectrometer can detect light of at least two different wavelengths as detection signals. The multiple detectors of the spectrometer do not have information about their positions at the stage of signal processing by the processing device 14, so they can also be treated as one of the single-pixel photodetectors.

[0026] Similarly, examples of an image sensor (color camera) in which a large number of pixels are arranged in a predetermined array include a CMOS and a CCD. Each pixel of the image sensor can detect light of at least two different wavelengths as a detection signal. Even when the processing device 14 extracts a single pixel from the image sensor and uses the signal acquired by that single pixel for processing, the pixel can be processed as not containing information about the color filter array (Bayer array) of the image sensor. Therefore, when the processing device 14 extracts and uses a single pixel from the image sensor, the image sensor can be used as a single-pixel detector.

[0027] The photoreceiver 44 obtains signal intensities according to the patterned lights PR1, ..., PRn. Basically, the number of patterned lights PR1, ..., PRn matches the number of light-receiving signals (measurement count) at the photoreceiver 44. The processing device 14 correlates the patterned lights PR1, ..., PRn with the light-receiving signals including signal intensity information, and outputs a reconstructed image G.

[0028] The light receivers 24a, 26a, and 28a of the light receiving units 24, 26, and 28 shown in FIG. 1 are similar to the light receiver 44 shown in FIG. 3. The light receivers 24a, 26a, and 28a can receive intensity values ​​of light of multiple wavelengths from the sample (object) 100, resulting from the projection of multiple two-dimensional pattern light (projected light) PR1, ..., PRn, each including at least two different wavelengths, onto the sample (object). Therefore, the first light receiver 24a can receive light from the object based on multiple projected light beams. The second light receiver 26a has a spatial arrangement different from that of the first light receiver 24a and can receive light from the object based on multiple projected light beams. The third light receiver 28a has a spatial arrangement different from that of the first light receiver 24a and the second light receiver 26a and can receive light from the object based on multiple projected light beams. In the signal processing step, the processing device 14 causes the photoreceivers 24a, 26a, and 28a to acquire a set of detection signals for at least two different wavelengths, each of which does not have information about the position. An example of a set of detection signals is light intensity values ​​of R, G, and B. Therefore, in this embodiment, the photoreceivers 24a, 26a, and 28a can acquire a set of light intensity values ​​of R, G, and B for at least two different wavelengths as detection signals.

[0029] The optical system 12 of the optical device 10 according to this embodiment shown in FIG. 1 differs from the optical system for performing general imaging processing shown in FIG. 3 in the number of light receiving sections and the arrangement of the light receiving sections.

[0030] It should be noted that single pixel imaging as an imaging process includes ghost imaging as well as compressed sensing, etc. In this specification, when referring to "single pixel imaging," an example of ghost imaging will be mainly described, but when referring to "single pixel imaging," compressed sensing is also included in addition to ghost imaging.

[0031] 1, the position of the light-receiving point of the first light-receiver 24a at position A is defined as the radius of the hemispherical space, and the position of the light-receiving point of the second light-receiver 26a at position B is closer than the radius of the hemispherical space, and the position of the light-receiving point of the third light-receiver 28a at position C is farther than the radius of the hemispherical space. The light-receiving axes of the light-receivers 24a, 26a, and 28a at positions A, B, and C are directed toward the center of the approximately hemispherical space (the position where the sample 100 is placed).

[0032] The processing device 14 is connected to the optical system 12. As shown in Fig. 4, the processing device 14 is, for example, a computer, and includes a processor 61 (controller), a ROM (storage unit) 62, a RAM 63, an auxiliary storage device 64 (storage unit), and a communication interface 65 (communication unit).

[0033] The processor 61 corresponds to the central part of a computer that performs processes such as calculations and controls required for the processing of the processing device 14, and performs integrated control of the entire processing device 14. The processor 61 executes control to realize various functions of the processing device 14 based on programs such as system software, application software, or firmware stored in a storage unit such as the ROM 62 or the auxiliary storage device 64. The processor 61 includes, for example, a central processing unit (CPU), a micro processing unit (MPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), or a field programmable gate array (FPGA). Alternatively, the processor 61 may be a combination of two or more of these. The processing device 14 may be provided with one or more processors 61.

[0034] The ROM 62 corresponds to the main memory of a computer centered around the processor 61. The ROM 62 is a non-volatile memory used exclusively for reading data. The ROM 62 stores, for example, an optical measurement program based on the flow shown in Fig. 5. The ROM 62 also stores data or various setting values ​​used by the processor 61 when performing various processes.

[0035] The RAM 63 corresponds to the main storage device of a computer centered around the processor 61. The RAM 63 is a memory used for reading and writing data. The RAM 63 is used as a so-called work area for storing data that is temporarily used when the processor 61 performs various processes. In this embodiment, the RAM 63 temporarily stores, for example, signals output when the light source 22 sequentially emits patterned light PR1, ..., PRn, and a plurality of light reception signals sequentially received by the photoreceivers 24a, 26a, and 28a when the patterned light PR1, ..., PRn is sequentially irradiated onto the sample 100.

[0036] The auxiliary storage device 64 corresponds to an auxiliary storage device of a computer centered around the processor 61. The auxiliary storage device 64 is, for example, an EEPROM (electrically erasable programmable read-only memory) (registered trademark), an HDD (hard disk drive), or an SSD (solid state drive). The auxiliary storage device 64 may also store an optical measurement program based on the flow shown in FIG. 5 above. The auxiliary storage device 64 may also store data used by the processor 61 when performing various processes, data generated by the processes in the processor 61, various setting values, etc.

[0037] The programs stored in the ROM 62 or the auxiliary storage device 64 include a program for controlling the processing device 14. For example, an optical measurement program based on the flow shown in FIG.

[0038] The communication interface 65 is an interface for communicating with other devices via a network or the like, either wired or wirelessly, receiving various information transmitted from other devices, and transmitting various information to other devices. The processor 61 of the processing device 14 receives the multiple light receiving signals obtained by the light receivers 24a, 26a, and 28a via the communication interface 65.

[0039] The processing device 14 performs various functions by having the processor 61 execute programs stored in the ROM 62 and / or the auxiliary storage device 64. It is preferable that the control program of the processing device 14 and the optical measurement program based on the flow shown in FIG. 5 are not stored in the ROM 62 and / or the auxiliary storage device 64 of the processing device 14 but are stored on an appropriate server or cloud. In this case, the control program is executed while communicating with the processor 61 of, for example, the optical device 10 via the communication interface 65. That is, the processing device 14 according to this embodiment may be included in the optical device 10, or may be located on a server or cloud of various inspection site systems located away from the optical device 10. Therefore, it is also preferable that the optical measurement program is stored on a server or cloud rather than stored in the ROM 62 or the auxiliary storage device 64, and is executed while communicating with the processor 61 of, for example, the optical device 10 via the communication interface 65. Therefore, the processor 61 (processing device 14) can execute the optical measurement program (optical measurement algorithm) shown in FIG. 5.

[0040] The processor 61 (processing device 14) controls the timing of light emission of the light source 22, the timing of acquisition of multiple light reception signals by the light receivers 24a, 26a, 28a of the light receiving units 24, 26, 28, and the acquisition of multiple light reception signals from the light receivers 24a, 26a, 28a.

[0041] Here, as a comparative example, it is assumed that the light receivers 24a, 26a, and 28a at the positions A, B, and C are not the single light receivers described above but are ordinary cameras (cameras that use an image sensor (area sensor) that captures images using a large number of pixels). It is also assumed that the light emitted from the light source 22 toward the sample 100 is not pattern light but white light.

[0042] When sample 100 is illuminated with white light from an appropriate direction, a camera at position A obtains an image of the region indicated by the dashed line in Figure 6(a), a camera at position B obtains an image of the region indicated by the dashed line in Figure 6(b), and a camera at position C obtains an image of the region indicated by the dashed line in Figure 6(c). The images shown in Figures 6(a)-6(c) reveal that the appearance of the region indicated by the dashed line on sample 100 changes depending on the positions A, B, and C at which the camera is positioned relative to the orientation of sample 100. In other words, the images shown in Figures 6(a)-6(c) show different expansion / contraction and distortion of the shape at each of the three positions A, B, and C.

[0043] Next, the operating principle of the optical device 10 of this embodiment will be described with reference to the flow chart shown in FIG.

[0044] The processor 61 of the processing device 14 of the optical device 10 of this embodiment controls the light source 22 to illuminate the first pattern light PR1 onto the sample 100, and causes the first photoreceiver 24a, the second photoreceiver 26a, and the third photoreceiver 28a to receive the reflected light of the first pattern light PR1 from the sample 100 (step S1).

[0045] The processor 61 of the processing device 14 similarly controls the light source 22 to illuminate the sample 100 with an nth (n is an integer equal to or greater than 2) patterned light PRn, and causes the first photoreceiver 24a, the second photoreceiver 26a, and the third photoreceiver 28a to receive the reflected light of the nth patterned light PRn from the sample 100. That is, the processing device 14 sequentially irradiates the sample 100 with n patterned light beams PR1, ..., PRn at an appropriate time, for example, and causes the first photoreceiver 24a, the second photoreceiver 26a, and the third photoreceiver 28a to receive the reflected light of the patterned light beams PR1, ..., PRn from the sample 100 resulting from the illumination of the sample 100 with the respective patterned light beams PR1, ..., PRn (step S2).

[0046] At this time, the processor 61 of the processing device 14 temporarily stores the plurality of light receiving signals from the first light receiver 24a, the plurality of light receiving signals from the second light receiver 26a, and the plurality of light receiving signals from the third light receiver 28a, for example, in the RAM 63. The plurality of light receiving signals from the first light receiver 24a, the plurality of light receiving signals from the second light receiver 26a, and the plurality of light receiving signals from the third light receiver 28a may be saved in the auxiliary storage device 64.

[0047] When the processor 61 of the processing device 14 determines that the pattern light irradiated sequentially from the light source 22 has not yet illuminated the sample 100 as the nth pattern light PRn, and the first photoreceiver 24a, the second photoreceiver 26a, and the third photoreceiver 28a have not received the reflected light of the nth pattern light PRn from the sample 100 (step S2-No), the processor 61 of the processing device 14 controls the light source 22 and the first photoreceiver 24a, the second photoreceiver 26a, and the third photoreceiver 28a until the nth pattern light PRn is illuminated onto the sample 100 and the first photoreceiver 24a, the second photoreceiver 26a, and the third photoreceiver 28a receive the reflected light of the nth pattern light PRn from the sample 100.

[0048] Then, when the processor 61 of the processing device 14 illuminates the nth pattern light PRn onto the sample 100 and causes the first photoreceiver 24a, the second photoreceiver 26a, and the third photoreceiver 28a to receive the reflected light of the nth pattern light PRn from the sample 100 (step S2-Yes), the processor 61 of the processing device 14 generates reconstructed images G1, G2, and G3 corresponding to the received light signals of each photoreceiver 24a, 26a, and 28a. The processor 61 of the processing device 14 generates a first reconstructed image G1 obtained by performing imaging processing such as processing based on the principle of single pixel imaging using a plurality of (e.g., n or a number close thereto) light receiving signals from the first light receiver 24a, a second reconstructed image G2 obtained by performing imaging processing such as processing based on the principle of single pixel imaging using a plurality of (e.g., n or a number close thereto) light receiving signals from the second light receiver 26a, and a third reconstructed image G3 obtained by performing imaging processing such as processing based on the principle of single pixel imaging using a plurality of (e.g., n or a number close thereto) light receiving signals from the third light receiver 28a (step S3). Here, when the processor 61 obtains the first reconstructed image G1, the second reconstructed image G2, and the third reconstructed image G3 by imaging processing, they are obtained using single pixel imaging processing.

[0049] In fact, photodetectors 24a, 26a, and 28a were placed at three mutually different positions A, B, and C in the approximately hemispherical space shown in Figure 1, and scattered light was measured at the three mutually different positions A, B, and C with respect to sample 100. As an imaging process, images G1, G2, and G3 were reconstructed using single pixel imaging (here, ghost imaging), and these images are shown in Figures 7(a) to 7(c).

[0050] Image G1 in Figure 7(a) reconstructed from a plurality of light receiving signals received by light receiver 24a shown at position A, image G2 in Figure 7(b) reconstructed from a plurality of light receiving signals received by light receiver 26a shown at position B, and image G3 in Figure 7(c) reconstructed from a plurality of light receiving signals received by light receiver 28a shown at position C differ from the images shown in Figures 6(a) to 6(c) obtained with a normal camera, and it can be seen that the images are not stretched or distorted depending on the arrangement of shooting positions A, B, and C.

[0051] Furthermore, it can be said that image G1 in Figure 7(a), which was reconstructed from multiple light receiving signals received by light receiver 24a shown at position A, image G2 in Figure 7(b), which was reconstructed from multiple light receiving signals received by light receiver 26a shown at position B, and image G3 in Figure 7(c), which was reconstructed from multiple light receiving signals received by light receiver 28a shown at position C, are able to almost reproduce the shape (pattern) of the line drawn on paper sample 100 shown in Figure 2.

[0052] Then, the processor 61 of the processing device 14 compares at least two of the first reconstructed image G1, the second reconstructed image G2, and the third reconstructed image G3 using, for example, addition, subtraction, multiplication, and division (step S4). For example, the processor 61 may use the first reconstructed image G1 as a reference to obtain a difference between the second reconstructed image G2 and / or use the first reconstructed image G1 as a reference to obtain a difference between the third reconstructed image G3.

[0053] When the value obtained by subtracting the second reconstructed image G2 from the first reconstructed image G1 as a reference substantially matches the value obtained by subtracting the third reconstructed image G3 from the first reconstructed image G1 as a reference, it is determined that the second reconstructed image G2 and the third reconstructed image G3 substantially match. Similarly, when the value obtained by subtracting the first reconstructed image G1 from the second reconstructed image G2 as a reference substantially matches the value obtained by subtracting the third reconstructed image G3 from the second reconstructed image G2 as a reference, it is determined that the first reconstructed image G1 and the third reconstructed image G3 substantially match. Since the processor 61 of the processing device 14 knows that the second reconstructed image G2 and the third reconstructed image G3 substantially match, as described above, it is determined that the first reconstructed image G1 also substantially matches the second reconstructed image G2 and the third reconstructed image G3.

[0054] Therefore, the processor 61 of the processing device 14 acquires object information I, such as that the BRDF of the paper sample 100 is isotropic (step S5). The object information I, such as that the BRDF is isotropic, includes the surface texture of the sample 100. The object information I here also includes the shape (pattern) of the lines applied to the sample 100. Furthermore, the object information I here includes the light reflectance, light transmittance, and light absorptance based on the signal intensity of the light reception signals of the reflected light of the pattern light PR1, ..., PRn at the light receivers 24a, 26a, 28a.

[0055] In this process, the intensity distribution of the projection pattern light PRn projected from the light source 22 for the nth time is expressed as I n (x, y), the detected signal at the αth photodetector (single detector) at that time is B n α Then, the function G representing the reconstructed image corresponding to the αth photodetector is α (x, y) can be obtained as follows:

[0056]

number

[0057] Here, a general function A that depends on the variable n in Eq. (1) n In contrast, n >A n Specifically, when the variable n takes the value of a total number N, such as n=n1, n2, …, N, it can be expressed as the following equation (2). That is, the function G in equation (1) α (x, y) is the average value obtained by multiplying the intensity distribution of the pattern light by the signal intensity of the detection signal for each time.

[0058]

number

[0059] As a key point of Equation (1), the function G representing the reconstructed image α One advantage of this method is that (x, y) is expressed in the same coordinate system (x, y) regardless of α. This means that when each of the photodetectors 24a, 26a, and 28a can receive a light signal from the sample 100, even if an image is reconstructed using the light signals received by the photodetectors 24a, 26a, and 28a arranged in any direction relative to the sample 100, the image will not be stretched or distorted. This is a significant difference from images captured by a general image sensor (such as the above-mentioned ordinary camera) (see Figures 6(a) to 6(c)).

[0060] 1, image G1 in Fig. 7(a) reconstructed from the light reception signal of light receiver 24a at position A, image G2 in Fig. 7(b) reconstructed from the light reception signal of light receiver 26a at position B, and image G3 in Fig. 7(c) reconstructed from the light reception signal of light receiver 28a at position C, all show little difference and have similar intensity distributions. This is consistent with the fact that, as described above, the first reconstructed image G1, second reconstructed image G2, and third reconstructed image G3 of the paper sample 100 substantially match each other and the BRDF of the paper sample 100 is almost isotropic.

[0061] ​Here, we have explained the case where images are reconstructed using ghost imaging at three different positions A, B, and C shown in Figure 1 (see Figures 7(a)-7(c)), but images can also be reconstructed in a similar manner using compressed sensing.

[0062] In addition, we have explained the case where images are reconstructed by single pixel imaging at three different positions A, B, and C shown in Figure 1 (see Figures 7(a)-7(c)). However, it is also possible to reconstruct images G at four or more spatially different positions. α (x, y) gives similar results.

[0063] Also, the following description mainly uses photodetectors (PDs) as the light receivers 24a, 26a, and 28a of the optical system 12 of the optical device 10, and processes based on the principle of single pixel imaging as the processing by the processing device 14. For example, depending on the arrangement of the shooting positions A, B, and C, it is possible to obtain an image that is not stretched or distorted, and the imaging processing is not limited to processing based on the principle of single pixel imaging as long as it is possible to acquire received light signals in the optical system 12 and / or process the acquired received light signals in the processing device 14. In this case, the light receivers 24a, 26a, and 28a can be appropriately image sensors such as area sensors that can receive light by dispersing RGB light and are used in general cameras.

[0064] In the present embodiment, an example has been described in which the processor 61 of the processing device 14 appropriately performs subtraction processing on the reconstructed images G1, G2, and G3. When the processor 61 acquires information I of a certain object using the optical device 10 according to the present embodiment, the information I can also be acquired by performing any one of addition, subtraction, multiplication, division, direct product, and tensor product between any two of the signals of the plurality of patterned lights PR1, ..., PRn (the intensity distributions of the plurality of projected lights), the first reconstructed image G1 based on the plurality of light receiving signals of the first light receiver 24a, the second reconstructed image G2 based on the plurality of light receiving signals of the second light receiver 26a, and the third reconstructed image G3 based on the plurality of light receiving signals of the third light receiver 28a. That is, the optical device 10 can acquire the information I of the object using, for example, any two of the three reconstructed images G1, G2, and G3. Alternatively, the optical device 10 can acquire the information I of the object using, for example, any one of the three reconstructed images G1, G2, and G3 and the intensity distributions of the plurality of projected lights. The object information I is not limited to the following, but may be at least one of the following information: the shape of the object, the surface properties of the object, the pattern on the surface of the object, the refractive index, the reflectance, the transmittance, the absorptance, the angular distribution of the reflected light intensity, the angular distribution of the transmitted light intensity, and the BRDF.

[0065] The processing device 14 of the optical device 10 according to this embodiment includes a processor 61. When at least a plurality of projection light beams (pattern light beams) PR1, ..., PRn having different spatial intensity distributions are projected toward an object (sample) 100, the processor 61 obtains object information I based on a first reconstructed image G1 corresponding to the plurality of light reception signals of the first light receiver 24a and a second reconstructed image G2 corresponding to the plurality of light reception signals of the second light receiver 26a by imaging processing using a plurality of light reception signals of a first light receiver 24a that can receive light from the object based on the plurality of projection light beams PR1, ..., PRn and a plurality of light reception signals of a second light receiver 26a that has a different spatial arrangement from the first light receiver 24a and can receive light from the object based on the plurality of projection light beams PR1, ..., PRn. In addition to the processor 61, the processing device 14 of the optical device 10 preferably also has a RAM 63 for temporarily storing multiple received light signals in sequence, and / or an auxiliary memory device 64 for storing multiple received light signals and also storing the first reconstructed image G1, the second reconstructed image G2, and information I.

[0066] When at least a plurality of projection lights PR1, ..., PRn having different spatial intensity distributions from each other are projected toward the object 100, the processor 61 of the processing device 14 acquires information I of the object 100 based on at least one reconstructed image selected from the third reconstructed image G3 corresponding to the plurality of received light signals of the third photoreceiver 28a, which is obtained using imaging processing, in addition to the first reconstructed image G1 and the second reconstructed image G2, using a plurality of received light signals of the third photoreceiver 28a, which has a spatial arrangement different from that of the first photoreceiver 24a and the second photoreceiver 26a and can receive light from the object 100 based on the plurality of projection lights PR1, ..., PRn.

[0067] The optical device 10 includes a light source 22 that projects at least a plurality of projection lights PR1, ..., PRn having different spatial intensity distributions toward the object 100, a first light receiver 24a that can receive light from the object 100 based on the plurality of projection lights PR1, ..., PRn, a second light receiver 26a that has a different spatial arrangement from the first light receiver 24a and can receive light from the object 100 based on the plurality of projection lights PR1, ..., PRn, a third light receiver 28a that has a different spatial arrangement from the first light receiver 24a and the second light receiver 26a and can receive light from the object 100 based on the plurality of projection lights PR1, ..., PRn, and the above-mentioned processing device 14 (processor 61).

[0068] The optical object information acquisition method of this embodiment includes projecting at least a plurality of projection lights PR1, ..., PRn having different spatial intensity distributions toward the object, obtaining a plurality of received light signals from a first photodetector 24a that can receive light from the object based on the plurality of projection lights PR1, ..., PRn, and a second photodetector 26a that has a different spatial arrangement from the first photodetector 24a and can receive light from the object based on the plurality of projection lights PR1, ..., PRn, respectively, and acquiring information I of the object based on a first reconstructed image G1 corresponding to the plurality of received light signals from the first photodetector 24a and a second reconstructed image G2 corresponding to the plurality of received light signals from the second photodetector 26a, obtained using imaging processing.

[0069] Obtaining the plurality of received light signals includes obtaining the plurality of received light signals by a third light receiver 28a, which has a spatial arrangement different from that of the first light receiver 24a and the second light receiver 26a and can receive light from the object based on the plurality of projected light beams PR1, ..., PRn. Obtaining the object information I also includes obtaining the object information I based on at least one reconstructed image selected from the first reconstructed image G1 and the second reconstructed image G2, as well as a third reconstructed image G3 corresponding to the plurality of received light signals of the third light receiver 28a, which is obtained using imaging processing.

[0070] In addition, the optical object information acquisition program of this embodiment causes a computer (processing device 14) to execute the following steps: project at least a plurality of projection lights PR1, ..., PRn having different spatial intensity distributions toward the object; obtain a plurality of received light signals from a first photodetector 24a that can receive light from the object based on the plurality of projection lights PR1, ..., PRn, and a second photodetector 26a that has a different spatial arrangement from the first photodetector 24a and can receive light from the object based on the plurality of projection lights PR1, ..., PRn; and acquire information I of the object based on a first reconstructed image G1 corresponding to the plurality of received light signals from the first photodetector 24a and a second reconstructed image G2 corresponding to the plurality of received light signals from the second photodetector 26a, obtained using imaging processing. In the optical object information acquisition program, the computer (processing device 14) is caused to obtain a plurality of received light signals by a third photodetector 28a, which has a different spatial arrangement from the first photodetector 24a and the second photodetector 26a and is capable of receiving light from the object based on a plurality of projected lights PR1, ..., PRn, and the computer (processing device 14) is caused to obtain information I of the object based on at least two reconstructed images selected from the third reconstructed image G3 corresponding to the plurality of received light signals of the third photodetector 28a, obtained using imaging processing, in addition to the first reconstructed image G1 and the second reconstructed image G2.

[0071] Therefore, according to this embodiment, it is possible to provide a processing device (optical object information acquisition device) for an optical device 10 capable of acquiring information I related to an object (sample 100), an optical device 10, an optical object information acquisition method (optical measurement method), and an optical object information acquisition program (optical measurement program).

[0072] In the above explanation, the detailed arrangement of the photoreceivers 24a, 26a, 28a at positions A, B, and C was not set, but it is more preferable that the three photoreceivers 24a, 26a, 28a are arranged, for example, so that the light receiving axes of the photoreceivers 24a, 26a, 28a are perpendicular to each other.

[0073] According to this embodiment, it is possible to provide a processing device (optical object information acquisition device) 14 of an optical device 10 capable of acquiring information I relating to an object 100, an optical device 10, an optical object information acquisition method (optical measurement method), and an optical object information acquisition program (optical measurement program).

[0074] (Variation) As shown in Fig. 8, the optical device 10 sets up a substantially spherical space. The sample 100 shown in Fig. 2 is placed in an appropriate orientation at the center of the substantially hemispherical space shown in Fig. 8.

[0075] 8, position A described with reference to FIG. 1 is designated as position A1, position B as position B1, and position C as position C1. Furthermore, the position on the opposite side of position A1 across the center of the substantially spherical space (the position where sample 100 is placed) is designated as position A2. Similarly, the position on the opposite side of position B1 across the center of the substantially spherical space is designated as position B2, and the position on the opposite side of position C1 across the center of the substantially spherical space is designated as position C2.

[0076] The light-receiving point of the light-receiver 24b is located at position A2, the light-receiving point of the light-receiver 26b is located at position B2, and the light-receiving point of the light-receiver 28b is located at position C2. These light-receivers 24b, 26b, and 28b are preferably the same as the light-receivers 24a, 26a, and 28a, and are preferably controlled by the processor 61 of the processing device 14.

[0077] When patterned light PR1, ..., PRn is sequentially projected onto a sample 100, which is paper, from the same light source 22 as in the example described in the first embodiment, the photoreceiver 24a at position A1, the photoreceiver 26a at position B1, and the photoreceiver 28a at position C1 each receive a light reception signal reflected from the sample 100. This causes the processor 61 of the processing device 14 to generate reconstructed images G1a, G2a, and G3a (not shown) of the reflected light based on the respective multiple light reception signals of the photoreceiver 24a at position A1, the photoreceiver 26a at position B1, and the photoreceiver 28a at position C1.

[0078] On the other hand, when patterned light PR1, ..., PRn is sequentially projected onto a sample 100, which is paper, from the same light source 22 as in the example described in the first embodiment, the photoreceiver 24b at position A2, the photoreceiver 26b at position B2, and the photoreceiver 28b at position C2 each receive a light reception signal that has passed through the sample 100. Then, the processor 61 of the processing device 14 generates reconstructed images G1b, G2b, and G3b (not shown) of the transmitted light based on the respective multiple light reception signals of the photoreceiver 24b at position A2, the photoreceiver 26b at position B2, and the photoreceiver 28b at position C2.

[0079] The processor 61 of the processing device 14 compares at least two selected from the signals of the patterned light PR1, ..., PRn, the three reconstructed images G1a, G2a, G3a of reflected light, and the three reconstructed images G1b, G2b, G3b of transmitted light.

[0080] The processor 61 of the processing device 14 then obtains object information I relating to the sample 100 .

[0081] In this variant, the reconstructed images are described as being a comparison of at least two of the three reconstructed images of reflected light and / or at least two of the three reconstructed images of transmitted light, but it is also possible to obtain object information I relating to sample 100 by comparing at least two of all six reconstructed images.

[0082] The photodetectors 24a, 26a, and 28a located at positions A1, B1, and C1 may not be required. That is, the processor 61 of the processing device 14 may compare at least two selected from the signals of the patterned light PR1, ..., PRn and the three reconstructed images G1b, G2b, and G3b of the transmitted light to obtain object information I related to the sample 100.

[0083] Alternatively, light receivers may be placed at at least two or three selected from positions A1, A2, B1, B2, C1, and C2. In this case, the processor 61 of the processing device 14 may compare at least two selected from the signals of the patterned light PR1, ..., PRn and the two or three reconstructed images obtained from the light receiving signals of the light receivers, to obtain object information I related to the sample 100.

[0084] According to this modified example, it is possible to provide a processing device (optical object information acquisition device) 14 of an optical device 10 capable of acquiring information I relating to an object 100, an optical device 10, an optical object information acquisition method (optical measurement method), and an optical object information acquisition program (optical measurement program).

[0085] (Second embodiment) An optical device 10 according to a second embodiment will be described with reference to Figures 9 and 10. This embodiment is a modified example of the first embodiment, and the same components as those described in the first embodiment or components having the same functions are denoted by the same reference numerals as much as possible, and detailed descriptions thereof will be omitted.

[0086] The following embodiments will be described using the imaging processing technology of the optical device 10 according to the first embodiment described above, which explains that the reconstructed images G1, G2, and G3 based on multiple received light signals are not stretched or distorted even at spatially different detection positions (see Figures 2 and 7).

[0087] As shown in FIG. 9, the optical system 12 of the optical device 10 according to this embodiment has a light source 22, a first light receiving section 24, and a second light receiving section .

[0088] The first light receiver 24a of the first light receiving unit 24 is disposed adjacent to the light source 22, and the light receiving axis of the first light receiver 24a is preferably parallel to, for example, the optical axis of the light source 22. It is more preferable that the optical axis of the pattern light PR1, ..., PRn from the light source 22 and the light receiving axis of the first light receiver 24a are coaxial.

[0089] The second light receiver 26a of the second light receiving unit 26 is located at a position away from the light source 22 and the first light receiving unit 24, and has a different spatial arrangement. It is preferable that the light receiving axis of the second light receiver 26a of the second light receiving unit 26 is non-parallel to the optical axis of the light source 22 and the light receiving axis of the first light receiver 24a.

[0090] In the following description of this embodiment, photodetectors are used as an example of the first light receiver 24a and the second light receiver 26a. The light source 22 sequentially projects various pattern light PR1, ..., PRn onto the sample 100, and the reflected light (specular reflected light and scattered light) generated by the sample 100 is detected by the two light receivers (the first light receiver 24a and the second light receiver 26a), respectively.

[0091] The processor 61 of the processing device 14 reconstructs an image of the sample 100 by imaging processing using signals from the pattern light PR1, ..., PRn projected from the light source 22 and multiple received light signals from the first photodetector 24a and the second photodetector 26a.

[0092] Here, when the processor 61 obtains the first reconstructed image G1 and the second reconstructed image G2 by imaging processing, it is assumed that they are obtained using single pixel imaging processing. For example, if the single pixel imaging is ghost imaging, the reconstructed image G α (x, y) can be obtained using equation (1) above.

[0093] Here, the plurality of light receiving signals B at the detectors 24a and 26a n α depends on the BRDF of sample 100 (denoted as ρ(x, y, θ, φ)). For example, the received light signal B n α can be expressed as the following equation (3) using ρ(x, y, θ, φ), which is the BRDF of sample 100.

[0094]

number

[0095] S(x, y, θ, φ) corresponds to the area per pixel of the projected pattern light PR1, . . . , PRn as viewed from the direction of the light receivers 24a and 26a, but the specific function form differs depending on the arrangement of the optical system 12.

[0096] Equations (1) and (3) are used to calculate the reconstructed image G αThis means that (x, y) depends on ρ(x, y, θ, φ), which is the BRDF of the sample 100. That is, by inputting the received light signals from the first light receiver 24a and the second light receiver 26a to the processor 61 of the processing device 14, it is possible to estimate information I of the BRDF at each point on the sample 100, i.e., the spatial distribution of the BRDF, according to the flow (program) shown in Fig. 5. Therefore, the optical device 10 according to this embodiment can obtain information I of the sample (object) 100.

[0097] As a simplified example, consider a case where the optical device 10 according to this embodiment is applied to a mirror-surface sample 100 (without scratches 100a) shown in FIG.

[0098] Here, the light receiving axis of the first light receiver 24a is perpendicular to the surface of the specular sample 100, and the optical axis of the pattern light PR1, ..., PRn from the light source 22 is approximately aligned with or adjacent to, and approximately parallel to, the light receiving axis of the first light receiver 24a. In other words, the light receiving axis of the first light receiver 24a is arranged to be aligned with or approximately aligned with the optical axes of the multiple projection lights irradiated from the light source 22. Unlike the paper described in the first embodiment, the BRDF of the specular sample 100 cannot be said to be isotropic.

[0099] FIG. 9 is a schematic diagram showing a series of processing steps (see FIG. 5) for obtaining object information I when the mirror-finished sample 100 has no scratches.

[0100] The first photoreceiver 24a detects, as a received light signal, the reflected light resulting from irradiation of the patterned light PR1, ..., PRn from the light source 22 onto the mirrored sample 100. On the other hand, the second photoreceiver 26a does not detect, as a received light signal, the reflected light resulting from irradiation of the patterned light PR1, ..., PRn from the light source 22 onto the mirrored sample 100.

[0101] When the light receiving signals from the first light receiver 24a and the second light receiver 26a are input to the processing device 14 and reconstructed through imaging processing, the shape of the sample 100 appears in the reconstructed image G1 of the first light receiver 24a to which reflected light is incident, but the reconstructed image G2 of the second light receiver 26a to which reflected light is not incident is a uniform image.

[0102] At this time, the reconstructed images G1 and G2 are not stretched or distorted due to the arrangement of the photodetectors 24a and 26a. Therefore, by processing this result again in the processing device 14, it is possible to estimate object information I such as the BRDF of the sample 100. The processor 61 of the processing device 14 aligns the orientations of the reconstructed images G1 and G2 and, for example, adds them together to obtain an image of the appearance of the sample 100 as object information I.

[0103] Then, since a shape corresponding to the sample 100 is obtained in one reconstructed image G1 and a shape corresponding to the sample 100 is not obtained in the other reconstructed image G2, it is possible to obtain information I regarding the surface texture of the sample 100. Then, in this example, the processing device 14 of the optical device 10 can estimate that the sample 100 is a star-shaped mirror surface facing the first photodetector 24a.

[0104] Note that the information (object information) I regarding the mirrored sample 100 here includes information on the BRDF, including the anisotropy of the object due to the fact that an image of the mirrored sample 100 was obtained in the first reconstructed image G1 but not in the second reconstructed image G2.

[0105] 7(a)-7(c), reconstructed images G1, G2, and G3 were obtained from the plurality of light receiving signals from the three light receivers 24a, 26a, and 28a, respectively. In contrast, in this embodiment, as shown in FIG. 9, an image corresponding to the sample 100 was obtained in the reconstructed image G1 using the light receiving signal from the light receiver 24a, but an image corresponding to the sample 100 was not obtained in the reconstructed image G2 using the light receiving signal from the light receiver 26a. The differences between these embodiments include whether the optical axis of the pattern light (projected light) PR1, ..., PRn from the light source 22 is parallel to the light receiving axis of the first light receiver 24a (see FIG. 9) or not (see FIG. 1), but are thought to be largely due to differences in the BRDF of the surface of the sample 100.

[0106] 9 uses a mirror-finished sample 100. Therefore, when patterned light PR1, ..., PRn such as parallel light is projected onto the mirror-finished sample 100 from the light source 22 directly above the mirror-finished sample 100 as shown in FIG. 9, the reflected light of the patterned light PR1, ..., PRn enters only the first light receiver 24a, which is also disposed directly above the mirror-finished sample 100.

[0107] On the other hand, in the examples shown in Figures 1 and 7(a) to 7(c), paper is used as sample 100, and the BRDF of paper is isotropic. Therefore, in the examples shown in Figures 7(a) to 7(c), even if light is irradiated from a single direction onto paper sample 100, the scattered light is isotropic, resulting in similar light intensity being received by all of the photodetectors 24a, 26a, and 28a at positions A, B, and C. The fact that similar images G1, G2, and G3 were reconstructed by all of the photodetectors 24a, 26a, and 28a at positions A, B, and C can be said to be an indication that the BRDF of paper is isotropic.

[0108] Next, FIG. 10 shows a schematic diagram of a series of processing flows (see FIG. 5) up to obtaining object information I when the mirror-finished sample 100 has a flaw 100a.

[0109] 10, consider a case where a scratch 100a is present on a mirror-finished sample 100. The light source 22 and light-receiving units 24, 26 are the same as those of the optical device 10 shown in FIG.

[0110] Since the sample 100 has a mirror surface, the first photoreceiver 24a detects, as a received light signal, reflected light (specularly reflected light) resulting from irradiation of the sample 100 with the patterned light PR1, ..., PRn from the light source 22. In the example shown in Fig. 10, unlike the example shown in Fig. 9, the second photoreceiver 26a detects, as a received light signal, reflected light (scattered light) resulting from irradiation of the sample 100 with the patterned light PR1, ..., PRn from the light source 22.

[0111] As shown in Fig. 10, the first reconstructed image G1 captured the external shape of the sample 100. Unlike the example shown in Fig. 9, the second reconstructed image G2 captured a shape corresponding to a scratch 100a on the sample 100. This is because the second photoreceiver 26a detected the reflected light caused by the scratch 100a.

[0112] 10, the shape of the scratch 100a may be obtained regardless of whether the scratch 100a on the mirrored sample 100 is anisotropic. This is because the presence of the scratch 100a on the mirrored sample 100 slightly reduces the specularly reflected light component to the first light receiver 24a, which may appear as a dark area in the first reconstructed image G1.

[0113] However, if the change in brightness due to the scratch 100a is weak compared to the intensity of the specularly reflected light, the effect of the scratch 100a will be almost completely hidden in the first reconstructed image G1 based on the light reception signal from the first light receiver 24a, and as a result, it will be possible to reconstruct only the appearance (star-shaped) of the mirrored sample 100. For this reason, in Figure 10, the first reconstructed image G1 from the first light receiver 24a shows the appearance (star-shaped) of the mirrored sample 100, and does not show the scratch 100a.

[0114] 9 due to the anisotropy of the scratch 100a on the mirrored sample 100. However, depending on the anisotropy of the scratch 100a, the reflected light of the patterned lights PR1, ..., PRn from the light source 22 may not be incident on the second photoreceiver 26a, and an image of the scratch 100a may not be reconstructed in the second reconstructed image G2.

[0115] 10, the appearance (star-shaped) of the mirrored sample 100 is reconstructed in the first reconstructed image G1, and a scratch 100a made in the mirrored sample 100 is reconstructed in the second reconstructed image G2. In this case, the optical device 10 according to this embodiment acquires the intensity of the reflected light corresponding to the irradiation of the sample 100 with patterned light PR1, ..., PRn from the light source 22, and the spread (angular distribution) of the reflected light, and can acquire information I of the object (sample 100).

[0116] By performing calculations such as subtraction on these images (first reconstructed image G1 and second reconstructed image G2), the processing device 14 can estimate from the BRDF where the scratch 100a is located on the sample 100 and in which direction the light is scattered.

[0117] In this embodiment, an example has been described in which a specular sample 100 is used. As described in the first embodiment, the optical device 10 according to this embodiment can also acquire information I about the sample 100 whose BRDF is isotropic.

[0118] The processing device 14 of the optical device 10 includes a processor 61. When at least a plurality of projection light beams PR1, ..., PRn having different spatial intensity distributions are projected toward a sample (object) 100, the processor 61 performs imaging processing using a plurality of light reception signals from a first light receiver 24a that can receive light from the sample 100 based on the plurality of projection light beams PR1, ..., PRn, and a plurality of light reception signals from a second light receiver 26a that has a different spatial arrangement from the first light receiver 24a and can receive light from the sample 100 based on the plurality of projection light beams PR1, ..., PRn. The processor 61 acquires information I of the sample 100 based on a first reconstructed image G1 corresponding to the plurality of light reception signals from the first light receiver 24a and a second reconstructed image G2 corresponding to the plurality of light reception signals from the second light receiver 26a.

[0119] When the processor 61 acquires information I of the sample (object) 100 based on the first reconstructed image G1 and the second reconstructed image G2, it performs addition, subtraction, multiplication, division, Cartesian product, or tensor product between any two of the multiple light receiving signals of the first light receiver 24a, the multiple light receiving signals of the second light receiver 26a, and the intensity distributions of the multiple projection lights PR1, ..., PRn.

[0120] When the processor 61 performs imaging processing to obtain the first reconstructed image G1 and the second reconstructed image G2, they are obtained based on the principle of single pixel imaging, for example.

[0121] The optical object information acquisition method includes projecting at least a plurality of projection lights PR1, ..., PRn having different spatial intensity distributions toward a sample (object) 100, obtaining a plurality of received light signals from a first photodetector 24a that can receive light from the sample 100 based on the plurality of projection lights PR1, ..., PRn, and a second photodetector 26a that has a different spatial arrangement from the first photodetector 24a and can receive light from the sample 100 based on the plurality of projection lights PR1, ..., PRn, respectively, and acquiring information I of the sample 100 based on a first reconstructed image G1 corresponding to the plurality of received light signals from the first photodetector 24a and a second reconstructed image G2 corresponding to the plurality of received light signals from the second photodetector 26a, which are obtained by performing imaging processing.

[0122] The optical object information acquisition program causes a computer (processor 61) to execute the following steps: project at least a plurality of projection lights PR1, ..., PRn having different spatial intensity distributions toward a sample (object) 100; obtain a plurality of received light signals from a first photodetector 24a that can receive light from the object based on the plurality of projection lights PR1, ..., PRn, and a second photodetector 26a that has a different spatial arrangement from the first photodetector 24a and can receive light from the sample 100 based on the plurality of projection lights PR1, ..., PRn; and acquire information I of the sample 100 based on a first reconstructed image G1 corresponding to the plurality of received light signals from the first photodetector 24a and a second reconstructed image G2 corresponding to the plurality of received light signals from the second photodetector 26a, which are obtained by performing imaging processing.

[0123] According to this embodiment, it is possible to provide a processing device (optical object information acquisition device) 14 of an optical device 10 capable of acquiring information I relating to an object 100, an optical device 10, an optical object information acquisition method (optical measurement method), and an optical object information acquisition program (optical measurement program).

[0124] (Third embodiment) An optical device 10 according to the third embodiment will be described with reference to Figures 11 to 13. This embodiment is a modification of the first and second embodiments, and the same components as those described in the first and second embodiments or components having the same functions are denoted by the same reference numerals as much as possible, and detailed descriptions thereof will be omitted.

[0125] As shown in FIG. 11, the optical system 12 of the optical device 10 according to this embodiment has a light source 22, a first light receiving section 24, a second light receiving section 26, and a third light receiving section .

[0126] The light source 22, the first light receiving section 24, and the second light receiving section 26 are arranged as described in the second embodiment.

[0127] The third light receiver 28 a of the third light receiving unit 28 is located at a position away from the light source 22 , the first light receiving unit 24 , and the second light receiving unit 26 .

[0128] For example, it is preferable to arrange the three photoreceivers 24a, 26a, and 28a so that the plane passing through the light receiving axis of the first photoreceiver 24a and all of the light receiving points of the second photoreceiver 26a and the plane passing through the light receiving axis of the first photoreceiver 24a and all of the light receiving points of the third photoreceiver 28a are non-parallel to each other.

[0129] The light receiving axis of the third light receiver 28a of the third light receiving unit 28 may be arranged so as to be perpendicular to the optical axis of the light source 22, the light receiving axis of the first light receiver 24a, and the light receiving axis of the second light receiver 26a. Therefore, the light receivers 24a, 26a, and 28a are arranged so that the plane formed by the light receiving axis of the first light receiver 24a and the light receiving axis of the second light receiver 26a is non-parallel to the plane formed by the light receiving axis of the first light receiver 24a and the light receiving axis of the third light receiver 28a.

[0130] For example, by arranging three photodetectors 24a, 26a, and 28a in this manner, it becomes easier to detect anisotropic scratches 100a or defects present on the sample 100. Furthermore, by using three or more photodetectors 24a, 26a, and 28a, it becomes possible to estimate the BRDF of the sample 100 even if it has a three-dimensional shape or unevenness. For example, a fourth photodetector (not shown) may be arranged at any position.

[0131] In the following description of this embodiment, photodetectors are used as examples of the first light receiver 24a, the second light receiver 26a, and the third light receiver 28a. The light source 22 sequentially projects various pattern light PR1, ..., PRn onto the sample 100, and the reflected light (specular reflected light, scattered light) generated by the sample 100 is detected by the three light receivers (the first light receiver 24a, the second light receiver 26a, and the third light receiver 28a).

[0132] As a simplified example, consider a case where a scratch 100a exhibiting anisotropy is present on a mirrored sample 100, as shown in a schematic diagram in Figure 11. Assume that the sample 100 in this example looks similar to the sample 100 (with scratch 100a) shown in Figure 10. Assume that the scratch 100a on the mirrored sample 100 has anisotropy in that it scatters light in the direction of the third photodetector 28a but does not scatter light in the directions of the first photodetector 24a and the second photodetector 26a.

[0133] 12 shows that the patterned light PR1, ..., PRn from the light source 22 facing the mirror-finished sample 100 is specularly reflected. When the patterned light PR1, ..., PRn is irradiated onto the scratch 100a, the reflected light is scattered at an appropriate angle. For example, FIG. 12 shows the spread of specularly reflected light 102 and scattered light 104 when the light source 22 facing the mirror-finished sample 100 (with the scratch 100a) shown in FIG. 11 sequentially irradiates the sample 100 with, for example, patterned light PR1, ..., PRn. On the surface of the mirror-finished sample 100 away from the scratch 100a, the patterned light PR1, ..., PRn is reflected (specularly reflected) from each point on the surface of the mirror-finished sample 100 with a relatively narrow spread, for example, in a substantially conical shape, as indicated by the reference symbol 102. Therefore, the pattern light PR1, ..., PRn reflected from the surface of the mirror-finished sample 100 away from the scratch 100a can be received by a first photoreceiver 24a that is coaxial with the optical axis of the light source 22 or adjacent to the light source 22 and has a light receiving axis that is approximately parallel to the optical axis of the light source 22. The processor 61 of the processing device 14 uses the detection signal of the first photoreceiver 24a to perform imaging processing, for example, based on the principle of single pixel imaging, to reconstruct a first reconstructed image G1. The first reconstructed image G1, which uses the multiple received light signals of the first photoreceiver 24a, captures the external shape (star-shaped) of the sample 100.

[0134] Strictly speaking, the shape of the scratch may appear in the first reconstructed image G1 based on the multiple light receiving signals from the first light receiver 24a, regardless of whether the scratch 100a is anisotropic or not. However, as described above, if the change in brightness due to the scratch 100a is weak compared to the intensity of the specularly reflected light, the effect of the scratch 100a will be almost completely hidden in the first reconstructed image G1, and as a result, only the appearance (star-shaped) of the sample 100 can be reconstructed. Therefore, in the example shown in FIG. 11, the first reconstructed image G1 based on the multiple light receiving signals obtained by the first light receiver 24a shows the appearance (star-shaped) of the sample.

[0135] On the other hand, the pattern light PR1, ..., PRn reflected from the surface of the mirror sample 100, excluding the scratch 100a, is not or is unlikely to be incident on the second photoreceiver 26a and the third photoreceiver 28a, which are located away from the first photoreceiver 24a and have different light receiving axes.

[0136] The scratch 100a on the surface of the mirror sample 100 reflects (scatters) the pattern light PR1, ..., PRn with a relatively wide spread at each position, as indicated by the reference numeral 104. However, the scattered light (reflected light) 104 may have a large spread in some directions and a small spread in other directions, that is, the light may have anisotropy in the way it spreads.

[0137] In this embodiment, as shown in FIG. 11 , due to the anisotropy of the spread of light when the patterned light PR1, ..., PRn is irradiated onto the sample 100 and reflected, the second photodetector 26a does not receive the reflected light from the flaw 100a, but the third photodetector 28a receives the reflected light from the flaw 100a. The processor 61 of the processing device 14 performs imaging processing, such as single-pixel imaging, using the detection signals from the second photodetector 26a and the third photodetector 28a, simultaneously with the detection signal from the first photodetector 24a, to reconstruct a second reconstructed image G2 and a third reconstructed image G3. The second reconstructed image G2, which uses the multiple light-receiving signals from the second photodetector 26a, provides a uniform image. The third reconstructed image G3, which uses the multiple light-receiving signals from the third photodetector 28a, provides the shape of the flaw 100a.

[0138] Then, the processor 61 of the processing device 14 obtains information I about the surface of the sample 100 using the first reconstructed image G3, the second reconstructed image G2, and the third reconstructed image G3.

[0139] The processor 61 of the processing device 14 has information such as the position and orientation of the light-receiving axis and light-receiving point of the first light receiver 24a, the light-receiving axis and light-receiving point of the second light receiver 26a, and the light-receiving axis and light-receiving point of the third light receiver 28a. Therefore, by performing calculations on these reconstructed images G1, G2, and G3 in the processing device 14, it is possible to estimate the location of the flaw 100a on the sample 100 and also determine the anisotropy of the BRDF of the flaw 100a. This is an advantage obtained by using three or more detectors 24a, 26a, and 28a. In other words, by using the detectors 24a, 26a, and 28a to obtain the direction and magnitude of the reflected light of the patterned light PR1, ..., PRn from the light source 22 reflected by the sample 100, information I of the sample 100 (object) can be obtained more accurately.

[0140] For this reason, the optical device 10 may overlook the presence of information I such as the flaw 100a in the reconstructed images G1 and G2 using the light reception signals from the light receivers 24a and 26a located at two different positions, but the possibility of overlooking the presence of information I such as the flaw 100a can be reduced in the reconstructed images G1, G2, and G3 using the light reception signals from the light receivers 24a, 26a, and 28a located at three different positions. Therefore, according to the optical device 10 of this embodiment, the angular resolution of the BRDF obtained from the surface of the sample 100 (object) can be improved by using three or more single detectors 24a, 26a, and 28a.

[0141] The reconstructed image G3 of the third light receiving unit 28a varies greatly depending on whether the flaw 100a has anisotropy. Depending on the anisotropy, the flaw 100a may appear in both the second reconstructed image G2 and the third reconstructed image G3, or may appear in the second reconstructed image G2 but not in the third reconstructed image G3. Furthermore, if the flaw 100a is isotropic and does not have anisotropy, the image of the flaw 100a may appear in the first reconstructed image G1, the second reconstructed image G2, and the third reconstructed image G3.

[0142] Therefore, by using three or more light receivers 24a, 26a, and 28a whose light receiving axes are oriented in different directions, it is possible to obtain information I about the object (sample 100) more reliably.

[0143] 13 shows an example in which the sample 100 is the same as that shown in FIG. 12, but the light source 22 does not face the sample 100 directly, and the patterned light PR1, ..., PRn from the light source 22 is obliquely incident. The surface of the mirrored sample 100 may be inclined relative to the position directly facing the light source 22. In this case, unlike the example shown in FIG. 11, the patterned light PR1, ..., PRn from the light source 22 is not incident on the light receiver 24a adjacent to the light source 22. Furthermore, the patterned light PR1, ..., PRn from the light source 22 irradiated onto the scratch 100a is spread by the scratch 100a and can be received by at least one of the light receivers 24a, 26a, and 28a. Using three or more photodetectors 24a, 26a, and 28a with their light-receiving axes oriented in different directions increases the likelihood that specular reflection or scattered light will be received by one or two of the three photodetectors 24a, 26a, and 28a, compared to using one or two photodetectors. Therefore, it becomes easier to obtain a reconstructed image of the entire sample 100, including the scratch 100a, using reconstructed images G1, G2, and G3 based on the light-receiving signals of the photodetectors 24a, 26a, and 28a.

[0144] Furthermore, even if there is a scratch 100a or the like on the sample 100 and the light from the scratch 100a has anisotropy in the way it spreads, the likelihood that the scattered light will be received by any of the photoreceivers 24a, 26a, 28a can be increased compared to when one or two photoreceivers are used. Therefore, it is possible to easily obtain a reconstructed image of the scratch 100a on the sample 100 using the reconstructed images G1, G2, G3 that use the light reception signals of the photoreceivers 24a, 26a, 28a.

[0145] 12 and 13, the spatial distribution of the BRDF of the sample 100, which is an example of the object information I, changes depending on the surface condition of the object. Even in such a case, as described in this embodiment, by using three or more photoreceivers 24a, 26a, and 28a in the optical system 12 of the optical device 10, it is possible to more reliably acquire the object information I, such as the BRDF of the surface of the sample 100 (the direction in which each reflected light of the pattern lights PR1, ..., PRn travels, the magnitude of the traveling light, etc.), even when the sample 100 has a three-dimensional shape or unevenness.

[0146] According to this embodiment, it is possible to provide a processing device (optical object information acquisition device) 14 of an optical device 10 capable of acquiring information I relating to an object (sample) 100, an optical device 10, an optical object information acquisition method (optical measurement method), and an optical object information acquisition program (optical measurement program).

[0147] According to at least one of the embodiments described above, it is possible to provide a processing device (optical object information acquisition device) 14 of an optical device 10 capable of acquiring information I relating to an object (sample) 100, an optical device 10, an optical object information acquisition method (optical measurement method), and an optical object information acquisition program (optical measurement program).

[0148] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0149] 10...optical device, 12...optical system, 14...processing device, 22...light source, 24...first light receiving unit, 24a...first light receiving device, 26...second light receiving unit, 26a...second light receiving device, 28...third light receiving unit, 28a...third light receiving device, 40...light receiving unit, 42...optical element, 44...light receiving unit, 61...processor, 62...ROM, 63...RAM, 64...auxiliary storage device, 65...communication interface, 100...sample, 100a...flaw, A, B, C...position, G1, G2, G3...reconstructed image.

Claims

1. A processing device for an optical device, When multiple projection lights with different spatial intensity distributions are projected onto an object, a plurality of light receiving signals of a first light receiver capable of receiving light from the object based on the plurality of projected lights; a plurality of light receiving signals of a second light receiving device, the second light receiving device having a spatial arrangement different from that of the first light receiving device and capable of receiving light from the object based on the plurality of projected light beams; and acquiring information about the object based on a first reconstructed image corresponding to the plurality of light receiving signals of the first light receiver and a second reconstructed image corresponding to the plurality of light receiving signals of the second light receiver, the first reconstructed image being obtained by performing imaging processing using a signal processing unit. A processing unit having a processor.

2. and acquiring information about the object based on the first reconstructed image and the second reconstructed image by the processor includes performing any one of addition, subtraction, multiplication, division, direct product, and tensor product between any two of the plurality of light receiving signals of the first light receiver, the plurality of light receiving signals of the second light receiver, and the plurality of intensity distributions of the projection light. The processing device of claim 1 .

3. The processor: When at least the plurality of projection lights having different spatial intensity distributions are projected toward the object, In addition to the first reconstructed image and the second reconstructed image, a third reconstructed image corresponding to the plurality of light receiving signals of the third light receiver, obtained by performing the imaging process using a plurality of light receiving signals of a third light receiver, the third light receiver having a spatial arrangement different from that of the first light receiver and the second light receiver and capable of receiving light from the object based on the plurality of projection light beams; and acquiring information about the object based on at least one reconstructed image selected from the following: The processing device according to claim 1 or 2.

4. When the processor performs the imaging process to obtain the first reconstructed image and the second reconstructed image, the first reconstructed image and the second reconstructed image are obtained using a single pixel imaging process. The processing device according to claim 1 or 2.

5. a light source that projects at least the plurality of projection lights having different spatial intensity distributions toward the object; the first light receiver capable of receiving light from the object based on the plurality of projected lights; the second light receiver, which has a spatial arrangement different from that of the first light receiver and is capable of receiving light from the object based on the plurality of projected lights; The processing device according to claim 1 or 2. An optical device comprising:

6. At least one of the first light receiver and the second light receiver does not have spatial resolution.

6. The optical device according to claim 5.

7. the first light receiver and the light source are arranged so that a light receiving axis of the first light receiver and an optical axis of the plurality of projection lights coincide or substantially coincide; 6. The optical device according to claim 5.

8. the first light receiver and the second light receiver are any one of a photodetector, a photomultiplier tube, an optical power meter, a spectrometer, and an image sensor; 6. The optical device according to claim 5.

9. a light source that projects at least the plurality of projection lights having different spatial intensity distributions toward the object; the first light receiver capable of receiving light from the object based on the plurality of projected lights; the second light receiver, which has a spatial arrangement different from that of the first light receiver and is capable of receiving light from the object based on the plurality of projected lights; the third light receiver, which has a spatial arrangement different from that of the first light receiver and the second light receiver and is capable of receiving light from the object based on the plurality of projection lights; The processing device according to claim 3 ; An optical device comprising:

10. The information about the object is at least one of information about the shape of the object, the surface texture of the object, the pattern on the surface of the object, the refractive index, the reflectance, the transmittance, the absorptance, the angular distribution of the reflected light intensity, the angular distribution of the transmitted light intensity, and BRDF. The processing device according to claim 1 or 2.

11. The plurality of projection lights are at least a plurality of lights having different wavelengths from each other. The processing device according to claim 1 or 2.

12. projecting a plurality of projection lights having different spatial intensity distributions toward an object; obtaining a plurality of light receiving signals from a first light receiver capable of receiving light from the object based on the plurality of projected light beams and a second light receiver having a spatial arrangement different from that of the first light receiver and capable of receiving light from the object based on the plurality of projected light beams, respectively; acquiring information about the object based on a first reconstructed image corresponding to the plurality of light receiving signals from the first light receiver and a second reconstructed image corresponding to the plurality of light receiving signals from the second light receiver, which are obtained by performing imaging processing; An optical object information acquisition method comprising:

13. obtaining the plurality of received light signals includes obtaining the plurality of received light signals by a third light receiver that is spatially arranged differently from the first light receiver and the second light receiver and that can receive light from the object based on the plurality of projected light beams; acquiring the information of the object includes acquiring the information of the object based on at least one reconstructed image selected from the first reconstructed image, the second reconstructed image, and a third reconstructed image corresponding to the plurality of light receiving signals of the third light receiver obtained by performing the imaging processing. The method for optically acquiring object information according to claim 12.

14. projecting a plurality of projection lights having different spatial intensity distributions toward an object; obtaining a plurality of light receiving signals from a first light receiver capable of receiving light from the object based on the plurality of projected light beams and a second light receiver having a spatial arrangement different from that of the first light receiver and capable of receiving light from the object based on the plurality of projected light beams, respectively; acquiring information about the object based on a first reconstructed image corresponding to the plurality of light receiving signals from the first light receiver and a second reconstructed image corresponding to the plurality of light receiving signals from the second light receiver, which are obtained by performing imaging processing; An optical object information acquisition program that causes a computer to execute the above.

15. obtaining the plurality of received light signals includes obtaining the plurality of received light signals by a third light receiver, the third light receiver having a spatial arrangement different from that of the first light receiver and the second light receiver, and capable of receiving light from the object based on the plurality of projected light beams; acquiring the information of the object based on at least two reconstructed images selected from the first reconstructed image, the second reconstructed image, and a third reconstructed image corresponding to the plurality of light receiving signals of the third light receiver obtained by performing the imaging processing; The optical object information acquisition program according to claim 14, which causes the computer to execute the following:

Images