Recording device for generating a 3D image of a three-dimensional object and method

Abstract

Recording device (10) for generating a 3D recording of a three-dimensional object (11), wherein the recording device (10) has a plurality of projection planes (12) for illuminating the object (11), wherein the plurality of projection planes (12) can be projected onto the object (11), wherein the projection planes (12) each have a wavelength-dependent distance (zp(λ)) to a central projection plane (12) from the plurality of projection planes (12), comprising - a light source (13) for generating a light beam (14) in a pattern plane (15), - a first beam splitter (16) for splitting an illumination beam (17) from the light beam (14) and for splitting a recording beam (18) from an observation beam (19) reflected by the object (11), - with a first beam splitter input (20) for receiving the light beam (14) and - with a first beam splitter output (21) for outputting the illumination beam (17) and, - with a second beam splitter input (22) for receiving the observation beam (19) and - with a second beam splitter output (23) for outputting the receiving beam (18), wherein the second beam splitter input (22) corresponds to the first beam splitter output (21), - a chromatic element (24) for focusing the illumination beam (17) split by the first beam splitter (16) onto the plurality of projection planes (12) such that the pattern plane (15) is conjugated to one of the projection planes (12) from the plurality of projection planes (12) at a specific projection wavelength, - a second beam splitter (25) for dividing the receiving beam (18) into a first receiving beam portion (26) and a second receiving beam portion (27), - with a third beam splitter input (28) for receiving the receiving beam (18) and, - with a third beam splitter output (29) for outputting the first receiving beam portion (26) and, - with a fourth beam splitter output (30) for outputting the second receiving beam portion (27), - a focusing optics (47) arranged between the first beam splitter (16) and the second beam splitter (25), - a detection unit (31) for detecting a first image (32) in a first image plane (33) of the first recording beam portion (26) and a second image (34) in a second image plane (35) of the second recording beam portion (27) of the object (11), - with a first matrix sensor (36) for two-dimensionally detecting the first intensity data (37) of the first recording beam portion (26) as a first image (32) in the first image plane (33), wherein the first matrix sensor (36) is arranged downstream of the third beam splitter output (29) of the second beam splitter (25) with respect to the beam direction of the first recording beam portion (26), - with a second matrix sensor (38) for two-dimensionally detecting the second intensity data (39) of the second receiving beam portion (27) as a second image (34) in the second image plane (35), wherein the second matrix sensor (38) is arranged downstream of the fourth beam splitter output (30) of the second beam splitter (25) with respect to the beam direction of the second receiving beam portion (27), - wherein the first image (32) and the second image (34) have corresponding pixels, wherein the corresponding pixels can each be assigned to the same object points of the three-dimensional object (11), - a calculation unit (40) for calculating at least one longitudinal coordinate of a plurality of object points of the object (11) from the corresponding image points of the first image and the second image in order to generate a 3D image of the three-dimensional object (11).

Description

[0001] The invention relates to a recording device having the features of independent patent claim 1 and to a method having the features of independent patent claim 15.

[0002] In many areas of technology, it is now desirable to create 3D images. However, there are areas in which the objects to be recorded are small and difficult to access, and yet have to be recorded from various difficult-to-access perspectives in order to obtain a 3D image. At the same time, the recording devices cannot be large and must be flexible and, ideally, mobile. If, for example, components in devices or modules are to be analyzed without dismantling the devices, in-situ 3D images are required. One application for this is the recording of the shape of machined or injection-molded components in the installed state in order to determine any deformations caused by assembly.

[0003] EP1084379A1 discloses an optoelectronic shape detection system using chromatic coding with illumination planes, which involves a spectral evaluation of the light reflected from the sample. The disadvantage is the need for a spectral measurement.

[0004] A chromatic confocal scanning device is known from US 2014 / 0 043 619 A1.

[0005] DE102020110298A1 discloses a device and method for optically measuring surface topography, in which multiple individual images are acquired at different wavelengths. Unfortunately, this method is slow.

[0006] From DE102016211748A1 a chromatic confocal measuring arrangement for distance measurement is known.

[0007] DE102015210016A1 discloses a method for determining spatially resolved height information of a sample using a wide-field microscope. The height information is determined pixel by pixel using a modulation method. Unfortunately, this method is slow.

[0008] WO 2013 / 171309 A1 discloses a light microscope and a method for image acquisition using a light microscope that operates with a galvanic mirror. A disadvantage is the presence of moving parts.

[0009] WO 99 / 24786 A1 discloses an optoelectronic system based on spatiochromatic triangulation with a prism-based spectrometer array. A disadvantage is the complexity of the system. Prisms also exhibit material-dependent dispersion.

[0010] DE102007019267A1 discloses a measuring arrangement for three-dimensional measurement of an object, which uses a dot matrix as illumination and a prism-based spectrometer arrangement. A similar arrangement is also known from DE102009025815A1.

[0011] From DE102020200214A1 a confocal measuring device for 3D measurement of an object surface is known, which works with a pinhole and a lens array.

[0012] From DE 34 28 593 A1 an optical surface measuring device with a longitudinal dispersion device is known.

[0013] From DE102006007170A1 a method and an arrangement for fast and robust chromatic-confocal 3D measurement technology with a spectral decomposition of the light by prisms are known.

[0014] From WO2019 / 176938A1 a wavelength detector and a confocal measuring device are known which requires a spectral evaluation device.

[0015] DE 10 2005 043 627 A1 discloses a method for distance measurement based on the chromatic confocal imaging principle with a wavelength-selective evaluation of the light remitted from a measuring surface. A distance-dependent wavelength spectrum and a spectral reflection are recorded separately. The measured values of the distance-dependent wavelength spectrum are corrected with corresponding measured values of the spectral reflection. A disadvantage is the complex design. Another disadvantage is that the image plane lies on a pinhole array and the image sensor is arranged at a distance behind it, thus not in the image plane. Since the light hitting the image sensor in such a non-imaging system is highly defocused, the resolution of the image sensor cannot be fully utilized, and the system's resolution is limited to the aperture grid.

[0016] DE102013008582A1 discloses a method and device for chromatic confocal multipoint measurement, in which the distance is scanned point by point. Unfortunately, this method is slow.

[0017] WO 95 / 00 871 A1 discloses a three-dimensional imaging device comprising a broadband light source, an arrangement for forming point sources, a focusing element for focusing the light from each point source onto an object, a beam splitter, a chromatic color filter unit, a plurality of light sensors, and an electronic processing unit for determining the position of each point on the object parallel to the axis of the focusing element. The focusing element is axially chromatic. This device is suitable for three-dimensional inspection. However, this imaging device has elements in the form of a Nipkow disk, i.e., it has movable elements. Such imaging devices are larger in size and therefore limited in their application. At the same time, the movable elements make the structure complex and prone to failure.

[0018] It is therefore an object of the present invention to at least partially overcome at least one of the disadvantages described above. In particular, the object of the invention is to provide a receiving device that requires little space, allows for rapid recording, and has no rotating or moving parts.

[0019] The above object is achieved by a recording device having the features of independent patent claim 1 and by a method having the features of independent patent claim 15. Further features and details of the invention emerge from the subclaims, the description, and the drawings. Features and details described in connection with the recording device according to the invention naturally also apply in connection with the method according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is always made to each other.

[0020] A first aspect of the invention is a recording device for generating a 3D recording of a three-dimensional object, wherein the recording device has a plurality of projection planes for illuminating the object, wherein the plurality of projection planes can be projected onto the object, wherein the projection planes each have a wavelength-dependent distance to a central projection plane from the plurality of projection planes, comprising - a light source for generating a light beam in a pattern plane, - a first beam splitter for splitting an illumination beam from the light beam and for splitting a recording beam from an observation beam reflected by the object, - with a first beam splitter input for receiving the light beam and - with a first beam splitter output for outputting the illumination beam and, - with a second beam splitter input for receiving the observation beam and - with a second beam splitter output for outputting the receiving beam, where the second beam splitter input corresponds to the first beam splitter output, - a chromatic element for focusing the illumination beam split by the first beam splitter onto the plurality of projection planes, - such that the pattern plane is conjugated to one of the projection planes from the plurality of projection planes at a specific projection wavelength, - a second beam splitter for dividing the receiving beam into a first receiving beam portion and a second receiving beam portion, - with a third beam splitter input for receiving the recording beam and, - with a third beam splitter output for outputting the first receiving beam portion and, - with a fourth beam splitter output for outputting the second receiving beam portion, - a focusing optic arranged between the first beam splitter and the second beam splitter, - a detection unit for detecting a first image in a first image plane of the first recording beam portion and a second image in a second image plane of the second recording beam portion of the object, - with a first matrix sensor for two-dimensionally capturing the first intensity data of the first receiving beam portion as a first image in the first image plane, wherein the first matrix sensor is arranged downstream of the third beam splitter output of the second beam splitter with respect to the beam direction of the first receiving beam portion, - with a second matrix sensor for two-dimensionally capturing the second intensity data of the second receiving beam portion as a second image in the second image plane, wherein the second matrix sensor is arranged downstream of the fourth beam splitter output of the second beam splitter with respect to the beam direction of the second receiving beam portion, - wherein the first image and the second image have corresponding pixels, wherein the corresponding pixels can each be assigned to the same object points of the three-dimensional object, - a calculation unit for calculating at least one longitudinal coordinate of a plurality of object points of the object from the corresponding image points of the first image and the second image in order to generate a 3D image of the three-dimensional object.

[0021] The projection planes can be projected onto the object. This can mean that the recording device can be positioned such that the object is at least partially located within the projection planes. With a stationary recording device, the object can be positioned within the projection planes in such a way that the object can be at least partially imaged onto the matrix sensors. Advantageously, the optical axis can intersect the object. In the mathematical sense, the projection planes can be a family of projection planes with a longitudinal coordinate zp in the direction of the optical axis as a parameter, where the longitudinal coordinate zp in turn depends on the projection wavelength λ as a parameter.

[0022] The pattern plane is conjugate to one of the projection planes from the multitude of projection planes, each at a specific projection wavelength. This means that the pattern plane is sharply projected onto a projection plane at a specific projection wavelength. Advantageously, with regard to a projection wavelength, the distance between the pattern plane and the projection plane can be free of further conjugate planes (intermediate image planes). Due to the spectral bandwidth of the light beam, there are several projection planes which can be perpendicular to the optical axis and parallel to one another and which can each be a distance from a central projection plane. The central projection plane can be taken as the projection plane which is conjugate to the pattern plane at a central projection wavelength, i.e. a central wavelength of the light source.

[0023] If the object surface intersects a specific projection plane at a point or line, this point or line can be sharply imaged onto the first and second matrix sensors at the projection wavelength corresponding to this projection plane. At all other wavelengths of the light source, this line cannot be sharply imaged onto the matrix sensors. Thus, the projection plane containing the specified intersection point or line of intersection can be determined by determining the sharply imaged wavelength of the image point or several image points on the line.

[0024] The first image and the second image have corresponding pixels, whereby the corresponding pixels can each be assigned to the same object points of the three-dimensional object. The object can be imaged simultaneously onto the two matrix sensors. Thus, each imaged object point can be imaged with a pixel on the first sensor and a pixel on the second sensor. The pixel on the first sensor and the pixel on the second sensor are then corresponding pixels.

[0025] Two identical matrix sensors can be used, each aligned in the same way. In this case, the corresponding pixels can have the same indices on the first and second matrix sensors. However, the image on the second matrix sensor can also be mirrored relative to the first matrix sensor. In this case, the indices of corresponding pixels can be mirrored accordingly and can be converted accordingly to determine the corresponding pixels.

[0026] It is particularly advantageous if the light beam is flat in the pattern plane. "Flat" means that the entire sensor area of the first and second matrix sensors can be illuminated by the light beam. Or, mathematically speaking, this can mean that the illuminated area of the light source exceeds the corresponding dimensions of the matrix sensors in terms of a length and a width multiplied by a projection scale and an image scale.

[0027] Here, the light source extends to the pattern plane. This means that the pattern plane is located in the beam path before the first beam splitter.

[0028] A pattern is arranged in the pattern plane, which also illuminates the object by the light beam and is thus projected. Advantageously, the pattern of the pattern plane can have at least one first pattern point and at least one second pattern point alternating in at least one direction. In particular, patterns can be used which have a first pattern point with a different specific luminous exitance than the second pattern point, wherein the spectral distribution of the first and second pattern points can be the same. Advantageously, the second pattern point can ideally have an intensity of zero, i.e. be dark, i.e. block out light or be non-emitting. The pattern can represent a local modulation of the specific luminous emission. Despite the local modulation of the specific luminous emission, the color temperature can be location-independent.Advantageously, the first and second images can be evaluated only at the bright image areas that correspond to the first pattern areas. If the pattern contains dark second pattern areas, ideally with an intensity of zero, these areas may appear dark on the image sensors. However, these areas in the image may each contain background radiation and thus have intensity values other than zero. These background intensity values can be used to correct the intensity values present at the bright first image areas. In particular, the intensity value of a first (bright) area can be corrected separately for each matrix sensor using the intensity values of the adjacent second (dark) areas.

[0029] The specific luminous flux can be described as a photometric quantity, the luminous flux emanating from a surface element of a light source.

[0030] The matrix sensors can be implemented, for example, as CCD or CMOS sensors for pixel-by-pixel image capture or as vidicon tubes. These allow spatially resolved light intensity values to be recorded as images.

[0031] The second beam splitter input corresponds to the first beam splitter output. This can mean that the observation beam enters the first beam splitter via the same path as the illumination beam exits, only in the opposite direction. If the first beam splitter is designed as a beam splitter cube, the first beam splitter output and the second beam splitter input can be on the same side of the cube.

[0032] The second beam splitter is provided for splitting the recording beam into a first recording beam portion and a second recording beam portion. The splitting of the recording beam into both portions can be performed using a splitting ratio that is continuously and monotonically wavelength-dependent. The splitting ratio of the second beam splitter can therefore exhibit a second wavelength dependence. This allows the wavelength to be determined from the intensity ratio of corresponding pixels on the first and second matrix sensors.

[0033] A chromatic element can be understood as a transmissive optical element with a focal length that is strongly wavelength-dependent. In contrast to an achromat, the chromatic aberration can be particularly pronounced in a chromatic element. Advantageously, the focal length can be monotonically wavelength-dependent. By means of the wavelength-dependent focal length, a chromatic focus offset can be achieved. This effect is generally often undesirable and is referred to in optical literature as longitudinal chromatic aberration. However, within the scope of this invention, longitudinal chromatic aberration can be exploited. The chromatic element can have a positive refractive power and therefore act as a converging lens. The positive refractive power can be caused by light refraction at the interfaces, by light refraction at internal gradients of the refractive index, and / or by diffraction of the light waves.For example, light can be focused using a Fresnel zone plate and assigned a “positive refractive power” within the meaning of the invention, even if the focusing effect is caused by diffraction of the light.

[0034] The chromatic focus offset of the chromatic element can be described by a longitudinal chromatic constant. The desired longitudinal chromatic constant can advantageously be greater than 1 mm / 100 nm, particularly advantageous at 10 mm / 250 nm, and optimal at 10 mm / 150 nm.

[0035] Examples of chromatic elements include combinations of high-index lenses with an Abbe number less than 45, ideally less than 25, and low-index lenses with an Abbe number greater than 55, ideally greater than 80. Examples of lens combinations are H-ZF71 / N-LASF41 (doublet) or S-NPH7 / LASFN31 / H-ZF71GT (triplet). The lenses with a low Abbe number can be used as a converging lens, and the lenses with a high Abbe number as a diverging lens, with the overall combination having a positive refractive power.

[0036] According to the invention, a calculation unit is provided for calculating at least one longitudinal coordinate of a plurality of object points of the object from the corresponding pixels of the first image and the second image in order to generate the 3D image of the three-dimensional object. As described above, an object point can only be sharply imaged onto the matrix sensors if the object point lies in a projection plane corresponding to a specific wavelength. A sharply imaged object point produces a higher intensity in the image than an object point that is not sharply imaged. The sharply imaged wavelength λ[x,y] can be determined from the intensities of the two pixels of the first and second images corresponding to the object point [x,y]. This can be done, for example, using the following formula: λ[x,y]=λ0−k2*ISensor1[x,y]−ISensor2[x,y]ISensor1[x,y]+ISensor2[x,y] λ0 can be the mean wavelength of the light source. The value k2 is a constant of the device that can be determined by calibration. I Sensor1 [x,y] is the intensity of the pixel on the first sensor, I Sensor2[x,y] on the second sensor. From λ [x,y], the longitudinal coordinate z [x,y] can be calculated. Each projection wavelength λ corresponds to a projection plane zp(λ). Its longitudinal coordinate zp(λ) can then be represented as the result z(x,y) = zp[λ(x,y)]. The longitudinal coordinate z can also be calculated directly from the intensity values by inserting the dependencies into each other. The dependency zp(λ) of the longitudinal coordinate of the projection planes can be calibrated or calculated from the first wavelength dependence of the chromatic element or determined via ray tracing simulation. Determining the longitudinal coordinates for several object points, ideally for all imaged object points, leads to a three-dimensional image of the object, or more precisely, the object surface. This approach enables the creation of the 3D image from a single acquisition cycle (live image).The 3D image can be represented as a set of spatial points [x, y, z] on the object surface. The calculation can be performed using a processing unit.

[0037] In particular, if the second wavelength dependence, i.e., that of the second beam splitter, is nonlinear, a calibration function can be used instead of the above formula to calculate the corresponding sharply imaging wavelength from the intensity values. Such a calibration function can be stored, for example, analytically or in the form of a look-up table.

[0038] By means of the recording device it is possible to carry out the depth calculation and the difference formation to generate a 3D image by imaging on two sensors, whereby the depth calculation to generate the 3D image is independent of the intensity of the light from the light source.

[0039] The design of the mounting device allows the available light to be used optimally.

[0040] Since the use of a spectrometer is not necessary, a higher resolution is possible because no spectral spreading of the sensor pixels is required.

[0041] At the same time, the simplified design allows the recording device to be designed as a mobile device. This allows, for example, components in devices or modules to be recorded without disassembling the devices or modules. Furthermore, applications in recording detailed bone shapes in fossils are conceivable. Furthermore, applications in prosthetics in medicine and dentistry are also being considered, for example, to create a model of a bone for the fabrication of an endoprosthesis or to create a three-dimensional model of a denture or parts thereof.

[0042] Within the scope of the invention, it may be advantageous for the light source to comprise a first divergently radiating light emitter and a first collimating lens. This light emitter can be configured with a small area, ideally as a point source, for example, an LED. Due to the divergence, the light radiation can be spread out over a large area in the pattern plane. The first collimating lens can ensure that the radiation is rectified in the pattern plane.

[0043] The light source can have a first pattern unit with a first pattern, wherein the first pattern is arranged in the pattern plane. This enables easy generation of the pattern in the pattern plane. At the same time, the proximity of the pattern or pattern unit to the light source ensures that the pattern can be well projected onto the object when the object is illuminated. Or more precisely, that the pattern can be well projected onto the plurality of projection planes. This makes it possible for the pattern plane to be sharply imaged onto the object at a sharply imaging projection wavelength pixel by pixel, thus creating a sharp 3D image.

[0044] At the same time, this is a favorable generation of different specific light emissions in order to carry out the depth calculation and thus the calculation of the longitudinal coordinates of the object points from the corresponding image points necessary to generate the 3D image.

[0045] The divergently radiating light emitter can be arranged in a light emitter plane, and a plane conjugate to the light emitter plane can be present, which is arranged between the first beam splitter and the object, in particular in front of the projection planes, more precisely, in front of the first of the projection planes. Particularly advantageously, the plane conjugate to the light emitter plane can be arranged at the position of the chromatic element. This beam path described in this paragraph can be understood as a further beam path interwoven with the projection beam path, as is known, for example, from Köhler illumination. The path between the light emitter and the projection planes can advantageously have exactly one plane conjugate to the light emitter plane.

[0046] The light source can also be a floodlight, which can be arranged directly in the pattern plane. It is also conceivable that the pattern unit is integrated into the light source.

[0047] It is also conceivable for the pattern unit to have a second pattern, the second pattern being inverted to the first pattern. This enables the creation of a planar light distribution in the pattern plane. Advantageously, the first and second patterns can be provided one after the other. For this purpose, the pattern unit can be designed to be switchable. Particularly advantageously, the first pattern can be a checkerboard pattern, and the second pattern can be inverted, i.e., by swapping the light and dark areas.

[0048] Within the scope of the invention, it is conceivable that a first deflecting mirror for deflecting the illumination beam by a specific angle, in particular for deflecting by an obtuse angle, is provided between the light source and the first beam splitter and / or that a second deflecting mirror for deflecting the observation beam by a specific angle, in particular for deflecting by an obtuse angle, is provided between the chromatic element and the object.

[0049] By using the first deflecting mirror and / or the second deflecting mirror, the beam bundles, i.e., the illumination beam bundle and the observation beam bundle, can be deflected. This influences the course of the beam path so that it can be adapted to spatial constraints. Thus, using the deflecting mirror, the installation space of the recording device can be adapted to the user's needs or the area of application. This is particularly advantageous for mobile applications.

[0050] Within the scope of the invention, it can be provided that a second collimator is arranged between the light source and the first beam splitter. According to the invention, a focusing optics is arranged between the first beam splitter and the second beam splitter.

[0051] This results in the illumination beam through the second collimator and the observation beam at the first beam splitter having a parallel beam section.

[0052] The focusing optics focus the observation beam in such a way that the installation space can be reduced. At the same time, the positioning of the focusing optics has a positive effect on the generation of the 3D image.

[0053] It is also conceivable for the fixture to be free of rotating elements. This simplifies the fixture design, reducing mechanical complexity and thus reducing susceptibility to wear and associated downtime. At the same time, moving parts lead to increased costs and design effort, which can be reduced by eliminating moving parts.

[0054] It is also conceivable for the chromatic element to comprise a diffractive optical element and / or a Fresnel lens and / or a meta-lens and / or a combination of a positive flint glass lens and a negative crown glass lens. Likewise, the chromatic element can be a Fresnel zone plate.

[0055] A diffractive optical element (DOE) is a type of optical component that manipulates light waves through the process of diffraction. It consists of microstructures or patterns that can control the phase or amplitude of the incident light.

[0056] A Fresnel lens is a type of compact optical component that uses a series of concentric grooves on its surface to focus light. The lens is designed to use less material and weight than conventional lenses, making it ideal for applications where size and weight are important, such as lighthouses, overhead projectors, camera lenses, and in-situ probes.

[0057] The metalens is a concept in physics and metamaterials that involves creating novel optical devices using artificially engineered materials. These metamaterials possess unique properties that allow light to be manipulated in unconventional ways and create lenses with extraordinary functions. Unlike conventional lenses based on refraction, metalenses direct light through sub-wavelength structures, enabling ultra-compact and high-resolution imaging systems. The design and implementation of metalenses hold significant potential for revolutionizing various optical applications, including microscopy, imaging, and data communications.

[0058] A flint glass lens is a lens made of optical glass characterized by a high refractive index and high dispersion. It is made from a special composition based on quartz and lead oxide and has an Abbe number of less than 50. The addition of lead oxide gives flint glass its unique optical properties and makes it suitable for the manufacture of lenses and prisms used in optical instruments such as telescopes, microscopes, and camera lenses. The higher refractive index of flint glass allows for better light diffraction, while its dispersion properties enable the separation of light into its individual colors, which is essential for correcting chromatic aberrations in optical systems.

[0059] A crown glass lens is a lens made of optical glass with a relatively low refractive index and low dispersion. It is made from a special composition based on quartz and potassium oxide and has an Abbe number greater than 50.

[0060] In optical systems, crown glass lenses are typically used to correct chromatic aberrations because they have a different refractive index than flint glass lenses. When combined with flint glass lenses, crown glass lenses help reduce chromatic aberration and improve the overall optical performance of the system.

[0061] Within the scope of the invention, it is optionally possible for a mask, in particular a shadow mask, such as a structured black chrome plate, or a pixel-by-pixel controllable TFT display or a pixel-by-pixel controllable backlit LCD display to be provided for generating the first pattern of the first pattern unit.

[0062] These configurations produce the pattern particularly simply and reliably. The pattern can be formed as a homogeneously illuminated surface or, advantageously, can have illuminated regions arranged translationally symmetrically in at least one direction, particularly advantageously in two linearly independent directions, which are surrounded by unilluminated regions.

[0063] A mask, a TFT display, or an LCD display allows the pattern to be created as a striped pattern, a checkerboard pattern, a honeycomb pattern with light and dark honeycombs, or a perforated grid. The pattern can advantageously have a period length of translational symmetry of 0.010 mm to 0.5 mm. Advantageously, there can be 10 to 1000 pattern periods.

[0064] Especially with displays, the pattern can be easily and quickly adapted to changing areas of application in terms of its period length or structure.

[0065] Furthermore, it can be provided within the scope of the invention that the second beam splitter comprises a first filter and / or a second filter, wherein the first filter for wavelength-dependent filtering of the first receiving beam portion is provided at the third beam splitter output of the second beam splitter and / or the second filter for wavelength-dependent filtering of the second receiving beam portion is provided at the fourth beam splitter output of the second beam splitter.

[0066] Wavelength-dependent filtering by the first filter and / or the second filter offers several advantages when acquiring 3D images. By simultaneously capturing a scene at multiple wavelengths, it enables the capture of depth information and facilitates accurate 3D reconstructions. Spectral imaging allows for better discrimination between different structures within the scene, resulting in more precise and detailed 3D representations. The use of the filters allows for the use of a cost-effective, wavelength-independent beamsplitter mirror.

[0067] It is particularly advantageous if the first filter has a monotonically increasing wavelength-dependent transmission and / or the second filter has a monotonically decreasing wavelength-dependent transmission.

[0068] A monotonically increasing wavelength-dependent transmission of an optical filter means that the transmission of the filter increases continuously with increasing wavelength. This means that the higher the wavelength of the light, the more light is transmitted through the filter. It is therefore a filter that increases the transmittance of light depending on its wavelength. In this way, the first and second portions of the recording beam can be received by the matrix sensors filtered with different wavelength dependencies, so that the wavelength of the respective pair of pixels can be deduced from the intensity ratio of the corresponding pixels.

[0069] A second beam splitter can also be advantageously used, which, without a filter, already has a monotonically wavelength-dependent beam splitter ratio. This can be achieved with a dielectric mirror layer that exhibits a continuous reflectivity curve with respect to wavelength. This can have the advantage of eliminating the need for filters, thus making more light available to the matrix sensors.

[0070] With regard to the present invention, it is conceivable that the chromatic element has a positive refractive power, wherein the refractive power has a first wavelength dependence, in particular a first monotonic wavelength dependence.

[0071] A positive refractive power of a chromatic element means that the element is capable of gathering and focusing light rays. It may have a convex shape and can be used to converge light rays.

[0072] The advantage of a chromatic element's positive refractive power can lie in its ability to deliberately create chromatic aberration in the illumination beam path and compensate for it in the observation beam path. Chromatic aberration is a widespread optical distortion that occurs when different colors of light are focused at different points. This leads to color fringing and reduced image sharpness in photography, but can be intentionally exploited here, especially in the form of longitudinal chromatic aberration.

[0073] This property is particularly advantageous for the precise reproduction of the pattern for generating the 3D image with the recording device, such as for capturing a three-dimensional surface model in order to accurately reproduce the structure of the object. By generating chromatic aberration, the chromatic element can enable the determination of longitudinal coordinates (i.e., in the direction of the optical axis) of the object's surface.

[0074] Furthermore, it is conceivable for the first beam splitter to have a splitting ratio of 80:20 to 20:80, preferably 70:30 to 30:70, and more preferably 60:40 to 40:60. The splitting ratio of the first beam splitter can be wavelength-independent. The first beam splitter is used to split the illumination beam from the light beam and to simultaneously direct the observation beam to the matrix sensors. The remainder of the illumination beam can be discarded as a residual beam.

[0075] The second beam splitter may have a second wavelength dependence, in particular a second monotonic wavelength dependence.

[0076] The second beam splitter splits the receiving beam into a first receiving beam portion and a second receiving beam portion depending on the wavelength. In this case, the spatially dependent wavelength information inherent in the receiving beam can be converted into spatially dependent intensity information, thus enabling the wavelength information to be obtained without the use of a spectrometer.

[0077] Beamsplitters offer versatility and efficiency in imaging systems, making them valuable tools for capturing and analyzing complex visual information in various scientific, medical, and industrial applications.

[0078] Within the scope of the invention, it may be advantageous for the first beam splitter and / or the second beam splitter to comprise a beam splitter plate or a beam splitter cube.

[0079] The design of the first and second beam splitters can be selected depending on the available installation space. This increases the flexibility of the mounting device design.

[0080] Within the scope of the invention, it is conceivable for the light beam to be a spectrally broadband light beam with a spectral bandwidth of at least 100 nm in a wavelength range from 400 nm to 1100 nm. Advantageously, the bandwidth can be at least 150 nm, particularly advantageously at least 200 nm. Furthermore, it can be advantageous to select a bandwidth of less than 300 nm in order to sufficiently minimize artifacts, for example, due to stray light or exceeding the specifications of anti-reflective coatings on the optical components used.

[0081] The advantage of using a broadband light beam for 3D imaging is that a wide spectrum of wavelengths can be captured simultaneously, increasing the accuracy and versatility of the acquired data.

[0082] Broadband light beams offer improved depth resolution in 3D imaging because they can more effectively measure various surface features due to the different wavelengths they encompass. The detectable depth range can also be expanded by increasing the bandwidth of the light beams.

[0083] The use of a broadband light beam enables the capture of fine details and complex surface structures that may not be captured with narrowband light sources.

[0084] With a wider range of wavelengths, broadband light facilitates precise measurements of objects with different reflectivities and enables more comprehensive and reliable 3D imaging of the objects.

[0085] Within the scope of the invention, it can be provided that a numerical aperture NA of the illumination of the object points on the object has a range from NA=0.05 to NA=0.25, preferably NA=0.08 to NA=0.18, more preferably NA=0.10 to NA=0.14. Advantageously, the object can be illuminated with an illumination beam path formed telecentrically between the chromatic element and the object and / or the object can be detected with an observation beam path formed telecentrically between the chromatic element and the object. The aforementioned telecentricity of the illumination beam path and / or the observation beam path can reduce, and ideally eliminate, an interfering transverse chromatic aberration. Particularly advantageously, both aforementioned telecentricities can be present.

[0086] The numerical aperture of the illumination of the object points is a measurement of the imaging device that indicates how much light from a point on the object can be captured in the imaging device. It is determined by the numerical aperture of the illumination optics and the illumination source.

[0087] The larger the numerical aperture of the illuminator, the more light is introduced into the imaging device and the more details and fine structures can be made visible. A higher numerical aperture improves the resolution and contrast performance of the imaging device. The numerical aperture specified above also serves to minimize potentially disruptive lateral chromatic aberration when imaging the object. However, an excessively high numerical aperture can increase the size of the device and lead to imaging errors. Therefore, an upper limit for the numerical aperture is recommended above, and a range that has proven to be favorable is specified.

[0088] A second aspect of the invention is a method for generating a 3D image of a three-dimensional object, in particular with a recording device according to the first aspect of the invention, comprising the following steps: - Arranging the three-dimensional object in a plurality of projection planes of the recording device; - Illuminating the three-dimensional object, comprising the following substeps: - generating the light beam using a light source in a pattern plane, - receiving the generated light beam by means of a first beam splitter input of a first beam splitter, - dividing an illumination beam from the light beam by means of the first beam splitter, - outputting the split illumination beam by means of a first beam splitter output of the first beam splitter, - focusing the emitted illumination beam onto the plurality of projection planes by means of a chromatic element, wherein the pattern plane is projected and wherein the pattern plane is conjugated to one of the projection planes from the plurality of projection planes at a respective projection wavelength, - Capturing the three-dimensional object, comprising the following sub-steps: - Reflecting the illumination beam as an observation beam by means of the three-dimensional object, - Passing the observation beam through the chromatic element, - receiving the transmitted observation beam by means of a second beam splitter input of the first beam splitter, wherein the second beam splitter input corresponds to the first beam splitter output, - dividing a recording beam from the observation beam by means of the first beam splitter, - outputting the split recording beam by means of a second beam splitter output of the first beam splitter, - receiving the output recording beam by means of a third beam splitter input of a second beam splitter, wherein a focusing optics is arranged between the first beam splitter and the second beam splitter, - dividing, in particular monotonically wavelength-dependently dividing, the receiving beam into a first receiving beam portion and a second receiving beam portion by means of the second beam splitter, - Outputting the first receiving beam component by means of the third beam splitter output of the second beam splitter and - outputting the second receiving beam portion by means of the fourth beam splitter output of the second beam splitter, - two-dimensionally detecting the first intensity data of the first recording beam component as a first image of a first image plane by means of a first matrix sensor of a detection unit and, - two-dimensionally capturing the second intensity data of a second recording beam component as a second image of a second image plane by means of a second matrix sensor of the capturing unit, wherein the first image and the second image have a plurality of corresponding pixels, each of which is assigned to an object point of the illuminated object, - Calculating at least one longitudinal coordinate of a plurality of object points of the object from the corresponding image points of the first image and second image by means of the calculation unit in order to generate the 3D image of the object.

[0089] The object can be illuminated using a telecentric beam path between the chromatic element and the object. Additionally or alternatively, the object can be captured using a telecentric beam path between the chromatic element and the object. This telecentricity can reduce, and ideally eliminate, disruptive lateral chromatic aberration.

[0090] Image points are understood here as pixels or pixel clusters, whereby image points can correspond in pairs (i.e., a pixel of the first image with a pixel of the second image), so that each pair of image points represents the image of one and the same object point. Pixel clusters can be adjacent pixels of the sensor that are combined by binning, for example, to increase the sensor's light sensitivity and / or image processing speed.

[0091] The reflection of the illumination beam as an observation beam can occur by reflection and / or by light scattering.

[0092] It is further conceivable that the light source comprises a pattern unit with a first pattern, wherein the first pattern is arranged in the pattern plane, so that the first pattern of the pattern plane is projected sharply onto a pattern projection plane from the plurality of projection planes at the assigned projection wavelength, while the projection onto the other projection planes may be blurred at this wavelength.

[0093] Advantageously, the pattern can have a period length of translational symmetry of 0.010 mm to 0.5 mm. Advantageously, there can be 10 to 1000 pattern periods.

[0094] This leads to a favorable generation of different specific light emissions in order to carry out the depth calculation and thus the calculation of the longitudinal coordinates of the object points from the corresponding image points necessary to generate the 3D image.

[0095] It is also conceivable that the plurality of projection planes are conjugated to the first image plane and the second image plane in order to calculate the longitudinal coordinate.

[0096] Within the scope of the invention, it is optionally possible for the pattern in the pattern plane to have first pattern points and second pattern points alternating in at least one direction, the first pattern points having a first specific light emission and the second pattern points having a second, lower, specific light emission, in particular a specific light emission of zero, and the second pattern points causing darkened image points in the first image and in the second image, and before calculating the longitudinal coordinate, the intensity values of the darkened image points are used to correct the intensity values of adjacent non-darkened image points in the first and second image. The first specific light emission can be constant across the first pattern points, ie independent of location, and the same for all first pattern points.

[0097] The different pattern areas can each have different specific light emissions, i.e. light and dark areas, which are created, for example, by the mask and can have the shape of a checkerboard or a striped pattern.

[0098] The different specific light emissions lead to different intensity values of the intensity data. Since these different intensities are available for each pixel and / or neighboring pixels, they can be used to correct the longitudinal coordinates. This allows systematic errors and / or contributions to the recorded intensities resulting from stray light and blurred images from other object areas at non-sharp wavelengths to be corrected before calculating the longitudinal coordinates.

[0099] Furthermore, within the scope of the invention, it can be provided that a control unit controls the light source, whereby a light distribution of the light source is changed. In particular, a checkerboard pattern or striped pattern can be used to generate a first 3D image of the object. In a further step, an inverted checkerboard pattern or striped pattern, i.e., with swapped light and dark areas compared to the first pattern, can be used to generate a second 3D image of the object. The first and second images can then be combined, for example by means of the computing unit, to generate an improved 3D image of the object.

[0100] The light distribution control can also allow calibration of the light source or light distribution depending on the object to be illuminated and recorded in order to improve the accuracy of the 3D recording.

[0101] Further advantages, features, and details of the invention will become apparent from the following description, which describes several embodiments of the invention in detail with reference to the drawings. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination. The invention is illustrated in the following figures: Fig. 1 a schematic representation of a receiving device according to a first embodiment, Fig. 2 a schematic representation of a receiving device according to a second embodiment, Fig. 3 a schematic representation of a receiving device according to a third embodiment, Fig. 4 a schematic representation of a method according to the invention, Fig. 5 a chromatic element, Fig. 6 another chromatic element, Fig. 7 and Fig. 8 exemplary filter characteristics, Fig. 9 a beam splitter characteristic curve.

[0102] In the Fig. 1 to 3 each depict a recording device 10 for generating 130 a 3D image of a three-dimensional object 11. The recording device 10 is free of rotating elements. The recording device 10 has a plurality of projection planes 12 for illuminating 120 the object 11, wherein the plurality of projection planes 12 can be projected onto the object 11, wherein the projection planes 12 each have a wavelength-dependent distance zp(λ) from a central projection plane 12 of the plurality of projection planes 12.

[0103] The recording devices 10 each comprise a light source 13 for generating 130 a light beam 14 in a pattern plane 15. The light source 13 of the Fig. 1 to Fig. 3 a divergently radiating light emitter 41 which comprises a first collimation optics 42. The collimation optics 42 is in Fig. 1 is integrated in the light emitter 41. The light beam 14 is a spectrally broadband light beam 14 with a spectral bandwidth of at least 100 nm in a wavelength range from 400 nm to 1100 nm.

[0104] In the Fig. 2 and Fig. 3, the light emitter 41 and the collimating optics 42 are two separate components of the recording device 10, which are arranged at a distance from each other. The respective distance zp(λ) can be adapted to the respective application. In addition to the first collimating optics 42, the recording device 10 of the Fig. 2 and Fig. 3 a second collimator 46, which is provided between the light source 13 and the first beam splitter 16.

[0105] Furthermore, a first beam splitter 16 designed as a beam splitter plate 51 is provided for splitting 150 an illumination beam 17 from the light beam 14 and for splitting 150 a recording beam 18 from an observation beam 19 reflected by the object 11.

[0106] The first beam splitter 16 has a first beam splitter input 20 for receiving 140 the light beam 14 and a first beam splitter output 21 for outputting 160 the illumination beam 17 and a second beam splitter input 22 for receiving 140 the observation beam 19 and a second beam splitter output 23 for outputting 160 the recording beam 18. The second beam splitter input 22 corresponds to the first beam splitter output 21. The first beam splitter 16 of the Fig. 1 to 3 has a splitter ratio of 80:20 for the light beam 14, so that 80% exits the first beam splitter 16 via the first beam splitter output 21 as the illumination beam 17 for illuminating 120 the object 11. The first beam splitter 16 also has a splitter ratio of 80:20 for the observation beam 19, so that 80% exits the first beam splitter 16 via the second beam splitter output 23. In a modification of this embodiment, a beam splitter with a splitter ratio of 50:50 is used.

[0107] For focusing 170 the illumination beam 17 split by the first beam splitter 16 onto the plurality of projection planes 12, Fig. 1 to 3, a chromatic element 24 with a positive refractive power and a first monotonic wavelength dependence is provided. This element focuses the illumination beam 17 such that the pattern plane 15 is conjugated to one of the projection planes 12 from the plurality of projection planes 12, each at a specific projection wavelength.

[0108] A Fresnel lens is provided in all embodiments. These are very compact and suitable for recording devices 10 that do not have a lot of space available. As a result, the object 11 can be illuminated with an illumination beam path formed telecentrically between the chromatic element 24 and the object 11, and can be captured with an observation beam path formed telecentrically between the chromatic element 24 and the object 11.

[0109] In the beam path of the recording beam 18, a second beam splitter 25 designed as a beam splitter cube 52 is then provided for splitting 270 the recording beam 18 into a first recording beam portion 26 and a second recording beam portion 27.

[0110] The second beam splitter 25 provides a third beam splitter input 28 for receiving 140 the receiving beam 18, a third beam splitter output 29 for outputting 160 the first receiving beam portion 26, a fourth beam splitter output 30 for outputting 160 the second receiving beam portion 27, and has a second monotonic wavelength dependence. A first filter 49 for wavelength-dependent filtering of the first receiving beam portion 26 is provided at the third beam splitter output 29 of the second beam splitter 25, and a second filter 50 for wavelength-dependent filtering of the second receiving beam portion 27 is provided at the fourth beam splitter output 30 of the second beam splitter 25.

[0111] Furthermore, the receiving device 10 of the Fig. 1 to 3, a detection unit 31 for detecting 200 a first image 32 in a first image plane 33 of the first recording beam portion 26 and a second image 34 in a second image plane 35 of the second recording beam portion 27 of the object 11. For this purpose, a first matrix sensor 36 is provided for two-dimensionally detecting 200 the first intensity data 37 of the first recording beam portion 26 as a first image 32 in the first image plane 33, wherein the first matrix sensor 36 is arranged downstream of the third beam splitter output 29 of the second beam splitter 25 with respect to the beam direction of the first recording beam portion 26.In addition, a second matrix sensor 38 is provided for two-dimensionally capturing 200 the second intensity data 39 of the second recording beam portion 27 as a second image 34 in the second image plane 35, wherein the second matrix sensor 38 is arranged downstream of the fourth beam splitter output 30 of the second beam splitter 25 with respect to the beam direction of the second recording beam portion 27. The first image 32 and the second image 34 comprise corresponding pixels, wherein the corresponding pixels can each be assigned to the same object points of the three-dimensional object 11.

[0112] For calculating at least one longitudinal coordinate of a plurality of object points of the object 11 from the corresponding image points of the first image and the second image, the recording device 10 has a respective calculation unit 40 in order to generate 130 a 3D image of the three-dimensional object 11.

[0113] In the examples of the Fig. 1 and Fig. 3, the respective recording device 10 provides a focusing optics 47 arranged between the first beam splitter 16 and the second beam splitter 25. Thus, the split recording beam 18 can be focused to the third beam splitter input 28 of the second beam splitter.

[0114] Both the Fig. 1 as well as the Fig. 2 and Fig. 3 have a first pattern unit 43 with a first pattern, wherein the first pattern 53 is arranged in the pattern plane 15. The pattern unit of the Fig. 1 is also integrated in the light emitter 41, so that the pattern plane 15 is identical to the radiating plane of the light emitter. Fig. 2 and Fig. 3, the pattern unit 43 is arranged in the beam path of the light beam bundling unit 14 after the first collimation optics 43. The position of the pattern plane 15 also shifts with the position of the first collimation optics 42.

[0115] The first pattern in the Fig. 1 is generated by a pixel-by-pixel backlit LCD display. In the Fig. 2 and Fig. 3, the pattern unit 43 provides a mask, in this case a structured black chrome plate. It should be noted that the representation of patterns 53, 54 in the figures is only schematic. In fact, it is a flat pattern in pattern plane 15, i.e., perpendicular to the drawing plane.

[0116] The pattern 53 is transported by the split and reflected beams and is thus detectable in the illumination beam 17, the observation beam 19, the recording beam 18, and the first recording beam portion 26 and the second recording beam portion 27. The pattern 53 is a checkerboard pattern in the present case and thus has a first pattern location 54 with a first wavelength and / or specific light emission and a second pattern location 55 with a second wavelength and / or specific light emission. These patterns 53 and the associated different intensity data can be used to correct the calculated longitudinal coordinates, resulting in an improved 3D image.

[0117] The receiving device 10 of the Fig. 3 has a small installation space; in order to accomplish this without having to accept any loss in the quality of the 3D images, a first deflecting mirror 44 for deflecting the illumination beam 17 by a specific angle and a second deflecting mirror 45 for deflecting the observation beam 19 by a specific angle are provided. The first deflecting mirror 44 is provided between the light source 13 and the first beam splitter 16. The first deflecting mirror 44 deflects the illumination beam 17 by an obtuse angle. The second deflecting mirror 45 is provided between the chromatic element 24 and the object 11. The second deflecting mirror 45 deflects the observation beam 19 by an obtuse angle.

[0118] The light source 13 as well as the first collimation optics 42, the second collimator 46 and the Fresnel lens 48 of the Fig. 1 to 3 are designed such that a numerical aperture NA of the illumination of the object points on the object 11 has a range of NA=0.05 to NA=0.25.

[0119] In Fig. 2, the divergently emitting light emitter 13 is arranged in a light emitter plane. A beam path 62 intertwined with the projection beam path is shown with dotted lines. In this intertwined beam path, a plane 63 conjugate to the light emitter plane is present, which can be identified by the dotted lines converging on the optical axis 65. The plane 63 of the intertwined beam path 62 conjugate to the light emitter plane lies between the first beam splitter 16 and the object 11, in this example in front of the first of the projection planes 12, i.e., in this case in front of zp(λ1). In a modification of the exemplary embodiment (not shown), the plane 63 conjugate to the light emitter plane can be arranged at the position of the chromatic element 24.The beam path described in this paragraph can be viewed as a further beam path intertwined with the projection beam path, as is known, for example, from Köhler illumination. The plane 63 conjugate to the light emitter plane is the plane perpendicular to the optical axis 65. For clarity, only the intersection point of this plane with the optical axis 65 is shown here.

[0120] In addition, as in Fig. 1, a control unit 61 is provided, this control unit 61 controls the light source 13 so that its light distribution is changed.

[0121] In Fig. 4 is a method 100 for generating 130 a 3D image of a three-dimensional object 11, in particular with a recording device 10 according to one of the Fig. 1 to 3, comprising the following steps: - arranging 110 the three-dimensional object 11 in a plurality of projection planes 12 of the recording device 10; - Illuminating 120 the three-dimensional object 11, comprising the following substeps: - generating 130 the light beam 14 by means of a light source 13 in a pattern plane 15, - receiving 140 the generated light beam 14 by means of a first beam splitter input of a first beam splitter 16, - dividing 150 an illumination beam 17 from the light beam 14 by means of the first beam splitter 16, - outputting 160 the split illumination beam 17 by means of a first beam splitter output 21 of the first beam splitter 16, - focusing 170 the output illumination beam 17 onto the plurality of projection planes 12 by means of a chromatic element 24, wherein the pattern plane 15 is projected and wherein the pattern plane 15 is conjugated to one of the projection planes 12 from the plurality of projection planes 12 at a respective specific projection wavelength, - Detecting 200 the three-dimensional object 11, comprising the following substeps: - Reflecting 210 the illumination beam 17 as an observation beam 19 by means of the three-dimensional object 11, - Passing 220 the observation beam 19 through the chromatic element 24, - receiving 230 the transmitted observation beam 19 by means of a second beam splitter input of the first beam splitter, wherein the second beam splitter input 22 corresponds to the first beam splitter output 21, - dividing 240 a receiving beam 18 from the observation beam 19 by means of the first beam splitter 16, - Outputting 250 the split recording beam 18 by means of a second beam splitter output 23 of the first beam splitter 16, - receiving 230 the output recording beam 18 by means of a third beam splitter input 28 of a second beam splitter 25, - dividing 270, in particular monotonically wavelength-dependent dividing 270, the receiving beam 18 into a first receiving beam portion 26 and a second receiving beam portion 27 by means of the second beam splitter 25, - Outputting 250 of the first receiving beam portion 26 by means of the third beam splitter output 29 of the second beam splitter 25 and - Outputting 250 the second receiving beam portion 27 by means of the fourth beam splitter output 30 of the second beam splitter 25, - two-dimensional detection 200 of the first intensity data 37 of the first recording beam portion 26 as a first image 32 of a first image plane 33 by means of a first matrix sensor 36 of a detection unit 31 and, - two-dimensional detection 200 of the second intensity data 39 of a second recording beam portion 27 as a second image 34 of a second image plane 35 by means of a second matrix sensor 38 of the detection unit 31, wherein the first image 32 and the second image 34 have a plurality of corresponding pixels, each of which is assigned to an object point of the illuminated object 11, - Calculating 300 at least one longitudinal coordinate of a plurality of object points of the object 11 from the corresponding image points of the first image and second image by means of the calculation unit 40 in order to generate 130 the 3D image of the object 11.

[0122] In the illustrated method 100, the light source 13 has a pattern unit with a first pattern 53, wherein the first pattern 53 is arranged in the pattern plane 15, so that the first pattern 53 of the pattern plane 15 is projected sharply onto a pattern projection plane 56 from the plurality of projection planes 12 at the sharply imaging projection wavelength, but is projected out of focus on the other projection planes.

[0123] The plurality of projection planes 12 are conjugated to the first image plane 33 and the second image plane 35 in order to calculate the longitudinal coordinate 300.

[0124] The pattern 53 in the pattern plane 15 has, alternating in at least one direction, at least one first pattern location 54 and at least one second pattern location 55. The at least one first pattern location 54 has a first wavelength and the at least one second pattern location 55 has a second wavelength, wherein the at least one first pattern location 54 of the pattern 53 and the at least one second pattern location 55 of the pattern 53 on the pattern plane 15 are conjugated to the respective wavelength-dependent pattern projection plane 12, 56. This results in the respective wavelength-dependent pattern projection plane 12, 56 being conjugated to the first image plane 33 and the second image plane 35, whereby the pattern is also recognizable in the images.

[0125] The first intensity data 37 of the first image have at least one first intensity value 57 for the at least first wavelength of the at least one first pattern location 54 and at least one second intensity value 58 for the at least second wavelength and the at least one second pattern location 55. The second intensity data 39 have at least one third intensity value 59 for the at least one first wavelength of the at least one first pattern location 54 and at least one fourth intensity value 60 for the at least one second wavelength of the at least one second pattern location 55. The at least one second intensity value 58 is used to correct 320 the at least one first intensity value 57, and the at least one fourth intensity value 60 is used to correct 320 the at least one third intensity value 59.

[0126] In addition, the light distribution of the light source 13 is changed by controlling the light source 13 by means of a control unit 61.

[0127] Fig. 5 shows a chromatic element as a doublet lens

[0128] Fig. Figure 6 shows another chromatic element, designed as a diffractive Fresnel lens. The diffractive zones are clearly visible, which are closer together toward the lens edge. At the same time, the zones on the left side of the lens have inclined surfaces. This allows for more effective light focusing than with a Fresnel zone plate.

[0129] Fig. 7 shows an exemplary spectral filter characteristic of the first filter 49 and Fig. 8 those of the second filter 50, as can be used in the second beam splitter 25. The use of such filters allows the second beam splitter mirror to be designed to be wavelength-independent.

[0130] Fig. Figure 9 shows the characteristic curve of another embodiment of a second beam splitter. This is implemented using a dielectric mirror layer, which exhibits the reflectivity shown at a 45° angle of incidence. The transmission is then ideally 1 minus the reflectivity. With this embodiment, it is possible to dispense with the first and second filters.

[0131] In the Fig. Figures 7 to 9 show idealized characteristic curves; in practice, technical nonlinearities would be expected, particularly in the upper and lower wavelength ranges. These can be compensated for by appropriate correction functions, which can be determined through calibration.

Claims

[1] Recording device (10) for generating a 3D recording of a three-dimensional object (11), wherein the recording device (10) has a plurality of projection planes (12) for illuminating the object (11), wherein the plurality of projection planes (12) can be projected onto the object (11), wherein the projection planes (12) each have a wavelength-dependent distance (zp(λ)) to a central projection plane (12) from the plurality of projection planes (12), comprising - a light source (13) for generating a light beam (14) in a pattern plane (15), - a first beam splitter (16) for splitting an illumination beam (17) from the light beam (14) and for splitting a recording beam (18) from an observation beam (19) reflected by the object (11), - with a first beam splitter input (20) for receiving the light beam (14) and - with a first beam splitter output (21) for outputting the illumination beam (17) and, - with a second beam splitter input (22) for receiving the observation beam (19) and - with a second beam splitter output (23) for outputting the receiving beam (18), wherein the second beam splitter input (22) corresponds to the first beam splitter output (21), - a chromatic element (24) for focusing the illumination beam (17) split by the first beam splitter (16) onto the plurality of projection planes (12) such that the pattern plane (15) is conjugated to one of the projection planes (12) from the plurality of projection planes (12) at a specific projection wavelength, - a second beam splitter (25) for dividing the receiving beam (18) into a first receiving beam portion (26) and a second receiving beam portion (27), - with a third beam splitter input (28) for receiving the receiving beam (18) and, - with a third beam splitter output (29) for outputting the first receiving beam portion (26) and, - with a fourth beam splitter output (30) for outputting the second receiving beam portion (27), - a focusing optics (47) arranged between the first beam splitter (16) and the second beam splitter (25), - a detection unit (31) for detecting a first image (32) in a first image plane (33) of the first recording beam portion (26) and a second image (34) in a second image plane (35) of the second recording beam portion (27) of the object (11), - with a first matrix sensor (36) for two-dimensionally detecting the first intensity data (37) of the first recording beam portion (26) as a first image (32) in the first image plane (33), wherein the first matrix sensor (36) is arranged downstream of the third beam splitter output (29) of the second beam splitter (25) with respect to the beam direction of the first recording beam portion (26), - with a second matrix sensor (38) for two-dimensionally detecting the second intensity data (39) of the second receiving beam portion (27) as a second image (34) in the second image plane (35), wherein the second matrix sensor (38) is arranged downstream of the fourth beam splitter output (30) of the second beam splitter (25) with respect to the beam direction of the second receiving beam portion (27), - wherein the first image (32) and the second image (34) have corresponding pixels, wherein the corresponding pixels can each be assigned to the same object points of the three-dimensional object (11), - a calculation unit (40) for calculating at least one longitudinal coordinate of a plurality of object points of the object (11) from the corresponding image points of the first image and the second image in order to generate a 3D image of the three-dimensional object (11). [2] Receiving device (10) according to claim 1, characterized by in that the light source (13) comprises a first divergently emitting light emitter (41) and a first collimation optic (42) and / or has a first pattern unit (43) with a first pattern, wherein the first pattern (53) is arranged in the pattern plane (15). [3] Receiving device (10) according to claim 1 or 2, characterized by , that a first deflecting mirror (44) for deflecting the illumination beam (17) by a specific angle, in particular for deflecting by an obtuse angle, is provided between the light source (13) and the first beam splitter (16) and / or that a second deflecting mirror (45) for deflecting the observation beam (19) by a specific angle, in particular for deflecting by an obtuse angle, is provided between the chromatic element (24) and the object (11). [4] Receiving device (10) according to one of the preceding claims, characterized by that a second collimator (46) is arranged between the light source (13) and the first beam splitter (16). [5] Receiving device (10) according to one of the preceding claims, characterized by that the receiving device (10) is free of rotating elements. [6] Receiving device (10) according to one of the preceding claims, characterized bythat the chromatic element (24) comprises a diffractive optical element and / or a Fresnel lens (48) and / or a meta-lens and / or a combination of a positive flint glass lens with a negative crown glass lens and / or a Fresnel zone plate. [7] Receiving device (10) according to one of the preceding claims, characterized by that a mask, in particular a structured black chrome plate, or a pixel-by-pixel controllable TFT display or a pixel-by-pixel controllable backlit LCD display is provided for generating the first pattern of the first pattern unit (43). [8] Receiving device (10) according to one of the preceding claims, characterized by , that a first filter (49) for wavelength-dependent filtering of the first receiving beam component (26) is provided at the third beam splitter output (29) of the second beam splitter (25) and / or that a second filter (50) for wavelength-dependent filtering of the second receiving beam component (27) is provided at the fourth beam splitter output (30) of the second beam splitter (25). [9] Receiving device (10) according to one of the preceding claims, characterized by that the chromatic element (24) has a positive refractive power, wherein the refractive power has a first wavelength dependence, in particular a first monotonic wavelength dependence. [10] Receiving device (10) according to one of the preceding claims, characterized by that the first beam splitter (16) has a splitter ratio of 80:20 to 20:80, preferably from 70:30 to 30:70, more preferably from 60:40 to 40:60, and / or that the second beam splitter (25) has a second wavelength dependence, in particular a second monotonic wavelength dependence. [11] Receiving device (10) according to one of the preceding claims, characterized bythat the first beam splitter (16) and / or the second beam splitter (25) comprises a beam splitter plate (51) or a beam splitter cube (52). [12] Receiving device (10) according to one of the preceding claims, characterized by that the light beam (14) is a spectrally broadband light beam (14) with a spectral bandwidth of at least 100nm in a wavelength range from 400nm to 1100nm. [13] Receiving device (10) according to one of the preceding claims, characterized bythat a numerical aperture NA of the illumination of the object points on the object (11) has a range from NA=0.05 to NA=0.25, preferably NA=0.08 to NA=0.18, more preferably NA=0.10 to NA=0.14, and / or that the object (11) can be illuminated with an illumination beam path formed telecentrically between the chromatic element (24) and the object (11) and / or the object (11) can be detected with an observation beam path formed telecentrically between the chromatic element (24) and the object (11). [14] Receiving device (10) according to one of the preceding claims, characterized byin that the light source (13) has a divergently emitting light emitter, wherein the divergently emitting light emitter (13) is arranged in a light emitter plane and in a beam path (62) intertwined with the projection beam path there is a plane (63) conjugated to the light emitter plane, which is arranged between the first beam splitter (16) and the first projection plane (12, zp(λ1)), in particular at the position of the chromatic element (24). [15] Method (100) for generating (130) a 3D image of a three-dimensional object (11), in particular with a recording device (10) according to one of the preceding claims, comprising the following steps: - arranging (110) the three-dimensional object (11) in a plurality of projection planes (12) of the recording device (10); - illuminating (120) the three-dimensional object (11), comprising the following sub-steps: - generating (130) the light beam (14) by means of a light source (13) in a pattern plane (15), - receiving (140) the generated light beam (14) by means of a first beam splitter input of a first beam splitter (16), - dividing (150) an illumination beam (17) from the light beam (14) by means of the first beam splitter (16), - outputting (160) the split illumination beam (17) by means of a first beam splitter output (21) of the first beam splitter (16), - focusing (170) the output illumination beam (17) onto the plurality of projection planes (12) by means of a chromatic element (24), wherein the pattern plane (15) is projected and wherein the pattern plane (15) is conjugated to one of the projection planes (12) from the plurality of projection planes (12) at a respective specific projection wavelength, - detecting (200) the three-dimensional object (11), comprising the following substeps: - reflecting (210) the illumination beam (17) as an observation beam (19) by means of the three-dimensional object (11), - passing (220) the observation beam (19) through the chromatic element (24), - receiving (230) the transmitted observation beam (19) by means of a second beam splitter input of the first beam splitter, wherein the second beam splitter input (22) corresponds to the first beam splitter output (21), - splitting (240) a recording beam (18) from the observation beam (19) by means of the first beam splitter (16), - outputting (250) the split recording beam (18) by means of a second beam splitter output (23) of the first beam splitter (16), - receiving (260) the output recording beam (18) by means of a third beam splitter input (28) of a second beam splitter (25), wherein a focusing optics (47) is arranged between the first beam splitter (16) and the second beam splitter (25), - dividing (270), in particular monotonously wavelength-dependently dividing (270), the receiving beam (18) into a first receiving beam portion (26) and a second receiving beam portion (27) by means of the second beam splitter (25), - outputting (280) the first receiving beam bundle portion (26) by means of the third beam splitter output (29) of the second beam splitter (25) and - outputting (280) the second receiving beam portion (27) by means of the fourth beam splitter output (30) of the second beam splitter (25), - two-dimensional detection (290) of the first intensity data (37) of the first recording beam portion (26) as a first image (32) of a first image plane (33) by means of a first matrix sensor (36) of a detection unit (31) and, - two-dimensional detection (290) of the second intensity data (39) of a second recording beam portion (27) as a second image (34) of a second image plane (35) by means of a second matrix sensor (38) of the detection unit (31), wherein the first image (32) and the second image (34) have corresponding pixels, which are each assigned to an object point of the illuminated object (11), - Calculating (300) at least one longitudinal coordinate of a plurality of object points of the object (11) from the corresponding image points of the first image and second image by means of the calculation unit (40) in order to generate the 3D image of the object (11). [16] Method (100) according to claim 15, characterized bythat the light source (13) has a pattern unit with a first pattern (53), wherein the first pattern (53) is arranged in the pattern plane (15) so that the first pattern (53) of the pattern plane (15) is projected onto the projection planes (12). [17] Method (100) according to one of claims 15 to 16, characterized by that the plurality of projection planes (12) are conjugated to the first image plane (33) and the second image plane (35) in order to calculate the longitudinal coordinate (300). [18] Method (100) according to one of claims 15 to 17, characterized byin that the pattern (53) in the pattern plane (15) has first pattern points (54) and second pattern points (55) alternating in at least one direction, wherein the first pattern points (54) have a first specific light emission and the second pattern points (55) have a second, lower, specific light emission, in particular a specific light emission of zero, and the second pattern points cause darkened image points in the first image and in the second image and, before calculating the longitudinal coordinate, the intensity values of the darkened image points are used to correct the intensity values of adjacent non-darkened image points in the first and second image. [19] Method (100) according to one of claims 15 to 18, characterized by that a control unit (61) controls the light source (13), whereby a light distribution of the light source (13) is changed.

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