DE102023120240A1 - Recording device for generating a 3D image of a three-dimensional object and method - Google Patents

Abstract

The invention relates to a recording device (10) for generating a 3D recording of a three-dimensional object (11), 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), a chromatic element (24) for focusing the illumination beam (17) split by the first beam splitter (16) onto the plurality of projection planes (12), a second beam splitter (25) for splitting the recording beam (18) into a first recording beam portion (26) and a second recording beam portion (27), a detection unit (31) with a first matrix sensor (36) with a second matrix sensor (38), a calculation unit (40) to produce a 3D image of the three-dimensional object (11).

Description

The invention relates to a recording device with the features of independent patent claim 1 and a method with the features of independent patent claim 14.

In many areas of technology, it is now desired to create 3D images. However, there are areas in which the objects to be recorded are small and difficult to access and yet must be recorded from various difficult-to-access perspectives in order to obtain a 3D image. At the same time, the recording devices must not 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 recordings are required. One application for this is, for example, recording the shape of machined or injection-molded components in the installed state in order to be able to determine any deformations caused by assembly.

Out of EP1084379A1 An optoelectronic form detection by chromatic coding with illumination planes is known, in which a spectral evaluation of the light reflected from the sample is carried out. The disadvantage is the need for a spectral measurement.

Out of US20140043619A A chromatic confocal scanning device is known.

Out of DE102020110298A1 A device and a method for optically measuring a surface topography are known in which several individual images are recorded at different wavelengths. The disadvantage of this method is that it is slow.

Out of DE102016211748A1 A chromatic confocal measuring arrangement for distance measurement is known.

Out of DE102015210016A1 A method for determining spatially resolved height information of a sample using a wide-field microscope is known. The height information is determined pixel by pixel using a modulation method. The disadvantage of this method is that it is slow.

Out of WO2013/171309A A light microscope and a method for image recording with a light microscope are known, which works with a galvanic mirror. The disadvantage is the presence of moving parts.

Out of WO99/24786A An optoelectronic system based on spatiochromatic triangulation with a prism-based spectrometer arrangement is known. The disadvantage of the system is the complexity. Prisms also exhibit a material-dependent dispersion.

Out of DE102007019267A1 A measuring arrangement for three-dimensional measurement of an object is known, which works with a point grid as illumination and a prism-based spectrometer arrangement. A similar arrangement is also known from DE102009025815A1 known.

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

Out of DE3428593A1 - an optical surface measuring device with a longitudinal dispersion device is known.

Out of DE102006007170A1 A method and an arrangement for fast and robust chromatic-confocal 3D measurement technology with a spectral decomposition of light by prisms are known.

Out of WO2019/176938A1 A wavelength detector and a confocal measuring device are known, which requires a spectral evaluation device.

Out of DE102013008582A1 A method and a device for chromatic-confocal multi-point measurement are known in which the distance is scanned point by point. The disadvantage of this method is that it is slow.

From the WO 95/00 871 A1 is known a three-dimensional imaging device with a broadband light source, an arrangement for forming point sources, a focusing element for focusing the light of each point source on an object, a beam splitter, a chromatic color filter unit, several 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 testing. However, this imaging device has elements in the form of a Nipkow disk, ie movable elements are provided. Such imaging devices have a larger design and are therefore limited in their field of application. At the same time, the movable elements make the structure complicated and prone to failure.

It is therefore an object of the present invention to at least partially overcome at least one of the disadvantages described above. In particular, it is an object of the invention to provide a receiving device which requires little space and is quick to receive and has no rotating or moving parts.

The above object is achieved by a recording device with the features of independent patent claim 1 and by a method with the features of independent patent claim 14. Further features and details of the invention emerge from the subclaims, the description and the drawings. Features and details that are 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 or can always be made to each other.

• - eine Lichtquelle zum Erzeugen eines Lichtstrahlbündels in einer Musterebene,
• - einen ersten Strahlteiler zum Abteilen eines Beleuchtungsstrahlbündels von dem Lichtstrahlbündel und zum Abteilen eines Aufnahmestrahlbündels von einem von dem Objekt zurückgeworfenen Beobachtungsstrahlbündel,
  • - mit einem ersten Strahlteilereingang zum Empfangen des Lichtstrahlbündels und
  • - mit einem ersten Strahlteilerausgang zum Ausgeben des Beleuchtungsstrahlbündels und,
  • - mit einem zweiten Strahlteilereingang zum Empfangen des Beobachtungsstrahlbündels und
  • - mit einem zweiten Strahlteilerausgang zum Ausgeben des Aufnahmestrahlbündels, wobei der zweite Strahlteilereingang dem ersten Strahlteilerausgang entspricht,
• - ein chromatisches Element zum Fokussieren des vom ersten Strahlteiler abgeteilten Beleuchtungsstrahlbündels auf die Vielzahl der Projektionsebenen,
• - derart, dass die Musterebene zu jeweils einer der Projektionsebenen aus der Vielzahl von Projektionsebenen jeweils bei einer bestimmten Projektionswellenlänge konjugiert ist,
• - einen zweiten Strahlteiler zum Teilen des Aufnahmestrahlbündels in einen ersten Aufnahmestrahlbündelanteil und einen zweiten Aufnahmestrahlbündelanteil,
  • - mit einem dritten Strahlteilereingang zum Empfangen des Aufnahmestrahlbündels und,
  • - mit einem dritten Strahlteilerausgang zum Ausgeben des ersten Aufnahmestrahlbündelanteils und,
  • - mit einem vierten Strahlteilerausgang zum Ausgeben des zweiten Aufnahmestrahlbündelanteils,
• - eine Erfassungseinheit zum Erfassen eines ersten Bilds in einer ersten Bildebene des ersten Aufnahmestrahlbündelanteils und eines zweiten Bilds in einer zweiten Bildebene des zweiten Aufnahmestrahlbündelanteils des Objekts,
• - mit einem ersten Matrixsensor zum zweidimensionalen Erfassen der ersten Intensitätsdaten des ersten Aufnahmestrahlbündelanteils als ein erstes Bild in der ersten Bildebene, wobei der erste Matrixsensor bezogen auf die Strahlrichtung des ersten Aufnahmestrahlbündelanteils dem dritten Strahlteilerausgang des zweiten Strahlteilers nachgeordnet angeordnet ist,
• - mit einem zweiten Matrixsensor zum zweidimensionalen Erfassen der zweiten Intensitätsdaten des zweiten Aufnahmestrahlbündelanteils als ein zweites Bild in der zweiten Bildebene, wobei der zweite Matrixsensor bezogen auf die Strahlrichtung des zweiten Aufnahmestrahlbündelanteils dem vierten Strahlteilerausgang des zweiten Strahlteilers nachgeordnet angeordnet ist,
• - wobei das erste Bild und das zweite Bild miteinander korrespondierende Bildpunkte aufweisen, wobei die korrespondierenden Bildpunkte jeweils denselben Objektpunkten des dreidimensionalen Objekts zuordenbar sind,
• - eine Berechnungseinheit zum Berechnen zumindest jeweils einer Längskoordinate mehrerer Objektpunkte des Objekts aus den korrespondierenden Bildpunkten des ersten Bilds und des zweiten Bilds, um eine 3D-Aufnahme des dreidimensionalen Objekts zu erzeugen.

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 from a middle 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, wherein 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 each 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 receiving 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 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.

The projection planes can be projected onto the object. This can mean that the recording device can be placed in such a way that the object is at least partially located within the projection planes. With a fixed recording device, the object can be located within the projection planes, in such a way that the object can be imaged at least partially on the matrix sensors. The optical axis can advantageously 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, whereby the longitudinal coordinate zp in turn depends on the projection wavelength λ as a parameter.

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

If the object surface intersects a certain projection plane at a point or in a line, this point or line can be sharply imaged on the first and second matrix sensors at the projection wavelength corresponding to this projection plane. For all other wavelengths of the light source, this line cannot be sharply imaged on the matrix sensors. The projection plane that contains the intersection point or line mentioned can therefore be determined if the sharply imaged wavelength of the image point or several image points on the line is determined.

The first image and the second image have pixels that correspond to one another, whereby the corresponding pixels can each be assigned to the same object points of the three-dimensional object. The object can be imaged on the two matrix sensors at the same time. Each imaged object point can thus correspond to one pixel on the first sensor and one pixel on the second sensor. The pixel on the first sensor and the pixel on the second sensor are then corresponding pixels.

Two identical matrix sensors can be used and they can be aligned in the same way. Then 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 compared to the first matrix sensor. Then the indices of corresponding pixels can be mirrored accordingly and can be converted accordingly to determine the corresponding pixels.

It is particularly advantageous if the light beam bundle is flat in the pattern plane. Flat means that the entire sensor surface of the first and second matrix sensors can be illuminated by the light beam bundle. Or expressed mathematically, 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.

The light source here reaches up to the pattern plane. This means that the pattern plane is located in the beam path before the first beam splitter.

A pattern is arranged in the pattern plane, which also illuminates the object by the light beam and is thus projected. The pattern of the pattern plane can advantageously 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 light emission (luminous exitance) than the second pattern point, whereby 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. blocking light or non-emitting. The pattern can represent a local modulation of the specific light emission. Despite the local modulation of the specific light emission, the color temperature can be independent of location. Advantageously, the first and second images can only be evaluated at the bright image points that correspond to the first pattern points. If the pattern contains dark second pattern points, ideally with an intensity of zero, these points can be shown as 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 compared with the intensity values of the adjacent second (dark) spots must be corrected separately for each matrix sensor.

The specific luminous flux can be described as a photometric quantity, the luminous flux emitted by a surface element of a light source.

The matrix sensors can be designed, for example, as CCD or CMOS sensors for pixel-by-pixel image recording or as vidicon tubes. Spatially resolved light intensity values can be registered as images.

The second beam splitter input corresponds to the first beam splitter output. This can mean that the observation beam enters the first beam splitter on 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 one and the same side surface of the cube.

The second beam splitter is designed to split the recording beam into a first recording beam portion and a second recording beam portion. The division of the recording beam into both portions can be carried out in a division ratio that is continuous and monotonically wavelength-dependent. The division ratio of the second beam splitter can therefore have a second wavelength dependency. This allows conclusions to be drawn about the wavelength from the intensity ratio of corresponding pixels on the first and second matrix sensors.

A chromatic element can be understood as a transmissive optical element with a focus length that is strongly dependent on the wavelength. In contrast to an achromat, the chromatic aberration can be particularly pronounced in the chromatic element. The focus length can advantageously be monotonously wavelength-dependent. A chromatic focus offset can be achieved using the wavelength-dependent focus length. This effect is generally often undesirable and is referred to in the optical literature as longitudinal chromatic aberration. However, the longitudinal chromatic aberration can be exploited within the scope of this invention. 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 with a Fresnel zone plate and assigned a "positive refractive power" to it within the meaning of the invention, even if the focusing effect is caused by diffraction of the light.

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

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

λ₀ kann die mittlere Wellenlänge der Lichtquelle sein. Der Wert k2 ist eine Konstante der Vorrichtung, die durch Kalibrieren bestimmt werden kann. I_Sensor1[x,y] ist die Intensität des Bildpunkts auf dem ersten Sensor, I_Sensor2[x,y] die auf dem zweiten Sensor. Aus λ [x,y] kann die Längskoordinate z [x,y] berechnet werden. Jede Projektionswellenlänge λ entspricht einer Projektionsebene zp(λ). Deren Längskoordinate zp(λ) kann dann als das Ergebnis z(x,y) = zp [λ (x,y)] dargestellt werden. Man kann auch gleich die Längskoordinate z aus den Intensitätswerten berechnen, wenn man die Abhängigkeiten ineinander einsetzt. Die Abhängigkeit zp(λ) der Längskoordinate der Projektionsebenen kann kalibriert werden oder aus der ersten Wellenlängenabhängigkeit des chromatischen Elements berechnet oder per Raytracing-Simulation ermittelt werden. Die Bestimmung der Längskoordinaten für mehrere Objektpunkte, idealerweise für alle abgebildeten Objektpunkte, führt zu einer dreidimensionalen Aufnahme des Objekts, genauer gesagt, der Objektoberfläche. Dieses Herangehen ermöglicht die Erstellung der 3D Aufnahme aus einem einzigen Aufnahmezyklus (Livebild). Die 3D Aufnahme kann als eine Menge von Raumpunkten [x,y,z] der Objektoberfläche vorliegen. Die Berechnung kann mit einer Recheneinheit durchgeführt werden.According to the invention, a calculation unit is provided for calculating at least one longitudinal coordinate of several 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 on the matrix sensors if the object point lies in a projection plane corresponding to a specific wavelength. A sharply imaged object point provides a higher intensity in the image than an object point that is not sharply imaged. The sharply imaging wavelength λ [x, y] can be determined from the intensities of the two pixels of the first and second image corresponding to the object point [x, y]. For example, this can be done using the following formula: $$\mathrm{\lambda }\left[\text{x},\text{y}\right]={\mathrm{\lambda }}_0-\text{k2}*\frac{{\text{I}}_{\text{Sensor1}}\left[\text{x},\text{y}\right]-{\text{I}}_{\text{Sensor2}}\left[\text{x},\text{y}\right]}{{\text{I}}_{\text{Sensor1}}\left[\text{x},\text{y}\right]+{\text{I}}_{\text{Sensor2}}\left[\text{x},\text{y}\right]}$$

λ ₀ 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] that 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 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 from the first wavelength dependence of the chromatic element or determined by ray tracing simulation. The determination of 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 3D image to be created from a single recording cycle (live image). The 3D image can be present as a set of spatial points [x,y,z] of the object surface. The calculation can be carried out with a computing unit.

In particular, if the second wavelength dependence, i.e. that of the second beam splitter, is non-linear, 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 analytically or in the form of a look-up table, for example.

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.

The design of the recording device allows the available light to be used optimally.

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

At the same time, the simplified structure makes it possible to design the recording device as a mobile device. This makes it possible, for example, to record components in devices or modules without dismantling the devices or modules. Applications in recording detailed bone shapes in fossils are also conceivable. Applications in prosthetics in the field of medicine and dentistry are also possible, for example to create a model of a bone for the production of an endoprosthesis or to create a three-dimensional model of a set of teeth or parts thereof.

Within the scope of the invention, it can be advantageous for the light source to comprise a first divergently emitting light emitter and a first collimating lens. This light emitter can be designed to be 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 cause the radiation to be rectified in the pattern plane.

The light source can have a first pattern unit with a first pattern, the first pattern being arranged in the pattern plane. This enables the pattern to be easily generated in the pattern plane. At the same time, the proximity of the pattern or the pattern unit to the light source ensures that the pattern can be projected well onto the object when the object is illuminated. Or, to be more specific, that the pattern can be projected well onto the multitude of projection planes. This makes it possible for the pattern plane to be projected sharply onto the object pixel by pixel at a sharply imaging projection wavelength, and to be able to generate a sharp 3D image.

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 for generating the 3D image.

The divergently emitting light emitter can be arranged in a light emitter plane and a plane conjugated 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. The plane conjugated to the light emitter plane can be arranged particularly advantageously 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 conjugated to the light emitter plane.

The light source can also be a surface radiator that can be arranged directly in the pattern plane. It is also conceivable that the pattern unit is integrated into the light source.

It is also conceivable that the pattern unit has a second pattern, the second pattern being inverted to the first pattern. This enables the flat light distribution to be produced in the pattern plane. The first and second patterns can advantageously be provided one after the other. For this purpose, the pattern unit can be designed to be switchable. It is particularly advantageous for the first pattern to be a checkerboard pattern and for the second pattern to be inverted, ie by swapping the light and dark areas.

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

By using the first deflection mirror and/or the second deflection 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 in such a way that it can be adapted to spatial restrictions. The installation space of the recording device can be adapted to the needs of the user or the area of application using the deflection mirror. This is particularly advantageous for mobile applications.

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 and/or a focusing optics is arranged between the first beam splitter and the second beam splitter.

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

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.

It is also conceivable that the mounting device is free of rotating elements. This ensures a simplified structure of the mounting device, i.e. the mechanical complexity is reduced so that the susceptibility to wear and the associated downtime can be reduced. At the same time, moving parts lead to increased costs and design effort, which can be reduced by dispensing with moving parts.

It is also conceivable that the chromatic element comprises a diffractive optical element and/or a Fresnel lens and/or a meta lens and/or a combination of a positive flint glass lens with a negative crown glass lens. The chromatic element can also be a Fresnel zone plate.

A diffractive optical element (DOE) is a type of optical device 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.

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 compared to traditional lenses, making it ideal for applications where size and weight are a concern, such as lighthouses, overhead projectors, camera lenses, and in-situ probes.

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

A flint glass lens is a lens made from an 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 allow light to be separated into its individual colors, which is essential for correcting chromatic aberrations in optical systems.

A crown glass lens is a lens made of an 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.

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.

Within the scope of the invention, it is optionally possible that 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 is provided for generating the first pattern of the first pattern unit.

These designs produce the pattern particularly easily and reliably. The pattern can be designed as a homogeneously illuminated surface or advantageously have illuminated areas arranged in a translationally symmetrical manner in at least one direction, particularly advantageously in two linearly independent directions, which are surrounded by unilluminated areas.

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

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

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.

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

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.
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 allowed to pass through the filter. It is therefore a filter that increases the permeability of light depending on its wavelength. In this way, the first and second parts of the recording beam can be received filtered with different wavelength dependencies by the matrix sensors, so that the wavelength of the respective pair of pixels can be deduced from the intensity ratio of the corresponding pixels.

It is also advantageous to use a second beam splitter, which already has a monotonous wavelength-dependent divider ratio without a filter. This can be achieved with a dielectric mirror layer, which has a continuous reflectivity curve with respect to the wavelength. This can have the advantage that no filters are required and therefore more light is available to the matrix sensors.

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.

A positive refractive power of a chromatic element means that the element is able to collect and focus light rays. It can have a convex shape and can be used to concentrate light rays.

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

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

It is also conceivable that the first beam splitter has a splitter ratio of 80:20 to 20:80, preferably 70:30 to 30:70, more preferably 60:40 to 40:60. The splitter ratio of the first beam splitter can be independent of the wavelength. The first beam splitter is used to split the illumination beam from the light beam and to guide the observation beam to the matrix sensors. The rest of the illumination beam can be discarded as a residual beam.

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

The second beam splitter divides the receiving beam into the first receiving beam portion and the second receiving beam portion depending on the wavelength. In this case, location-dependent wavelength information inherent in the receiving beam can be converted into location-dependent intensity information in order to be able to obtain the wavelength information without using a spectrometer.

Beamsplitters provide versatility and efficiency in imaging systems, making them valuable tools for capturing and analyzing complex visual information in a variety of scientific, medical and industrial applications.

Within the scope of the invention, it may be advantageous that the first beam splitter and/or the second beam splitter comprises a beam splitter plate or a beam splitter cube.

The design of the first beam splitter and the second beam splitter can be selected depending on the available installation space. This increases the flexibility of the design of a recording device.

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

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

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

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.

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

It can be provided within the scope of the invention that a numerical aperture NA of the illumination of the object points on the object has a range of 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 a disturbing transverse chromatic aberration, in Ideally, eliminate it. It is particularly advantageous if both of the telecentricities mentioned are present.

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

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

• - Anordnen des dreidimensionalen Objekts in einer Vielzahl von Projektionsebenen der Aufnahmevorrichtung;
• - Beleuchten des dreidimensionalen Objekts, aufweisend die folgenden Teilschritte:
  • - Erzeugen des Lichtstrahlbündels mittels einer Lichtquelle in einer Musterebene,
  • - Empfangen des erzeugten Lichtstrahlbündels mittels eines ersten Strahlteilereingangs eines ersten Strahlteilers,
  • - Abteilen eines Beleuchtungsstrahlbündels von dem Lichtstrahlbündel mittels des ersten Strahlteilers,
  • - Ausgeben des abgeteilten Beleuchtungsstrahlbündels mittels eines ersten Strahlteilerausgangs des ersten Strahlteilers,
  • - Fokussieren des ausgegebenen Beleuchtungsstrahlbündels auf die Vielzahl Projektionsebenen mittels eines chromatischen Elements, wobei die Musterebene projiziert wird und wobei die Musterebene zu jeweils einer der Projektionsebenen aus der Vielzahl von Projektionsebenen bei jeweils einer bestimmten Projektionswellenlänge konjugiert wird,
• - Erfassen des dreidimensionalen Objekts, aufweisend folgende Teilschritte:
  • - Zurückwerfen des Beleuchtungsstrahlbündels als ein Beobachtungsstrahlbündel mittels des dreidimensionalen Objekts,
  • - Durchleiten des Beobachtungsstrahlbündels durch das chromatische Element,
  • - Empfangen des durchgeleiteten Beobachtungsstrahlbündels mittels eines zweiten Strahlteilereingangs des ersten Strahlteilers, wobei der zweite Strahlteilereingang dem ersten Strahlteilerausgang entspricht,
  • - Abteilen eines Aufnahmestrahlbündels von dem Beobachtungsstrahlbündel mittels des ersten Strahlteilers,
  • - Ausgeben des abgeteilten Aufnahmestrahlbündels mittels eines zweiten Strahlteilerausgangs des ersten Strahlteilers,
  • - Empfangen des ausgegebenen Aufnahmestrahlbündels mittels eines dritten Strahlteilereingangs eines zweiten Strahlteilers,
  • - Teilen, insbesondere monoton wellenlängenabhängiges Teilen, des Aufnahmestrahlbündels in einen ersten Aufnahmestrahlbündelanteil und einen zweiten Aufnahmestrahlbündelanteil mittels des zweiten Strahlteilers,
  • - Ausgeben des ersten Aufnahmestrahlbündelanteils mittels des dritten Strahlteilerausgangs des zweiten Strahlteilers und
  • - Ausgeben des zweiten Aufnahmestrahlbündelanteils mittels des vierten Strahlteilerausgangs des zweiten Strahlteilers,
  • - zweidimensionales Erfassen der ersten Intensitätsdaten des ersten Aufnahmestrahlbündelanteils als ein erstes Bild einer ersten Bildebene mittels eines ersten Matrixsensors einer Erfassungseinheit und,
  • - zweidimensionales Erfassen der zweiten Intensitätsdaten eines zweiten Aufnahmestrahlbündelanteils als ein zweites Bild einer zweiten Bildebene mittels eines zweiten Matrixsensors der Erfassungseinheit, wobei das erste Bild und das zweite Bild eine Vielzahl korrespondierender Bildpunkte aufweisen, welche jeweils einem Objektpunkt des beleuchteten Objekts zugeordnet sind,
• - Berechnen zumindest einer Längskoordinate mehrerer Objektpunkte des Objekts aus den korrespondierenden Bildpunkten des ersten Bilds und zweiten Bilds mittels der Berechnungseinheit, um die 3D-Aufnahme des Objekts zu erzeugen.

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 output illumination beam onto the plurality of projection planes by means of a chromatic element, whereby the pattern plane is projected and whereby the pattern plane is conjugated to each of the projection planes from the plurality of projection planes at a respective specific projection wavelength,
• - Capturing the three-dimensional object, comprising the following substeps:
  • - 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 receiving 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 receiving beam by means of a third beam splitter input of a 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 portion 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 portion 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 portion as a second image of a second image plane by means of a second matrix sensor of the detection unit, wherein the first image and the second image have a plurality of corresponding image points, each of which is assigned to an object point of the illuminated object,
• - Calculating at least one longitudinal coordinate of several 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.

The object can be illuminated using a beam path that is telecentrically formed between the chromatic element and the object. Additionally or alternatively, the object can be captured using a beam path that is telecentrically formed between the chromatic element and the object. The aforementioned telecentricity can reduce, and ideally eliminate, a disturbing transverse chromatic aberration.

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

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

It is further conceivable that the light source has 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 associated projection wavelength, while the projection onto the other projection planes can be blurred at this wavelength.

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

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 for generating the 3D image.

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.

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 neighboring non-darkened image points in the first and second images. The first specific light emission can be constant across the first pattern points, i.e. independent of location, and the same for all first pattern points.

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.

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 so that systematic errors and/or contributions to the recorded intensities that result from scattered light and blurred images from other object areas at wavelengths that are not sharply imaged can be corrected before calculating the longitudinal coordinates.

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 stripe pattern can be used to generate a first 3D image of the object. In a further step, an inverted checkerboard pattern or stripe 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 merged, for example by means of the computing unit, in order to generate an improved 3D image of the object.

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.

• 1 eine schematische Darstellung einer Aufnahmevorrichtung nach einer ersten Ausführung,
• 2 eine schematische Darstellung einer Aufnahmevorrichtung nach einer zweiten Ausführung,
• 3 eine schematische Darstellung einer Aufnahmevorrichtung nach einer dritten Ausführung,
• 4 eine schematische Darstellung eines erfindungsgemäßen Verfahrens,
• 5 ein chromatisches Element,
• 6 ein anderes chromatisches Element,
• 7 und 8 beispielhafte Filterkennlinien,
• 9 eine Strahlteilerkennlinie.

Further advantages, features and details of the invention emerge from the following description, in which several embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description can each be essential to the invention individually or in any combination. The invention is shown in the following figures:

• 1 a schematic representation of a receiving device according to a first embodiment,
• 2 a schematic representation of a receiving device according to a second embodiment,
• 3 a schematic representation of a receiving device according to a third embodiment,
• 4 a schematic representation of a method according to the invention,
• 5 a chromatic element,
• 6 another chromatic element,
• 7 and 8 exemplary filter characteristics,
• 9 a beam splitter characteristic curve.

In the 1 to 3 a recording device 10 for generating 130 a 3D recording of a three-dimensional object 11 is shown. 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) to a middle projection plane 12 from the plurality of projection planes 12.

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 1 until 3 a divergently emitting light emitter 41 which comprises a first collimation optics 42. The collimation optics 42 are in 1 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.

In the 2 and 3 The light emitter 41 and the collimation optics 42 are two individual 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 area. In addition to the first collimation optics 42, the recording device 10 of the 2 and 3 a second collimator 46, which is provided between the light source 13 and the first beam splitter 16.

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.

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 1 to 3 has a splitter ratio of 80:20 for the light beam 14, so that 80% leaves 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% leaves 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.

For focusing 170 the illumination beam 17 split by the first beam splitter 16 onto the plurality of projection planes 12, 1 to 3 a chromatic element 24 with a positive refractive power with a first monotonic wavelength dependence is provided in each case. This focuses the illumination beam 17 in such a way 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. A Fresnel lens is provided here in all embodiments. These are very compact and are suitable for recording devices 10 that do not have a large installation 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.

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

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

Furthermore, the receiving device 10 of the 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 have pixels that correspond to one another, wherein the corresponding pixels can each be assigned to the same object points of the three-dimensional object 11.

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 calculation unit 40 in order to generate 130 a 3D recording of the three-dimensional object 11.

In the examples of the 1 and 3 the respective recording device 10 provides a focusing optics 47, which is arranged between the first beam splitter 16 and the second beam splitter 25. The split recording beam bundle 18 can thus be focused to the third beam splitter input 28 of the second beam splitter.

Both the 1 as well as the 2 and 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 1 also integrated in the light emitter 41, so that the pattern plane 15 is identical with the emitting plane of the light emitter. In the 2 and 3 the pattern unit 43 is arranged in the beam path of the light beam bundling 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.

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

The pattern 53 is transported by means of the divided and reflected beams and can thus be detected 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. The calculated longitudinal coordinates can be corrected using these patterns 53 and the associated different intensity data, leading to an improved 3D image.

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

The light source 13 as well as the first collimation optics 42, the second collimator 46 and the Fresnel lens 48 of the 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 from NA=0.05 to NA=0.25.

In 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 there is a plane 63 conjugated to the light emitter plane, which can be recognized by the fact that the dotted lines converge on the optical axis 65. The plane 63 of the intertwined beam path 62 conjugated 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. here in front of zp(λ1). In a modification of the embodiment not shown, the plane 63 conjugated to the light emitter plane can be arranged at the position of the chromatic element 24. This beam path described in this paragraph can be understood as a further beam path intertwined with the projection beam path, as is known, for example, from Köhler illumination. The plane 63 conjugated to the light emitter plane is the plane perpendicular to the optical axis 65. For the sake of clarity, only the intersection point of this plane with the optical axis 65 is shown here.

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

• - Anordnen 110 des dreidimensionalen Objekts 11 in einer Vielzahl von Projektionsebenen 12 der Aufnahmevorrichtung 10;
• - Beleuchten 120 des dreidimensionalen Objekts 11, aufweisend die folgenden Teilschritte:
• - Erzeugen 130 des Lichtstrahlbündels 14 mittels einer Lichtquelle 13 in einer Musterebene 15,
• - Empfangen 140 des erzeugten Lichtstrahlbündels 14 mittels eines ersten Strahlteilereingangs eines ersten Strahlteilers 16,
• - Abteilen 150 eines Beleuchtungsstrahlbündels 17 von dem Lichtstrahlbündel 14 mittels des ersten Strahlteilers 16,
• - Ausgeben 160 des abgeteilten Beleuchtungsstrahlbündels 17 mittels eines ersten Strahlteilerausgangs 21 des ersten Strahlteilers 16,
• - Fokussieren 170 des ausgegebenen Beleuchtungsstrahlbündels 17 auf die Vielzahl Projektionsebenen 12 mittels eines chromatischen Elementes 24, wobei die Musterebene 15 projiziert wird und wobei die Musterebene 15 zu jeweils einer der Projektionsebenen 12 aus der Vielzahl von Projektionsebenen 12 bei jeweils einer bestimmten Projektionswellenlänge konjugiert wird,
• - Erfassen 200 des dreidimensionalen Objekts 11, aufweisend folgende Teilschritte:
• - Zurückwerfen 210 des Beleuchtungsstrahlbündels 17 als ein Beobachtungsstrahlbündel 19 mittels des dreidimensionalen Objekts 11,
• - Durchleiten 220 des Beobachtungsstrahlbündels 19 durch das chromatische Element 24,
• - Empfangen 230 des durchgeleiteten Beobachtungsstrahlbündels 19 mittels eines zweiten Strahlteilereingangs des ersten Strahlteilers, wobei der zweite Strahlteilereingang 22 dem ersten Strahlteilerausgang 21 entspricht,
• - Abteilen 240 eines Aufnahmestrahlbündels 18 von dem Beobachtungsstrahlbündel 19 mittels des ersten Strahlteilers 16,
• - Ausgeben 250 des abgeteilten Aufnahmestrahlbündels 18 mittels eines zweiten Strahlteilerausgangs 23 des ersten Strahlteilers 16,
• - Empfangen 230 des ausgegebenen Aufnahmestrahlbündels 18 mittels eines dritten Strahlteilereingangs 28 eines zweiten Strahlteilers 25,
• - Teilen 270, insbesondere monoton wellenlängenabhängiges Teilen 270, des Aufnahmestrahlbündels 18 in einen ersten Aufnahmestrahlbündelanteil 26 und einen zweiten Aufnahmestrahlbündelanteil 27 mittels des zweiten Strahlteilers 25,
• - Ausgeben 250 des ersten Aufnahmestrahlbündelanteils 26 mittels des dritten Strahlteilerausgangs 29 des zweiten Strahlteilers 25 und
• - Ausgeben 250 des zweiten Aufnahmestrahlbündelanteils 27 mittels des vierten Strahlteilerausgangs 30 des zweiten Strahlteilers 25,
• - zweidimensionales Erfassen 200 der ersten Intensitätsdaten 37 des ersten Aufnahmestrahlbündelanteils 26 als ein erstes Bild 32 einer ersten Bildebene 33 mittels eines ersten Matrixsensors 36 einer Erfassungseinheit 31 und,
• - zweidimensionales Erfassen 200 der zweiten Intensitätsdaten 39 eines zweiten Aufnahmestrahlbündelanteils 27 als ein zweites Bild 34 einer zweiten Bildebene 35 mittels eines zweiten Matrixsensors 38 der Erfassungseinheit 31, wobei das erste Bild 32 und das zweite Bild 34 eine Vielzahl korrespondierender Bildpunkte aufweisen, welche jeweils einem Objektpunkt des beleuchteten Objekts 11 zugeordnet sind,
• - Berechnen 300 zumindest einer Längskoordinate mehrerer Objektpunkte des Objekts 11 aus den korrespondierenden Bildpunkten des ersten Bilds und zweiten Bilds mittels der Berechnungseinheit 40, um die 3D-Aufnahme des Objekts 11 zu erzeugen 130.

In 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 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 of 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, whereby the pattern plane 15 is projected and whereby 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 receiving 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 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 image points, which are each assigned to an object point of the illuminated object 11,
• - Calculating 300 at least one longitudinal coordinate of several 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 11 130.

In the method 100 shown, 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 blurred on the other projection planes.

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.

The pattern 53 in the pattern plane 15 has at least one first pattern location 54 and at least one second pattern location 55 alternating in at least one direction. 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 can also be recognized in the images.

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.

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.

5 shows a chromatic element as a doublet lens

6 shows another chromatic element, which is designed as a diffractive Fresnel lens. The diffractive zones are visible, which are closer together towards the edge of the lens. At the same time, the zones on the left-hand side of the lens have inclined surfaces. This makes it possible to focus the light more effectively than with a Fresnel zone plate.

7 shows an exemplary spectral filter characteristic of the first filter 49 and 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.

9 shows the characteristic curve of another version of a second beam splitter. This is realized by means of a dielectric mirror layer, which has the reflectivity shown at a 45° angle of incidence. The transmission is then ideally 1 minus the reflectivity. With this version, it is possible to dispense with the first and second filters.

In the 7 to 9 Idealized characteristics are shown; in practice, technical nonlinearities would be expected, particularly in the upper and lower wavelength ranges. These can be compensated by appropriate correction functions, which can be determined by calibration.

list of reference symbols

10

receiving device

11

object

12

projection plane

13

light source

14

light beam

15

pattern layer

16

first beam splitter

17

illumination beam

18

recording beam

19

observation beam bundle

20

first beam splitter input

21

first beam splitter output

22

second beam splitter input

23

second beam splitter output

24

chromatic element

25

second beam splitter

26

first part of the recording beam

27

second receiving beam portion

28

third beam splitter input

29

third beam splitter output

30

fourth beam splitter output

31

registration unit

32

first picture

33

first image plane

34

second picture

35

second image plane

36

first matrix sensor

37

first intensity data

38

second matrix sensor

39

second intensity data

40

calculation unit

41

emitting light emitter

42

first collimation optics

43

first sample unit

44

first deflection mirror

45

second deflection mirror

46

second collimator

47

focusing optics

48

Fresnel lens

49

first filter

50

second filter

51

beam splitter plate

52

beam splitter cube

53

Pattern

54

first sample position

55

second sample position

56

pattern projection plane

57

first intensity value

58

second intensity value

59

third intensity value

60

fourth intensity value

61

control unit

62

Intertwined beam path

63

conjugate plane of the interwoven beam path

65

optical axis

100

Proceedings

110

arranging

120

lighting

130

Generate

140

Received

150

compartments

160

Spend

170

Focus

200

Capture

210

throwing back

220

passing through

230

Received

240

compartments

250

Spend

260

Received

270

Split

280

Spend

290

Capture

300

Calculate

310

Conjugate

320

Correct

zp(λ)

Distance

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• EP 1084379A1 [0003]
• US 20140043619A [0004]
• DE 102020110298A1 [0005]
• DE 102016211748A1 [0006]
• DE 102015210016A1 [0007]
• WO 2013/171309A [0008]
• WO 99/24786A [0009]
• DE 102007019267A1 [0010]
• DE 102009025815A1 [0010]
• DE 102020200214A1 [0011]
• DE 3428593A1 [0012]
• DE 102006007170A1 [0013]
• WO 2019/176938A1 [0014]
• DE 102013008582A1 [0015]
• WO 95/00 871 A1 [0016]

Claims (19)

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 bundle (14) and - with a first beam splitter output (21) for outputting the illumination beam bundle (17) and, - with a second beam splitter input (22) for receiving the observation beam bundle (19) and - with a second beam splitter output (23) for outputting the recording beam bundle (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 bundle (17) split by the first beam splitter (16) onto the plurality of projection planes (12) in such a way 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 splitting the recording beam bundle (18) into a first recording beam bundle portion (26) and a second recording beam portion (27), - with a third beam splitter input (28) for receiving the recording beam (18) and, - with a third beam splitter output (29) for outputting the first recording beam portion (26) and, - with a fourth beam splitter output (30) for outputting the second recording beam portion (27), - 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 based on the Beam direction of the first recording beam portion (26) is arranged downstream of the third beam splitter output (29) of the second beam splitter (25), - with a second matrix sensor (38) for two-dimensionally capturing 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), - wherein the first image (32) and the second image (34) have pixels that correspond to one another, 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 pixels of the first image and the second image to create a 3D image of the three-dimensional object (11). receiving device (10) according to claim 1 , characterized 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). receiving device (10) according to claim 1 or 2 , characterized in that a first deflecting mirror (44) for deflecting the illumination beam (17) by a certain 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 certain angle, in particular for deflecting by an obtuse angle, is provided between the chromatic element (24) and the object (11). Recording device (10) according to one of the preceding claims, characterized in that a second collimator (46) is arranged between the light source (13) and the first beam splitter (16) and/or a focusing optics (47) is arranged between the first beam splitter (16) and the second beam splitter (25). Receiving device (10) according to one of the preceding claims, characterized in that the receiving device (10) is free of rotating elements. Recording device (10) according to one of the preceding claims, characterized in that 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. Recording device (10) according to one of the preceding claims, characterized in 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). Recording device (10) according to one of the preceding claims, characterized in that a first filter (49) for wavelength-dependent filtering of the first recording beam portion (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 recording beam portion (27) is provided at the fourth beam splitter output (30) of the second beam splitter (25). Recording device (10) according to one of the preceding claims, characterized in 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. Recording device (10) according to one of the preceding claims, characterized in that the first beam splitter (16) has a 80:20 to 20:80, preferably from 70:30 to 30:70, more preferably from 60:40 to 40:60, divider ratio and/or that the second beam splitter (25) has a second wavelength dependence, in particular a second monotonic wavelength dependence. Recording device (10) according to one of the preceding claims, characterized in that the first beam splitter (16) and/or the second beam splitter (25) comprises a beam splitter plate (51) or a beam splitter cube (52). Recording device (10) according to one of the preceding claims, characterized in that 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. Recording device (10) according to one of the preceding claims, characterized in that 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). Recording device (10) according to one of the preceding claims, characterized in 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). 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), - splitting (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) on 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 sub-steps: - 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 passed 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 of the first beam splitter (16), - outputting (250) the divided receiving beam (18) by means of a second beam splitter output (23) of the first beam splitter (16), - receiving (260) the output receiving beam (18) by means of a third beam splitter input (28) of a 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 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-dimensionally capturing (290) 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-dimensionally capturing (290) 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 pixels of the first image and second image by means of the calculation unit (40) in order to generate the 3D recording of the object (11). Procedure (100) according to claim 15 , characterized in that 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). Method (100) according to one of the Claims 15 until 16 , characterized in that the plurality of projection planes (12) are conjugated to the first image plane (33) and that of the second image plane (35) in order to calculate the longitudinal coordinate (300). Method (100) according to one of the Claims 15 until 17 , characterized in that the pattern (53) in the pattern plane (15) has alternating first pattern locations (54) and second pattern locations (55) in at least one direction, wherein the first pattern locations (54) have a first specific light emission and the second pattern locations (55) have a second, lower, specific light emission, in particular a specific light emission of zero, and the second pattern locations cause darkened image locations in the first image and in the second image and, before calculating the longitudinal coordinate, the intensity values of the darkened image locations are used to correct the intensity values of adjacent non-darkened image locations in the first and second images. Method (100) according to one of the Claims 15 until 18 , characterized in that a control unit (61) controls the light source (13), whereby a light distribution of the light source (13) is changed.

Images