• 专利附录
  • 专利说明
  • 权利要求
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    • 专利摘要:
    The invention relates to a projection device (4), comprising: a lighting unit (7) for emitting light (L); and a projection unit (8) having a mirror surface, wherein the projection unit (8) is arranged to project the light (L) emitted by the illumination unit (7) into an object space (2) by means of the mirror surface and to different in the object space (2) to form spatially structured patterns of light. The projection device (4) is characterized in that the mirror surface is deformable at least in regions and the projection unit (8) for forming the different spatially structured light patterns in the object space (2) has at least one actuator (12a, 12b) for at least partially deforming the mirror surface , The invention further relates to a projection method and a device (1) and a method for detecting a three-dimensional contour (3).
    公开号:CH715045A2
    申请号:CH6902019
    申请日:2019-05-25
    公开日:2019-11-29
    发明作者:Brahm C/O Fraunhofer-Institut Für Angewandte Optik Und Feinmechanik Anika；Reinlein c/o Fraunhofer-Institut für Angewandte Optik und Feinmechanik Claudia；Gebhart C/O Fraunhofer-Institut Für Angewandte Optik Und Feinmechanik Ingo
    申请人:Fraunhofer Ges Forschung；
    IPC主号:
    专利说明:

    Description [0001] The present document relates primarily to a projection device and a projection method. The document further relates to a device for the contactless detection of a three-dimensional contour, which contains the projection device, and a method for the contactless detection of a three-dimensional contour, which comprises the method steps of the projection method.
    Various devices and methods for detecting three-dimensional contours are known from the prior art. See e.g. ZHANG, Song: Recent progresses on real-time 3D shape measurement using digital] ringe projection techniques. In: Optics and Lasers in Engineering 48 (2010) No. 2, pp. 149-158.
    Typically, one or two cameras (e.g. in a stereo arrangement) are used to observe an object, the object e.g. can be illuminated by means of sequential or continuous pattern projection methods. Examples of such methods are binary code, phase shift, lattice, speckle or hybrid methods). Knowing the geometry of the system, a three-dimensional contour of the object can then be reconstructed or calculated using triangulation using the images of the object recorded by the cameras with the structured light patterns projected onto the surface of the object.
    [0004] The devices and methods for projecting the structured light patterns onto the three-dimensional contour to be measured form an important aspect. These projection devices and methods often significantly determine the application scenario and the reconstruction results.
    From DE 10 2011 010 265 A1 and DE19 633 686 C2, for example, projection devices are known which generate a defined intensity distribution in the object space or measurement volume according to the principles of reflection and deflection of light by means of tilting micromirrors. It is also known to use optical components such as liquid crystal screens (LCD, LCOS), slides or masks) for the projection of structured light patterns.
    Projection devices are known from DE 10 2012 002 161 A1, which e.g. Shape light emitted by a laser into a statistical pattern, in particular in the form of speckle patterns, using a diffusing screen and an acousto-optical modulator.
    DE 10 2013 013 791 A1 describes the projection using microlens arrays.
    DE 10 2015 208 285 A1 describes a projection method in which a pattern wheel made of metal is used as a structuring element. Alternatively, glass with a chrome coating can be used.
    US 6 028 672 A describes the projection of structured light patterns by means of diffractive elements.
    [0010] And DE 10 2011 014 779 A1 discloses a device for measuring distances and / or spatial coordinates of an object with free-form optics, which is designed in such a way that light emitted by an illumination unit by means of a free-form surface of the free-form optics results in a spatially structured light pattern an object plane is steered.
    [0011] However, these previously known projection devices and projection methods usually each have at least one of the following disadvantages:
    - They contain several optical components for beam guidance, beam shaping and projection. This increases the amount of work required for adjustment, the cost and the complexity of the system.
    - You are not working lossless; e.g. In the transmission of the light used to generate the structured light patterns through optical components (for example in the form of masks or slides), power losses of up to 50 percent can occur.
    - They are only suitable for projecting a fixed type of light pattern, which is determined by the optical components used. To vary the projection pattern, for example, masks, slides or other optical components must be moved in a translatory or rotary manner by means of a drive, but the type of light pattern often remains unchanged. This can also increase the complexity of the system considerably.
    - They are only suitable for a limited light wavelength range, e.g. only for the visible spectral range (VIS) or for the near infrared spectral range (NIR). A change of the spectral range from UV to IR or vice versa is often not possible or only possible to a very limited extent due to the optical components used for beam shaping and their wavelength-dependent transmission behavior.
    There is therefore a need for projection devices and projection methods which are suitable for projecting light from the widest possible spectral range, which have the lowest possible optical power losses and which can be produced or carried out with the least possible time and cost. In addition, they should be suitable for projecting a large number of different structured light patterns as quickly as possible, so that they e.g. can be used in methods for contactless detection of three-dimensional contours of moving or rapidly moving objects.
    A projection device and a projection method as well as a device and a method for contactless detection of a three-dimensional contour that achieve this are given in the independent claims and in the independent claims. The sub-claims describe special embodiments.
    CH 715 045 A2 [0014] A projection device comprising:
    a lighting unit for emitting light; and a projection unit with a mirror surface, the projection unit being set up to project the light emitted by the illumination unit into an object space by means of the mirror surface and to shape it into different spatially structured light patterns in the object space.
    The projection device is characterized in that the mirror surface is deformable at least in regions and that the projection unit for shaping the different spatially structured light patterns in the object space has at least one actuator for deforming the mirror surface at least in regions.
    The proposed projection device has a particularly low degree of complexity, since in addition to the deformable mirror surface, other optical components for beam shaping or beam guidance are not necessarily required. The projection device is thus compact, easy to adjust, stable and comparatively quick to produce and at low cost.
    Since the projecting of the spatially structured light pattern can only be carried out or can be carried out by reflection on the mirror surface, the projection device is also suitable for projecting light of a wide wavelength range. For example, With a suitable choice of the material of the mirror surface, no adjustment of the projection unit has to be carried out if the wavelength of the light which is used to form the spatially structured light pattern is changed from UV to IR. In addition, the shaping of the spatially structured light patterns by means of reflection is particularly low-loss and thus particularly efficient compared to methods in which transmitting optical elements are used to form light patterns. For example, Light sources with lower output can be used without loss of quality. This can reduce operating costs and extend the life of the light source in particular.
    Since the shaping of the different spatially structured light patterns in the object space can only be carried out or can be carried out by deforming the mirror surface, a large number of different structured light patterns can be projected very quickly and with little energy expenditure, without having to make complex changes to the projection device Need to become. For example, when using appropriate actuators, sequences of different structured light patterns with projection frequencies in the kHz range can be projected. Depending on the geometry of the projection process, it can e.g. be sufficient to deform the mirror surface by only a few micrometers or even only by a few nanometers in order to form sufficiently different spatially structured light patterns in the object space. In particular, the shaping of the different spatially structured light patterns by deforming the mirror surface is generally also particularly reproducible.
    The actuator is thus designed such that it can optionally be placed at least in a first position and in a second position. The at least one actuator and the mirror surface are then arranged and designed such that the mirror surface assumes a first surface shape when the at least one actuator is in the first position, and that the mirror surface when the at least one actuator is in the second position is a second surface shape different from the first surface shape. When the mirror surface takes the first surface shape, it is set up to shape light emitted by the lighting unit in the object space into a first spatially structured light pattern. And when the mirror surface takes on the second surface shape, it is set up to shape light emitted by the lighting unit in the object space into a second spatially structured light pattern that is different from the first spatially structured light pattern.
    Typically, however, the at least one actuator is each set up to be brought into a plurality of more than just two different positions. For example, the actuator can be continuously adjustable. The different positions of the actuator can be given, for example, by different spatial dimensions of the actuator or correspond to these. Usually, the at least one actuator is arranged and designed such that it can be adjusted in each case in a direction perpendicular or essentially perpendicular to the mirror surface, or in each case in a direction perpendicular or substantially perpendicular to that region of the mirror surface which it engages or to it is located closest.
    It is conceivable that the at least one actuator comprises at least one piezo element, at least one linear motor or at least one mechanical actuating unit that can be driven by a linear motor. In particular, the projection unit can also comprise a plurality of actuators. The actuators can then be adjustable or controllable independently of one another. For example, the actuators can be arranged rotationally symmetrically with respect to an axis of rotation. The axis of rotation can be arranged or aligned such that it intersects the mirror surface. If the projection unit comprises more than one actuator, these actuators can e.g. be arranged such that the shortest distances between adjacent actuators are in each case less than 10 mm, less than 5 mm, less than 1 mm, less than 0.5 mm or less than 0.1 mm. For example, The actuators can be designed as microelectronic or microelectromechanical components and can be produced using optical methods, in particular using optical lithography methods.
    [0022] The deformable mirror surface for shaping the various spatially structured light patterns can be designed as a free-form mirror surface. The free-form mirror surface can by any steady, constantly diffe
    CH 715 045 A2 can be provided with a surface that can be delimited or at least partially continuously differentiated. Based on the configuration of the lighting unit and the relative arrangement of the lighting unit and the free-form mirror surface to one another, in particular based on the beam guidance of the light emitted by the lighting unit and reflected on the free-form mirror surface, three-dimensional contour of the free-form mirror surface, which is necessary to form a desired spatially structured light pattern in the object space is to be calculated. Corresponding methods for calculating the three-dimensional contour of the free-form mirror surface are described, for example, in: BÖSEL, Christoph; GROSS, Herbert: Ray mapping approach for the efficient design of continuous freeform surfaces. In: Optics Express 24 (2016) No. 13, pp. 14271-14282.
    For shaping high-frequency structures of the spatially structured light pattern, the mirror surface can e.g. have a microstructuring. This can include that the mirror surface has height variations or local height variations perpendicular to the mirror surface, which can be up to 10 μm, up to 20 μm, up to 50 μm, up to 100 μm, up to 200 μm or up to 500 μm. Alternatively or additionally, the height variations or the local height variations of the microstructuring perpendicular to the mirror surface can have an amplitude of at least 0.5 μm or of at least 1 μm or of at least 5 μm or of at least 10 μm or of at least 20 μm or of at least 50 μm or of have at least 100 μm. Parallel to the mirror surface, these height variations of the mirror surface can have dimensions of up to 100 μm, up to 200 μm, up to 500 μm, up to 1 mm, up to 5 mm or up to 10 mm.
    [0024] The projection unit can have a substrate layer, in particular a metallic substrate layer, for forming the mirror surface. In other words, the mirror surface can be formed by a substrate layer, in particular by a metallic substrate layer, or by the surface of this substrate layer. A thickness of this substrate layer can e.g. not more than 1 mm, not more than 0.5 mm or not more than 0.2 mm.
    [0025] The projection unit can have at least one connecting element or at least one connecting layer on a rear side of the substrate layer facing away from the mirror surface. The at least one connecting element or the at least one connecting layer can be arranged between the at least one actuator and the substrate layer in order to transmit a deformation force from the at least one actuator to the substrate layer. The at least one connection layer can e.g. comprise at least one adhesive layer or at least one metal layer. If the connection layer is designed as a metal layer, it can in particular be designed as a metal foil or as a solder layer. The connecting elements can also be made of adhesive or metal or comprise adhesive or metal.
    The lighting unit can, for example, comprise at least one LED and / or at least one laser. However, it goes without saying that the lighting unit can also comprise other light sources. Because of its high spatial coherence, laser light allows e.g. a particularly precise shaping of the spatially structured light patterns to be projected. However, it is also conceivable that the lighting unit comprises further optical elements for beam shaping or beam collimation, for example one or more mirrors, one or more lenses, one or more optical switches or the like.
    [0027] A device for contactless detection of a three-dimensional contour is also proposed, comprising:
    a projection device of the type described above;
    at least one camera, preferably a first camera and a second camera, for taking pictures of an object arranged in the object space with the different spatially structured light patterns projected onto the object by means of the mirror surface; and an evaluation unit for determining a three-dimensional contour of an object arranged in the object space based on image data of images of the object recorded by means of the at least one camera, preferably of images of the object recorded by means of the first camera and the second camera, with those of the object by means of the mirror surface projected different spatially structured light patterns.
    The device can further comprise a control unit which is set up to control the at least one actuator in such a way that the at least one actuator deforms the mirror surface to form the different spatially structured light patterns in the object space. Typically, the control unit is also set up to control the at least one camera, preferably to control the first camera and the second camera, and possibly also to control the lighting unit. The control unit can then be set up to control the at least one actuator and the at least one camera, preferably the first camera and the second camera, in such a way that the at least one camera, preferably the first camera and the second camera, for each spatially structured light pattern A large number of different spatially structured light patterns, which is projected onto an object arranged in the object space by means of the mirror surface, in each case to record at least one image of the object with the spatially structured light pattern projected onto the object.
    [0029] In particular, the evaluation unit can be set up to detect or calculate the three-dimensional contour of the object arranged in the object space, for a plurality of object points of the object based on the image data of the images taken by the at least one camera, preferably based on the image data of the means pictures taken by the first camera and the second camera,
    CH 715 045 A2
    to identify pairs of points corresponding to one another and the respective object point in an image plane of the camera or the first camera and in a further plane, the further plane
    a) is an image plane of the second camera or
    b) is a virtual projection plane assigned to the mirror surface, and
    to determine depth information by triangulation as a function of positions of the points corresponding to one another and the respective object point in the image plane and in the further plane.
    The identification of the pairs of points corresponding to one another and the respective object point in the image plane and in the further plane can be carried out in a known manner. For example, a sequence of brightness values or possibly a sequence of color values can be assigned to each point in the image plane and in the further plane based on the sequence of images recorded by the at least one camera, the values of the sequence of brightness values or of color values corresponds to the brightness values or color values detected in the sequence of images at this point.
    A given point in the image plane of the camera or the first camera can then e.g. can be identified with a point corresponding to this point in the further plane by first determining the epipolar line corresponding to the given point in the image plane of the camera or the first camera in the further plane. In the next step, the sequence of brightness values or color values assigned to the respective point on the epipolar line in the further plane can then be correlated with that sequence of brightness values or color values that corresponds to the given point in the image plane is assigned to the camera or the first camera. As the point of the further plane, which corresponds to the given point in the image plane of the camera or the first camera, e.g. identify the point on the corresponding epipolar line in the further plane for which this correlation has a maximum value. Possible implementations of this method are described, for example, in WO 2015 022 384 A1 or in DE 10 2010 13 079 A1.
    In this way, the evaluation unit can determine three spatial coordinates for each of the plurality of object points that lie on the three-dimensional contour of the object, which coordinates define the position of this object point in space. The evaluation unit can then at least approximately reconstruct the three-dimensional contour of the object from these three-dimensional spatial coordinates of the plurality of object points. The evaluation unit can e.g. additionally use known interpolation or smoothing algorithms.
    [0033] A projection method is also proposed, which comprises at least the following steps:
    Shaping a first spatially structured light pattern in an object space by reflecting light on a mirror surface with a first surface shape;
    deforming the mirror surface at least in regions so that the mirror surface assumes a second surface shape that differs from the first surface shape; and
    Forming a second spatially structured light pattern in the object space that differs from the first spatially structured light pattern by reflecting light on the mirror surface with the second surface shape.
    [0034] The mirror surface can be deformed by means of at least one actuator, preferably by changing a piezo voltage of a piezo element or by adjusting a linear motor. The linear motor can be used to deform the mirror surface at least in regions, e.g. be coupled to the mirror surface via a mechanical actuating unit. To deform the mirror surface, it can be deformed at different positions on the mirror surface, in particular simultaneously. For example, the mirror surface can be deformed at different positions of the mirror surface that are arranged rotationally symmetrically relative to one another.
    [0035] Furthermore, a method for contactless detection of a three-dimensional contour is proposed, which comprises at least the following steps:
    Projecting different spatially structured light patterns onto an object arranged in an object space, specifically according to the projection method described above;
    Taking pictures of the object with the different spatially structured light patterns projected onto the object by means of at least one camera, preferably using a first camera and a second camera; and determining a three-dimensional contour of the object based on image data of the images captured by the at least one camera, preferably based on image data of the images captured by the first camera and the second camera.
    In the method for contactless detection of a three-dimensional contour, the deformation of the mirror surface to form the different spatially structured light patterns and the taking of the images of the object by means of the at least one camera, preferably by means of the first camera and the second camera, can be carried out synchronously be that the at least one camera, preferably the first camera and the second camera, for each of the plurality of different spatially structured light patterns that projects onto the object
    CH 715 045 A2 will take at least one image of the object with the spatially structured light pattern projected onto the object.
    Furthermore, in the method for contactless detection of a three-dimensional contour for a plurality of object points of the object based on the image data of the images taken by the at least one camera, preferably based on the image data of the images taken by the first camera and the second camera .
    pairs of points corresponding to one another and the respective object point are identified in an image plane of the camera or the first camera and in a further plane, the further plane
    a) is an image plane of the second camera or
    b) is a virtual projection plane assigned to the mirror surface, and
    - Depth information is determined by triangulation as a function of positions of the points corresponding to one another and the respective object point in the image plane and in the further image plane.
    The identification of corresponding points in the image plane of the camera or the first camera and in the further plane can e.g. are explained in the manner described above (see e.g. WO 2015 022 384 A1).
    Exemplary embodiments of the devices and methods proposed here are shown in the figures and are explained in more detail with reference to the following description. It shows:
    1 schematically shows a device for contactless detection of a three-dimensional contour, the device for contactless detection of the three-dimensional contour having a projection device with a deformable mirror surface;
    FIG. 2a schematically the projection device from FIG. 1, the deformable mirror surface for projecting a first structured light pattern being deformed such that it takes on a first surface shape;
    FIG. 2b schematically shows the projection device from FIG. 2a, the deformable mirror surface for projecting a second structured light pattern being deformed in such a way that it takes on a second surface shape;
    3 schematically shows a projection unit of the projection device from FIG. 1 in a perspective illustration; such as
    4 schematically shows a surface profile of the deformable mirror surface from FIG. 3.
    1 schematically shows a device 1 for contactless detection or measurement of a three-dimensional contour 3 arranged in an object space 2. The device 1 comprises a projection device 4, a detection unit 5 with a first camera 5a and a second camera 5b and a control - And evaluation unit 6. In alternative embodiments of the device 1, however, the detection unit 5 may optionally have only a single camera, for example only the first camera 5a.
    [0041] The projection device 4 has an illumination unit 7 and a projection unit 8. Here the lighting unit 7 comprises e.g. a light source in the form of a laser that emits visible green light with a wavelength of approximately 530 nm. However, the lighting unit 7 can also have a light source other than a laser, e.g. one or more LEDs, a mercury vapor lamp or the like. Likewise, in alternative embodiments, the lighting unit 7 can have a light source that emits light with a wavelength outside the visible spectral range, e.g. in UV, NIR or IR. In alternative embodiments, the lighting unit 7 can additionally have one or more optical elements for beam shaping or beam collimation, e.g. in the form of mirrors and / or lenses. These optical elements are then typically arranged between the light source of the illumination unit 7 and the mirror surface of the projection unit 8.
    The projection unit 8 here comprises a housing 9, a deformable or at least partially deformable metallic substrate layer 10, which forms a free-form mirror surface 10a and which closes off the housing 9 in regions, a connecting layer 11, which on a rear side of the substrate layer facing away from the free-form mirror surface 10a 10 is arranged, as well as an actuator unit 12 with a first actuator 12a and a second actuator 12b. In alternative embodiments, instead of the free-form mirror surface 10a, a “conventional” mirror surface can also be provided, for example a flat, parabolic or hyperbolic mirror surface. In alternative embodiments, the actuator unit 12 can also have only a single actuator or more than two actuators. The actuator unit 12 serves to deform or at least deform the free-form mirror surface 10a
    CH 715 045 A2 to be deformed in certain areas. By deforming or at least partially deforming the substrate layer 10 or the free-form mirror surface 10a, light L emitted by the illumination unit 7 and reflected on the free-form mirror surface 10a can be shaped into different spatially structured light patterns in the object space 2, which then pattern onto the three-dimensional contour 3 to be measured can be projected.
    The metallic substrate layer 10 in the present example is e.g. made of aluminum and has a maximum thickness of less than 0.15 mm. In alternative embodiments, the substrate layer 10 may also be formed from other metals or metal alloys and / or have a different maximum thickness, e.g. a larger maximum thickness. Preferably, however, those materials are used to form the free-form mirror surface 10a which have the largest possible and constant reflectivity over the widest possible spectral range. The free-form mirror surface 10a can also have a microstructuring 19, which is described in more detail below (see FIGS. 3 and 4). An area of the free-form mirror surface 10a here is approximately 20 cm 2. However, the area of the free-form mirror surface 10a can equally well be larger or smaller than 20 cm 2. The free-form mirror surface 10a preferably has a round, oval, elliptical or rectangular shape. However, it is understood that the free-form mirror surface 10a can also take other forms.
    The free-form mirror surface 10a can have any three-dimensional contour. It is usually completely or at least in sections continuously or continuously differentiable. The three-dimensional contour of the free-form mirror surface 10a can be selected or produced depending on what type of light pattern it is intended to form in the object space 2. For example, the three-dimensional contour of the free-form mirror surface 10a can be designed to form periodic or aperiodic stripe patterns. In principle, however, any type of spatially structured light pattern can be formed with free-form mirror surfaces of the type described here, depending on the design or shape of their surface contour. By deforming the three-dimensional contour of the free-form mirror surface 10a by means of the actuator unit 12, the spatially structured light patterns shaped in this way can then be further modified in a variety of ways.
    The connection layer 11 is arranged between the actuators 12a, 12b of the actuator unit 12. It serves to transmit deformation forces from the actuators 12a, 12b of the actuator unit 12 to the deformable substrate layer 10, and in particular to the deformable free-form mirror surface 10a. The connection layer 11 can e.g. comprise at least one adhesive layer and / or at least one metal layer. This metal layer can e.g. be formed as a solder layer or be given by a metal foil. A maximum thickness of the connecting layer 11 can be, for example, less than 1 mm, less than 0.5 mm or less than 0.2 mm. However, the thickness of the connection layer 11 can also assume larger values. In general, however, it is advantageous if the connection layer 11 is as thin as possible. The deformation of the substrate layer 10 or the free-form mirror surface 10a can be adjusted and reproduced very precisely by actuating the actuators 12a, 12b. Instead of the connection layer 11 shown here, only individual connection elements can also be provided (not shown), each of which is arranged between one of the actuators 12a, 12b and the substrate layer 10 and is designed to impart a deformation force between the actuators 12a, 12b and the substrate layer. These connecting elements can then e.g. also be formed by adhesive or metal.
    The actuators 12a and 12b of the actuator unit 12 are arranged in the housing 9 and are supported e.g. on an underside 9a of the housing 9. The housing 9 can e.g. be made of plastic, metal or another material. The actuators 12a and 12b can have an adjustable extent in a direction perpendicular or substantially perpendicular to the free-form mirror surface 10a. For example, the actuators 12a, 12b can each comprise one or more piezo elements, the extent of which can be adjusted perpendicularly or substantially perpendicularly to the free-form mirror surface 10a via a piezo voltage with nanometer accuracy. In alternative embodiments, the actuators 12a, 12b of the actuator unit 12 can also each have a linear motor or a mechanical actuating unit which can be adjusted via a linear motor. Depending on the geometry of the free-form mirror surface 10a, in particular depending on its lateral extent, the length or the extent of the actuators 12a, 12b in the direction perpendicular or substantially perpendicular to the free-form mirror surface 10a may be up to a few hundred micrometers or up to a few Be adjustable by millimeters. To stabilize the projection unit 8, an intermediate space 18 formed between the connecting layer 11 and the underside 9a of the housing 9, in which the actuators 12a, 12b are arranged, e.g. additionally be filled with an elastic or at least partially elastic filling material. A further layer can also be provided instead of this intermediate space 18. The actuators 12a, 12b can then e.g. be embedded in this additional layer.
    In a direction parallel or substantially parallel to the free-form mirror surface 10a, the different actuators 12a, 12b of the actuator unit 12 are spatially spaced apart from one another, so that a deformable force on different from the actuators 12a, 12b to the substrate layer 10 or to the free-form mirror surface 10a Positions of the free-form mirror surface 10a attacks or can attack. The deformation of the free-form mirror surface 10a can be adjusted and reproduced particularly precisely. In the exemplary embodiment of the actuator unit 12 shown here, a maximum distance between adjacent actuators 12a, 12b is, for example, less than 1 cm. In alternative embodiments, the maximum distance between adjacent actuators can also be less than 1 mm, less than 0.5 mm or less than 0.1 mm.
    CH 715 045 A2 The cameras 5a, 5b of the detection unit 5 can e.g. each have one or more CCD sensors or CMOS sensors. Alternatively or additionally, however, the detection unit 5 can also comprise one or more image sensors of another type.
    The control and evaluation unit 6 typically comprises a programmable processor, e.g. in the form of one or more microprocessors and / or one or more FPGAs or the like. The control and evaluation unit 6 is set up to control at least the actuator unit 12 and the detection unit 5, in particular thus the actuators 12a, 12b and the cameras 5a, 5b. In the exemplary embodiment shown here, the control and evaluation unit 6 is additionally set up to control the lighting unit 7. The control and evaluation unit 6 is connected to the lighting unit 7, to the actuators 12a, 12b and to the cameras 5a, 5b in each case via wired or wireless communication connections 13.
    The control and evaluation unit 6 is set up to adjust the length and / or the change in length of the actuators 12a, 12b perpendicularly or substantially perpendicularly to the free-form mirror surface 10a and thus to shape the surface shape or three-dimensional contour of the free-form mirror surface 10a as precisely and reproducibly as possible or to deform. The control and evaluation unit 6 is preferably set up to control the times at which the actuators 12a, 12b are actuated and / or at which the image sensors of the cameras 5a, 5b are exposed.
    The control and evaluation unit 6 is preferably also set up to control the actuators 12a, 12b independently of one another, i.e. to control the lengths and / or changes in length of the actuators 12a, 12b and / or the time of this change in length independently of one another. Depending on the geometry of the substrate layer 10 or the free-form mirror surface 10a and the maximum change in length of the actuators 12a, 12b, however, there may be limits, e.g. to prevent excessive deformation or damage to the substrate layer 10 and the free-form mirror surface 10a.
    2a and 2b show only schematically how a spatially structured light pattern formed by the projection unit 8 in the object space 2 can be changed by deforming the free-form mirror surface 10a. Recurring features here and in the following are each designated with the same reference symbols.
    In Fig. 2a, light L emitted by the lighting unit 7 is reflected on the free-form mirror surface 10a and projected into the object space 2, e.g. to the three-dimensional contour 3 from FIG. 1 arranged in the object space 2. In FIG. 2a, the control and evaluation unit 6 controls the actuators 12a, 12b in such a way that they have first lengths 14a, 14b perpendicular or essentially perpendicular to the free-form mirror surface 10a. The free-form mirror surface thus assumes a first surface shape 15a in FIG. 2a. The first surface shape 15a of the free-form mirror surface 10a forms the light L emitted by the illumination unit 7 in the object space 2 into a first stripe pattern 16a, which is given here only by way of example by a periodic stripe pattern with a first period length. It goes without saying that the free-form mirror surface 10a can also be designed to shape other light patterns.
    In Fig. 2b, light L emitted by the illumination unit 7 is in turn reflected on the free-form mirror surface 10a and projected into the object space 2, e.g. to the three-dimensional contour 3 from FIG. 1 arranged in the object space 2. In FIG. 2b, the control and evaluation unit 6 controls the actuators 12a, 12b in such a way that they have second lengths 17a, 17b perpendicular or essentially perpendicular to the free-form mirror surface 10a which are different from the first lengths 14a, 14b shown in FIG. 2a. The free-form mirror surface thus takes on a second surface shape 15b in FIG. 2b, which is different from the first surface shape 15a shown in FIG. 2a. The second surface shape 15b of the free-form mirror surface 10a forms the light L emitted by the illumination unit 7 in the object space 2 into a second stripe pattern 16b, which is different from the first stripe pattern 16b shown in FIG. 2a. For example, For example, the second stripe pattern 16b may have a second period length that is different from the first period length of the first stripe pattern 16a. Alternatively or additionally, the second stripe pattern 16b may e.g. also be aperiodic or the like.
    It is understood that by deforming the actuators 12a, 12b of the actuator unit 12 in this way, a large number of different spatially structured light patterns are formed in the object space 2 and e.g. can be projected onto the three-dimensional contour 3. The control and evaluation unit 6 and the actuators 12a, 12b can e.g. be designed such that a frequency with which the lengths of the actuators 12a, 12b and thus a spatial structure of the spatially structured light pattern formed in the object space 2 can be changed can be at least 100 Hz, at least 1 kHz or at least 10 kHz.
    3 schematically shows a modified embodiment of the projection unit 8 in a perspective view. The projection unit 8 according to FIG. 3 in turn comprises the substrate layer 10 with the free-form mirror surface 10a, the connection layer 11 and the actuator unit 12 in the form of a further layer, in which the actuators can be embedded, for example. Alternatively, the actuator unit 12 according to FIG. 3 can also be in the form of one or more piezoelectric layers. A microstructuring 19 of the free-form mirror surface 10a is additionally highlighted in FIG. 3. The microstructuring 19 can e.g. include local elevations and depressions of the free-form mirror surface 19. These local elevations and depressions can include, for example, height variations of up to 10 μm, up to 20 μm, up to 50 μm, up to 100 μm, up to 200 μm or up to 500 μm perpendicular or substantially perpendicular to the mirror surface. Alternatively or additionally, the height variations or
    CH 715 045 A2 the local height variations of the microstructuring 19 perpendicular to the mirror surface an amplitude of at least 0.5 μm or of at least 1 μm or of at least 5 μm or of at least 10 μm or of at least 20 μm or of at least 50 μm or of at least 100 μm. Parallel to the mirror surface, these height variations of the mirror surface can have dimensions of up to 100 μm, up to 200 μm, up to 500 μm, up to 1 mm, up to 5 mm or up to 10 mm. The microstructuring serves to form or generate spatially high-frequency structures of the spatially structured light patterns to be projected into the object space.
    4 shows an example of a section through the free-form mirror surface of the wader projection unit 8 according to FIG.
    with a local height profile of the microstructuring 19 of the free-form mirror surface 10a, the section plane being to run perpendicular to the plane of the drawing in FIG. 3. In Fig. 4 it can be seen that the height of the free-form mirror surface 10a in the lateral direction, i.e. parallel or essentially parallel to the free-form mirror surface 10a (in FIG. 4 this is the x-direction), has height variations of approximately 10 micrometers over a length of 0.5 mm and additional height variations of less than approximately locally over lengths of approximately 50 micrometers 1 micron.
    A device for contactless detection of the three-dimensional contour 3 can be carried out with the device 1 according to FIG. 1. This procedure includes at least the following steps:
    The light L emitted by the illumination unit 7 is reflected on the free-form mirror surface 10a and successively shaped into different spatially structured light patterns. This large number of different spatially structured light patterns is projected onto the three-dimensional contour 3 in the object space 2. Examples of such spatially structured light patterns are the light patterns 16a and 16b shown in FIGS. 2a and 2b. For example, For carrying out the method, several hundred or several thousand different spatially structured light patterns can be successively projected onto the three-dimensional contour 3. The shaping of the different spatially structured light patterns includes the above-described shaping of the free-form mirror surface 10a by changing the length of the actuators 12a, 12b, which are controlled by the control and evaluation unit 6.
    The control and evaluation unit 6 controls the actuators 12a, 12b and the cameras 5a, 5b synchronously in such a way that the cameras 5a, 5b for each of the plurality of different spatially structured light patterns that are projected onto the three-dimensional contour 3 , each take at least one image of the contour 3 with the respective spatially structured light pattern projected onto the contour 3. The control and evaluation unit 6 is set up to calculate the spatial structure of the contour 3 based on image data of these images captured by the cameras 5a, 5b.
    For this purpose, the control and evaluation unit 6 identifies for a plurality of object points 3a, 3b, 3c on the contour 3 a pair of points in an image plane 20a of the first camera 5a and in an image plane 20b of the second camera 5b, which are mutually exclusive and correspond to the respective object point 3a, 3b, 3c. In FIG. 1, for example, the point 3c 'in the image plane 20a of the first camera 5a and the point 3c in the image plane 20b of the second camera 5b form such a pair of points which correspond to one another and the object point 3c on the contour 3. Possible methods for identifying the corresponding points 3c ', 3c in the image planes 20a, 20b of the cameras 5a, 5b are described, for example, in WO 2015 022 384 A1 or in DE102012013079A1, as explained at the beginning. Of course, in order to identify the corresponding points 3c ', 3c in the image planes 20a, 20b of the cameras 5a, 5b, other e.g. Methods known from the prior art can be used.
    Based on the known spatial arrangement of the image planes 20a, 20b of the cameras 5a, 5b, depth information and thus a spatial coordinate of the point 3c on the contour 3 can then be calculated for the pair of points 3c ', 3c. A corresponding procedure can be used to calculate the spatial coordinates of the object points 3a, 3b and a large number of further object points on the contour 3.
    In a modified embodiment e.g. only the first camera 5a is used. In this case, the control and evaluation unit 6 can then determine a virtual projection plane 21, from which the light L for projecting the spatially structured light pattern is projected into the object space 2 and onto the contour 3. In this case, the control and evaluation unit 6 then identifies, for each of the object points 3a, 3b, 3c on the contour 3, a pair of points in the image plane 20a of the first camera 5a and in the virtual projection plane 21, each other and the respective object point 3a, 3b, 3c correspond. In FIG. 1, for example, the point 3c 'in the image plane 20a of the first camera 5a and the point 3c' in the virtual projection plane 21 form such a pair of points that correspond to one another and the object point 3c on the contour 3.
    权利要求:
    Claims (23)
    [1]
    claims
    A projection device (4) comprising:
    a lighting unit (7) for emitting light (L); and a projection unit (8) with a mirror surface, the projection unit (8) being set up to project the light (L) emitted by the illumination unit (7) into an object space (2) by means of the mirror surface and to differentiate it in the object space (2) to form spatially structured light patterns (16a, 16b);
    characterized in that the mirror surface is deformable at least in regions and the projection unit (8) for shaping the different spatially structured light patterns (16a, 16b) in the object space (2) has at least one actuator (12a, 12b) for at least regionally deforming the game surface.
    CH 715 045 A2
    [2]
    2. Projection device (4) according to claim 1, characterized in that the mirror surface for shaping the spatially structured light pattern (16a, 16b) is designed as a free-form mirror surface (10a).
    [3]
    3. Projection device (4) according to one of the preceding claims, characterized in that the mirror surface for shaping high-frequency structures of the spatially structured light patterns (16a, 16b) has a microstructuring (19).
    [4]
    4. Projection device (4) according to claim 3, characterized in that the microstructuring (19) perpendicular to the mirror surface has local height variations that have an amplitude of up to 10 μm or of up to 20 μm or of up to 50 μm or of up to 100 μm or up to 200 μm or up to 500 μm.
    [5]
    5. Projection device (4) according to claim 3 or 4, characterized in that the microstructuring (19) perpendicular to the mirror surface has local height variations that have an amplitude of at least 0.5 μm or at least 1 μm or at least 5 μm or at least Have 10 μm or at least 20 μm or at least 50 μm or at least 100 μm.
    [6]
    6. Projection device (4) according to claim 4 or 5, characterized in that the height variations of the microstructuring (19) parallel to the mirror surface each up to 100 microns or up to 200 microns or up to 500 microns or up to 1 mm or extend up to 5 mm or up to 10 mm.
    [7]
    7. Projection device (4) according to one of the preceding claims, characterized in that the projection unit (8) for forming the mirror surface has a substrate layer (10), in particular a metal substrate layer (10) with a thickness of at most 1 mm, preferably with a thickness of at most 0.5 mm, particularly preferably with a thickness of at most 0.2 mm.
    [8]
    8. The projection device (4) according to claim 7, characterized in that the projection unit (8) has at least one connecting element or at least one connecting layer (11) on a rear side of the substrate layer (10) facing away from the mirror surface, the at least one connecting element or the at least one connecting layer (11) for transmitting a deformation force from the at least one actuator (12a, 12b) to the substrate layer (10) is arranged between the at least one actuator (12a, 12b) and the substrate layer (10).
    [9]
    9. Projection device (4) according to claim 8, characterized in that the at least one connecting layer (11) comprises at least one adhesive layer or at least one metal layer, in particular in the form of a metal foil or a solder layer.
    [10]
    10. Projection device (4) according to one of the preceding claims, characterized in that the at least one actuator (12a, 12b) comprises at least one piezo element, at least one linear motor or at least one mechanical actuating unit which can be driven by a linear motor.
    [11]
    11. Projection device (4) according to one of the preceding claims, characterized in that the at least one actuator (12a, 12b) comprises a plurality of actuators (12a, 12b) which can be adjusted or controlled independently of one another.
    [12]
    12. Projection device (4) according to one of the preceding claims, characterized in that the at least one actuator (12a, 12b) comprises a plurality of actuators (12a, 12b) which are arranged rotationally symmetrically.
    [13]
    13. Projection device (4) according to one of the preceding claims, characterized in that the lighting unit (7) comprises at least one LED and / or at least one laser.
    [14]
    14. A device for contactless detection of a three-dimensional contour (3), comprising:
    a projection device (4) according to one of the preceding claims;
    at least one camera (5a, 5b), preferably a first camera (5a) and a second camera (5b), for taking pictures of an object arranged in the object space (2) with the different spatially structured light patterns projected onto the object by means of the mirror surface ( 16a, 16b); and an evaluation unit (6) for determining a three-dimensional contour (3) of an object arranged in the object space (2) based on image data from images of the object taken by means of the at least one camera (5a, 5b), preferably by means of the first camera (5a) and the second camera (5b) recorded images of the object, with the different spatially structured light patterns (16a, 16b) projected onto the object by means of the mirror surface.
    [15]
    15. The apparatus of claim 14, further comprising:
    a control unit (6) for controlling the at least one actuator (12a, 12b) and for controlling the at least one camera (5a, 5b), preferably for controlling the first camera (5a) and the second camera (5b);
    the control unit (6) being set up to control the at least one actuator (12a, 12b) and the at least one camera (5a, 5b), preferably the first camera (5a) and the second camera (5b), in such a way that the at least one a camera (5a, 5b), preferably the first camera (5a) and the second camera (5b), for each spatially structured light pattern (16a, 16b) of the plurality of different spatially structured light patterns (16a, 16b)
    CH 715 045 A2 of the mirror surface is projected onto an object arranged in the object space (2), in each case to take at least one image of the object with the spatially structured light pattern (16a, 16b) projected onto the object.
    [16]
    16. Device according to one of claims 14 and 15, wherein the evaluation unit is set up for detecting the three-dimensional contour (3) of the object arranged in the object space (2), for a plurality of object points (3a, 3b, 3c) of the object based on the Image data of the images recorded by means of the at least one camera, preferably based on the image data of the images recorded by means of the first camera (5a) and the second camera (5b),
    - each pair (3c ', 3c; 3c', 3c ') of points corresponding to each other and the respective object point (3c) in an image plane (20a) of the camera or the first camera (5a) and in a further plane (20b, 21 ), the further level (20b, 21)
    a) an image plane (20b) of the second camera (5b) or
    b) is a virtual projection plane (21) assigned to the mirror surface, and depth information by triangulation as a function of positions of the points (3c ', 3c; 3c'; 32c ') corresponding to each other and the respective object point (3c) in the image plane (20a ) and in the further level (20b, 21).
    [17]
    17. projection method comprising the steps:
    Forming a first spatially structured light pattern (16a) in an object space (2) by reflecting light (L) on a mirror surface with a first surface shape (15a);
    deforming the mirror surface at least in regions so that the mirror surface assumes a second surface shape (15b) that differs from the first surface shape; and
    Forming a second spatially structured light pattern (16b) different from the first spatially structured light pattern (16a) in the object space (2) by reflection of light (L) on the mirror surface with the second surface shape (15b).
    [18]
    18. The projection method according to claim 17, characterized in that the deformation of the mirror surface is carried out by means of at least one actuator (12a, 12b), preferably by changing a piezo voltage of a piezo element or by adjusting a linear motor.
    [19]
    19. Projection method according to one of claims 17 and 18, characterized in that the mirror surface is deformed simultaneously at different positions of the mirror surface.
    [20]
    20. The projection method as claimed in claim 19, characterized in that the mirror surface is deformed at various positions of the mirror surface which are arranged rotationally symmetrically relative to one another.
    [21]
    21. A method for contactless detection of a three-dimensional contour (3), comprising the steps:
    Projecting different spatially structured light patterns (16a, 16b) onto an object arranged in an object space (2) according to the method according to one of claims 17 to 20;
    Taking pictures of the object with the different spatially structured light patterns (16a, 16b) projected onto the object by means of at least one camera (5a, 5b), preferably by means of a first camera (5a) and a second camera (5b); and
    Determining a three-dimensional contour (3) of the object based on image data of the images captured by the at least one camera (5a, 5b), preferably based on image data of the images captured by the first camera (5a) and the second camera (5b).
    [22]
    22. The method according to claim 21, characterized in that the deformation of the mirror surface to form the different spatially structured light patterns (16a, 16b) and the taking of the images of the object by means of the at least camera (5a, 5b), preferably by means of the first camera ( 5a) and the second camera (5b), are carried out synchronously such that the at least one camera (5a, 5b), preferably the first camera (5a) and the second camera (5b), for each of the plurality of different spatially structured light patterns (16a, 16b), which is projected onto the object, takes at least one image of the object with the spatially structured light pattern (16a, 16b) projected onto the object.
    [23]
    23. The method according to any one of claims 21 and 22, characterized in that for a plurality of object points (3a, 3b, 3c) of the object based on the image data of the images taken by means of the at least one camera (5a, 5b, 5c), preferably based on the image data of the images recorded by the first camera (5a) and the second camera (5b), pairs (3c, 3c; 3c ', 3c') of each other and points corresponding to the respective object point (3c) in the image plane (20a ) of the camera or the first camera (5a) and in a further plane (20b, 21), the further plane (20b, 21)
    a) an image plane (20b) of the second camera (5b) or
    b) is a virtual projection plane (21) assigned to the mirror surface, and
    CH 715 045 A2, depth information is determined by triangulation as a function of positions of the points (3c ', 3c; 3c', 3c ') corresponding to one another and the respective object point in the image plane (20a) and in the further plane (20b, 21) ,
    CH 715 045 A2

    CH 715 045 A2


    CH 715 045 A2
    CH 715 045 A2

    0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 x [mm]
    9:46
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    DE102018208417.3A|DE102018208417A1|2018-05-28|2018-05-28|Projection device and projection method|
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