Optical system and 3D measuring device

Abstract

The application provides an optical system and a 3D measuring device, the optical system comprising at least one light reflecting device, the light reflecting device being located on a light path between an object to be measured and a camera, and the light reflecting device being used for turning the light path between the object to be measured and the camera; wherein: the light reflecting device is used for reflecting a laser beam in a first direction incident on the optical system, and the reflected laser beam in a second direction is incident on the camera; wherein the first direction is a direction from the object to be measured to the light reflecting device; and the second direction is a direction from the light reflecting device to the camera. Through the application, the light path between the object to be measured and the camera is turned by the light reflecting device, the working volume of the 3D measuring device is effectively reduced, and the production space utilization is improved.

Description

Technical Field

[0001] This application relates to the field of machine vision technology, and in particular to an optical system and a 3D measurement device. Background Technology

[0002] 3D measurement equipment consists of a laser and a camera. The laser projects a laser beam onto the surface of the object to be measured (i.e., the target object), and the camera captures an image of the laser beam reflected from the object. After obtaining the laser image, taking a line laser image as an example, the center line of the line laser beam can be acquired. This center line is then converted according to pre-calibrated sensor parameters to obtain the spatial coordinates (i.e., three-dimensional coordinates) of the object at its current position. Based on these spatial coordinates, and in conjunction with the scanning of a conveyor belt, the three-dimensional structure of the object can be measured (i.e., 3D measurement).

[0003] In the process of measuring the 3D structure of objects based on laser images, the field of view (FOV) and depth of field (DOF) of the imaging system are key parameters, primarily determined by the optical system design parameters of the 3D measurement equipment. From the perspective of optical design principles, expanding the field of view or increasing the depth of field usually requires increasing the optical path length. However, this design approach directly leads to an increase in the working distance of the 3D measurement equipment, thus creating a constraint between the equipment's working size and measurement performance. Therefore, how to achieve equivalent or higher levels of field of view coverage and depth of field adaptability while maintaining a compact structural design has become an important research direction for improving the practical application of 3D measurement equipment. Utility Model Content

[0004] This application provides an optical system including at least one light-reflecting device located in the optical path between an object under test and a camera, and the light-reflecting device is used to refract the optical path between the object under test and the camera; wherein:

[0005] The light reflecting device is used to reflect a laser beam incident on the optical system in a first direction, and the reflected laser beam in a second direction is incident on the camera.

[0006] Wherein, the first direction is the direction from the object under test to the light reflecting device;

[0007] The second direction is the direction from the light-reflecting device to the camera.

[0008] This application proposes a 3D measurement device, which includes a laser, a camera, and the aforementioned optical system; wherein: the laser is used to emit a laser beam toward the object to be measured, and the laser beam, after being reflected by the object to be measured, is incident on the optical system in a first direction;

[0009] The camera is used to receive a laser beam reflected by the optical system in a second direction, and to image the object under test based on the laser beam to obtain a laser image;

[0010] The laser image is used to perform 3D measurement on the object under test.

[0011] As can be seen from the above technical solutions, in this embodiment, by adding a light-reflecting device to the optical path between the object under test and the camera, and using this device to fold the optical path between them, a novel reduction in the device's working volume is achieved while maintaining the effective measurement optical path length. By utilizing the light-reflecting device to fold the laser transmission path at multiple stages, the system maintains the original field of view (FOV) and depth of field (DOF) parameters while compressing the device's working volume. This optical path reconstruction method effectively balances the contradiction between measurement accuracy and device compactness, providing a new technical path for the miniaturization of 3D measurement equipment.

[0012] By employing a folded object distance optical path design (i.e., adding light reflection devices to fold the object distance), the optical path is folded, achieving sufficient object distance and viewing angle within a limited device size. This effectively reduces the working volume of the 3D measurement equipment while ensuring sufficient measurement field of view and accuracy. It can maintain high-precision measurement functions. After the laser image captured by the camera is processed by the algorithm, the three-dimensional contour information of the object under test can be generated to achieve 3D measurement, meeting the accuracy requirements of industrial 3D measurement and suitable for 3D measurement applications.

[0013] By employing a folded optical path design, the 3D measurement equipment achieves a more compact structure, effectively reducing its working volume and making it suitable for space-constrained industrial applications. Through a well-designed optical path configuration, not only is the working volume reduced, but high-precision laser measurement capabilities are also ensured, meeting the needs of various industrial 3D measurement tasks and making it suitable for industrial 3D measurement tasks in confined spaces. Attached Figure Description

[0014] Figure 1 This is a hardware structure diagram of an optical system according to one embodiment of this application;

[0015] Figure 2 This is a hardware structure diagram of a 3D measurement device according to one embodiment of this application;

[0016] Figure 3 This is a hardware structure diagram of a 3D measurement device according to one embodiment of this application;

[0017] Figure 4 This is a hardware structure diagram of a 3D measurement device according to one embodiment of this application;

[0018] Figure 5 This is a hardware structure diagram of a 3D measurement device according to one embodiment of this application;

[0019] Figure 6 This is a flowchart illustrating a 3D measurement method according to one embodiment of this application;

[0020] Figure 7 This is a schematic diagram of the structure of a 3D measuring device according to one embodiment of this application;

[0021] Figure 8 This is a hardware structure diagram of a 3D measurement device according to one embodiment of this application. Detailed Implementation

[0022] This application provides an optical system that may include at least one light-reflecting device located in the optical path between the object under test and the camera, and which causes a refraction of the optical path between the object under test and the camera. See also Figure 1 The diagram shown is a schematic of the structure of the optical system, which may include K light reflecting devices, where K can be a positive integer.

[0023] A light reflecting device is used to reflect a laser beam in a first direction from an incident optical system, and the reflected laser beam in a second direction is incident on a camera; wherein the first direction is from the object under test to the light reflecting device; and the second direction is from the light reflecting device to the camera.

[0024] For example, any of the light reflecting devices includes any of the following: a plane mirror; a curved mirror; a prism; a beam splitter; a reflective grating; or a reflective waveplate.

[0025] For example, the optical system includes a first light reflecting device, which is a plane mirror, wherein: the plane mirror is used to reflect a laser beam incident on the plane mirror in a first direction, and the reflected laser beam in a second direction is incident on the camera; wherein the first angle corresponding to the first direction is the same as the second angle corresponding to the second direction; wherein the first angle is the angle between the first direction and the normal direction; and the second angle is the angle between the second direction and the normal direction.

[0026] For example, the optical system may include a second light reflecting device and a third light reflecting device, wherein the second light reflecting device is a plane mirror and the third light reflecting device is a right-angle prism; wherein: the plane mirror is used to reflect the laser beam incident on the plane mirror in a first direction, and the reflected laser beam in a third direction is incident on the right-angle prism; the angle between the first direction and the normal direction and the angle between the third direction and the normal direction are the same; the right-angle prism is used to reflect the laser beam incident on the right-angle prism in a third direction, and the reflected laser beam in a second direction is incident on the camera; the second direction is the opposite direction of the third direction.

[0027] For example, the third direction is parallel to the horizontal plane where the object to be measured is located, and the third direction is perpendicular to the right-angle prism; the second direction is parallel to the horizontal plane where the object to be measured is located, and the second direction is perpendicular to the right-angle prism.

[0028] For example, the optical system includes a fourth light reflecting device and a fifth light reflecting device, wherein the fourth light reflecting device is a first plane mirror and the fifth light reflecting device is a second plane mirror; the first plane mirror is used to reflect a laser beam incident in a first direction, and the reflected laser beam in a fourth direction is incident on the second plane mirror; wherein the angle between the first direction and the normal direction and the angle between the fourth direction and the normal direction are the same; the second plane mirror is used to reflect a laser beam in a fourth direction incident on the second plane mirror, and the reflected laser beam in a second direction is incident on a camera; wherein the angle between the fourth direction and the normal direction and the angle between the second direction and the normal direction are the same.

[0029] This application provides a 3D measurement device, see [link to relevant documentation] Figure 2 The diagram shows the structure of the 3D measurement device, which may include a laser, a camera, and the aforementioned optical system. Specifically: the laser emits a laser beam towards the object to be measured, and after reflection from the object, the laser beam is incident on the optical system in a first direction, where it is reflected; the camera receives the laser beam reflected by the optical system in a second direction, and images the object to be measured based on the laser beam to obtain a laser image; the laser image is used for 3D measurement of the object to be measured.

[0030] For example, the camera may include a lens and an image sensor; the lens is used to receive a laser beam reflected by an optical system in a second direction and focus the laser beam onto the image sensor; the image sensor is used to image the object to be measured based on the received laser beam to obtain a laser image.

[0031] For example, the lens may include, but is not limited to, a SAM lens.

[0032] For example, the laser can be a point laser and the 3D measurement device can be a laser displacement sensor; or, the laser can be a line laser and the 3D measurement device can be a 3D laser profile sensor or a line laser stereo camera; or, the laser can be a structured light laser and the 3D measurement device can be a structured light stereo camera.

[0033] For example, the 3D measurement device may also include a housing and a connector; on this basis, the laser, optical system and camera are fixed in the housing via the connector.

[0034] As can be seen from the above technical solutions, in this embodiment, by adding a light-reflecting device to the optical path between the object under test and the camera, and using this device to fold the optical path between them, a novel reduction in the device's working volume is achieved while maintaining the effective measurement optical path length. By utilizing the light-reflecting device to fold the laser transmission path at multiple stages, the system maintains the original field of view (FOV) and depth of field (DOF) parameters while compressing the device's working volume. This optical path reconstruction method effectively balances the contradiction between measurement accuracy and device compactness, providing a new technical path for the miniaturization of 3D measurement equipment.

[0035] By employing a folded object distance optical path design (i.e., adding light reflection devices to fold the object distance), the optical path is folded, achieving sufficient object distance and viewing angle within a limited device size. This effectively reduces the working volume of the 3D measurement equipment while ensuring sufficient measurement field of view and accuracy. It can maintain high-precision measurement functions. After the laser image captured by the camera is processed by the algorithm, the three-dimensional contour information of the object under test can be generated to achieve 3D measurement, meeting the accuracy requirements of industrial 3D measurement and suitable for 3D measurement applications.

[0036] By employing a folded optical path design, the 3D measurement equipment achieves a more compact structure, effectively reducing its working volume and making it suitable for space-constrained industrial applications. Through a well-designed optical path configuration, not only is the working volume reduced, but high-precision laser measurement capabilities are also ensured, meeting the needs of various industrial 3D measurement tasks and making it suitable for industrial 3D measurement tasks in confined spaces.

[0037] The technical solutions described above in the embodiments of this application will be explained below in conjunction with specific application scenarios.

[0038] This application proposes a 3D measurement device based on the principle of laser triangulation, comprising a collaborative measurement system of a laser and a camera. Specifically, a 3D laser contour sensor is used as a typical example, consisting of a laser (i.e., a laser generating unit) and a camera (i.e., an image acquisition unit). The laser generates a linear beam that is projected onto the surface of the object to be measured, while the camera simultaneously acquires the laser image reflected from the object's surface. The laser beam emitted by the laser is collimated by a collimating lens to form a sub-millimeter-level linear spot, which undergoes geometric deformation after being projected onto the surface of the object. The camera acquires the deformed laser stripe image, and the coordinates of the laser centerline are calculated using a sub-pixel-level light stripe center extraction algorithm. Based on pre-established sensor coordinate system calibration parameters, the height of the object is measured. Combined with a conveyor belt or other transmission device, a scanning-type 3D measurement is completed.

[0039] It should be noted that the 3D measurement equipment in this application encompasses all measurement devices based on line laser triangulation, including but not limited to 3D laser profile sensors, monocular structured light imaging devices, or binocular structured light imaging devices. Its core architecture involves projecting a structured laser beam using a laser, combined with a high-precision image sensor to achieve three-dimensional coordinate calculation. This technical solution is adaptable to industrial inspection scenarios with varying measurement ranges. By adjusting parameters such as lens focal length, baseline distance, and intersection angle, it can meet the full-scale three-dimensional measurement needs, from microelectronic components to large mechanical parts. For example, the laser can be a point laser, and the 3D measurement device can be a laser displacement sensor, i.e., a point laser-based 3D measurement device. Alternatively, the laser can be a line laser, and the 3D measurement device can be a 3D laser profile sensor (i.e., a line laser profiler) or a line laser stereo camera, i.e., a line laser-based 3D measurement device. Or, the laser can be a structured light laser, and the 3D measurement device can be a structured light stereo camera, i.e., a structured light-based 3D measurement device.

[0040] For example, see Figure 3 The diagram shows the structure of a 3D measurement device. 1 represents the laser, 2 represents the object to be measured, 3 represents the lens, 4 represents the image sensor, 5 represents the working volume of the 3D measurement device, 6 represents the device volume of the 3D measurement device, and 7 represents the field of view of the laser.

[0041] In a 3D measurement device, laser 1 can emit a laser beam toward the object to be measured 2. For example, if laser 1 emits a laser beam vertically downwards, taking a 3D laser contour sensor as an example, then laser 1 emits a linear laser beam vertically downwards. During operation, the linear laser beam forms a laser line covering the surface of the object to be measured 2. In this way, the linear laser beam is used to scan the contour information of the surface of the object to be measured 2.

[0042] After the object under test 2 receives the laser beam emitted by the laser 1, that is, after the laser beam illuminates the surface of the object under test 2, the object under test 2 will reflect the laser beam at a certain angle. Since the object under test 2 will reflect the laser beam in multiple directions, one or more reflection directions can be the reflection direction pointing towards the lens 3, such as the upper right direction pointing towards the lens 3. Based on this, when the object under test 2 reflects the laser beam, it will reflect the laser beam towards the lens 3 at a certain angle, and the laser beam enters the lens 3.

[0043] Lens 3 can be a camera lens, a SAM lens, or other types of lenses; there are no restrictions. After the laser beam enters lens 3, lens 3 can receive the laser beam and project it onto image sensor 4, and the laser beam is focused by lens 3.

[0044] Image sensor 4 is the imaging device of the camera. The laser beam passes through lens 3 and forms a clear laser image on image sensor 4. In other words, image sensor 4 can image the object under test 2 based on the laser beam to obtain a laser image. The laser image is used to perform 3D measurement on the object under test 2, that is, 3D measurement can be performed based on the laser image to achieve accurate measurement of the surface of the object under test 2.

[0045] exist Figure 3 In the diagram, 7 represents the field of view of the laser. When the object under test 2 moves into the field of view 7 of the laser, the laser 1 emits a laser beam vertically downwards, and the laser beam illuminates the surface of the object under test 2.

[0046] exist Figure 3 In this embodiment, 6 represents the volume of the 3D measurement device, which is the volume of the laser 1, lens 3 and sensor 4. The volume of the 3D measurement device is not limited in this embodiment.

[0047] exist Figure 3 In this diagram, 5 represents the working volume of the 3D measuring device, and the straight line from the object under test 2 to the lens 3 represents the optical path distance between the object under test 2 and the lens 3. Obviously, the longer the optical path distance between the object under test 2 and the lens 3, the larger the working volume 5 of the 3D measuring device.

[0048] In response to the above findings, this application proposes a 3D measurement device. The 3D measurement device includes a laser and a camera. Based on the laser and camera, an optical system can be added to the optical path between the object under test and the camera. This optical system includes at least one light-reflecting device, which is located in the optical path between the object under test and the camera. The light-reflecting device is used to deflect the optical path between the object under test and the camera. For example, the light-reflecting device reflects a laser beam incident on the optical system in a first direction, and the reflected laser beam in a second direction is incident on the camera. The first direction is from the object under test towards the light-reflecting device; the second direction is from the light-reflecting device towards the camera.

[0049] Thus, the 3D measurement device can also include a light-reflecting device. Based on this, by deploying the light-reflecting device and employing a folded object distance optical path design, the optical path distance between the object under test and the camera can be kept constant, while reducing the working volume of the 3D measurement device, thereby facilitating its use in confined working environments. When reconstructing the three-dimensional structure of the object under test 2 based on laser images, by folding the optical path distance between the object under test 2 and the camera (such as lens 3), the optical path length between the object under test 2 and the camera can be kept constant. While maintaining the original imaging field of view and imaging depth parameters, the working volume of the 3D measurement device is compressed, effectively balancing the contradiction between measurement accuracy and device compactness.

[0050] For example, the number of light reflecting devices is at least one, such as one, two, three, four, or more, without limitation.

[0051] For example, any one of the optical reflecting devices includes any of the following: a plane mirror; a curved mirror; a prism; a beam splitter; a reflective grating; or a reflective waveplate. Of course, the above are just a few examples, and there is no limitation on the type of each optical reflecting device.

[0052] For example, if there is only one light reflecting device, then the light reflecting device can be a plane mirror, a curved mirror, a prism, a beam splitter, a reflective grating, or a reflective waveplate.

[0053] For example, if there are two light reflecting devices, they can include a first light reflecting device and a second light reflecting device. The first and second light reflecting devices can be of the same type, such as both being plane mirrors. They can also be of different types, such as the first light reflecting device being a plane mirror and the second light reflecting device being a prism. In summary, the first light reflecting device can be a plane mirror, a curved mirror, a prism, a beam splitter, a reflective grating, or a reflective waveplate. Similarly, the second light reflecting device can also be a plane mirror, a curved mirror, a prism, a beam splitter, a reflective grating, or a reflective waveplate.

[0054] For example, if there are three optical reflecting devices, then these devices can include a first optical reflecting device, a second optical reflecting device, and a third optical reflecting device. The first and second optical reflecting devices can be of the same type, or they can be different types. Similarly, the first and third optical reflecting devices can be of the same type, or they can be different types. The second and third optical reflecting devices can also be of the same type, or they can be different types. Furthermore, the first optical reflecting device can be a plane mirror, a curved mirror, a prism, a beam splitter, a reflective grating, or a reflective waveplate. Similarly, the second optical reflecting device can be a plane mirror, a curved mirror, a prism, a beam splitter, a reflective grating, or a reflective waveplate. The third light reflecting device can be a plane mirror, a curved mirror, a prism, a beam splitter, a reflective grating, or a reflective waveplate.

[0055] For example, if the number of light reflecting devices is four, then the light reflecting devices may include a first light reflecting device, a second light reflecting device, a third light reflecting device, and a fourth light reflecting device. When the number of light reflecting devices is greater, the implementation method of the light reflecting devices is similar, and will not be described again in this embodiment.

[0056] In summary, when there are at least two optical reflective devices, the different optical reflective devices can be of the same type or different types. For each optical reflective device, it can be: a plane mirror, a curved mirror, a prism, a beam splitter, a reflective grating, or a reflective waveplate.

[0057] For example, a plane mirror refracts incident light according to the law of reflection, forming a virtual image of an object. The object and image are symmetrical about the reflecting surface. Curved mirrors can be divided into spherical mirrors and aspherical mirrors. A spherical mirror has a spherical surface (such as a concave sphere), which can refract light beams and generate virtual or real images. The working surface of an aspherical mirror can be any curved surface, such as a parabola, hyperboloid, ellipsoid, or cylinder.

[0058] Prisms, also known as reflecting prisms, can include right-angle prisms, polarizing prisms, and beam splitters. A reflecting prism is a polyhedron formed by several optical planes, functioning as a combination of several plane mirrors. By rotating the optical axis as required, it can form an inverted or upright image. A beam splitter is formed by coating a specific dielectric film on its reflecting surface. It can partially reflect and partially transmit light of a certain wavelength, ensuring an appropriate ratio between the two, or reflect a component of the incident light within a certain wavelength range while transmitting a component within another wavelength range.

[0059] A reflective grating is a special optical element that can decompose incident light into spectra of different frequencies. The basic principle of a reflective grating is to utilize the diffraction phenomenon of light; after light is reflected at a certain angle, interference occurs, thus forming a diffraction spectrum. A reflective waveplate is a new type of optical element, manufactured based on holographic technology and reflective liquid crystal technology, which can convert natural light into ring-polarized or linearly polarized light.

[0060] For example, when there is only one optical reflector, an additional optical reflector can be added to the optical path between the object under test and the camera. This optical reflector causes the optical path between the object under test and the camera to be deflected. Based on this, the laser beam reflected by the object under test enters this optical reflector, which can reflect the laser beam, and the reflected laser beam enters the camera lens.

[0061] For example, an optical system may include a light reflecting device. For ease of distinction, this light reflecting device will be referred to as the first light reflecting device. The first light reflecting device can be a plane mirror, a curved mirror, a prism, a beam splitter, a reflective grating, a reflective waveplate, etc. For ease of description, we will take a plane mirror as an example of the first light reflecting device. Based on this, the plane mirror is used to reflect the laser beam incident on the plane mirror in a first direction, and the reflected laser beam in a second direction is then incident on the camera.

[0062] For example, the first direction is from the object being measured towards the plane mirror, meaning the laser beam is incident on the plane mirror in the first direction, i.e., the laser beam is incident on the plane mirror in the direction of incidence. The second direction is from the plane mirror towards the camera (such as a lens), meaning the laser beam is incident on the camera in the second direction, i.e., the laser beam is emitted from the plane mirror in the direction of exit, and the plane mirror reflects the laser beam in the second direction.

[0063] For a plane mirror, the first angle corresponding to the first direction is the same as the second angle corresponding to the second direction. The first angle is the angle between the first direction and the normal direction, which can be understood as the incident angle of the laser beam. The second angle is the angle between the second direction and the normal direction, which can be understood as the exit angle of the laser beam. Obviously, the incident angle and the exit angle of the laser beam can be the same.

[0064] For example, when there are two optical reflective devices, two optical reflective devices can be added to the optical path between the object under test and the camera, causing the optical path between the object under test and the camera to be deflected. Based on this, the laser beam reflected by the object under test enters the first optical reflective device, which can reflect the laser beam, and the reflected laser beam enters the second optical reflective device, which can reflect the laser beam, and the reflected laser beam enters the camera lens.

[0065] For example, an optical system can include two light-reflecting devices. These two light-reflecting devices can be of different types. The first light-reflecting device can be a plane mirror, a curved mirror, a prism, a beam splitter, a reflective grating, a reflective waveplate, etc., and the second light-reflecting device can be a plane mirror, a curved mirror, a prism, a beam splitter, a reflective grating, a reflective waveplate, etc. The difference between these two light-reflecting devices is that they are different types. For ease of distinction, these two light-reflecting devices are referred to as the second light-reflecting device and the third light-reflecting device. For ease of description, we will take a plane mirror as the second light-reflecting device and a right-angle prism as the third light-reflecting device as an example.

[0066] A plane mirror is used to reflect a laser beam incident on the mirror in a first direction, and the reflected laser beam in a third direction is then incident on a right-angle prism. A right-angle prism is used to reflect a laser beam incident on the prism in a third direction, and the reflected laser beam in a second direction is then incident on a camera.

[0067] For example, the first direction is from the object being measured towards the plane mirror, meaning the laser beam is incident on the plane mirror in the first direction, i.e., the laser beam's incident direction relative to the plane mirror. The third direction is from the plane mirror towards the right-angle prism, meaning the laser beam is incident on the right-angle prism in the third direction, i.e., the laser beam's incident direction relative to the right-angle prism, and the laser beam exits from the plane mirror in the third direction, i.e., the laser beam's exit direction relative to the plane mirror, and the plane mirror reflects the laser beam in the third direction. The second direction is from the right-angle prism towards the camera, meaning the laser beam is incident on the camera in the second direction, i.e., the laser beam's incident direction relative to the camera, and the laser beam exits from the right-angle prism in the second direction, i.e., the laser beam's exit direction relative to the right-angle prism, and the right-angle prism reflects the laser beam in the second direction.

[0068] For a plane mirror, the first angle corresponding to the first direction is the same as the third angle corresponding to the third direction. The first angle is the angle between the first direction and the normal direction, which can be understood as the incident angle of the laser beam. The third angle is the angle between the third direction and the normal direction, which can be understood as the exit angle of the laser beam. Obviously, the incident angle and the exit angle of the laser beam can be the same.

[0069] For a right-angle prism, the second direction is the opposite of the third direction. The second direction corresponds to the incident angle of the laser beam on the right-angle prism, and the third direction corresponds to the exit angle of the laser beam on the right-angle prism. The sum of the incident angle and the exit angle of the laser beam can be 180 degrees.

[0070] In one possible implementation, the third direction can be parallel to the horizontal plane where the object to be measured is located, and the third direction can be perpendicular to the right-angle prism; the second direction can be parallel to the horizontal plane where the object to be measured is located, and the second direction can be perpendicular to the right-angle prism. The above is just an example, and there are no restrictions on the second direction and the third direction, as long as they correspond to the working principle of the right-angle prism, and the second direction is the opposite direction of the third direction.

[0071] For example, an optical system may include two light reflecting devices. These two light reflecting devices can be of the same type; that is, both the first and second light reflecting devices can be plane mirrors, curved mirrors, prisms, beam splitters, reflective gratings, reflective waveplates, etc. For ease of distinction, these two light reflecting devices are referred to as the fourth light reflecting device and the fifth light reflecting device. For the sake of description, we will use the fourth light reflecting device as the first plane mirror and the fifth light reflecting device as the second plane mirror as an example for explanation.

[0072] Based on this, a first plane mirror is used to reflect a laser beam incident in a first direction, and the reflected laser beam in a fourth direction can be incident on a second plane mirror. A second plane mirror is used to reflect a laser beam incident in a fourth direction, and the reflected laser beam in a second direction can be incident on a camera (such as a camera lens).

[0073] For example, the first direction is from the object under test to the first plane mirror, meaning the laser beam enters the first plane mirror in the first direction. The fourth direction is from the first plane mirror to the second plane mirror, meaning the laser beam enters the second plane mirror in the fourth direction and exits from the first plane mirror in the fourth direction; that is, the laser beam is directed towards the exit direction of the first plane mirror, and the first plane mirror reflects the laser beam from the fourth direction. Furthermore, the second direction is from the second plane mirror to the camera, meaning the laser beam enters the camera in the second direction and exits from the second plane mirror in the second direction; that is, the laser beam is directed towards the exit direction of the second plane mirror.

[0074] For the first plane mirror, the first angle corresponding to the first direction is the same as the fourth angle corresponding to the fourth direction. The first angle is the angle between the first direction and the normal direction, which is the incident angle of the laser beam. The fourth angle is the angle between the fourth direction and the normal direction, which is the exit angle of the laser beam. For the second plane mirror, the fourth angle corresponding to the fourth direction is the same as the second angle corresponding to the second direction. The fourth angle is the angle between the fourth direction and the normal direction, which is the incident angle of the laser beam, and the second angle is the angle between the second direction and the normal direction, which is the exit angle of the laser beam.

[0075] For example, when there are three optical reflective devices, three optical reflective devices can be added to the optical path between the object under test and the camera. These three optical reflective devices cause the optical path between the object under test and the camera to be deflected. Based on this, the laser beam reflected by the object under test enters the first optical reflective device, which reflects the laser beam. The reflected laser beam enters the second optical reflective device, which reflects the laser beam. The reflected laser beam enters the third optical reflective device, which reflects the laser beam. The reflected laser beam then enters the camera.

[0076] Furthermore, when there are four or more optical reflective devices, the implementation method is similar and will not be repeated here. For ease of description, we will take two optical reflective devices as an example. The implementation method is similar when there are one, three, four or more optical reflective devices.

[0077] In one possible implementation, the light reflecting device may include a second light reflecting device and a third light reflecting device. The second light reflecting device may be a plane mirror, and the third light reflecting device may be a prism. The prism may include a right-angle prism, a polarizing prism, and a beam splitter, etc., with the third light reflecting device being a right-angle prism.

[0078] See Figure 4 The diagram shows the structure of a 3D measurement device. 1 represents the laser, 2 represents the object to be measured, 3 represents the lens, 4 represents the sensor (such as an image sensor), 5 represents the working volume of the 3D measurement device, 6 represents the device volume of the 3D measurement device, 7 represents the field of view of the laser, 8 represents the second light reflecting device (taking a plane mirror as an example), and 9 represents the third light reflecting device (taking a right-angle prism as an example).

[0079] For example, the 3D measurement device may also include a housing and a connector; on this basis, a laser, a second light reflector, a third light reflector and a camera can be fixed in the housing through the connector.

[0080] In a 3D measurement device, laser 1 can emit a laser beam toward the object to be measured 2. For example, if laser 1 emits a laser beam vertically downwards, taking a 3D laser contour sensor as an example, then laser 1 emits a linear laser beam vertically downwards. During operation, the linear laser beam forms a laser line covering the surface of the object to be measured 2. In this way, the linear laser beam is used to scan the contour information of the surface of the object to be measured 2.

[0081] After receiving the laser beam emitted by laser 1, that is, after the laser beam illuminates the surface of the object under test 2, the object under test 2 will reflect the laser beam at a certain angle. Since the object under test 2 will reflect the laser beam in multiple directions, one or more reflection directions can be the reflection direction pointing towards the plane mirror 8, such as the upper right direction pointing towards the plane mirror 8. Based on this, when the object under test 2 reflects the laser beam, it will reflect the laser beam towards the plane mirror 8 at a certain angle. The laser beam enters the plane mirror 8, and the reflection direction of the laser beam is recorded as the first direction. Obviously, after being reflected by the object under test, the laser beam enters the plane mirror 8 in the first direction.

[0082] The plane mirror 8 can receive the laser beam reflected by the object 2 under test, reflect the laser beam, and the reflected laser beam enters the right-angle prism 9. That is, the plane mirror 8 reflects the laser beam to the right-angle prism 9. For example, the plane mirror 8 can reflect the laser beam incident on the plane mirror 8 in a first direction, and the reflected laser beam in a third direction can enter the right-angle prism 9; wherein, the angle between the first direction and the normal direction and the angle between the third direction and the normal direction can be the same.

[0083] For example, after a laser beam strikes the surface of the object under test 2, the object under test 2 reflects the laser beam at a certain angle. The reflected laser beam enters the plane mirror 8, meaning the laser beam is reflected to the plane mirror 8. The plane mirror 8 reflects the laser beam, and the reflected laser beam enters the right-angle prism 9. The incident angle and the exit angle of the laser beam can be the same. For example, when the laser beam enters the plane mirror 8 at an angle x, the plane mirror 8 reflects the laser beam, and the laser beam leaves the mirror 8 at an angle x. Thus, the laser beam passes through the plane mirror 8 at a certain incident angle, and the plane mirror 8 reflects the laser beam at the same angle as the incident angle. Furthermore, when the laser beam enters the right-angle prism 9, the laser beam needs to travel a certain distance before entering the right-angle prism 9, thereby refracting the light path.

[0084] The right-angle prism 9 can receive and reflect the laser beam reflected by the plane mirror 8, and the reflected laser beam enters the lens 3. In other words, the right-angle prism 9 can reflect the laser beam to the camera's lens 3. For example, the right-angle prism 9 is used to reflect the laser beam in the third direction that is incident on the right-angle prism, and the reflected laser beam in the second direction enters the camera's lens 3.

[0085] For example, the laser beam reflected by the plane mirror 8 enters the right-angle prism 9 after traveling a certain distance. Inside the right-angle prism 9, the laser beam undergoes two total internal reflections before entering the lens 3. Of course, the two total internal reflections inside the right-angle prism 9 are just an example; the working principle of the right-angle prism 9 is not limited, as long as it can reflect the laser beam. For the right-angle prism 9, the incident direction and the exit direction of the laser beam can be opposite. For example, if the laser beam enters the right-angle prism 9 at an angle y, when the right-angle prism 9 reflects the laser beam, the laser beam can leave the right-angle prism 9 at an angle y'. Angle y' can be the opposite direction of angle y, that is, the laser beam exits in a direction parallel to the original incident light. For the right-angle prism 9, a fixed lateral displacement is formed between the exiting laser beam and the original incident laser beam, effectively compressing the object distance and maintaining the consistency of the optical path.

[0086] In summary, within the right-angle prism 9, the laser beam undergoes two reflections and exits in the opposite direction to the incident light, creating a certain displacement between it and the original incident light, thus folding within the right-angle prism 9. The laser beam travels a certain distance within the right-angle prism 9 before exiting, thereby reversing the optical path.

[0087] Lens 3 can be a camera lens, a SAM lens, or other types of lenses; there are no restrictions. After the laser beam enters lens 3, lens 3 can receive the laser beam and project it onto image sensor 4, and the laser beam is focused by lens 3.

[0088] Image sensor 4 is the imaging device of the camera. The laser beam passes through lens 3 and forms a clear laser image on image sensor 4. In other words, image sensor 4 can image the object under test 2 based on the laser beam to obtain a laser image. The laser image is used to perform 3D measurement on the object under test 2, that is, 3D measurement can be performed based on the laser image to realize the three-dimensional contour measurement of the object under test 2.

[0089] In summary, the camera can receive a laser beam reflected by the optical system in a second direction, and obtain a laser image based on the laser beam reflecting onto the object under test. For example, lens 3 receives the laser beam reflected by the optical system in a second direction and focuses the laser beam onto image sensor 4. Image sensor 4 then obtains a laser image based on the received laser beam reflecting onto the object under test.

[0090] exist Figure 4 In the diagram, 7 represents the field of view of the laser. When the object under test 2 moves into the field of view 7 of the laser, the laser 1 emits a laser beam vertically downwards, and the laser beam illuminates the surface of the object under test 2.

[0091] exist Figure 4 In the figure, 6 represents the volume of the 3D measurement equipment, that is, the volume of the 3D measurement equipment consisting of laser 1, plane mirror 8, right-angle prism 9, lens 3 and sensor 4.

[0092] See Figure 4 As shown, by deploying the plane mirror 8 and the right-angle prism 9, the optical path distance between the object under test 2 and the lens 3 can be reduced. This reduces the distance between the object under test 2 and the 3D measuring device, thereby reducing the working size of the 3D measuring device. For example, by comparing... Figure 4 and Figure 3 It can be seen that the working volume of 3D measurement equipment has been significantly reduced. Figure 4 In the diagram, 5 represents the working volume of the 3D measurement equipment, and the straight line from the object under test 2 to the plane mirror 8, the right-angle prism 9, and the lens 3 represents the optical path distance between the object under test 2 and the lens 3. Clearly, by deploying the plane mirror 8 and the right-angle prism 9, the optical path distance between the object under test 2 and the lens 3 can be altered, allowing the system to maintain the original imaging field of view (FOV) and imaging depth of field (DOF) parameters while compressing the working volume of the 3D measurement equipment.

[0093] In one possible implementation, the light reflecting device includes a fourth light reflecting device and a fifth light reflecting device, wherein the fourth light reflecting device is a first planar reflector and the fifth light reflecting device is a second planar reflector.

[0094] See Figure 5 The diagram shows the structure of a 3D measuring device. 1 represents the laser, 2 represents the object to be measured, 3 represents the lens, 4 represents the sensor (such as an image sensor), 5 represents the working volume of the 3D measuring device, 6 represents the device volume of the 3D measuring device, 7 represents the field of view of the laser, 8 represents the first plane mirror, and 10 represents the second plane mirror, i.e., two plane mirrors are used.

[0095] For example, the 3D measurement device may also include a housing and a connector; on this basis, a laser, a first planar reflector, a second planar reflector and a camera can be fixed in the housing through the connector.

[0096] In the 3D measurement device, laser 1 emits a laser beam towards the object under test 2. After receiving the laser beam emitted by laser 1, that is, after the laser beam illuminates the surface of the object under test 2, the object under test 2 will reflect the laser beam at a certain angle. Since the object under test 2 will reflect the laser beam in multiple directions, one or more reflection directions can be the reflection direction pointing towards the first plane mirror 8. That is, when the object under test 2 reflects the laser beam, it will reflect the laser beam towards the first plane mirror 8 at a certain angle. The laser beam enters the first plane mirror 8. The reflection direction of the laser beam is recorded as the first direction. After being reflected by the object under test, the laser beam enters the first plane mirror 8 in the first direction.

[0097] The first plane mirror 8 can receive the laser beam reflected by the object 2 under test and reflect it. The reflected laser beam then enters the second plane mirror 10, meaning the first plane mirror 8 reflects the laser beam to the second plane mirror 10. The second plane mirror 10 can receive the laser beam reflected by the first plane mirror 8 and reflect it. The reflected laser beam then enters the lens 3, meaning the second plane mirror 10 can reflect the laser beam to the camera's lens 3.

[0098] After the laser beam enters lens 3, lens 3 receives the laser beam and directs it to image sensor 4, where it is focused. The laser beam forms a clear laser image on image sensor 4, which then images the object under test 2 based on the laser beam. This laser image is used for 3D measurement of the object's three-dimensional structure; that is, 3D measurement can be performed based on the laser image. Combined with a transmission device, scanning achieves three-dimensional contour measurement.

[0099] See Figure 5 As shown, by deploying the first plane mirror 8 and the second plane mirror 10, the optical path distance between the object to be measured 2 and the lens 3 can be refracted, reducing the working size of the 3D measurement equipment. For example, by comparing... Figure 5 and Figure 3 It can be seen that the working volume of 3D measurement equipment has been significantly reduced. Figure 5 In the diagram, 5 represents the working volume of the 3D measuring device, and the straight line from the object under test 2 to the first plane mirror 8, the second plane mirror 10, and the lens 3 represents the optical path distance between the object under test 2 and the lens 3. Clearly, by deploying two plane mirrors (i.e., the first plane mirror 8 and the second plane mirror 10), the optical path between the object under test 2 and the lens 3 can be deflected, maintaining the optical path length unchanged.

[0100] As can be seen from the above technical solutions, by adding a light-reflecting device to the optical path between the object under test and the camera, and using this device to deflect the optical path, a novel reduction in the device's working size is achieved by introducing optical path folding technology, while maintaining the effective measurement optical path length. This solution utilizes the light-reflecting device to perform multi-stage deflection of the laser transmission path, enabling the system to compress the device's working size while maintaining the original imaging field of view (FOV) and depth of field (DOF) parameters. This optical path reconstruction method effectively balances the contradiction between measurement accuracy and device compactness.

[0101] This embodiment proposes an imaging method based on a 3D laser contour sensor and its miniaturized optical path design method. By adopting an optical path design with folded object distance (i.e., adding light reflection devices to fold the object distance), the optical path is folded, achieving sufficient object distance and viewing angle within a limited device size. This effectively reduces the working volume of the 3D measurement device while ensuring sufficient measurement field of view and accuracy, maintaining high-precision measurement functionality. After processing by the algorithm, the laser image captured by the camera can generate the three-dimensional contour information of the object under test, realizing 3D measurement and meeting the accuracy requirements of industrial 3D measurement. It is suitable for 3D measurement applications.

[0102] By employing optical path folding design (such as using right-angle prisms and reflectors to achieve multiple folds of the object distance in the imaging optical path, which can be accomplished using multiple reflectors and / or right-angle prisms), the working volume is significantly reduced while maintaining high-precision measurement capabilities. This results in a more compact structure for the 3D measurement equipment, effectively reducing its working size and making it suitable for space-constrained industrial applications. Furthermore, a well-designed optical path configuration not only reduces the working volume but also ensures high-precision laser measurement capabilities, meeting the needs of various industrial 3D measurement tasks. It is suitable for industrial 3D measurement tasks in confined spaces, such as surface contour measurement and dimensional inspection, demonstrating broad application prospects.

[0103] This application proposes a 3D measurement method that can be applied to a 3D measurement device. The 3D measurement device may include a laser and a camera, and may also include an optical system. The optical system includes at least one light-reflecting device, such as adding a light-reflecting device to the optical path between the object under test and the camera. This light-reflecting device is used to deflect the light path between the object under test and the camera. See also... Figure 6 The diagram shown is a flowchart of the 3D measurement method, which may include:

[0104] Step 601: Acquire a laser image; wherein, the laser emits a laser beam toward the object under test, the optical reflector receives the laser beam reflected by the object under test and reflects the laser beam, the camera receives the laser beam reflected by the optical reflector, and the laser image is obtained by imaging the object under test based on the laser beam.

[0105] For example, as the object under test moves along the direction of motion, a laser beam is projected onto the surface of the object by a laser, and a camera captures an image of the object, thus obtaining a laser image of the object. For instance, when the object under test moves horizontally (e.g., at a constant speed) below the laser along the direction of motion, a certain position A of the object will be located at a designated position below the laser, and the laser beam will be projected onto that designated position. In this way, a laser image of that position A of the object can be acquired. For example, the designated position can be directly below the laser, or slightly to the left or right of the directly below position; there are no restrictions on the designated position, as long as it is located below the laser and the laser can project a laser beam onto that designated position.

[0106] Step 602: Perform 3D measurement on the object under test based on the laser image. There are no restrictions on this process.

[0107] For example, the number of light-reflecting devices can be at least one.

[0108] For each light reflecting device, the light reflecting device can be any of the following: a plane mirror; a curved mirror; a prism (such as a right-angle prism); a beam splitter; a reflective grating; or a reflective waveplate.

[0109] For example, a camera may include a lens and a sensor, such that the lens can receive a laser beam reflected by a light reflecting device and output the laser beam to an image sensor, and focus the laser beam onto the image sensor; the image sensor can image the object under test based on the third laser beam to obtain a laser image.

[0110] Based on the same concept as the method described above, this application proposes a 3D measurement device that can be applied to a 3D measurement equipment. The 3D measurement equipment may include a laser and a camera, and also includes an optical system. The optical system includes at least one light-reflecting device, such as adding a light-reflecting device to the optical path between the object to be measured and the camera. This light-reflecting device is used to deflect the light path between the object to be measured and the camera. See also... Figure 7 The diagram shown is a structural schematic of the 3D measuring device, which may include:

[0111] The acquisition module 71 is used to acquire laser images; the laser emits a laser beam towards the object under test, the optical reflector receives the laser beam reflected by the object under test and reflects the laser beam, the camera receives the laser beam reflected by the optical reflector, and the laser image is obtained by imaging the object under test based on the laser beam.

[0112] Reconstruction module 72 is used for 3D measurement of the three-dimensional structure of the object under test based on laser images.

[0113] For example, the number of light-reflecting devices can be at least one.

[0114] For each light reflecting device, the light reflecting device can be any of the following: a plane mirror; a curved mirror; a prism (such as a right-angle prism); a beam splitter; a reflective grating; or a reflective waveplate.

[0115] Based on the same application concept as the method described above, this application proposes an electronic device (such as a 3D measuring device). The 3D measuring device may include a laser and a camera. It may also include an optical system, such as at least one light-reflecting device, for example, by adding a light-reflecting device to the optical path between the object under test and the camera. This light-reflecting device is used to deflect the optical path between the object under test and the camera. See also... Figure 8 As shown, the 3D measurement device may further include: a processor 81 and a machine-readable storage medium 82, the machine-readable storage medium 82 storing machine-executable instructions that can be executed by the processor 81; the processor 81 is used to execute the machine-executable instructions to implement the 3D measurement method disclosed in the above example of this application.

[0116] Based on the same concept as the above method, this application also provides a machine-readable storage medium storing a plurality of computer instructions, which, when executed by a processor, can implement the 3D measurement method disclosed in the above examples of this application.

[0117] The aforementioned machine-readable storage medium can be any electronic, magnetic, optical, or other physical storage device that can contain or store information, such as executable instructions, data, etc. For example, machine-readable storage media can be: RAM (Random Access Memory), volatile memory, non-volatile memory, flash memory, storage drives (such as hard disk drives), solid-state drives, any type of storage disk (such as optical discs, DVDs, etc.), or similar storage media, or combinations thereof.

[0118] Based on the same concept as the methods described above, this application also provides a computer program product, which may include a computer program. When executed by a processor, the computer program implements the 3D measurement method disclosed in the examples above.

[0119] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, embodiments of this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0120] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. An optical system, characterized in that, The optical system includes at least one light-reflecting device located in the optical path between the object under test and the camera, and the light-reflecting device is used to refract the optical path between the object under test and the camera; wherein: The light reflecting device is used to reflect a laser beam incident on the optical system in a first direction, and the reflected laser beam in a second direction is incident on the camera. Wherein, the first direction is the direction from the object under test to the light reflecting device; The second direction is the direction from the light-reflecting device to the camera.

2. The optical system according to claim 1, characterized in that, For any one of all optical reflective devices, the optical reflective device includes any of the following: Plane mirror; curved mirror; prism; beam splitter; reflective grating; reflective waveplate.

3. The optical system according to claim 1, characterized in that, The optical system includes a first light reflecting device, which is a plane mirror, wherein: the plane mirror is used to reflect a laser beam incident on the plane mirror in a first direction, and the reflected laser beam in a second direction is incident on the camera; Wherein, the first angle corresponding to the first direction is the same as the second angle corresponding to the second direction; Wherein, the first angle is the angle between the first direction and the normal direction; The second angle is the angle between the second direction and the normal direction.

4. The optical system according to claim 1, characterized in that, The optical system includes a second light reflecting device and a third light reflecting device, wherein the second light reflecting device is a plane mirror and the third light reflecting device is a right-angle prism; wherein: The planar reflector is used to reflect a laser beam incident in a first direction, and the reflected laser beam in a third direction is incident on the right-angle prism; wherein the angle between the first direction and the normal direction and the angle between the third direction and the normal direction are the same. The right-angle prism is used to reflect a laser beam in a third direction that is incident on the right-angle prism, and the reflected laser beam in a second direction is incident on the camera. The second direction is the opposite direction of the third direction.

5. The optical system according to claim 4, characterized in that, The third direction is parallel to the horizontal plane where the object to be measured is located, and the third direction is perpendicular to the right-angle prism; the second direction is parallel to the horizontal plane where the object to be measured is located, and the second direction is perpendicular to the right-angle prism.

6. The optical system according to claim 1, characterized in that, The optical system includes a fourth light reflecting device and a fifth light reflecting device, wherein the fourth light reflecting device is a first plane mirror and the fifth light reflecting device is a second plane mirror; wherein: The first planar reflector is used to reflect a laser beam incident on the first planar reflector in a first direction, and the reflected laser beam in a fourth direction is incident on the second planar reflector; wherein, the angle between the first direction and the normal direction and the angle between the fourth direction and the normal direction are the same. The second planar reflector is used to reflect a laser beam incident in a fourth direction onto the second planar reflector, and the reflected laser beam in the second direction is incident on the camera; wherein the angle between the fourth direction and the normal direction and the angle between the second direction and the normal direction are the same.

7. A 3D measuring device, characterized in that, The 3D measurement device includes a laser, a camera, and an optical system as described in any one of claims 1-6; wherein: The laser is used to emit a laser beam toward the object under test, and the laser beam, after being reflected by the object under test, is incident on the optical system in a first direction. The camera is used to receive a laser beam reflected by the optical system in a second direction, and to image the object under test based on the laser beam to obtain a laser image; The laser image is used to perform 3D measurement on the object under test.

8. The 3D measuring device according to claim 7, characterized in that, The camera includes a lens and an image sensor; The lens is used to receive a laser beam reflected by the optical system in a second direction and focus the laser beam onto the image sensor; the image sensor is used to image the object under test based on the received laser beam to obtain the laser image.

9. The 3D measuring device according to claim 8, characterized in that, The footage includes Sam's shots.

10. The 3D measuring device according to claim 7, characterized in that, The laser is a point laser, and the 3D measuring device is a laser displacement sensor; or... The laser is a line laser, and the 3D measurement device is a 3D laser profile sensor or a line laser stereo camera; or... The laser is a structured light laser, and the 3D measurement device is a structured light stereo camera.

11. The 3D measuring device according to claim 7, characterized in that, The 3D measurement device also includes a housing and a connector; the laser, the optical system, and the camera are fixed inside the housing via the connector.

Images