A 3D scanning device and its control method

Abstract

This invention discloses a three-dimensional scanning device and its control method. The device includes a multispectral structured light generating unit for generating structured light of at least two wavelengths to illuminate an object to be scanned, with different working surface positions for the different wavelengths of structured light; at least one imaging system including a high-dispersion imaging lens and an image sensor, wherein the high-dispersion imaging lens is used to collect scattered light beams onto the same imaging plane, and the scattered light beams are formed by the scattering of structured light of corresponding wavelengths by different working surface positions of the object to be scanned; the image sensor includes at least two channels, with different channels used to collect scattered light beams corresponding to different wavelengths of structured light; the working surface positions of the structured light of different wavelengths are conjugate to the imaging plane of the image sensor. Thus, structured light of different wavelengths can scan different working surfaces of the object to be scanned, and the scattered light corresponding to different working surfaces is collected and imaged onto the same plane by the lens, achieving large depth-of-field scanning.

Description

Technical Field

[0001] This invention relates to the field of three-dimensional scanning technology, and in particular to a three-dimensional scanning device and its control method. Background Technology

[0002] In 3D scanning equipment, the problem of insufficient scanning depth of field is often encountered. This is because for general imaging systems, there is only one clear image position, and the 3D scanning accuracy is also the highest at that position. Once the position deviates from the clear image position, it is necessary to solve the scanning accuracy by fitting algorithms such as the centroid method, which often results in a loss of accuracy.

[0003] Therefore, a common practice in scanning equipment is to add a distance indicator to the user, so that the user can stay in a fixed position while scanning. This makes the operation extremely inconvenient for the user and greatly reduces the ease of use and popularity of 3D scanning equipment. Summary of the Invention

[0004] This invention provides a three-dimensional scanning device and its control method, which can achieve large depth-of-field scanning.

[0005] To achieve the above objectives, one embodiment of the present invention provides a three-dimensional scanning device, comprising: a multispectral structured light generating unit and at least one imaging system;

[0006] The multispectral structured light generating unit is used to generate structured light of at least two wavelengths to illuminate the object to be scanned, wherein the working surface positions of the structured light of different wavelengths are different;

[0007] The imaging system includes a high dispersion imaging lens and an image sensor. The high dispersion imaging lens is used to collect scattered light beams onto the same imaging plane. The scattered light beams are formed by scattering structured light of corresponding wavelengths at different working surface positions of the object to be scanned. The image sensor includes at least two channels, and different channels are used to collect scattered light beams corresponding to structured light of different wavelengths. The working surface positions of structured light of different wavelengths are conjugate with the imaging plane of the image sensor.

[0008] Optionally, the imaging system includes a first imaging system and a second imaging system; the multispectral structured light generating unit is used to form a first scanning beam and a second scanning beam, the first imaging system is located on the path of the transmission of the first scattered beam, the second imaging system is located on the path of the transmission of the second scattered beam, the first scattered beam is the beam scattered by the first scanning beam by a first object to be scanned, the second scattered beam is the beam scattered by the second scanning beam by a second object to be scanned, and the first object to be scanned and the second object to be scanned are the same object or different objects.

[0009] Optionally, the 3D scanning device further includes: a controller and a distance sensor, wherein the controller is connected to the distance sensor, the multispectral structured light generating unit and the image sensor respectively, and the distance sensor is used to acquire the working distance between the multispectral structured light generating unit and the object to be scanned;

[0010] The controller is used to control the multispectral structured light generating unit to emit structured light of a wavelength corresponding to the corresponding working surface position according to the working distance, and to control the image sensor on the imaging plane that is conjugate to the corresponding working surface position to start.

[0011] Optionally, the high dispersion imaging lens includes at least one optical lens capable of refraction or diffraction.

[0012] Optionally, the large dispersion imaging lens includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially from the object side to the image side;

[0013] Wherein, the first lens is a convex-concave lens, the second lens is a concave-concave lens, the third lens is a convex-convex lens, the fourth lens is a convex-convex lens, and the fifth lens is a concave-concave lens;

[0014] The fourth lens and the fifth lens are cemented together to form a cemented lens.

[0015] Optionally, the image sensor includes multiple channel elements, which are arranged in an array, and the total number of channels in each channel element is the square of the number of channels in a single row.

[0016] Optionally, each channel element includes a first channel, a second channel, a third channel, and a fourth channel, with the first channel to the fourth channel arranged sequentially to form a four-way grid channel element; or, each channel element includes a first channel, a second channel, a third channel, a fourth channel, a fifth channel, a sixth channel, a seventh channel, an eighth channel, and a ninth channel, with the first channel to the ninth channel arranged sequentially to form a nine-way grid channel element.

[0017] To achieve the above objectives, another embodiment of the present invention proposes a control method for a three-dimensional scanning device, implemented by the three-dimensional scanning device described in any embodiment of the present invention. The control method includes: controlling a multispectral structured light generating unit to generate structured light of at least two wavelengths to illuminate the object to be scanned.

[0018] The channels in the control image sensor corresponding to the at least two wavelengths of structured light are activated to collect the scattered beams formed by the scattering of the structured light of the at least two wavelengths by the object to be scanned.

[0019] Optionally, the three-dimensional scanning device further includes a distance sensor; and before the control of the multispectral structured light generating unit to generate structured light of at least two wavelengths to illuminate the object to be scanned, it further includes:

[0020] The working distance between the multispectral structured light generating unit and the object to be scanned is obtained;

[0021] The working surface position close to the object to be scanned is determined based on the working distance;

[0022] The control of the multispectral structured light generation unit to generate structured light of at least two wavelengths to illuminate the object to be scanned includes:

[0023] Based on the working surface position and the first preset correspondence, the multispectral structured light generating unit is controlled to emit structured light with a wavelength corresponding to the corresponding working surface position; wherein, the first preset correspondence is the correspondence between the working surface position and the wavelength of the structured light emitted by the multispectral structured light generating unit;

[0024] The activation of the channels in the controlled image sensor corresponding to the at least two wavelengths of structured light includes:

[0025] Based on the working surface position and the second preset correspondence, the image sensor on the imaging plane that is conjugate to the corresponding working surface position is activated; wherein, the second preset correspondence is the conjugate correspondence between the working surface position and the imaging plane of the image sensor.

[0026] Optionally, after activating the channels in the image sensor corresponding to the at least two wavelengths of structured light, the method further includes:

[0027] The image sensor acquires a first image, and based on the comparison result between the first image and the object to be scanned, the multispectral structured light generating unit is controlled to shut down the unused wavelengths generated.

[0028] According to embodiments of the present invention, a three-dimensional scanning device and its control method include: a multispectral structured light generating unit and at least one imaging system; the multispectral structured light generating unit is used to generate structured light of at least two wavelengths to illuminate the object to be scanned, wherein the working surfaces of the structured light of different wavelengths are at different positions; the imaging system includes a high-dispersion imaging lens and an image sensor, the high-dispersion imaging lens is used to collect scattered light beams onto the same imaging plane, the scattered light beams are formed by the scattering of structured light of corresponding wavelengths by different working surfaces of the object to be scanned; the image sensor includes at least two channels, different channels are used to collect scattered light beams corresponding to structured light of different wavelengths; wherein the working surfaces of the structured light of different wavelengths are conjugate to the imaging plane of the image sensor. Thus, structured light of different wavelengths can scan different working surfaces of the object to be scanned, and then the scattered light corresponding to different working surfaces is collected and imaged onto the same plane by the imaging lens, achieving a large depth-of-field scanning of the object to be scanned.

[0029] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structure of the three-dimensional scanning device proposed in the embodiments of the present invention;

[0032] Figure 2 This is a schematic diagram of the structure of a three-dimensional scanning device according to an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the structure of a three-dimensional scanning device proposed in another embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of the structure of a three-dimensional scanning device according to another embodiment of the present invention;

[0035] Figure 5 This is a schematic diagram of the structure of a large dispersion imaging lens in a three-dimensional scanning device according to an embodiment of the present invention;

[0036] Figure 6 This is the MTF diagram at 450nm of the high dispersion imaging lens in the three-dimensional scanning device proposed in this embodiment of the invention;

[0037] Figure 7 This is the MTF diagram at 550nm of the high dispersion imaging lens in the three-dimensional scanning device proposed in this embodiment of the invention;

[0038] Figure 8 This is the MTF diagram at 650nm of the high dispersion imaging lens in the three-dimensional scanning device proposed in this embodiment of the invention;

[0039] Figure 9 This is the MTF diagram at 780nm of the high dispersion imaging lens in the three-dimensional scanning device proposed in this embodiment of the invention;

[0040] Figure 10 This is the MTF diagram at 850nm of the high dispersion imaging lens in the three-dimensional scanning device proposed in this embodiment of the invention;

[0041] Figure 11 This is a channel layout diagram of an image sensor in a three-dimensional scanning device according to an embodiment of the present invention;

[0042] Figure 12 This is a channel arrangement diagram of the image sensor in a three-dimensional scanning device proposed in another embodiment of the present invention;

[0043] Figure 13 This is a flowchart of the scanning method of the three-dimensional scanning device proposed in the embodiments of the present invention. Detailed Implementation

[0044] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0045] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0046] Figure 1 This is a schematic diagram of the structure of the three-dimensional scanning device proposed in an embodiment of the present invention. Figure 1 As shown, the three-dimensional scanning device includes: a multispectral structured light generating unit 101 and at least one imaging system 102;

[0047] The multispectral structured light generating unit 101 is used to generate structured light of at least two wavelengths to illuminate the object 103 to be scanned, wherein the working surface positions of the structured light of different wavelengths are different.

[0048] The imaging system 102 includes a high dispersion imaging lens 1021 and an image sensor 1022. The high dispersion imaging lens 1021 is used to collect scattered light beams onto the same imaging plane. The scattered light beams are formed by the scattering of structured light of corresponding wavelengths by different working surface positions of the object to be scanned 103. The image sensor 1022 includes at least two channels, and different channels are used to collect scattered light beams corresponding to structured light of different wavelengths. The working surface positions of structured light of different wavelengths are conjugate with the imaging plane of the image sensor 1022.

[0049] Among them, such as Figure 1 As shown, the structured light of at least two wavelengths may include a first wavelength structured light 1041 and a second wavelength structured light 1042. The working surface of the first wavelength structured light 1041 is located at a first working surface 1051, and the working surface of the second wavelength structured light 1042 is located at a second working surface 1052. The image sensor 1022 is provided with at least a first channel 1 for sensing the first wavelength structured light 1041 and a second channel 2 for sensing the second wavelength structured light 1042.

[0050] In an optical system, conjugate refers to the phenomenon where light rays originate from one object's plane, pass through the optical system, and form a clear image on another plane. These two planes are called conjugate planes.

[0051] The multispectral structured light generating unit 101 emits structured light 1041 of a first wavelength and structured light 1042 of a second wavelength. When the structured light 1041 of the first wavelength encounters the object 103 to be scanned, located at the first working surface 1051, the object 103 scatters the structured light 1041 of the first wavelength, and the light is collected by the high dispersion imaging lens 1021 into the first channel 1 of the image sensor 1022. Similarly, when the structured light 1042 of the second wavelength encounters the object 103 to be scanned, located at the second working surface 1052, the object 103 scatters the structured light 1042 of the second wavelength, and the light is collected by the high dispersion imaging lens 1021 into the second channel 2 of the image sensor 1022.

[0052] In this way, by simultaneously generating two or more wavelengths of structured light by the multispectral structured light generating unit 101, an image of the object to be scanned 103 can be obtained.

[0053] In one example, the multispectral structured light generating unit 101 can simultaneously generate structured light of five wavelengths, such as 450nm, 550nm, 650nm, 780nm, and 850nm. The corresponding working surface positions are 150mm, 220mm, 300mm, 450mm, and 550mm from the multispectral structured light generating unit 101, respectively. Since there is a 400mm interval between 150mm and 550mm, the 3D scanning device can capture images of the object 103 within this 400mm range. Therefore, when scanning the object 103, it can be placed between 150mm and 550mm, and the 3D scanning device can scan it without needing to move the device step-by-step to align it with the object. Combined with the high-dispersion imaging lens, a 3D image of the object 103 can be obtained in a single scan. The more wavelengths generated by the multispectral structured light generation unit 101 and the more corresponding color image sensor channels it produces, the more clearly imaged areas there are, and the higher the accuracy of the scanning device. This increases the depth of field of the 3D scanning device, greatly improves the scanning rate, and simplifies the corresponding scanning steps.

[0054] Optionally, Figure 2 This is a schematic diagram of the structure of a three-dimensional scanning device according to an embodiment of the present invention. Figure 3 This is a schematic diagram of the structure of a three-dimensional scanning device proposed in another embodiment of the present invention, as shown below. Figure 2 and Figure 3 As shown, the imaging system 102 includes a first imaging system 102A and a second imaging system 102B; a multispectral structured light generating unit 101 is used to form a first scanning beam and a second scanning beam. The first imaging system 102A is located on the path of the transmission of the first scattered beam, and the second imaging system 102B is located on the path of the transmission of the second scattered beam. The first scattered beam is the beam scattered by the first scanning beam by the first object to be scanned 103A, and the second scattered beam is the beam scattered by the second scanning beam by the second object to be scanned 103B. The first object to be scanned 103A and the second object to be scanned 103B are the same object or different objects.

[0055] It should be noted that, Figure 1 In the illustrated embodiment, there is one imaging system 102. In other embodiments, there may be two or more imaging systems 102. The number of imaging systems 102 is set according to the requirements.

[0056] For example, such as Figure 2 As shown, there are two objects to be scanned, and the imaging system 102 may include two imaging systems: a first imaging system 102A and a second imaging system 102B. In this embodiment, the structured light emitted by the multispectral structured light generating unit 101 can be split, for example, by a beam splitting unit into a first scanning beam and a second scanning beam. The structured light emitted by each scanning beam has the same wavelength. The first scanning beam is used to scan the first object to be scanned 103A and is scattered into a first scattered beam. The second scanning beam is used to scan the second object to be scanned 103B and is scattered into a second scattered beam. The first imaging system 102A is set in the transmission direction of the first scattered beam, and the second imaging system 102B is set in the transmission direction of the second scattered beam. In other embodiments, it may also be split into three or four beams, etc., to simultaneously measure the objects 103 to be scanned in different directions. Figure 2 This is merely an example and is not intended to be a specific limitation. In other embodiments, the beam-splitting unit may be a polarizing beam-splitting prism, etc.

[0057] In another embodiment, such as Figure 3 As shown, the object to be scanned 103 is a single object, and the structured light emitted by the multispectral structure generating unit 101 is still a single beam. However, a first imaging system 102A and a second imaging system 102B are set along the transmission path of this scanning beam. The first imaging system 102A is used to receive a portion of the scattered beam from the scanning beam, and the second imaging system 102B is used to receive the other portion of the scattered beam from the scanning beam. In this way, without changing the original imaging system, the number of wavelengths of the structured light emitted by the multispectral structure generating unit 101 can be increased (for example, if the multispectral structure generating unit 101 can emit 5 wavelengths simultaneously, then 5 more wavelengths can be added, and the 10 wavelengths can be ordered in ascending order. The first imaging system 102A can image the structured light of the first 5 wavelengths, and the second imaging system 102B can image the structured light of the last 5 wavelengths). Alternatively, with the number of wavelengths of structured light emitted by the multispectral structure generating unit 101 remaining unchanged, the number of wavelengths received by a single imaging system decreases (for example, the multispectral structure generating unit 101 can emit 5 wavelengths simultaneously, and the 5 wavelengths are ordered in order of magnitude; the first imaging system 102A can image the structured light of the first 2 wavelengths, and the second imaging system 102B can image the structured light of the last 3 wavelengths). The fewer wavelengths received by the imaging system, the lower the design requirements for the imaging system.

[0058] It should be noted that, in Figure 3 In one embodiment, after scanning the same object 103, images acquired by different image sensors can be fused to obtain an overall image of the same object 103.

[0059] Optionally, Figure 4 This is a schematic diagram of the structure of a three-dimensional scanning device according to another embodiment of the present invention; as shown. Figure 4 As shown, the three-dimensional scanning device also includes: a controller 106 and a distance sensor 107. The controller 106 is connected to the distance sensor 107, the multispectral structured light generating unit 101 and the image sensor 1022 respectively. The distance sensor 107 is used to collect the working distance between the multispectral structured light generating unit 101 and the object to be scanned 103.

[0060] The controller 106 is used to control the multispectral structured light generating unit 101 to emit structured light of a wavelength corresponding to the corresponding working surface position according to the working distance, and to control the image sensor 1022 on the imaging plane that is conjugate to the corresponding working surface position to start.

[0061] Understandably, in order to further refine the scanning of the object 103, or when the object 103 is small (less than the overall depth of field), and to avoid wasting energy by simultaneously activating all the structured light in the multispectral structured light generation unit 101, the working distance between the 3D scanning device and the object 103 can be obtained before scanning. Then, the channels of the structured light and image sensor with wavelengths adapted to that working distance are selectively activated based on that working distance.

[0062] For example, taking the multispectral structured light generating unit 101 as an example that can simultaneously emit structured light of five wavelengths (450nm (150mm), 550nm (220mm), 650nm (300mm), 780nm (450mm) and 850nm (550mm)), if the measured working distance is 200mm to 250mm, which is close to the working surface position of 220mm and 300mm, then the structured light with wavelengths of 550nm and 650nm can be turned on, and the image sensor 1022 that can collect structured light with wavelengths of 550nm and 650nm can be activated at the same time.

[0063] In other embodiments, the position of the multispectral structured light generating unit 101 can be adjusted to adjust the working distance so that the working distance is exactly equal to the working surface position, thereby achieving the best imaging effect (for example, when scanning fine devices); or by adjusting, when the object to be scanned 103 is not within the depth of field, the object to be scanned 103 is within the maximum depth of field.

[0064] Optionally, the high dispersion imaging lens 1021 includes at least one optical lens capable of refraction or diffraction.

[0065] Specifically, for the large dispersion imaging lens 1021, the optimal object-side working distance for structured light with a wavelength of 450nm is 150mm, for structured light with a wavelength of 550nm it is 220mm, for structured light with a wavelength of 650nm it is 300mm, for structured light with a wavelength of 780nm it is 450mm, and for structured light with a wavelength of 850nm it is 550mm.

[0066] Correspondingly, the multispectral structured light generating unit 101 also contains structured light with five wavelengths: 450nm, 550nm, 650nm, 780nm, and 850nm. During operation, the five wavelengths of structured light are emitted simultaneously. The optimal object-side working distance for the 450nm structured light is 150mm, for the 550nm structured light it is 220mm, for the 650nm structured light it is 300mm, for the 780nm structured light it is 450mm, and for the 850nm structured light it is 550mm.

[0067] Five wavelengths of structured light are scattered by the object to be scanned 103 and then uniformly received by the high dispersion imaging lens 1021 and converged onto the five-channel color image sensor 1022. The 450nm beam is received and responded to by the 450nm channel, the 550nm beam by the 550nm channel, the 650nm beam by the 650nm channel, the 780nm beam by the 780nm channel, and the 850nm beam by the 850nm channel. With the entire device fixed, there are five clearly imaged planes simultaneously, expanding the scanning depth of the device and improving its accuracy.

[0068] Optionally, Figure 5 This is a schematic diagram of the structure of a large dispersion imaging lens in a three-dimensional scanning device according to an embodiment of the present invention; as shown. Figure 5 As shown, the large dispersion imaging lens 1021 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5 arranged sequentially from the object side to the image side; wherein, the first lens L1 is a convex-concave lens, the second lens L2 is a concave-concave lens, the third lens L3 is a convex-convex lens, the fourth lens L4 is a convex-convex lens, and the fifth lens L5 is a concave-concave lens; the fourth lens L4 and the fifth lens L5 are cemented together to form a cemented lens.

[0069] It should be noted that the first lens L1 is a convex-concave lens with negative optical power, allowing object-side rays to enter the imaging system 102 smoothly. This causes the light to enter the second lens L2 at a smaller angle of incidence, reducing the proportion of higher-order aberrations, while also reducing the lens aperture and shortening the overall length of the high-dispersion imaging lens. The second lens L2 is a concave-concave lens with negative optical power, further smoothing the object-side rays into the imaging system, reducing the proportion of higher-order aberrations, and also correcting field curvature. Thus, the two lenses work together to bring in large-angle light rays smoothly into the imaging system 102. The third lens L3 is a convex-convex lens with positive optical power, collimating the light beam and effectively reducing spherical and chromatic aberrations, resulting in higher image quality. The fourth lens L4 and the fifth lens L5 are cemented lenses, which reduce the light spot and have a focusing effect. Cementing them together shortens the overall length of the high-dispersion imaging lens.

[0070] Optionally, the design parameters of the large dispersion imaging lens 1021 are shown in the table below:

[0071] Surface serial number Radius of curvature (mm) Thickness (mm) Refractive index Abbe number surface infinity S1 5.76 1.01 1.755 27.6 S2 30.31 0.94 S3 -7.05 1 1.65 33.6 S4 3.71 0.9 S5 (Aperture) infinity 0.2 S6 7.56 3 1.755 52.3 S7 -5.62 1.34 S8 5.66 1.89 1.728 45.7 S9 -2.99 2.25 1.773 36.2 S10 6.13 1.96 Image infinity 0

[0072] The surface numbers S1-S10 in the table above are numbered according to the surface sequence of each lens. "S5" represents the aperture of a large dispersion imaging lens. The radius of curvature represents the curvature of the lens surface. A positive value means that the surface bends towards the image plane, and a negative value means that the surface bends towards the object plane. The thickness represents the central axial distance between the current surface and the next surface. The refractive index represents the ability of the material between the current surface and the next surface to deflect light. A blank space represents the current position as air, with a refractive index of 1.

[0073] Under this high dispersion imaging lens, Figures 6 to 10 This is the MTF curve of the high dispersion imaging lens in this embodiment at 450nm-850nm. Figures 6 to 10 In the diagram, the T-line represents the change in image sharpness from the center to the edge in the horizontal direction, and the R-line represents the change in image sharpness from the center to the edge in the vertical direction. From... Figures 6 to 10 It can be seen that this high dispersion imaging lens has high resolution.

[0074] Optionally, Figure 11 This is a channel layout diagram of an image sensor in a three-dimensional scanning device according to an embodiment of the present invention; Figure 12 This is a channel layout diagram of the image sensor in a three-dimensional scanning device according to another embodiment of the present invention; as shown below. Figure 11 and Figure 12As shown, the image sensor 1022 includes multiple channel elements 001 arranged in an array. The total number of channels in each channel element 001 is the square of the number of channels in a single row. For example, each channel element 001 includes a first channel, a second channel, a third channel, and a fourth channel, arranged sequentially to form a four-channel grid. Alternatively, each channel element includes a first channel, a second channel, a third channel, a fourth channel, a fifth channel, a sixth channel, a seventh channel, an eighth channel, and a ninth channel, arranged sequentially to form a nine-channel grid. That is, the channels in the channel elements are arranged in rows and columns, and the number of channels in each row is the same as the number of channels in each column.

[0075] When arranged in the aforementioned example, it is beneficial for device manufacturing and subsequent channel extraction. The more channels there are, the higher the accuracy of the extracted object 103 to be scanned.

[0076] Optionally, the multispectral structured light generation unit 101 includes an edge-emitting LD light source or a VCSEL light source. The edge-emitting LD light source or VCSEL light source can emit a laser beam with a bandwidth of less than ±2nm. The filter unit in the image sensor 1022 is a narrowband filter with a bandwidth of ±2nm, which only allows light of a single wavelength to pass through.

[0077] Figure 13 This is a flowchart of a scanning method using a 3D scanning device according to an embodiment of the present invention. This method is implemented using a 3D scanning device according to any embodiment of the present invention, such as... Figure 13 As shown, the scanning method includes:

[0078] S101 controls the multispectral structured light generating unit to generate structured light of at least two wavelengths to illuminate the object to be scanned.

[0079] S102, control the activation of the channels in the image sensor corresponding to at least two wavelengths of structured light, so as to collect the scattered beam formed by the scattering of at least two wavelengths of structured light by the object to be scanned.

[0080] The device can pre-store the correspondence between wavelengths and channels. During scanning, the multispectral structured light generation unit simultaneously emits at least two wavelengths of structured light. The first wavelength of structured light is clearly projected onto the first working surface, and the second wavelength is clearly projected onto the second working surface. After being scattered by the scanned object, the structured light of several wavelengths is uniformly received and converged onto the image sensor by the high-dispersion imaging lens. The special optical design of the high-dispersion imaging lens ensures that both the first working surface (first wavelength) and the second working surface (second wavelength) are conjugate with the image sensor. This gives the imaging system at least two clearly imaged working surfaces, expanding the device's working depth of field. Furthermore, the imaging system does not need to be moved, ensuring the stability and imaging accuracy of the device.

[0081] Among them, the image sensor can be a color image sensor, which consists of a filter and a photosensitive unit. Each channel of the color image sensor can only respond to a single wavelength. The color image sensor contains at least two channels, which correspond one-to-one with the wavelength of the structured light.

[0082] It should be noted that if the imaging system consists of multiple groups, and the beam generated by the multispectral structured light generation unit is split into multiple beams, multiple image sensors can be activated simultaneously when scanning multiple objects. If the number of objects to be scanned is less than the number of image sensors, only the image sensor corresponding to the object to be scanned can be activated.

[0083] Optionally, the 3D scanning device also includes a distance sensor; and before controlling the multispectral structured light generating unit to generate structured light of at least two wavelengths to illuminate the object to be scanned, it also includes:

[0084] Obtain the working distance between the multispectral structured light generator and the object to be scanned;

[0085] Determine the position of the working surface close to the object to be scanned based on the working distance;

[0086] S101 controls the multispectral structured light generating unit to generate structured light of at least two wavelengths to illuminate the object to be scanned, including:

[0087] Based on the working surface position and the first preset correspondence, the multispectral structured light generating unit is controlled to emit structured light with a wavelength corresponding to the corresponding working surface position; wherein, the first preset correspondence is the correspondence between the working surface position and the wavelength of the structured light emitted by the multispectral structured light generating unit;

[0088] S102 controls the activation of channels in the image sensor corresponding to at least two wavelengths of structured light, including:

[0089] Based on the working surface position and the second preset correspondence, the image sensor whose imaging plane is conjugate with the corresponding working surface position is activated; wherein, the second preset correspondence is the conjugate correspondence between the working surface position and the imaging plane of the image sensor.

[0090] The first and second preset correspondences can be pre-defined. To further improve the accuracy of scanning the object, or when the object is small (less than the overall depth of field), and to avoid wasting energy by simultaneously activating all structured light from the multispectral structured light generator, the working distance between the 3D scanning device and the object can be obtained before scanning. Then, the channels of the structured light and image sensor with wavelengths adapted to that working distance are selectively activated based on this working distance.

[0091] For example, taking the multispectral structured light generation unit as an example that can simultaneously emit structured light of five wavelengths (450nm (150mm), 550nm (220mm), 650nm (300mm), 780nm (450mm) and 850nm (550mm)), if the measured working distance is 200mm to 250mm, which is close to the working surface position of 220mm and 300mm, then the structured light with wavelengths of 550nm and 650nm can be turned on, and the image sensor that can collect structured light with wavelengths of 550nm and 650nm can be activated at the same time.

[0092] In other embodiments, the position of the multispectral structured light generating unit (i.e., the position of the scanner) can be adjusted to adjust the working distance so that the working distance is exactly equal to the position of the working surface, thereby achieving the best imaging effect (e.g., when fine scanning is required); or when the object to be scanned is not within the depth of field, the adjustment can be made so that the object to be scanned is within the maximum depth of field.

[0093] Optionally, after activating the channels in the image sensor corresponding to at least two wavelengths of structured light, the method further includes:

[0094] The system acquires a first image from an image sensor and, based on the comparison between the first image and the object to be scanned, controls the multispectral structured light generation unit to shut down any unused wavelengths generated.

[0095] In other words, when there is no distance sensor or the scanning accuracy requirement is low (such as scanning a vehicle's hood), the object to be scanned can be placed within the depth of field of the device based on experience. Then, all wavelengths of structured light that the multispectral structured light generation unit can produce are turned on, and the unused parts of the structured light are turned off based on the acquired image to save the device's energy consumption.

[0096] In the first image, if a scattered light point corresponding to the object to be scanned can be seen, the structured light of the wavelength corresponding to the channel of the image sensor is utilized. Otherwise, the structured light generated by the multispectral structured light generating unit is not scattered by the object to be scanned, and the scattered light point of the structured light of that wavelength cannot be captured in the image sensor. Therefore, it is not utilized, and the light source in the multispectral structured light generating unit that generates the structured light of that wavelength can be turned off.

[0097] In summary, the three-dimensional scanning device and its control method proposed in the embodiments of the present invention include: a multispectral structured light generating unit and at least one imaging system; the multispectral structured light generating unit is used to generate structured light of at least two wavelengths to illuminate the object to be scanned, wherein the working surface positions of the structured light of different wavelengths are different; the imaging system includes a high dispersion imaging lens and an image sensor, the high dispersion imaging lens is used to collect scattered light beams to the same imaging plane, the scattered light beams are formed by the scattering of structured light of corresponding wavelengths by different working surface positions of the object to be scanned; the image sensor includes at least two channels, different channels are used to collect scattered light beams corresponding to structured light of different wavelengths; wherein the working surface positions of the structured light of different wavelengths are conjugate with the imaging plane of the image sensor. Thus, structured light of different wavelengths can scan different working surfaces of the object to be scanned, and then the scattered light corresponding to different working surfaces is collected and imaged onto the same plane by the imaging lens, realizing a large depth-of-field scanning of the object to be scanned.

[0098] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0099] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A three-dimensional scanning device, characterized in that, include: A multispectral structured light generation unit and at least one imaging system; The multispectral structured light generating unit is used to generate structured light of at least two wavelengths to illuminate the object to be scanned, wherein the working surface positions of the structured light of different wavelengths are different; The imaging system includes a high dispersion imaging lens and an image sensor. The high dispersion imaging lens is used to collect scattered light beams onto the same imaging plane. The scattered light beams are formed by scattering structured light of corresponding wavelengths at different working surface positions of the object to be scanned. The image sensor includes at least two channels, and different channels are used to collect scattered light beams corresponding to structured light of different wavelengths. The working surface positions of structured light of different wavelengths are conjugate with the imaging plane of the image sensor.

2. The three-dimensional scanning device according to claim 1, characterized in that, The imaging system includes a first imaging system and a second imaging system; the multispectral structured light generating unit is used to form a first scanning beam and a second scanning beam. The first imaging system is located on the path of the transmission of the first scattered beam, and the second imaging system is located on the path of the transmission of the second scattered beam. The first scattered beam is the beam scattered by the first scanning beam from a first object to be scanned, and the second scattered beam is the beam scattered by the second scanning beam from a second object to be scanned. The first object to be scanned and the second object to be scanned may be the same object or different objects.

3. The three-dimensional scanning device according to claim 1 or 2, characterized in that, Also includes: The system includes a controller and a distance sensor. The controller is connected to the distance sensor, the multispectral structured light generating unit, and the image sensor, respectively. The distance sensor is used to acquire the working distance between the multispectral structured light generating unit and the object to be scanned. The controller is used to control the multispectral structured light generating unit to emit structured light of a wavelength corresponding to the corresponding working surface position according to the working distance, and to control the image sensor on the imaging plane that is conjugate to the corresponding working surface position to start.

4. The three-dimensional scanning device according to claim 1, characterized in that, The high dispersion imaging lens includes at least one refracting or diffractive optical lens.

5. The three-dimensional scanning device according to claim 1, characterized in that, The high dispersion imaging lens includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially from the object side to the image side; Wherein, the first lens is a convex-concave lens, the second lens is a concave-concave lens, the third lens is a convex-convex lens, the fourth lens is a convex-convex lens, and the fifth lens is a concave-concave lens; The fourth lens and the fifth lens are cemented together to form a cemented lens.

6. The three-dimensional scanning device according to claim 1, characterized in that, The image sensor includes multiple channel elements, which are arranged in an array. The total number of channels in each channel element is the square of the number of channels in a single row.

7. The three-dimensional scanning device according to claim 6, characterized in that, Each of the channel elements includes a first channel, a second channel, a third channel, and a fourth channel, which are arranged sequentially to form a four-grid channel element. Alternatively, each of the channel elements includes a first channel, a second channel, a third channel, a fourth channel, a fifth channel, a sixth channel, a seventh channel, an eighth channel, and a ninth channel, with the first to the ninth channels arranged sequentially to form a nine-square grid of channel elements.

8. A control method for a three-dimensional scanning device, characterized in that, Implemented by the three-dimensional scanning device as described in any one of claims 1-7, the control method includes: Control the multispectral structured light generation unit to generate structured light of at least two wavelengths to illuminate the object to be scanned; The channels in the control image sensor corresponding to the at least two wavelengths of structured light are activated to collect the scattered beams formed by the scattering of the at least two wavelengths of structured light by the object to be scanned.

9. The control method for the three-dimensional scanning device according to claim 8, characterized in that, The three-dimensional scanning device further includes a distance sensor; and before the control multispectral structured light generating unit generates structured light of at least two wavelengths to illuminate the object to be scanned, it also includes: The working distance between the multispectral structured light generating unit and the object to be scanned is obtained; The working surface position close to the object to be scanned is determined based on the working distance; The control of the multispectral structured light generation unit to generate structured light of at least two wavelengths to illuminate the object to be scanned includes: Based on the working surface position and the first preset correspondence, the multispectral structured light generating unit is controlled to emit structured light with a wavelength corresponding to the corresponding working surface position; wherein, the first preset correspondence is the correspondence between the working surface position and the wavelength of the structured light emitted by the multispectral structured light generating unit; The activation of the channels in the controlled image sensor corresponding to the at least two wavelengths of structured light includes: Based on the working surface position and the second preset correspondence, the image sensor on the imaging plane that is conjugate to the corresponding working surface position is activated; wherein, the second preset correspondence is the conjugate correspondence between the working surface position and the imaging plane of the image sensor.

10. The control method for the three-dimensional scanning device according to claim 8, characterized in that, After activating the channels in the image sensor corresponding to the at least two wavelengths of structured light, the method further includes: The image sensor acquires a first image, and based on the comparison result between the first image and the object to be scanned, the multispectral structured light generating unit is controlled to shut down the unused wavelengths generated.

Images