A three-dimensional scanning system

Abstract

This application provides a three-dimensional scanning system, comprising: a transmitter for emitting a composite line pattern beam toward a scanned object, wherein the composite line pattern includes a measurement line pattern and an coded line pattern, and multiple measurement lines in the measurement line pattern are uniquely encoded by the brightness distribution of the coded lines in the coded line pattern; a receiver for acquiring the composite line pattern beam reflected by the scanned object and generating a composite line image, the composite line image including a measurement line image and a coded line image; and a processor for decoding the measurement line image according to the coded line image to identify multiple measurement lines, and using the identified multiple measurement lines to calculate the depth information of the scanned object based on the principle of line laser scanning.

Description

Technical Field

[0001] This application relates to the field of three-dimensional imaging technology, and more particularly to a three-dimensional scanning system. Background Technology

[0002] Existing 3D scanning systems typically use DLP (Digital Light Probe) at the transmitter to project a pre-set multi-frame fringe pattern (such as Gray code or phase-shifted fringes) onto the object's surface, easily achieving high-precision measurement results. However, DLP is costly, structurally complex, and projecting multiple frames of fringes is not conducive to dynamic 3D measurement. While using speckle-based structured light technology (such as Kinect, RealSense D435 / D455) to project a single-frame speckle pattern onto the object's surface and calculate the depth of the scanned object's points using a matching algorithm can measure dynamic objects, its accuracy is limited.

[0003] To address the aforementioned issues, existing technologies have proposed line laser scanning, where the scanner's transmitter projects one or more laser lines onto the object's surface, which are then captured by the receiver. Based on the principle of line laser scanning, each laser line corresponds to a light plane equation. A ray can be determined by the optical center of the receiver and a point on the laser line in the image. The three-dimensional coordinates of the scanned object's point can be determined by the intersection of this ray and the light plane equation. However, when the transmitter emits multiple laser lines, the receiver captures these multiple laser lines, resulting in a multi-line image. Consequently, a ray originating from any point on any laser line in the multi-line image will intersect multiple light planes, resulting in multiple intersection points. This makes it impossible to uniquely determine the light plane equation corresponding to each laser line.

[0004] To uniquely determine the plane equation corresponding to a laser line, existing methods propose using laser lines of multiple colors, encoding the laser lines by combining the different colors of adjacent laser lines in space. This method requires a color camera to capture the laser line image; however, the Bayer filter in the color camera reduces the camera's sensitivity. For example, when using blue or red laser lines, only 1 / 4 of the pixels in the color camera are sensitive, while the remaining 3 / 4 are almost unresponsive; similarly, when using green laser lines, only half of the pixels in the color camera are sensitive. Furthermore, encoding laser lines using color combinations is unsuitable for scanning objects with rich colors. Summary of the Invention

[0005] This application provides a three-dimensional scanning system, which aims to solve the problem of reducing cost and power consumption in related technologies while ensuring high-precision measurement results.

[0006] To address the aforementioned technical problems, this application provides a three-dimensional scanning system, comprising: a transmitter for emitting a composite line pattern beam toward a scanned object, wherein the composite line pattern includes a measurement line pattern and an encoding line pattern, and multiple measurement lines in the measurement line pattern are uniquely encoded by the brightness distribution of the encoding lines in the encoding line pattern; a receiver for acquiring the composite line pattern beam reflected by the scanned object and generating a composite line image, the composite line image including a measurement line image and an encoding line image; and a processor for decoding the measurement line image based on the encoding line image to identify multiple measurement lines, and using the identified multiple measurement lines to calculate the depth information of the scanned object based on the principle of line laser scanning.

[0007] The beneficial effects of this application are as follows: Compared with the prior art, this application provides a three-dimensional scanning system that combines coded line patterns and measurement line patterns. It can obtain high-precision three-dimensional scanning information using only two frames of patterns. While ensuring accuracy, it not only reduces cost and power consumption, but also eliminates the need to attach external markers to the scanned object, reducing labor costs and increasing the scanning speed, thereby improving the speed of three-dimensional reconstruction. Attached Figure Description

[0008] To more clearly illustrate the related technologies or the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the related technologies or the embodiments of this application will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application, and not all embodiments. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0009] Figure 1 This application provides a schematic diagram of a three-dimensional scanning system structure. Figure 2(a) is a schematic diagram of the multi-line pattern structure in the composite line pattern beam provided in the embodiment of this application; Figure 2(b) is a schematic diagram of another multi-line pattern structure in the composite line pattern beam provided in the embodiment of this application; Figure 3(a) is a schematic diagram of the measurement line pattern structure in the composite line pattern beam provided in the embodiment of this application; Figure 3(b) is a schematic diagram of another coded line pattern structure in the composite line pattern beam provided in the embodiment of this application; Figure 4(a) is a schematic diagram of the design structure of a pattern modulation element provided in an embodiment of this application; Figure 4(b) is a schematic diagram of another design structure of a pattern modulation element provided in an embodiment of this application; Figure 5 This is a schematic diagram of the design structure of another pattern modulation element provided in an embodiment of this application; Figure 6This is a schematic diagram of the design structure of another pattern modulation element provided in an embodiment of this application; Figure 7 This is a schematic diagram of the structure of the line laser scanning principle provided in the embodiments of this application; Figures 8(a) and 8(b) are schematic diagrams of an optical system structure provided in an embodiment of this application; Figure 9 This is another schematic diagram of an optical system structure provided in an embodiment of this application; Figure 10 This is a schematic diagram of another optical system structure provided for an embodiment of this application. Detailed Implementation

[0010] To make the objectives, technical solutions, and advantages of this application more apparent and understandable, this application will be clearly and completely described below in conjunction with its embodiments and corresponding drawings. Throughout, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions. It should be understood that the various embodiments of this application described below are merely illustrative of this application and are not intended to limit this application. That is, all other embodiments obtained by those skilled in the art based on the various embodiments of this application without creative effort are within the scope of protection of this application. Furthermore, the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0011] Figure 1 This is a schematic diagram of the system structure of a three-dimensional scanning system according to this application. The system includes a transmitter 10, a receiver 11, and a processor (not shown). The transmitter 10 is used to emit a composite line pattern beam 12 towards the object being scanned. The composite line pattern beam 12 includes a measurement line pattern 120 and an encoding line pattern 121. Multiple measurement lines in the measurement line pattern 120 are uniquely encoded by the brightness distribution of the encoding lines in the encoding line pattern 121. The receiver 11 is used to acquire the composite line pattern beam 12 reflected by the object being scanned and generate a composite line image, which is transmitted to the processor. The composite line image includes an encoding line image and a measurement line image. The processor is used to decode the measurement line image based on the brightness of the encoding lines in the encoding line image to identify multiple measurement lines. The depth information of the object being scanned is obtained using the identified multiple measurement lines and based on the principle of line laser scanning.

[0012] Furthermore, after obtaining the depth information of the scanned object, the processor can acquire the intrinsic and extrinsic parameters of the transmitter 10 and receiver 11 in the 3D scanning system, and combine the intrinsic and extrinsic parameters with the depth information of the scanned object to obtain the point cloud map of the scanned object; on the other hand, the processor can also perform 3D reconstruction on the obtained point cloud map of the scanned object to obtain the 3D model of the scanned object.

[0013] In one embodiment, the measurement line pattern 120 includes multiple measurement lines 1201, and the encoding line pattern 121 includes multiple encoding lines of different brightness, such as... Figure 1 The coding lines 1210, 1211, and 1212 are shown; wherein, the measuring lines in the measuring line pattern 1201 and the coding lines in the coding line pattern 121 are preferably laser lines, and the multiple laser lines are parallel to each other. Further, the laser lines projected by the transmitting end 10 include those in the vertical direction, as shown in Figure 2(a); or those in a near-vertical direction, as shown in Figure 2(b). It should be noted that the vertical laser line described in this embodiment is defined as the laser line whose extension direction is perpendicular to the baseline between the transmitting end 10 and the receiving end 11. That is, when the transmitting end 10 emits a horizontal laser line, if it is perpendicular to the baseline between the transmitting end 10 and the receiving end 11, it also belongs to the vertical laser line described in this embodiment.

[0014] Figure 3 is a schematic diagram of a composite line pattern beam emitted by a transmitter according to the present application. It illustrates the principle of uniquely encoding multiple measurement lines in a measurement line pattern using three different brightness levels of encoding lines included in the encoding line pattern. In one embodiment, each measurement line in the measurement line pattern coincides with and is aligned with at least one encoding line in the encoding line pattern. That is, each measurement line in the measurement line pattern and its aligned encoding line are projected to the same position in space. Thus, the unique encoding of multiple measurement lines in the measurement line pattern is achieved through the arrangement and combination of the brightness levels of the encoding lines in the encoding line pattern.

[0015] In one embodiment, as shown in Figures 3(a) and 3(b), when the transmitting end projects a composite line pattern beam, the unique encoding of multiple measurement lines in the measurement line pattern is achieved by arranging and combining the brightness of the encoding lines in the encoding line pattern. This includes: in Figure 3(a), at least one encoding line is projected at the location of each measurement line contained in the measurement line pattern, and multiple measurement lines correspond to multiple encoding lines; if the brightness of all encoding lines is the same, the unique encoding of the measurement lines cannot be achieved; if an encoding line pattern including encoding lines with different brightness is projected, as shown in Figure 3(b), there are 3 different brightness encoding lines in the encoding line pattern. Different encodings can be obtained by arranging and combining encoding lines with different brightness. Based on this, the unique encoding of each measurement line is achieved by combining the brightness states of the 3 adjacent encoding lines in the horizontal direction of each measurement line, and the unique encoding of 27 measurement lines can be achieved.

[0016] In the coding line pattern shown in Figure 3(b), the multiple coding lines in the pattern include three brightness distributions, denoted as bright (L), dark (D), and none (N). Taking the brightness of the three coding lines that coincide with and are adjacent to each measurement line in the horizontal direction to achieve unique coding for each measurement line as an example, the coding for measurement line 1 is LDN, the coding for measurement line 2 is DNL, ​​and the coding for measurement line 3 is NLN. Therefore, for a coding line pattern with at least three brightness distributions and utilizing at least three coding lines that coincide with and are adjacent to each measurement line in the horizontal direction, according to the above coding principle, at least 27 codes can be achieved, that is, at least 27 unique codings for each measurement line can be achieved, and the coding for each measurement line is different. It should be noted that, in addition to selecting the coding lines that are aligned with and adjacent to the current measurement line for coding, the coding line aligned with the current measurement line and the two coding lines before or after that aligned coding line can also be selected to achieve unique coding, which is not restricted here.

[0017] Furthermore, the brightness of each coded line in the coding line pattern is determined by its energy; different energies result in different brightness. Using the energy of each measuring line in the measuring line pattern as a benchmark, assuming the energy of each measuring line in the measuring line pattern is E, the energy of each coded line in the coding line pattern can be designed to be at least E, E / 2, and 0. Therefore, each coded line in the coding line pattern includes at least three brightness levels, which can be denoted as 1, 0.5, and 0, as shown in Figure 3(b). By arranging and combining these at least three different brightness levels of the coded lines, at least 27 possible combinations of codes can be obtained, achieving unique coding for at least 27 measuring lines.

[0018] It should be understood that, generally, the field of view of the transmitter 10 is larger than that of the receiver 11. Therefore, the line patterns at both ends of the composite line pattern beam projected by the transmitter 10 may not be acquired by the receiver 11. Thus, in practical applications, the encoding and decoding calculations of the measurement lines at both ends of the measurement line pattern can be ignored. In addition, this embodiment does not limit the encoding form used for the encoding lines. It can be represented by numbers, letters, or text, as shown in Figures 3(a) and 3(b). For measurement line 1 in the measurement line pattern, based on the brightness of the encoding line in the encoding line pattern, the encoding corresponding to measurement line 1 can be represented by the text as bright, dark, or none; or by the numbers as 10N, where N represents none (i.e., the encoding line has no brightness), 1 represents bright, and 0 represents dark; the remaining measurement lines are analogous, and will not be elaborated here.

[0019] In summary, Figures 3(a) and 3(b) only illustrate the example of encoding lines with three different brightness levels in the encoding line pattern and encoding the measurement line using three encoding lines. In addition to being aligned with the measurement line, the encoding lines can also be distributed near the measurement line, such as on the left or right side of the measurement line. The encoding principle is the same as in the above embodiments, and will not be repeated here.

[0020] Furthermore, according to the encoding principle of the above embodiments, the encoding line pattern can also include at least two different brightness encoding lines. Specifically, when the encoding line pattern includes two different brightness encoding lines, encoding a certain measurement line using two encoding lines yields 4 possible codes, achieving unique encoding for the four measurement lines; encoding a certain measurement line using three encoding lines yields 8 possible codes, achieving unique encoding for the eight measurement lines. When the encoding line pattern includes four different brightness encoding lines, encoding a certain measurement line using three encoding lines yields 64 possible codes, achieving unique encoding for the 64 measurement lines; encoding a certain measurement line using four encoding lines yields 256 possible codes, achieving unique encoding for the 256 measurement lines. Similarly, when the encoding line pattern includes n different brightness encoding lines, encoding a certain measurement line using m encoding lines yields n possible codes, achieving unique encoding for the n measurement lines, where n and m are integers greater than 2.

[0021] Based on the above encoding principle, the transmitter 10 transmits the measurement line pattern and the coded line pattern shown in Figures 3(a) and 3(b) to the object being scanned. The transmitted line pattern is reflected by the object and collected by the receiver 11. A composite line image containing the measurement line image and the coded line image is then transmitted to the processor. The processor uses the coded line image in the composite line image to decode the measurement line image, so as to uniquely determine each measurement line in the measurement line pattern shown in Figure 3(a) transmitted by the transmitter 10. Thus, each measurement line in the measurement line pattern transmitted by the transmitter and each measurement line in the measurement line image collected by the receiver form a one-to-one correspondence. This allows the processor to use the measurement lines with a one-to-one correspondence and perform depth calculation based on the line laser scanning principle to obtain the depth information of the object being scanned. The process of decoding the measurement line image using the coded line image in the composite line image is the reverse process of encoding multiple measurement lines in the measurement line pattern using the brightness of the coded line in the coded line pattern.

[0022] The decoding process is illustrated by taking the unique encoding of any measurement line in the measurement line pattern using the brightness of the encoded lines in the encoded line pattern as an example. Preferably, each measurement line in the measurement line pattern is pre-assigned a corresponding code, and the unique code of each measurement line in the encoded line pattern and the correspondence between each measurement line are stored (e.g., stored as a lookup table). The processor identifies the position of the encoded lines adjacent to the current measurement line based on the pixel value difference of the neighboring pixels of the pixel region corresponding to the current measurement line in the composite line image, and compares the brightness of the encoded lines adjacent to the current measurement line with the preset brightness of the measurement line to obtain the unique code of the current measurement line. Thus, the measurement line number corresponding to the code can be found from the correspondence to identify the current measurement line, thereby realizing the decoding of each measurement line; wherein, the preset brightness of each measurement line in the measurement line pattern is the same.

[0023] For example, when encoding using three coded lines distributed near a certain measurement line, the brightness of the coded line is compared with the preset brightness of the measurement line. The code obtained by comparing the brightness distribution is LDN. As shown in Figure 3(b), this code corresponds to measurement line 1, thereby realizing the decoding of the measurement line to uniquely identify the current measurement line.

[0024] In one embodiment, the processor identifies the position of the coded lines adjacent to the current measurement line based on the pixel value difference of the neighboring pixels of the pixel region corresponding to the current measurement line in the composite line image, and obtains the unique code of the current measurement line based on the brightness of the coded lines adjacent to the current measurement line and the preset brightness of the measurement line for decoding, thereby identifying multiple measurement lines. Specifically, when the receiving end acquires the composite line pattern beam reflected back from the scanned object, some pixels in the receiving end can respond to the reflected composite line pattern beam to generate a composite line image including the measurement line image and the coded line image and transmit it to the processor, that is, some pixels in the receiving end do not respond; wherein, the pixel value corresponding to the responding pixel is numerically different from the pixel value corresponding to the non-responding pixel, and the pixel value corresponding to the non-responding pixel is 0 or a constant value. Therefore, a pixel value threshold can be preset, and the composite line image can be detected pixel by pixel. The pixel value of each pixel in the composite line image is compared with the pixel value threshold. Pixels that are greater than and / or equal to the pixel value threshold are defined as responding pixels. The responding pixels are searched in the neighborhood pixels of the pixel area corresponding to the current measurement line, thereby identifying the position of the coded line and decoding the current measurement line according to the brightness of the coded line.

[0025] In one embodiment, the measurement line image and the coded line image are two independent frames, and at least some pixels in the two frames are aligned. Therefore, when decoding the current measurement line, the coded line corresponding to the current measurement line can be obtained by finding the pixels whose pixel values ​​have changed in the corresponding pixel region and its neighboring pixels in the coded line image based on the coordinate information of the current measurement line in the measurement line image and the alignment relationship between the images. The pixel values ​​of the pixels corresponding to the coded line are compared with the pixel values ​​of the pixels corresponding to the measurement line to obtain the brightness state of the coded line. The current measurement line is then decoded based on the brightness state of the coded line to uniquely determine the current measurement line.

[0026] Based on the encoding / decoding principles corresponding to Figures 3(a) and 3(b), this application combines... Figure 1 Figure 4(a) to Figure 6 An exemplary description of the system design of a 3D scanning system is provided.

[0027] like Figure 1 The three-dimensional scanning system shown includes a transmitter 10, a receiver 11, and a processor. The transmitter 10 projects a composite line pattern beam 12 onto the object being scanned. The receiver 11 collects the composite line pattern beam 12 reflected back from the object being scanned, generates a composite line image, and transmits it to the processor. The processor receives the composite line image and processes it to obtain the depth information of the object being scanned.

[0028] In one embodiment, the transmitting end 10 includes a light source 101 and a pattern modulation element 102. The light source 101 is used to emit a light beam to the pattern modulation element 102. The pattern modulation element 102 modulates the light beam emitted by the light source 101 to obtain a composite line pattern beam 12 including a measurement line pattern 120 and an encoding line pattern 121. The measurement line pattern 120 has the same brightness for each measurement line, and the encoding line pattern 121 includes at least two encoding lines with different brightness, so as to achieve unique encoding of the measurement lines through the brightness distribution of the encoding lines.

[0029] Preferably, the light source 101 can be a light-emitting diode (LED), an edge-emitting laser (EEL), a vertical-cavity surface-emitting laser (VCSEL), or a light source array composed of multiple light sources. The light emitted can be any one or more combinations of visible light, infrared light, blue light, green light, or ultraviolet light.

[0030] In one embodiment, when the light source 101 in the transmitter 10 includes at least two sub-light sources, the at least two sub-light sources are used to emit light beams to the pattern modulation element 102 respectively. The pattern modulation element 102 is used to modulate the light beams emitted by the at least two sub-light sources and project a composite line pattern beam 12 onto the scanned object. The composite line pattern beam 12 includes a measurement line pattern and an encoding line pattern. The wavelengths of the light beams emitted by the at least two sub-light sources may be the same or different. Each sub-light source may share a pattern modulation element or a pattern modulation element 102 may be provided on the light-emitting side of each sub-light source. The pattern modulation element 102 includes a mask.

[0031] Specifically, when the wavelengths of the emitted beams from at least two sub-light sources are the same, pattern modulation elements 102 are respectively provided on the light-emitting side of the at least two sub-light sources, and the emitted beams are divided into measurement line patterns and coding line patterns, so as to avoid the coding line patterns and measurement line patterns overlapping in space when they are imaged at the receiving end 11, thus making it impossible to distinguish between the coding line patterns and measurement line patterns; when the wavelengths of the emitted beams from at least two sub-light sources are not the same, the at least two sub-light sources can share a pattern modulation element or have pattern modulation elements respectively provided, and they can emit beams simultaneously or in a time-division manner, without any restrictions.

[0032] Furthermore, if pattern modulation elements are respectively set on the light-emitting side of each sub-light source, taking the pattern modulation element as a Mask as an example, the Mask designs corresponding to at least two sub-light sources are shown in Figure 4(a) and Figure 4(b). One Mask is only used to form a measurement line pattern, and the other is only used to form an encoding line pattern. Each sub-light source in the transmitting end emits a beam to a different pattern modulation element. The different pattern modulation elements modulate the beam emitted by each sub-light source to obtain a measurement line pattern and an encoding line pattern, and project them onto the scanned object so as to form a composite line pattern beam 12 containing the measurement line pattern and the encoding line pattern when it reaches the surface of the scanned object.

[0033] Taking the example of setting a single mask on the light-emitting side of each sub-light source, the mask fabrication process is explained as follows: Based on a preset input beam and a preset output beam, a pattern conforming to the design requirements is created. This pattern is then fabricated onto a mask using photolithography to form the pattern modulation element Mask required in this embodiment, as shown in Figures 4(a) and 4(b). It should be noted that in this embodiment, the pattern conforming to the preset requirements must satisfy the condition that the light beam emitted by the light source, after passing through the pattern modulation element, can form a measurement line pattern or an encoding line pattern, thereby enabling the unique encoding of each measurement line in the measurement line pattern using the encoding line pattern.

[0034] In one embodiment, the first mask, which only allows the measurement line pattern to pass through, is shown in Figure 4(a). The first pattern area 50 is a pattern that only forms the measurement line pattern. When the transmitting end emits a light beam to this area, the pattern in this area can transmit all light, forming the measurement line pattern shown in Figure 3(a). At this time, the energy of each measurement line is denoted as E, and the brightness state can be denoted as 1. In another embodiment, the second mask, which only allows the encoding line pattern to pass through, is shown in Figure 4(b). The second pattern area 51 is composed of lines. When the transmitting end emits a light beam to this area, the area can transmit all light. At this time, the brightness state of the encoding line passing through this area is the same as the brightness state of the measurement line. The energy is denoted as E, and the brightness state can be denoted as 1. The third pattern area... The third pattern area 52 consists of several square patterns, each with the same size and spacing. When the transmitting end emits a light beam to this area, the square areas are fully transparent, while the non-square areas (such as the spacing between squares) are completely opaque. When the size and spacing of each square are sufficiently small (e.g., on the order of micrometers), only half of the area of ​​the third pattern area 52 is transparent, equivalent to a semi-transparent effect, allowing some light to pass through. In this case, the energy of the encoding line passing through this area 52 is recorded as E / 2, and the brightness state is recorded as 0.5. The fourth pattern area 53 consists of the area within the dashed frame. This area is completely opaque, meaning that when the transmitting end emits a light beam to this area, the beam cannot pass through it. In this case, the energy of the encoding line is recorded as 0, and the brightness state is also recorded as 0. Thus, a light beam passing through the Mask shown in Figure 4(b) can form at least three different brightness states of encoding lines as shown in Figure 3(b), thereby uniquely encoding the measurement line based on the combination of brightness states of the encoding lines.

[0035] Figure 5 This is a schematic diagram of a pattern modulation element according to the present application. In one embodiment, the wavelengths of the emitted beams from each sub-light source are different, so the emission side of each sub-light source can share a single pattern modulation element. Taking the pattern modulation element as a mask as an example, the design of the mask shared by the emission side of each sub-light source is as follows: Figure 5As shown, the mask has a reference pattern. When the light beam emitted from the transmitting end passes through this pattern, a measurement line pattern and an encoding line pattern are formed and projected onto the scanned object. Specifically, the reference pattern includes a fifth pattern area 54, a sixth pattern area 55, and a seventh pattern area 56, and each pattern area is coated with a light-transmitting film. Preferably, when each sub-light source is at least a first wavelength sub-light source and a second wavelength sub-light source, the fifth pattern area 54 may be coated with a first wavelength light-transmitting film, indicating that only the first wavelength light is allowed to pass through this area; the seventh pattern area 56 may be coated with a second wavelength light-transmitting film, indicating that only the second wavelength light is allowed to pass through this area; the sixth pattern area 55 may be coated with a third wavelength light-transmitting film with a transmittance of only 50%, indicating that this area can transmit both a portion of the first wavelength light and a portion of the second wavelength light. It should be noted that the pattern area 55 is composed of several squares spaced apart, wherein only the area where the squares are located can transmit light, and the remaining areas are completely opaque.

[0036] When the first wavelength sub-light source and the second wavelength sub-light source are turned on simultaneously at the transmitting end, the emitted light beam passes through the pattern modulation element to form a measurement line pattern and is projected onto the object being scanned. Specifically, the fifth pattern region 54 passes through the first wavelength light, the seventh pattern region 56 passes through the second wavelength light, and the sixth pattern region 55 passes through a portion of the first wavelength light and a portion of the second wavelength light, such as 50% of the first wavelength light and 50% of the second wavelength light. Thus, the light energy obtained through each pattern region is E, and the brightness state is 1, thereby forming the measurement line pattern shown in Figure 3(a) and projecting it onto the object being scanned. When the transmitter only turns on the first wavelength sub-light source, the fifth pattern region 54 transmits the first wavelength light, and the light energy obtained through this region is E, with a brightness state of 1. The sixth pattern region 55 transmits 50% of the first wavelength light, and since the second wavelength sub-light source is not turned on, the light energy obtained through this region is E / 2, with a brightness state of 0.5. The seventh pattern region 56 only allows the second wavelength light to pass through, and the transmitter turns on the first wavelength sub-light source. At this time, the light energy obtained through this region is 0, and the brightness state is 0. Thus, the coding line pattern formed by at least three different brightness state coding line combinations as shown in Figure 3(b) can be obtained. It should be noted that when the transmitter only turns on the second wavelength sub-light source, the principle of obtaining the coding line pattern is the same as that of obtaining the coding line pattern when only the first wavelength sub-light source is turned on, and will not be repeated here.

[0037] Figure 6 This is a schematic diagram of another patterned optical modulation element provided in this application. In one embodiment, the wavelengths of the emitted beams from each sub-light source are different, so the emission side of each sub-light source can share a single patterned modulation element. Taking the patterned modulation element as a mask as an example, the mask design shared by the emission side of each sub-light source is as follows: Figure 6As shown, the mask has a reference pattern. When the light beam emitted from the transmitting end passes through this pattern, a measurement line pattern and an encoding line pattern are formed and projected onto the scanned object. The reference pattern includes an eighth pattern area 57, a ninth pattern area 58, and a tenth pattern area 59. Preferably, each sub-light source includes a first wavelength sub-light source and a second wavelength sub-light source. The eighth pattern area 57 may be uncoated to allow light beams of all wavelengths to pass through. The ninth pattern area 58 may be coated with a light-transmitting film that allows all first wavelength light and a portion of the second wavelength light (e.g., 50%) to pass through. The tenth pattern area 59 may be coated with a light-transmitting film that allows all first wavelength light and does not allow second wavelength light to pass through.

[0038] Specifically, when only the first wavelength sub-light source is turned on in the transmitter, since each pattern region on the pattern modulation element can transmit the first wavelength light, the energy of the first wavelength light obtained through each pattern region is E, and the brightness state is recorded as 1, thus forming the measurement line pattern shown in Figure 3(a). When only the second wavelength sub-light source is turned on in the transmitter, the eighth pattern region 57 can transmit all the second wavelength light, and the energy of the second wavelength light obtained through this region is E, and the brightness state is recorded as 1; the ninth pattern region 58 can transmit 50% of the second wavelength light, and the energy of the second wavelength light obtained through this region is E / 2, and the brightness state is recorded as 0.5; the tenth pattern region 59 cannot transmit the second wavelength light, and the energy of the second wavelength light obtained through this region is 0, and the brightness state is recorded as 0; thus, when the transmitter turns on the second wavelength sub-light source alone, the coding line pattern shown in Figure 3(b) can be obtained.

[0039] Furthermore, when the transmitting end transmits the coded line pattern and the measurement line pattern to the scanned object at 10 minutes, the coded line pattern and the measurement line pattern are reflected sequentially by the scanned object to the receiving end 11. The receiving end 11 sequentially acquires the coded line pattern and the measurement line pattern and generates a composite line image accordingly, which is transmitted to the processor. The composite line image includes the coded line image and the measurement line image.

[0040] In one embodiment, the receiver 11 includes a monochrome image sensor and a filter. The monochrome image sensor is used to acquire the composite line pattern beam reflected back from the scanned object and generate a corresponding image, which is then transmitted to the processor. The monochrome image sensor can be any one or more of a charge-coupled device (CCD), complementary metal-oxide-semiconductor (CMOS), avalanche diode (AD), or single-photon avalanche diode (SPAD). The filter is disposed on the light-incident side of the monochrome image sensor and is preferably a narrow-band filter that matches the wavelength of the light source. It is used to suppress background light noise in other bands so that only the composite line pattern beam or the measurement line pattern in the composite line pattern beam passes through the filter and is acquired by the monochrome image sensor.

[0041] In another embodiment, the receiver 11 further includes a color image sensor, which includes an image sensor and a Bayer filter disposed on the light-incident side of the image sensor, for acquiring the texture of the scanned object and transmitting it to the processor. The processor renders the point cloud map of the scanned object according to the texture of the scanned object to obtain a textured point cloud model or performs texture mapping on the three-dimensional model of the scanned object to obtain a textured three-dimensional model.

[0042] Furthermore, when the black and white image sensor only acquires the measurement line pattern in the composite line pattern beam to generate a measurement line image and transmits it to the processor, the color image sensor is also provided with a narrow-band filter on the light-incident side that matches the light source wavelength of the emitting coded line, so that the color image sensor is only used to acquire the coded line pattern in the composite line pattern beam to generate a coded line image and transmit it to the processor, so that the processor can identify multiple measurement lines in the measurement line image based on the coded line image.

[0043] It should be understood that, compared to color image sensors, monochrome image sensors have better sensitivity and higher signal-to-noise ratio in the acquired images. Using monochrome sensors to acquire composite line pattern beams is beneficial for high-precision measurement of the scanned object. In this embodiment, color image sensors are only used to acquire coded line patterns for encoding or the texture of the scanned object, and are not directly used for measuring the scanned object, so they do not affect the measurement accuracy.

[0044] Furthermore, the receiver 12 may also include an imaging lens for receiving a composite line pattern beam reflected back from the scanned object, allowing the composite line pattern beam to propagate to and pass through a filter to form an image on a corresponding pixel of the image sensor. Preferably, the imaging lens comprises a single lens or a lens group consisting of multiple lenses.

[0045] In some embodiments, the processor can be a dedicated circuit, such as a dedicated SOC chip, FPGA chip, ASIC chip, etc., which includes a CPU, memory, bus, etc. It can also include general-purpose processing circuits. For example, when the 3D scanning system is integrated into a smart terminal such as a mobile phone, television, computer, scanner, etc., the processing circuit in the terminal can serve as at least part of the processor.

[0046] In some embodiments, the processor decodes the measurement line image based on the coded line image to identify multiple measurement lines in the measurement line image, and uses the identified multiple measurement lines to calculate the depth information of the scanned object based on the principle of line laser scanning. Specifically, as shown in the figure... Figure 7As shown, based on the principle of line laser scanning, a measurement line emitted by the transmitter towards the scanned object can form a laser scalpel plane. Each laser scalpel plane corresponds to a laser scalpel plane equation, which can be obtained through calibration. The receiver acquires the beam reflected from the scanned object, forming a measurement line image containing the measurement line on the camera's imaging plane. The processor extracts any point on any measurement line in the measurement line image and, starting from the optical center at the receiver, forms a ray with any point on the measurement line (denoted as p). By finding the intersection of this ray with the laser scalpel plane, the three-dimensional coordinates of p can be determined, thus obtaining the depth information of the scanned object.

[0047] Furthermore, the processor can extract the centerline of the measurement line in the measurement line image using a centerline extraction algorithm. Starting from the optical center at the receiving end, a ray is formed with any center point of the measurement line. The intersection of this ray with the light blade plane determines the three-dimensional coordinates of the corresponding center point, thus obtaining the depth information of the scanned object. Compared to directly calculating the depth information of the scanned object from any point on the measurement line, this embodiment calculates the centerline on the measurement line to obtain the corresponding center point with sub-pixel coordinates, and uses the sub-pixel center point to obtain the depth information of the scanned object, thereby improving the accuracy of the depth information.

[0048] However, if a 3D scanning system emits only one measurement line to scan the object, the obtained data will be relatively sparse. To obtain denser data, multiple measurement lines need to be emitted. When the transmitter emits multiple measurement lines, the receiver accordingly acquires the multiple measurement lines reflected back from the object to obtain a measurement line image. A ray originating from any point on any measurement line in the measurement line image and forming a ray with the optical center of the receiver will intersect with the light planes corresponding to the multiple measurement lines emitted by the transmitter, resulting in multiple intersection points. This makes it impossible to uniquely determine the equation of the light plane corresponding to the current measurement line in the measurement line image.

[0049] To uniquely determine the optical blade plane equation corresponding to the current measurement line in the measurement line image, this embodiment controls the transmitter to emit a composite line pattern beam including an coded line pattern and a measurement line pattern. The coded line pattern is used to uniquely encode multiple measurement lines in the measurement line pattern. The receiver then collects the reflected composite line pattern beam and generates a composite line image containing the coded line image and the measurement line image. The processor can then use the coded line image in the composite line image to decode the measurement line image to identify each measurement line, thereby uniquely determining the optical blade plane equation corresponding to the current measurement line. This allows for further obtaining the depth information of the scanned object based on the aforementioned line laser scanning principle.

[0050] Based on the system design of the three-dimensional scanning system provided in the embodiments of this application, Figures 8(a) to 8(b) are shown in Figure 8(a). Figure 10 An exemplary optical system architecture for a 3D scanning system is shown.

[0051] Figures 8(a) and 8(b) are schematic diagrams of the optical system structure of a three-dimensional scanning system according to this application. Specifically, the optical system includes a first transmitting end 20, a second transmitting end 21, and a receiving end 22. The first transmitting end 20 and the second transmitting end are used to emit composite line pattern beams, including measurement line patterns and coded line patterns, to the scanned object, respectively. The receiving end 22 is used to collect the composite line pattern beams reflected back by the scanned object and generate a composite line image. It should be noted that, in order to better illustrate the optical system provided in this embodiment, this embodiment only uses the independent configuration of the first transmitting end 20 and the second transmitting end 21 as an example. However, in actual applications, the transmitting end can also be integrated. When the transmitting end is designed as an integrated unit, the light source included in each transmitting end corresponds to the sub-light source included in the light source of the integrated transmitting end.

[0052] In some embodiments, each transmitting end includes a light source and a pattern modulation element, as shown in Figures 8(a) and 8(b). The first transmitting end 20 includes a first light source 200 and a first pattern modulation element 202, and the second transmitting end 21 includes a second light source 210 and a second pattern modulation element 212. The first light source 200 and the second light source 210 are used to emit light beams to the first pattern modulation element 202 and the second pattern modulation element 212, respectively. The light beam emitted by the first light source 200 is modulated by the first pattern modulation element 202 to form a measurement line pattern and is projected onto the scanned object 26, as shown in Figure 8(a). The light beam emitted by the second light source 210 is modulated by the second pattern modulation element 212 to form an encoding line pattern and is projected onto the scanned object 26, as shown in Figure 8(b).

[0053] Furthermore, the wavelengths of the light beams emitted by the first transmitting end 20 and the second transmitting end 21 may be the same or different. In one embodiment, when the wavelengths of the light beams emitted by the transmitting ends are different, the first light source 200 and the second light source 210 are preferably a blue laser light source and a green laser light source, respectively, used to emit blue light and green light to the corresponding pattern modulation elements. The blue laser light source forms a measurement line pattern after being modulated by the first pattern modulation element 202, and the green laser light source forms an encoding line pattern after being modulated by the second pattern modulation element 212. The measurement line pattern and encoding line pattern obtained using different wavelengths, projected onto the scanned object in this embodiment, can be used to scan objects that are prone to scattering, such as translucent teeth.

[0054] In other embodiments, when the wavelengths of the light beams emitted by the transmitting end are the same, the first light source 200 and the second light source 210 are preferably near-infrared laser light sources, used to emit light beams to the pattern modulation elements in a time-division manner. After being modulated by each pattern modulation element, measurement line patterns and coding line patterns are formed and projected onto the object being scanned for scanning of general objects.

[0055] It should be noted that the wavelength selected for the emitting end of the optical system depends on the properties of the object being scanned. For example, as mentioned above, if the object being scanned is a translucent tooth or other object that is prone to scattering light, then blue laser, green laser, or other lasers with shorter wavelengths can be used. If it is a general object, then near-infrared laser is generally used. This application does not limit this.

[0056] In one embodiment, the emitting end further includes collimating elements disposed between the light source and the pattern modulation element, for collimating the light beam emitted by the light source to the pattern modulation element, such as collimating element 201 disposed between the first light source 200 and the first pattern modulation element 202, and collimating element 211 disposed between the second light source 210 and the second pattern modulation element 212. Preferably, the collimating element includes a lens or a lens group composed of multiple lenses. It should be noted that, in addition to collimating the light beam emitted by the light source, the collimating element can also be used to homogenize the light beam emitted by the light source.

[0057] In some embodiments, the receiver 22 includes a monochrome image sensor 220, a color image sensor 221, a beam splitter 222, and an imaging lens 223. The monochrome image sensor and the color image sensor are disposed on both sides of the beam splitter 222, preferably in an "L" shape, so as to share a single imaging lens 223. Preferably, a filter is disposed between the monochrome image sensor 220 and the color image sensor 221 and the beam splitter 222. The composite line pattern beam reflected back from the scanned object is collimated and focused by the imaging lens 223 onto the beam splitter 222. The beam splitter 222 splits the reflected beam into two beams. One beam, after passing through the filter, is left with only the blue light measurement line pattern and is acquired by the monochrome image sensor 220. The other beam, after passing through the filter, is left with only the green light coding line pattern and is acquired by the color image sensor. It should be noted that the filter in this embodiment can be a single device, or it can be integrated into the beam splitter 222 or integrated into the black and white image sensor 220 and the color image sensor 221 respectively. No limitation is made here.

[0058] In one embodiment, the imaging lens 223 is a lens group consisting of one or more lenses, used to focus the composite line pattern beam reflected back from the scanned object, so that the composite line pattern beam reflected back from the scanned object is correspondingly imaged onto the corresponding pixel in the image sensor.

[0059] In another embodiment, when it is necessary to acquire the texture information of the scanned object 26, the color image sensor 221 in the receiver 22 is used to acquire the texture information of the scanned object 26, and the black and white image sensor 220 is used to acquire the composite line pattern beam reflected back by the scanned object. To improve the imaging clarity of the color image sensor 221, the optical system in this embodiment also includes a coaxial illumination unit 23. Preferably, the coaxial illumination unit 23 is disposed on the light-incident side of the receiver 22 and is used to provide an ambient light-like light signal to the color image sensor 221; the coaxial illumination unit 23 includes a light source 230, a collimating lens 231, and a semi-transparent and semi-reflective optical element 232. The light source 230 emits a beam of light to the collimating lens 231, and the beam is collimated by the collimating lens 231 to the semi-transparent and semi-reflective optical element 232, wherein part of the beam of light is deflected through the semi-transparent and semi-reflective optical element 232 to the receiver 22. It should be noted that the light source 230 of the coaxial illumination unit 23 is preferably a white light source, such as an LED.

[0060] Specifically, when the composite line pattern beam reflected back from the scanned object and the beam emitted by the coaxial illumination unit 23 simultaneously enter the receiving end 22, the beam splitting element 222 in the receiving end 22 splits the beam received by the receiving end into two beams. One beam enters the color image sensor 221 to obtain the texture image of the scanned object, and the other beam enters the black and white image sensor 220. A narrow-band filter is provided in front of the black and white image sensor 220 to filter ambient light, allowing only the composite line pattern beam emitted by the transmitting end to pass through so as to form an image of the composite line pattern on the black and white image sensor 220. It should be noted that when the color image sensor 221 is used to acquire the texture information of the scanned object 26, no filter is required on the light-incident side of the color image sensor 221.

[0061] In one embodiment, a collimating lens 24 is further provided on the light-incident side of the coaxial illumination section 23. The collimating lens 24 is used to collimate the composite line pattern light beam reflected back from the scanned object to the coaxial illumination section 23 and allow it to pass through the coaxial illumination section 23. Preferably, the collimating lens 24 can be a single lens or a lens group composed of multiple lenses.

[0062] In one embodiment, the 3D scanning system further includes a deflecting optical element 25, used to receive a light beam emitted from the transmitting end and deflect it to the object being scanned 26 to achieve scanning of the object 26, and also used to receive a light beam reflected back from the object being scanned 26 and reflect it to the receiving end 22, thereby changing the transmitting and receiving optical paths of the 3D scanning system, making the transmitting and receiving optical paths partially coaxial, reducing the volume, and realizing the miniaturization of the 3D scanning system. Preferably, the deflecting optical element 25 may include any one of a rotating mirror, a reflecting mirror, a prism, or a MEMS, without limitation herein.

[0063] Figure 9This is a schematic diagram of the optical system structure of another three-dimensional scanning system provided in this application. Compared with the optical system structures shown in Figures 8(a) and 8(b), the optical system provided in this embodiment differs in the transmitting end, while the receiving end is the same as described above, and will not be repeated here.

[0064] In one embodiment, the transmitting end 30 includes at least a first light source 300, a second light source 301, a beam combiner 302, and a pattern modulation element 303. The first light source 300 and the second light source 301 are respectively disposed on different light-incident sides of the beam combiner 302, and the pattern modulation element 303 is disposed on the light-outceasing side of the beam combiner 302. Specifically, the first light source 300 and the second light source 301 are used to emit light beams of different wavelengths to the beam combiner 302 in a time-division manner. The beam combiner 302 is used to homogenize the two different wavelength light beams and combine them into a single beam that propagates to the pattern modulation element 303. The pattern modulation element 303 is used to modulate the received light beam to obtain a measurement line pattern and an encoding line pattern, which are then projected onto the scanned object 26.

[0065] In one embodiment, the beam homogenizing and combining element 302 includes at least two beam homogenizing elements and at least one beam combining element 3022. At least one beam homogenizing element is provided on the light-emitting side of at least two different wavelength light sources, such as a first beam homogenizing element 3020 corresponding to the first light source 300 and a second beam homogenizing element 3021 corresponding to the second light source 301. This homogenizes the light beam emitted by the light source at the energy level and collimates it to the beam combining element 3022, thereby improving light energy utilization and avoiding coherent light. The beam combining element 3022 is used to integrate the light beams emitted by different light sources onto the same optical path and project them onto the pattern modulation element 303. It should be noted that the beam homogenizing element in this embodiment can be a single lens or a combination of multiple lenses. The lens can be one or more combinations of compound eye lenses, diffusers, microlenses, etc. The beam combining element preferably includes one or more combinations of dichroic mirrors, prisms, etc., but this is not limited here.

[0066] Furthermore, since in this embodiment, the beams emitted from different wavelength light sources are integrated into the same optical path and projected onto the pattern modulation element by the beam combining element 302, in one embodiment, the pattern modulation element 303 includes at least one mask for modulating the beam projected by the beam combining element 302 to generate a measurement line pattern and an encoding line pattern. To achieve the simultaneous generation of measurement lines and encoding lines using only one pattern modulation element, lines that transmit only the light source wavelength corresponding to the emission measurement line pattern and the light source wavelength corresponding to the emission encoding line pattern can be photolithographically etched on the same mask.

[0067] In one embodiment, the transmitting end further includes a projection lens 304 for collimating the light beam projected by the collimating pattern modulation element 303 onto the object being scanned. It should be noted that the projection lens may include a single lens or a combination of multiple lenses, and no limitation is made here.

[0068] Figure 10 This is a schematic diagram of the optical system structure of another three-dimensional scanning system provided in this application. The optical system includes a transmitter 50, a receiver 22, and a deflection optical element 25. It should be noted that the function and composition of the optical element with the same name in the transmitter in this embodiment are the same as those described above, and will not be repeated here.

[0069] In one embodiment, the transmitting end 50 includes a light source, a collimating and homogenizing section, a pattern modulation element, a reflective element, a semi-transparent and semi-reflective element, a beam combining element, and a collimating element. The first light source 500 and the second light source 501 emit light beams of different wavelengths to the first collimating and homogenizing section 502 and the second collimating and homogenizing section 503, respectively. The first collimating and homogenizing section 502 collimates the light beam emitted by the first light source 500 to the corresponding first pattern modulation element 504, and the second collimating and homogenizing section 503 collimates the light beam emitted by the second light source 501 to the reflective element 507, and the reflective element 507 reflects the light beam to the second pattern modulation element 505. The first pattern modulation element 504 and the second pattern modulation element 505 modulate the light beam to correspondingly form a measurement line pattern and an encoding line pattern, which are then projected onto the semi-transparent and semi-reflective element 506. It should be noted that the reflective element includes a mirror, a prism, etc., whichever can reflect the light beam; no limitation is imposed here.

[0070] Furthermore, the beam emitted by the first light source 500 is modulated by the first pattern modulation element 504 to form a measurement line pattern and propagates through the semi-transparent and semi-reflective element 506 to the beam combining element 508. The beam emitted by the second light source 501 is modulated by the second pattern modulation element 505 to form an encoding line pattern and is reflected by the semi-transparent and semi-reflective element 506 to the beam combining element 508. The beam combining element 508 is used to combine the measurement line pattern and the encoding line pattern into a composite line pattern beam and collimates it by the collimating element 509 before projecting it onto the deflecting optical element 25. The deflecting optical element 25 is used to change the scanning direction of the composite line pattern beam so that the composite line pattern beam scans the scanned object 26, and to receive the composite line pattern beam reflected back by the scanned object 26 and reflect it to the receiving end 22.

[0071] In one embodiment, the transmitter 50 further includes a projection lens 509, which is disposed on the light-emitting side of the light combining element 508, and its image plane is located precisely on the light-emitting surfaces of the first image modulation element 504 and the second pattern modulation element 504, so that the measurement line pattern and the encoding line pattern can be highly aligned when projected onto the scanned object 26, that is, the encoding line pattern can be precisely projected onto the position corresponding to the measurement line pattern. Preferably, the projection lens 509 is used to collimate the light beam integrated by the light combining element 508 and project it onto the deflecting optical element 25.

[0072] In one embodiment, the transmitter 50 further includes an illumination unit 510 for providing ambient light-like illumination to the scanned object 26. Specifically, when the scanned object 25 is in a dark environment (such as teeth or gums), the illumination unit 510 can be turned on to provide supplementary light to the scanned object 25 in order to obtain the texture information of the scanned object 26. Preferably, the illumination unit 510 includes a light source and a collimating element. The light source is a white light source (such as an LED) to mimic ambient light. In this case, the light source emits a beam of light to the collimating element and, after being collimated by the collimating element, it is emitted towards the deflecting optical element 25. Under the deflection of the deflecting optical element 25, the light is projected onto the scanned object 26 to provide supplementary light.

[0073] In one embodiment, the receiver 22 in this implementation is the same as the receiver shown in FIG8, and will not be described again here.

[0074] Specifically, the first light source 500 uses a blue laser light source with a wavelength of 450nm, and the second light source 501 uses a blue laser light source with a wavelength of 405nm. The beam emitted by the first light source 500 is modulated by the first pattern modulation element 504 to form a measurement line pattern, and the beam emitted by the second light source 501 is modulated by the second pattern modulation element 505 to form an encoding line pattern. The measurement line pattern and the encoding line pattern are integrated by the beam combining element 508 to form a composite line pattern beam, which is then collimated by the projection lens 509 and propagated to the deflection optical element 25. The deflection optical element 25 is used to change the propagation direction of the composite line pattern beam to complete the scanning of the object 26 being scanned.

[0075] Furthermore, the transmitting end 50 emits a white light beam and blue laser beams of different wavelengths to the object being scanned 26. The beam emitted by the transmitting end 50 to the object being scanned 26 is reflected back to the deflecting optical element 25, which deflects the reflected beam to the receiving end 22. The imaging lens 223 in the receiving end 22 focuses the reflected beam to the beam splitter 222. The beam splitter 222 splits the beam received by the receiving end into two beams. One white light beam enters the color image sensor 221 to obtain the texture image of the object being scanned, and the other blue light beam (i.e., beams in the 450nm and 405nm bands) enters the black and white image sensor 220. A blue light filter is provided in front of the black and white image sensor 220, which only allows the composite line pattern beam emitted by the transmitting end to pass through so as to form an image on the black and white image sensor 220, thereby filtering stray light.

[0076] It should be noted that the various embodiments in this application are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0077] It should also be noted that, in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0078] The above description of the disclosed embodiments enables those skilled in the art to implement or use the content of this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined in this application may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A three-dimensional scanning system, characterized by, include: The transmitting end is used to emit a composite line pattern beam toward the scanned object, wherein the composite line pattern includes a measurement line pattern and an encoding line pattern, and the multiple measurement lines in the measurement line pattern are uniquely encoded by the brightness distribution of the encoding lines in the encoding line pattern; The receiving end is used to acquire the composite line pattern beam reflected by the scanned object and generate a composite line image, the composite line image including a measurement line image and an encoding line image; The processor is configured to decode the measurement line image based on the encoded line image to identify the multiple measurement lines, and to calculate the depth information of the scanned object based on the identified multiple measurement lines and the principle of line laser scanning.

2. The three-dimensional scanning system of claim 1, wherein, The processor is also used to acquire the intrinsic and extrinsic parameters of the transmitter and the receiver, and combine the intrinsic and extrinsic parameters with the depth information of the scanned object to obtain a point cloud map of the scanned object.

3. The three-dimensional scanning system of claim 2, wherein, The processor is used to perform three-dimensional reconstruction of the point cloud map of the scanned object to obtain a three-dimensional model of the scanned object.

4. The three-dimensional scanning system of any one of claims 1 to 3, wherein, The step of calculating the depth information of the scanned object using the identified multiple measurement lines and based on the principle of line laser scanning includes: The equation of the optical blade plane corresponding to each measurement line in the measurement line pattern emitted by the transmitter is pre-calibrated; Each measurement line in the measurement line image is identified to uniquely determine the light knife plane equation corresponding to each line. Any point on any measurement line is extracted and a ray is formed from the optical center of the receiving end and any point on the currently extracted measurement line. The intersection point of the ray and the light knife plane equation corresponding to the current measurement line is calculated to obtain the depth information of the scanned object.

5. The three-dimensional scanning system according to any one of claims 1 to 3, characterized in that, The multiple measurement lines in the measurement line pattern are uniquely encoded by the brightness distribution of the encoding lines in the encoding line pattern, including: using the brightness distribution of at least two adjacent encoding lines in the horizontal direction of each measurement line to uniquely encode each measurement line.

6. The three-dimensional scanning system of claim 5, wherein, The method of uniquely encoding each measurement line by utilizing the brightness distribution of at least two adjacent encoding lines in the horizontal direction of each measurement line includes: uniquely encoding the current measurement line by utilizing at least three encoding lines that are aligned with and adjacent to the current measurement line in the horizontal direction; or uniquely encoding the current measurement line by utilizing an encoding line aligned with the current measurement line and at least two encoding lines preceding or following the aligned encoding line.

7. The three-dimensional scanning system of any one of claims 1-3, wherein, The measurement lines in the measurement line pattern emitted by the transmitting end and the encoding lines in the encoding line pattern include vertical or near-vertical laser lines; wherein, the vertical laser line is defined as the laser line extending in a direction perpendicular to the baseline between the transmitting end and the receiving end.

8. The three-dimensional scanning system of any one of claims 1-3, wherein, The coding line pattern includes at least two coding lines with different brightness levels, and the measurement line pattern has all measurement lines with the same brightness.

9. The three-dimensional scanning system of any one of claims 1-3, wherein, The processor is configured to decode the measurement line image based on the encoded line image to identify the multiple measurement lines, including: Based on the pixel value differences of the neighboring pixels of the pixel region corresponding to the current measurement line in the composite line image, the positions of the coded lines adjacent to the current measurement line are identified; The unique code of the current measurement line is obtained based on the brightness of the adjacent coding lines and the preset brightness of the measurement line, and the multiple measurement lines are decoded by the unique code to identify the multiple measurement lines.

10. The three-dimensional scanning system according to any one of claims 1 to 3, characterized in that, The processor is configured to decode the measurement line image based on the encoded line image to identify the multiple measurement lines, including: Each measurement line in the measurement line pattern is pre-assigned a corresponding code, and the unique code of each measurement line in the code line pattern and the correspondence between each measurement line are stored. The position of the coded line next to the current measurement line is identified by the difference in pixel value of the neighboring pixels of the pixel region corresponding to the current measurement line in the composite line image. The brightness of the coded line next to the current measurement line is compared with the preset brightness of the measurement line to obtain the unique code of the current measurement line. The measurement line number corresponding to the code is found from the correspondence to identify the current measurement line.

11. The three-dimensional scanning system of any one of claims 1-3, wherein, The transmitting end includes a light source and a pattern modulation element. The light source is used to emit a light beam to the pattern modulation element, and the pattern modulation element is used to modulate the light beam emitted by the light source and project the composite line pattern light beam, which includes the coded line pattern and the measurement line pattern, onto the scanned object.

12. The three-dimensional scanning system of claim 11, wherein, The transmitting end further includes a collimating element disposed between the light source and the pattern modulation element, used to collimate the light beam emitted by the light source to the pattern modulation element; wherein, the pattern modulation element is a Mask.

13. The three-dimensional scanning system of claim 12, wherein, The transmitter also includes a projection lens, which is used to collimate the light beam projected by the pattern modulation element onto the scanned object.

14. The three-dimensional scanning system of any one of claims 12-13, wherein, The light source includes at least two sub-light sources, which are used to emit light beams to the pattern modulation element respectively. After being modulated by the pattern modulation element, the light beams are projected onto the scanned object to project the coded line pattern and the measurement line pattern respectively. The light beams emitted by the at least two sub-light sources have the same or different wavelengths.

15. The three-dimensional scanning system of claim 14, wherein, Pattern modulation elements are respectively provided on the light-emitting side of the at least two sub-light sources, and the light beams emitted by the at least two sub-light sources form the coding line pattern and the measurement line pattern respectively after passing through the corresponding pattern modulation elements.

16. The three-dimensional scanning system of claim 15, wherein, The pattern modulation element corresponding to one sub-light source includes a first pattern area, and the light passing through the first pattern area forms the measurement line pattern, wherein each measurement line in the measurement line pattern has the same brightness; the pattern modulation element corresponding to the other sub-light source includes a second pattern area, a third pattern area and a fourth pattern area, wherein the second pattern area is composed of lines, and the light passing through the second pattern area forms an encoding line with the same brightness as the measurement line. The third pattern area is composed of several square patterns, allowing some light to pass through. The light passing through the third pattern area forms a coding line with a brightness different from the measurement line. The fourth pattern area is an opaque area, allowing no light to pass through.

17. The three-dimensional scanning system according to any one of claims 15-16, characterized in that, When the wavelengths of the at least two sub-light sources are the same, the at least two sub-light sources are blue laser sources or near-infrared laser sources.

18. The three-dimensional scanning system according to any one of claims 15-16, characterized in that, When the wavelengths of the at least two sub-light sources are different, the at least two sub-light sources include a blue laser source and a green laser source, or two blue laser sources with different wavelengths.

19. The three-dimensional scanning system as described in claim 14, characterized in that, When the wavelengths of the light beams emitted by each sub-light source are different, each sub-light source shares a pattern modulation element. The light beams emitted by each sub-light source are then processed by the pattern modulation element to form the coding line pattern and the measurement line pattern.

20. The three-dimensional scanning system of claim 19, wherein, When each sub-light source includes at least a first wavelength sub-light source and a second wavelength sub-light source, the pattern modulation element is provided with a reference pattern, and the reference pattern is coated with a light-transmitting film corresponding to the wavelength of each sub-light source; when the light beam emitted by each sub-light source passes through the reference pattern, the measurement line pattern and the coding line pattern are formed and projected onto the scanned object.

21. The three-dimensional scanning system of claim 20, wherein, The reference pattern includes a fifth pattern area, a sixth pattern area, and a seventh pattern area; wherein, the fifth pattern area is coated with a first wavelength light-transmitting film, allowing only the first wavelength of light to pass through; the seventh pattern area is coated with a second wavelength light-transmitting film, allowing only the second wavelength of light to pass through; and the sixth pattern area is coated with a third wavelength light-transmitting film, allowing some of the first wavelength of light and some of the second wavelength of light to pass through.

22. The three-dimensional scanning system of claim 21, wherein, When the transmitter simultaneously turns on the first wavelength sub-light source and the second wavelength sub-light source, the light passes through each pattern area to obtain a measurement line pattern; when the transmitter turns on the first wavelength sub-light source or the second wavelength sub-light source, the light emitted by the first wavelength sub-light source or the second wavelength sub-light source passes through each pattern area to obtain an encoding line pattern.

23. The three-dimensional scanning system of claim 20, wherein, The reference pattern includes an eighth pattern area, a ninth pattern area, and a tenth pattern area; wherein, the eighth pattern area is uncoated and allows all wavelengths of light to pass through; the ninth pattern area is coated with a light-transmitting film that allows all first wavelengths of light to pass through and a portion of second wavelengths of light to pass through; and the tenth pattern area is coated with a light-transmitting film that allows all first wavelengths of light to pass through and does not allow second wavelengths of light to pass through.

24. The three-dimensional scanning system of claim 23, wherein, When the transmitter turns on the first wavelength sub-light source, the light emitted by the first wavelength sub-light source passes through each pattern area to obtain the measurement line pattern; when the transmitter turns on the second wavelength sub-light source, the light emitted by the second wavelength sub-light source passes through each pattern area to obtain the encoding line pattern.

25. The three-dimensional scanning system according to any one of claims 19 to 24, characterized in that, When the light beams emitted by the at least two sub-light sources have different wavelengths, the emitting end further includes a beam homogenizing and combining element, which is disposed between the light source and the pattern modulation element, for homogenizing the light beams emitted with different wavelengths and integrating them into the same optical path to propagate to the pattern modulation element.

26. The three-dimensional scanning system of claim 25, wherein, The beam-splitting element includes a beam-splitting element and a beam-combining element. The beam-splitting element is used to homogenize and collimate the light beam emitted by the light source to the beam-combining element. The beam-combining element is used to integrate the light beams emitted by different light sources after being collimated by the collimating element into the same optical path and project them onto the pattern modulation element.

27. The three-dimensional scanning system of claim 26, wherein, The light-diffusing element includes any one of a compound eye lens, a diffuser, or a microlens, and the beam-combining element includes a dichroic mirror or a prism.

28. The three-dimensional scanning system of any one of claims 26-27, wherein, When the wavelengths of the at least two sub-light sources are different, the at least two sub-light sources are a blue laser light source and a green laser light source, wherein the blue laser light source is used to form a blue light measurement line pattern, and the green laser light source is used to form a green light coding line pattern.

29. The three-dimensional scanning system of any one of claims 19-24, wherein, When the light beams emitted by the at least two sub-light sources have different wavelengths, the emitting end further includes a collimating and homogenizing section for collimating and homogenizing the light beams emitted by the light sources and propagating them to the pattern modulation element.

30. The three-dimensional scanning system of claim 29, wherein, The emitting end also includes a reflective element disposed in the optical path between the collimating and homogenizing section and the pattern modulation element, for reflecting the collimated and homogenized light beam to the pattern modulation element, thereby changing the emission optical path to achieve miniaturization.

31. The three-dimensional scanning system of claim 30, wherein, The transmitter also includes a beam combining element, used to receive the measurement line pattern and the coded line pattern modulated by the pattern modulation element, and to synthesize a composite line pattern beam and project it onto the object being scanned.

32. The three-dimensional scanning system of claim 31, wherein, The transmitting end also includes a semi-transparent and semi-reflective element, disposed between the pattern modulation element and the light combining element, for transmitting or reflecting the measurement line pattern or coding line pattern obtained by the pattern modulation element to the light combining element.

33. The three-dimensional scanning system of any one of claims 30-32, wherein, When the wavelengths of the at least two sub-light sources are different, the at least two sub-light sources are blue laser light sources with different wavelengths.

34. The three-dimensional scanning system of any one of claims 31-32, wherein, The transmitter also includes a projection lens, which is located on the light-emitting side of the light combining element. The image plane of the projection lens is located exactly on the light-emitting surface of the pattern modulation element, so that the coded line pattern is exactly distributed and arranged along the measurement line pattern.

35. The three-dimensional scanning system of any one of claims 1-3, wherein, The receiving end includes a black and white image sensor, which is used to acquire the composite line pattern beam reflected back by the scanned object and generate the composite line image, or only to acquire the measurement line pattern in the composite line pattern beam reflected back by the scanned object and generate the measurement line image.

36. The three-dimensional scanning system of claim 35, wherein, The black and white image sensor has a filter on the light-incident side to suppress background light noise, so that only the composite line pattern beam or the measurement line pattern in the composite line pattern beam passes through the filter and is acquired by the black and white image sensor.

37. The three-dimensional scanning system as described in claim 35, characterized in that, The receiving end also includes a color image sensor, which is used to acquire the texture of the scanned object.

38. The three-dimensional scanning system of claim 37, wherein, When the black-and-white image sensor is used only to acquire the measurement line pattern in the composite line pattern beam reflected back from the scanned object and generate a multi-line image, the color image sensor is also provided with a filter that matches the wavelength of the beam emitting the coded line pattern, so that the color image sensor is used only to acquire the coded line pattern in the composite line pattern beam.

39. The three-dimensional scanning system of claim 38, wherein, The receiving end also includes a beam splitter for splitting the reflected composite line pattern beam so that the measurement line pattern and the coded line pattern are acquired by the black-and-white image sensor and the color image sensor, respectively.

40. The three-dimensional scanning system of any one of claims 36-39, wherein, The receiving end also includes an imaging lens for focusing the composite line pattern beam reflected back from the scanned object onto the corresponding pixel in the image sensor.

41. The three-dimensional scanning system of any one of claims 37-39, wherein, The three-dimensional scanning system further includes an illumination unit, which includes an illumination source and a collimation element. The illumination source emits a light beam to the collimation element, and the light beam collimated by the collimation element provides ambient light for the scanned object.

42. The three-dimensional scanning system of any one of claims 37-39, wherein, The three-dimensional scanning system also includes a coaxial illumination unit, which is located on the light-incident side of the receiving end and is used to provide ambient light to the color image sensor so as to obtain a clear texture of the scanned object.

43. The three-dimensional scanning system of claim 42, wherein, The coaxial illumination unit includes an illumination source, a collimating lens, and a semi-transparent and semi-reflective optical element. The illumination source emits a light beam to the collimating lens, which then collimates the beam before it reaches the semi-transparent and semi-reflective optical element. A portion of the light beam is deflected by the semi-transparent and semi-reflective optical element to the object being scanned to provide supplemental illumination to the object.

44. The three-dimensional scanning system of any one of claims 1-3, wherein, The three-dimensional scanning system also includes a deflecting optical element, which is used to receive a light beam emitted by the transmitting end and reflect it to the object being scanned to achieve scanning of the object being scanned, and is also used to receive a light beam reflected back by the object being scanned and deflect it to the receiving end.

45. The three-dimensional scanning system of claim 44, wherein, The deflecting optical element includes any one of a rotating mirror, a reflecting mirror, a prism, or a MEMS.

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