Method and system for inhibiting strong mutual reflection based on polarization complementary logic coding

Abstract

The invention relates to a method and a system for inhibiting strong mutual reflection based on polarization complementary logic coding. The method comprises the following steps: acquiring calibration parameters of a camera and a projector; generating a polarization phase shift stripe based on the calibration parameter, designing a high-frequency complementary logic code word, and embedding the high-frequency complementary logic code word into a polarization channel through polarization modulation to obtain a composite stripe pattern; the method comprises the following steps: calculating to obtain a linear polarization degree image through an acquired multi-angle polarization image, extracting a high-reflection region from the linear polarization degree image by adopting an adaptive threshold segmentation method, and carrying out binarization processing on the linear polarization degree image to obtain a binarized linear polarization degree mask; and on the basis of a decoding range of a binary linear polarization degree mask constraint high-reflection region, decoding the composite stripe pattern to obtain absolute phase level information, and performing noise suppression on the absolute phase level information by adopting a self-adaptive threshold algorithm. The method can effectively solve the influence of mutual reflection and high dynamic range of the surfaces of the measured object, and improves the precision and stability of three-dimensional reconstruction.

Description

Technical Field

[0001] The present disclosure relates to the technical field of optical three-dimensional measurement, and in particular to a method and system for suppressing strong interreflection based on polarization complementary logic coding. Background Art

[0002] Fringe projection profilometry (FPP) is a non-contact optical 3D measurement technology. This technology projects structured light fringes onto the surface of an object through a projector, and then uses a camera to capture the deformed fringe image caused by the object's morphology. After phase extraction, phase unwrapping and system calibration, the 3D geometric information of the object is reconstructed. Due to its fast measurement speed, high accuracy and excellent resolution, FPP has been widely used in industrial inspection, reverse engineering and cultural heritage digitization.

[0003] In existing 3D reconstruction technology, there are often complex optical phenomena on the surface of the measured object, especially the problem of strong mutual reflection. Specifically, due to the irregular shape, high reflectivity and unevenness of the object surface, the incident light often undergoes multiple reflections and scattering between multiple surfaces, causing some light to mix with each other. This multipath reflection phenomenon not only causes obvious phase jumps in the collected images, but also introduces additional noise and edge blur, which greatly reduces the reconstruction accuracy of traditional fringe encoding and phase unwrapping technologies.

[0004] At present, common solutions mainly try to alleviate the interference caused by interreflection through local filtering or global optimization, but these methods are usually difficult to fundamentally eliminate the phase ambiguity and noise interference caused by multiple reflections, especially in complex lighting and high-reflection scenes. In addition, some methods may cause image details to be lost or edge information to be damaged during the processing process, which further affects the accuracy of the reconstruction results. Summary of the invention

[0005] In order to solve the problems of phase ambiguity caused by multiple reflections and phase jump and noise interference caused by mutual reflection in the traditional method based on fringe coding and phase unwrapping, the present disclosure proposes a method for suppressing strong mutual reflection based on polarization complementary logic coding to solve the above problems.

[0006] According to one aspect of the present disclosure, a method for suppressing strong interreflection based on polarization complementary logic coding is provided, comprising: S10, obtaining calibration parameters of the camera and the projector, wherein the calibration parameters are obtained by projecting a phase shift pattern and a Gray code pattern onto a calibration board; S20, generating polarization phase shift stripes based on the calibration parameters, designing high-frequency complementary logic codewords, embedding the high-frequency complementary logic codewords into polarization channels through polarization modulation, and obtaining a composite stripe pattern integrating polarization coding and high-frequency complementary logic codewords; S30, acquiring the collected multi-angle polarization image, calculating a linear polarization degree map through the multi-angle polarization image, extracting a high reflection area from the linear polarization degree map using an adaptive threshold segmentation method, and binarizing the linear polarization degree map to obtain a binary linear polarization degree mask, wherein the multi-angle polarization image is obtained by reflecting the composite fringe pattern through the surface of the object; S40, based on the binary linear polarization degree mask to constrain the decoding range of the high reflection area, the composite fringe pattern is decoded to obtain absolute phase order information, and the absolute phase order information is subjected to noise suppression by using an adaptive threshold algorithm.

[0007] Preferably, after step S40, the method further includes: performing phase unwrapping on the absolute phase order information, and generating a three-dimensional reconstructed point cloud based on the calibration parameters.

[0008] Preferably, obtaining calibration parameters of the camera and the projector includes: calibrating parameters of the camera and the projector according to the projected phase shift pattern and Gray code pattern, and then determining a mapping relationship between pixel coordinates and three-dimensional space.

[0009] Preferably, generating polarization phase shift fringes based on the calibration parameters includes: filtering out mirror reflection light interference through orthogonal polarizers, and generating polarization phase shift fringes in combination with a polarization phase shift structured light equation, wherein the polarization phase shift structured light equation is: , In the formula, is the background light intensity, is the stripe modulation degree, is the phase value caused by the surface of the measured object, N is the total number of phase shift steps, n For the n Index of the amplitude-phase shift plot.

[0010] Preferably, high-frequency complementary logic codewords are designed, and the complementary logic codewords are embedded in a polarization channel through polarization modulation to obtain a composite stripe pattern that integrates polarization coding and high-frequency complementary logic codewords, including: using high-frequency patterns to design complementary logic codewords, matching the codeword period with a defocus blur function, and embedding the complementary logic codewords into a polarization modulation channel so that the codeword intensity is associated with the local polarization response characteristics.

[0011] Preferably, binarizing the linear polarization degree map to obtain a binary linear polarization degree mask includes: calculating a dynamic threshold based on local linear polarization degree characteristics, comparing each pixel value of the linear polarization degree map with the dynamic threshold, and generating a binary linear polarization degree mask marking a high reflection area, which is expressed as: , In the formula, is the area threshold function, for The size of the area.

[0012] Preferably, the absolute phase order information is phase unwrapped, which is expressed as: , In the formula, is the truncated phase, is the fringe order of the first four patterns, This is the fringe order synthesized from the last four patterns.

[0013] According to one aspect of the present disclosure, a system for suppressing strong interreflection based on polarization complementary logic coding is provided, comprising: A calibration parameter acquisition module is used to acquire calibration parameters of the camera and the projector, wherein the calibration parameters are obtained by projecting a phase shift pattern and a Gray code pattern onto a calibration board; A composite stripe pattern calculation module generates polarization phase shift stripes based on the calibration parameters, designs high-frequency complementary logic codewords, embeds the high-frequency complementary logic codewords into polarization channels through polarization modulation, and obtains a composite stripe pattern integrating polarization coding and high-frequency complementary logic codewords; A binary linear polarization degree mask acquisition module is used to acquire the collected multi-angle polarization image, calculate a linear polarization degree map through the multi-angle polarization image, extract a high reflection area from the linear polarization degree map using an adaptive threshold segmentation method, and perform a binary linear polarization degree mask on the linear polarization degree map, wherein the multi-angle polarization image is obtained by reflecting the composite fringe pattern through the surface of the object; The absolute phase order information noise suppression module decodes the composite fringe pattern to obtain absolute phase order information based on a binary linear polarization degree mask to constrain the decoding range of the high reflection area, and adopts an adaptive threshold algorithm to suppress the noise of the absolute phase order information.

[0014] According to one aspect of the present disclosure, an electronic device is provided, comprising: a processor; and a memory for storing instructions executable by the processor; wherein the processor is configured to: execute the above-mentioned method for suppressing strong interreflection based on polarization complementary logic coding.

[0015] According to one aspect of the present disclosure, a computer-readable storage medium is provided, on which computer program instructions are stored. When the computer program instructions are executed by a processor, the method for suppressing strong interreflection based on polarization complementary logic coding is implemented.

[0016] Compared with the prior art, the beneficial effects of the present disclosure are: 1) The present invention can accurately identify and suppress mutual reflection noise and high dynamic areas by dynamically estimating the linear polarization degree and adjusting the polarization direction of the projected fringes in real time, thereby greatly improving the coding signal-to-noise ratio and providing cleaner image data for subsequent three-dimensional reconstruction.

[0017] 2) The composite coding strategy disclosed in the present invention combines polarization coding with high-frequency complementary logic codewords, which can not only effectively resist the stripe blur caused by defocusing, but also suppress high-light interference, ensuring the stability and accuracy of the encoded information under complex lighting conditions; polarization phase-shifted stripes can reduce ambient stray light or reflection interference and improve the signal-to-noise ratio.

[0018] 3) In the encoding stage, the present invention designs a special polarization complementary logic pattern and utilizes the difference of polarized light in different reflection paths to separate the main reflection signal from the secondary mutual reflection interference; in the decoding stage, an optimized algorithm is used to process the image data to further reduce the phase jump and noise interference caused by mutual reflection, thereby achieving high-precision and robust three-dimensional reconstruction.

[0019] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

[0020] Further features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings herein are incorporated into the specification and constitute a part of the specification. These drawings illustrate embodiments consistent with the present disclosure and are used to illustrate the technical solutions of the present disclosure together with the specification.

[0022] Figure 1 A flow chart of a method for suppressing strong interreflection based on polarization complementary logic coding is shown; Figure 2 A schematic diagram of a phase-shifted Gray code pattern used to determine the internal and external parameters of a projector and a camera in an example of the present disclosure is shown; Figure 3 A schematic diagram of a pattern for three-dimensional reconstruction of an object under test in an example of the present disclosure is shown; Figure 4 A complementary logic noise schematic diagram in an example of the present disclosure is shown; Figure 5 A schematic diagram showing the error analysis results of the standard metal gauge block experiment in the disclosed example is shown; Figure 6 A schematic diagram of the three-dimensional reconstruction results of a complex metal experiment in an example of the present disclosure is shown; Figure 7 A structural block diagram of a system for suppressing strong interreflection based on polarization complementary logic coding in an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0023] Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0024] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0025] The term "and / or" herein is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the term "at least one" herein represents any combination of at least two of any one or more of a plurality of. For example, including at least one of A, B, and C can represent including any one or more elements selected from the set consisting of A, B, and C.

[0026] In addition, in order to better illustrate the present disclosure, numerous specific details are given in the following specific embodiments. It should be understood by those skilled in the art that the present disclosure can also be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present disclosure.

[0027] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] Example 1 Based on the above ideas, the present invention proposes a method for suppressing strong interreflection based on polarization complementary logic coding. Figure 1 A flow chart of a method for suppressing strong interreflection based on polarization complementary logic coding is shown. The method comprises: S10, obtaining calibration parameters of the camera and the projector, wherein the calibration parameters are obtained by projecting a phase shift pattern and a Gray code pattern onto a calibration board; S20, generating polarization phase shift stripes based on the calibration parameters, designing high-frequency complementary logic codewords, embedding the high-frequency complementary logic codewords into polarization channels through polarization modulation, and obtaining a composite stripe pattern integrating polarization coding and high-frequency complementary logic codewords; S30, acquiring the collected multi-angle polarization image, calculating a linear polarization degree map through the multi-angle polarization image, extracting a high reflection area from the linear polarization degree map using an adaptive threshold segmentation method, and binarizing the linear polarization degree map to obtain a binary linear polarization degree mask, wherein the multi-angle polarization image is obtained by reflecting the composite fringe pattern through the surface of the object; S40, based on the binary linear polarization degree mask to constrain the decoding range of the high reflection area, the composite fringe pattern is decoded to obtain absolute phase order information, and the absolute phase order information is subjected to noise suppression by using an adaptive threshold algorithm.

[0029] The disclosed embodiment provides a method for suppressing strong interreflection based on polarization complementary logic coding. The method gradually converts the original image into a high-precision three-dimensional point cloud through multi-step collaborative processing. The core process is as follows: First, a camera-projector system with orthogonal polarization configuration is used to collect a target object image sequence modulated by a polarization complementary logic composite coding pattern, wherein the original image contains polarization phase shift stripes and high-frequency complementary logic codewords (such as XOR coding patterns); the wrapped phase is extracted from the polarization phase shift stripes; the degree of linear polarization (DOLP) is further calculated, the high-reflection area is segmented and dynamically binarized, and the binarization result is used to distinguish The effective signal and noise areas are divided into two areas; secondly, the high-frequency complementary logic pattern (such as XOR code) is decoded, and the XOR operation result is converted into Gray code. The decoding process needs to be combined with polarization information to avoid code confusion caused by mutual reflection; then, the adaptive threshold algorithm and area threshold filtering are used to eliminate isolated noise and uneven illumination interference in the decoded image. The image after eliminating the decoded image retains the effective coding area and provides clean data for phase unfolding; the decoded Gray code is combined with the polarization constraint to robustly unfold the wrapped phase, eliminate the jump error, and finally convert the phase into a three-dimensional point cloud through calibration parameters to complete the reconstruction. The method for suppressing strong interreflection based on polarization complementary logic coding includes the following steps: S10, obtaining calibration parameters of the camera and the projector, wherein the calibration parameters are obtained by projecting a phase shift pattern and a Gray code pattern onto a calibration board.

[0030] In this embodiment, the optical centers of the projector and the camera are placed on the same horizontal line and aimed at the object to be measured. The angle between the two is about 10° and the distance is about 15 cm. First, place the center calibration plate at the object to be measured and adjust the focal length of the camera and projector to ensure that the edge of the dot is clearly visible. Next, project the Figure 2 The 36 phase-shifted Gray code patterns shown. By shooting n groups (n>6) of patterns, the internal and external parameters of the system can be calculated to complete the calibration and establish the geometric relationship between the camera and the projector.

[0031] In order to improve the accuracy of the measurement, the system needs to be accurately calibrated during the acquisition process. The calibration process includes the calibration of the camera's internal and external parameters to ensure the accurate mapping of the camera coordinate system to the world coordinate system; at the same time, the projection stripes of the projector need to be calibrated to ensure the correspondence between the collected image data and the projection stripes, providing accurate geometric information for subsequent three-dimensional reconstruction. According to the projected phase shift pattern and Gray code pattern, the parameters of the camera and projector are calibrated, and then the mapping relationship between the pixel coordinates and the three-dimensional space is determined as follows: , In the formula, , is the pixel coordinate of the three-dimensional point after being projected onto the image plane, , and is the point coordinate in three-dimensional space relative to the camera coordinate system, , is the product of focal length and pixel scaling, , is the principal point coordinate, that is, the position of the image center in pixel coordinates, is the camera intrinsic parameter matrix.

[0032] In this embodiment, the projector is an LCD projector, and the polarization state of its output is linear polarized light. According to Malus's law, by placing polarizers at different angles to receive the target pattern, the interference of the polarizers rotated 90 degrees can effectively filter the influence of the reverse mirror mutual reflection light.

[0033] The counter-rotating specular reflection light is expressed as: , In the formula, is the angle of the camera at the polarizer, is the angle of the projector at the polarizer, Indicates the phase, is the strength of the counterclockwise rotation component.

[0034] The specular reflection light with positive rotation is expressed as: , In the formula, is the phase, usually zero, is the strength of the clockwise rotation component.

[0035] The formula for the light intensity received by the camera is: , In the formula, is the non-polarized light component.

[0036] The time-sharing multi-frame coding acquisition strategy is adopted to capture the three-dimensional information of the object under test by designing 7 groups of structured light coding patterns with specific phase relationships. Combined with complementary logic modulation technology, the dual constraint relationship between light intensity and polarization state is constructed in the time dimension, and the principle of polarization interference is used to suppress the specular reflection component at the physical layer. By establishing a multi-frame coded light intensity response model, the single reflection signal and multiple mutual reflection interference signals on the target surface can be effectively separated, significantly reducing the problem of excessive dynamic range in local areas caused by differences in optical properties of the material surface.

[0037] S20, generating polarization phase shift stripes based on the calibration parameters, designing high-frequency complementary logic codewords, embedding the high-frequency complementary logic codewords into polarization channels through polarization modulation, and obtaining a composite stripe pattern integrating polarization coding and high-frequency complementary logic codewords.

[0038] Many traditional measurement techniques usually assume ideal conditions in the measurement environment and ignore the effects of mutual reflection and local saturation. However, in complex measurement objects and challenging environments, global illumination effects can significantly reduce the accuracy and performance of structured light technology. To solve this problem, a common approach is to use polarization technology, which can significantly improve the anti-interference ability of structured light measurement. Another widely used solution is to set the frequency of the projected pattern to be higher than the optical transmission bandwidth of the measurement scene. The complementary logic coding method aims to increase the frequency of the coding pattern to reduce the impact of multiple reflections on the metal surface. The method proposed in this embodiment combines their advantages, and filters out the reverse rotating mirror reflection light through orthogonal polarization, and uses polarization phase shift technology to achieve full polarization coding.

[0039] In the embodiment of the present disclosure, by adjusting the polarization direction and the design of high-frequency complementary logic codewords, the coded stripes are projected onto the surface of the target object to generate a hybrid coded stripe pattern with high anti-interference ability, ensuring that the image quality can still be effectively controlled under complex lighting. Among them, the 10 composite stripe patterns used for 3D reconstruction of the object under test are as follows: Figure 3 shown.

[0040] The intensity of the three-step phase-shifted sinusoidal fringe image is: , In the formula, is the average light intensity, is the stripe modulation degree, is the phase value caused by the surface of the object being measured.

[0041] Different from the traditional black and white stripes, the polarization phase shift stripes are used in this embodiment. The polarization beam splitting technology can separate the object light and the reference light, reduce the ambient stray light or reflection interference, and improve the signal-to-noise ratio. and They are all vectors. After superposition for: , In the formula, is the Stokes intensity parameter of the projector's horizontal polarization state, is the Stokes intensity parameter of the projector's vertical polarization state.

[0042] The orthogonal polarizers are used to filter out the interference of the mirror reflection light, and the polarization phase shift stripes are generated by combining the polarization phase shift structured light equation. The polarization phase shift structured light equation is: , In the formula, is the background light intensity, is the stripe modulation degree, is the phase value caused by the surface of the measured object, N is the total number of phase shift steps, n For the n Index of the amplitude-phase shift plot.

[0043] In the disclosed embodiment, by integrating polarization characteristic analysis with high-frequency complementary logic coding, the problems of mutual reflection and high dynamic range on the surface of the object under test in a complex lighting environment are effectively solved. The core steps are as follows: using a linear polarizer group to collect a polarization image sequence of the target; making a polarization complementary logic pattern; and designing a polarization-complementary logic composite code.

[0044] The color information is processed based on complementary logic operation. The basic principle is to regard the value of each color channel (RGB) as a binary number and use the characteristics of complementary logic operation: for two binary bits, if they are the same, output 0, and if they are different, output 1. Let A and B be two color pixels, and their RGB components are represented as and The color complementary logic operation is performed independently for each channel: , In the formula, is the value of the red channel at point A, is the value of the red channel at point B, is the value of the green channel at point A, is the value of the green channel at point B, is the value of the blue channel at point A, is the value of the blue channel at point B.

[0045] In the color XOR logic processing, the value of each color channel is first converted into the corresponding 8-bit binary representation, and then the XOR logic operation is performed bit by bit on the binary values ​​of the corresponding channels of the two pixels to generate a new binary result. Next, the XOR logic result of each channel is converted from binary form back to a decimal value, and finally a new RGB color value is constructed. This process is completed independently on each color channel, effectively realizing the encoding and processing of color information.

[0046] Furthermore, by combining polarization coding with high-frequency complementary logic codewords, the complementary logic coding method aims to increase the frequency of the coding pattern to reduce the impact of mutual reflection and high dynamic range; the effect of polarization coding effectively reduces the interference of ambient light, and combining the two to generate composite coding stripes greatly improves the robustness to ambient light interference and reduces the impact of mutual reflection on three-dimensional reconstruction.

[0047] Designing high-frequency complementary logic codewords, embedding the complementary logic codewords into a polarization channel through polarization modulation, and obtaining a composite stripe pattern integrating polarization coding and high-frequency complementary logic codewords, including: using high-frequency patterns to design complementary logic codewords, matching the codeword period with a defocus blur function, embedding the complementary logic codewords into a polarization modulation channel, making the codeword intensity correlated with the local polarization response characteristics, and the frequencies of different patterns are related in the following ways: , In the formula, is the frequency of the pattern after pattern conversion, is the sinusoidal fringe frequency of the pattern, is the template frequency of the pattern, N is the total number of phase shift steps.

[0048] To avoid errors caused by local illumination saturation, the frequency of the projected pattern must comply with the constraints .

[0049] Since polarization complementary logic encoding has high-frequency information, the use of image enhancement technology can effectively reduce the noise generated in the subsequent decoding of complementary logic, and mutual reflection often leads to local image saturation. The method in this embodiment can effectively eliminate these interference information and provide a clean data basis for subsequent encoding.

[0050] S30, acquiring the collected multi-angle polarization image, calculating a linear polarization degree map through the multi-angle polarization image, extracting a high-reflection area from the linear polarization degree map using an adaptive threshold segmentation method, and binarizing the linear polarization degree map to obtain a binary linear polarization degree mask, wherein the multi-angle polarization image is obtained by reflecting the composite stripe pattern through the surface of the object.

[0051] In this embodiment, the collected polarization image is processed to calculate the linear polarization degree of each pixel. The linear polarization degree reflects the degree of polarization of light and can effectively distinguish the reflection characteristics of different surface areas. The high-reflection area is identified by calculating the linear polarization value, and an adaptive threshold segmentation method is further used to remove the influence of mutual reflection noise on the image.

[0052] High-reflection areas are identified through threshold segmentation to suppress mutual reflection noise. The linear polarization degree is a physical quantity that characterizes the state of polarized light and is used to describe the degree of linear polarization at a specific azimuth angle. Specifically: , In the formula, is the maximum light intensity, is the minimum light intensity.

[0053] The collected polarization images are used to calculate the linear polarization degree of each pixel, and the adaptive threshold segmentation method is used to accurately identify the high-reflection area.

[0054] Since polarization complementary logic coding has high-frequency information, the use of image enhancement technology can effectively reduce the noise generated in the subsequent complementary logic decoding. In addition, mutual reflection often leads to local image saturation. This method can effectively eliminate these interference information and provide a clean data basis for subsequent encoding.

[0055] The polarization direction of the projected fringes is dynamically adjusted based on the linear polarization degree distribution to optimize the signal-to-noise ratio of the target area. Specifically: , In the formula, is the light intensity of the XOR pattern with a polarization angle of 90 degrees, is the light intensity of the XOR pattern with a polarization angle of 0 degrees.

[0056] S40, based on the binary linear polarization degree mask to constrain the decoding range of the high reflection area, the composite fringe pattern is decoded to obtain absolute phase order information, and the absolute phase order information is subjected to noise suppression by using an adaptive threshold algorithm.

[0057] In this embodiment, the binarized pattern is decoded by a complementary pattern, and then an adaptive threshold algorithm is applied to suppress noise in the image containing Gray code modulation. In order to solve the possible errors when converting the captured XOR pattern into a Gray code pattern, this embodiment proposes to reduce the interference in the image by noise suppression to ensure the accuracy of the pattern, and then use the area threshold function to remove errors caused by uneven illumination and noise, thereby improving the accuracy and robustness of the conversion.

[0058] When converting the captured complementary logic pattern into a Gray code pattern, compensation or adjustment is required to ensure that the final encoding result is accurate. This is because in the actual encoding process, the complementary logic pattern may be affected by noise, ambient light or other interference factors, resulting in a deviation between the generated pattern and the ideal code. Figure 4 As shown, if these errors are not corrected, they may cause errors in the subsequent decoding process and affect the overall accuracy. By correcting these errors, the compensation step ensures that the final Gray code pattern can better reflect the original information and optimize the efficiency and accuracy of the subsequent decoding process.

[0059] The binarization threshold is dynamically adjusted according to the local linear polarization value to eliminate edge noise in the complementary logic decoding process and compensate for codeword blur caused by defocusing. Specifically: , In the formula, is the binarization image function, is the noise area generated by XOR stripes, is the area function.

[0060] The linear polarization degree map is binarized to obtain a binary linear polarization degree mask, including: calculating a dynamic threshold based on local linear polarization degree characteristics, comparing each pixel value of the linear polarization degree map with the dynamic threshold, and generating a binary linear polarization degree mask marking a high reflection area, which is expressed as: , In the formula, is the area threshold function, for The size of the area.

[0061] After step S40, phase unwrapping is performed on the absolute phase order information, and a three-dimensional reconstructed point cloud is generated based on the calibration parameters.

[0062] In this embodiment, the coded stripes are solved by the phase unwrapping algorithm to restore the phase information of the target object surface. In the phase unwrapping process, constraints are added to suppress the phase jump problem caused by multipath reflection and mutual reflection, thereby improving the accuracy and stability of phase solution. The absolute phase level information is phase unwrapped, which is expressed as: , In the formula, is the truncated phase, is the fringe order of the first four patterns, This is the fringe order synthesized from the last four patterns.

[0063] Specifically, and The interval is half a period, only The periodic order of the interval is used to assign the truncated phase, and The periodic order of the interval is used to determine the values ​​of other parts, which can effectively avoid using the phase truncation. The cycle order is thus fundamentally eliminated, which results in jump errors caused by phase cycle encoding errors.

[0064] The disclosed embodiment is verified by conducting experiments on metal cylinders and metal standard gauge blocks. Figure 5 The reconstruction results of the standard gauge block are shown. The standard plane of the metal plate is fitted. The RMSE values ​​obtained by the three reconstruction methods are 0.2749, 0.1899 and 0.1475 respectively. The measurement error of this embodiment is Figure 5 As shown in (g), the error distribution is the smallest and the RMSE is 0.1475. Figure 6 The reconstruction results of complex metals using this embodiment and traditional complementary Gray codes are demonstrated, and experiments prove that the disclosed embodiment can reconstruct objects with high robustness.

[0065] Example 2 As another aspect of the embodiments of the present disclosure, a strong mutual reflection suppression system 100 based on polarization complementary logic coding is also provided. Figure 7 As shown, including: A calibration parameter acquisition module 1 is used to acquire calibration parameters of a camera and a projector, wherein the calibration parameters are obtained by projecting a phase shift pattern and a Gray code pattern onto a calibration board; The composite stripe pattern calculation module 2 generates polarization phase shift stripes based on the calibration parameters, designs high-frequency complementary logic codewords, embeds the high-frequency complementary logic codewords into the polarization channel through polarization modulation, and obtains a composite stripe pattern integrating polarization coding and high-frequency complementary logic codewords; A binary linear polarization degree mask acquisition module 3 acquires the collected multi-angle polarization image, calculates a linear polarization degree map through the multi-angle polarization image, extracts a high reflection area from the linear polarization degree map using an adaptive threshold segmentation method, and performs a binary linear polarization degree mask on the linear polarization degree map, wherein the multi-angle polarization image is obtained by reflecting the composite fringe pattern through the surface of the object; The absolute phase order information noise suppression module 4 decodes the composite fringe pattern to obtain absolute phase order information based on the binary linear polarization degree mask to constrain the decoding range of the high reflection area, and adopts an adaptive threshold algorithm to suppress the noise of the absolute phase order information.

[0066] In the absence of any contradiction, the above modules in the system of the embodiment of the present disclosure can implement any implementation of the above method.

[0067] Based on the description of the above embodiments, it can be seen that the embodiments of the present disclosure can achieve the following technical effects: 1) The present invention can accurately identify and suppress mutual reflection noise and high dynamic areas by dynamically estimating the linear polarization degree and adjusting the polarization direction of the projected fringes in real time, thereby greatly improving the coding signal-to-noise ratio and providing cleaner image data for subsequent three-dimensional reconstruction.

[0068] 2) The composite coding strategy disclosed in the present invention combines polarization coding with high-frequency complementary logic codewords, which can not only effectively resist the stripe blur caused by defocusing, but also suppress high-light interference, ensuring the stability and accuracy of the encoded information under complex lighting conditions; polarization phase-shifted stripes can reduce ambient stray light or reflection interference and improve the signal-to-noise ratio.

[0069] 3) In the encoding stage, the present invention designs a special polarization complementary logic pattern and utilizes the difference of polarized light in different reflection paths to separate the main reflection signal from the secondary mutual reflection interference; in the decoding stage, an optimized algorithm is used to process the image data to further reduce the phase jump and noise interference caused by mutual reflection, thereby achieving high-precision and robust three-dimensional reconstruction.

[0070] The embodiment of the present disclosure also proposes an electronic device, comprising: a processor; a memory for storing instructions executable by the processor; wherein the processor is configured to implement the above-mentioned method for suppressing strong interreflection based on polarization complementary logic coding. The electronic device can be provided as a terminal, a server, or other forms of equipment.

[0071] The present disclosure also provides a computer-readable storage medium on which computer program instructions are stored, and when the computer program instructions are executed by a processor, the method for suppressing strong interreflection based on polarization complementary logic coding is implemented. The computer-readable storage medium may be a non-volatile computer-readable storage medium.

[0072] Those skilled in the art will understand that in the above-mentioned method and system for suppressing strong interreflection based on polarization complementary logic coding in the specific implementation mode, the writing order of each step does not mean a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of each step should be determined by its function and possible internal logic.

[0073] The flow chart and block diagram in the accompanying drawings show the possible architecture, function and operation of the system, method and computer program product according to multiple embodiments of the present disclosure. In this regard, each square box in the flow chart or block diagram can represent a part of a module, program segment or instruction, and a part of the module, program segment or instruction includes one or more executable instructions for realizing the specified logical function. In some alternative implementations, the function marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two continuous square boxes can actually be executed substantially in parallel, and they can sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs the specified function or action, or can be implemented with a combination of special hardware and computer instructions.

[0074] The embodiments of the present disclosure have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for suppressing strong interreflection based on polarization complementary logic coding, characterized in that: The steps include: S10, obtaining calibration parameters of the camera and the projector, wherein the calibration parameters are obtained by projecting a phase shift pattern and a Gray code pattern onto a calibration board; S20, generating polarization phase shift stripes based on the calibration parameters, designing high-frequency complementary logic codewords, embedding the high-frequency complementary logic codewords into polarization channels through polarization modulation, and obtaining a composite stripe pattern integrating polarization coding and high-frequency complementary logic codewords; S30, acquiring the collected multi-angle polarization image, calculating a linear polarization degree map through the multi-angle polarization image, extracting a high reflection area from the linear polarization degree map using an adaptive threshold segmentation method, and binarizing the linear polarization degree map to obtain a binary linear polarization degree mask, wherein the multi-angle polarization image is obtained by reflecting the composite fringe pattern through the surface of the object; S40, based on the binary linear polarization degree mask to constrain the decoding range of the high reflection area, the composite fringe pattern is decoded to obtain absolute phase order information, and the absolute phase order information is subjected to noise suppression by using an adaptive threshold algorithm.

2. The method according to claim 1, characterized in that After step S40, the method further includes: performing phase unwrapping on the absolute phase order information, and generating a three-dimensional reconstructed point cloud based on the calibration parameters.

3. The method according to claim 1, characterized in that The calibration parameters of the camera and the projector are obtained, including: calibrating the parameters of the camera and the projector according to the projected phase shift pattern and Gray code pattern, and then determining the mapping relationship between the pixel coordinates and the three-dimensional space.

4. The method according to any one of claims 1 or 3, characterized in that: The polarization phase shift fringes are generated based on the calibration parameters, including: filtering out the interference of mirror reflection light by orthogonal polarizers, and generating polarization phase shift fringes in combination with a polarization phase shift structured light equation, wherein the polarization phase shift structured light equation is: ， In the formula, is the background light intensity, For the stripe modulation, is the phase value caused by the surface of the measured object, N is the total number of phase shift steps, n For the n Index of the amplitude-phase shift plot.

5. The method according to claim 1, characterized in that High-frequency complementary logic codewords are designed, and the complementary logic codewords are embedded in a polarization channel through polarization modulation to obtain a composite stripe pattern that integrates polarization coding and high-frequency complementary logic codewords, including: using high-frequency patterns to design complementary logic codewords, matching the codeword period with a defocus blur function, and embedding the complementary logic codewords into a polarization modulation channel so that the codeword intensity is associated with the local polarization response characteristics.

6. The method according to claim 1, characterized in that The linear polarization degree map is binarized to obtain a binary linear polarization degree mask, including: calculating a dynamic threshold based on local linear polarization degree characteristics, comparing each pixel value of the linear polarization degree map with the dynamic threshold, and generating a binary linear polarization degree mask marking a high reflection area, which is expressed as: ， In the formula, is the area threshold function, for The size of the area.

7. The method according to claim 2, characterized in that The absolute phase order information is phase unwrapped and expressed as: ， In the formula, is the truncated phase, is the fringe order of the first four patterns, The fringe order of the last four patterns.

8. A system for suppressing strong interreflection based on polarization complementary logic coding, characterized in that: include: A calibration parameter acquisition module is used to acquire calibration parameters of the camera and the projector, wherein the calibration parameters are obtained by projecting a phase shift pattern and a Gray code pattern onto a calibration board; A composite stripe pattern calculation module generates polarization phase shift stripes based on the calibration parameters, designs high-frequency complementary logic codewords, embeds the high-frequency complementary logic codewords into polarization channels through polarization modulation, and obtains a composite stripe pattern integrating polarization coding and high-frequency complementary logic codewords; A binary linear polarization degree mask acquisition module is used to acquire the collected multi-angle polarization image, calculate a linear polarization degree map through the multi-angle polarization image, extract a high reflection area from the linear polarization degree map using an adaptive threshold segmentation method, and perform a binary linear polarization degree mask on the linear polarization degree map, wherein the multi-angle polarization image is obtained by reflecting the composite fringe pattern through the surface of the object; The absolute phase order information noise suppression module decodes the composite fringe pattern to obtain absolute phase order information based on a binary linear polarization degree mask to constrain the decoding range of the high reflection area, and adopts an adaptive threshold algorithm to suppress the noise of the absolute phase order information.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method for suppressing strong interreflection based on polarization complementary logic coding as described in any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method for suppressing strong interreflection based on polarization complementary logic coding as described in any one of claims 1 to 7 is implemented.

Images