Counter sinking point cloud rapid acquisition method based on coding structured light

Abstract

The invention discloses a counter sinking point cloud rapid acquisition method based on coding structured light, and the method comprises the steps: designing and generating specific coding structured light, irradiating the specific coding structured light to the surface of a nest hole, and forming a light spot with a specific mode and a coding sequence; heterodyne operation is carried out through wrapping phases outside multiple frequencies, so that absolute phase information of the countersink surface is obtained; then multi-view stereo matching is carried out on the modulated image on the basis of structured light multi-view imaging to obtain matched pixel point sets located at the same spot facing position, parallax between the matched pixel point sets is calculated to measure depth information of the spot facing surface, and three-dimensional point cloud data of the spot facing surface are obtained on the basis of the depth information; reconstructing the three-dimensional point cloud data to obtain a complete three-dimensional point cloud model of the countersink, and further obtaining size information of the countersink; the device has the characteristics of high precision, rapidness, stability and the like, realizes high-precision and high-efficiency detection of the dimple depth, further realizes automatic assembly of large thin-walled parts, improves the efficiency, and reduces the labor cost.

Description

Technical Field

[0001] The invention belongs to the technical field of countersunk hole vision detection, and particularly relates to a method for quickly obtaining a countersunk hole point cloud based on coded structured light. Background Art

[0002] Since there is no directly measurable reference plane for the conical countersunk hole, the traditional general caliper cannot directly measure the depth of the countersunk hole, and usually some special measuring tools need to be used. At present, the detection of the depth of the countersunk hole mainly relies on manual sampling inspection, and the staff uses a sleeve, a steel ball and a micrometer to indirectly measure the depth value. However, this method is easily affected by physiological factors such as the visual fatigue of the staff and individual differences, resulting in missed inspections or misinspections, making the detection results different and unable to meet the requirements of modern industry for fast, precise and accurate detection and measurement.

[0003] The vision detection of the countersunk hole based on an industrial camera has been widely applied and popularized. This non-contact detection method has the characteristics of high precision, speed and stability. However, the traditional methods for detecting countersunk holes mainly include contact type, monocular structured light system, point laser scanning, etc., but they are respectively limited by low efficiency and easy to be affected by operation errors; the viewing angle is limited, and there is a large measurement blind area when encountering hole edges, shadows or deep cavities; the accuracy is easily affected by surface reflection and tilt angle. And using a specific structured light fusion binocular stereo vision system for countersunk hole detection has the following advantages: 1. Enhance the detection ability of deep holes and inclined planes: binocular imaging compensates for the measurement blind area of the monocular structured light; 2. High phase and 3D reconstruction accuracy: the specific structured light pattern design combined with the absolute phase decoding algorithm improves the 3D reconstruction accuracy. 3. Non-contact, high speed and high automation: suitable for on-line detection and embedded industrial detection, and the efficiency is much higher than the traditional scheme.

[0004] Therefore, the invention discloses a method for quickly obtaining a countersunk hole point cloud based on coded structured light. Summary of the Invention

[0005] The invention discloses a method for quickly obtaining a countersunk hole point cloud based on coded structured light. A detection device is built based on structured light binocular imaging, and image processing algorithms are comprehensively used to realize high-precision and high-efficiency detection of the depth of the countersunk hole.

[0006] The invention is realized through the following technical solutions: A method for quickly obtaining the countersunk hole point cloud based on coded structured light irradiates the surface of the countersunk hole with structured light having a specific code to obtain a modulated image, calculates the wrapped phase using the light intensity information in the modulated image, performs heterodyne operation on the wrapped phases at different frequencies to obtain the absolute phase, stereoscopically matches the matching pixel point sets located at the same countersunk hole position under multiple perspectives based on the absolute phase, calculates the disparity between the matching pixel point sets to measure the depth information of the countersunk hole surface, and obtains the three-dimensional point cloud data of the countersunk hole surface based on the depth information; after processing the three-dimensional point cloud data, a three-dimensional point cloud model of the countersunk hole is obtained, and the dimension information of the countersunk hole is obtained based on the three-dimensional point cloud model.

[0007] To better implement the present invention, further, it specifically includes the following steps: Step 1: Generate multi-frequency heterodyne coded structured light with specific spectral characteristics, time domain characteristics, and amplitude characteristics, irradiate the surface of the countersunk hole with the multi-frequency heterodyne coded structured light, and use a camera to collect the modulated image; Step 2: Perform Fourier transform on the light intensity information in the modulated image to obtain the wrapped phase; Step 3: Use the multi-frequency heterodyne algorithm to unwrap the wrapped phase and obtain the absolute phase; Step 4: Perform multi-perspective stereo matching on the modulated images from different perspectives to obtain the matching pixel point sets located at the same countersunk hole position, calculate the disparity between the matching pixel point sets to measure the depth information of the countersunk hole surface, and obtain the three-dimensional point cloud data of the countersunk hole surface based on the depth information; Step 5: Reconstruct the three-dimensional point cloud data to obtain a complete three-dimensional point cloud model of the countersunk hole, and obtain the dimension information of the countersunk hole based on the three-dimensional point cloud model.

[0008] To better implement the present invention, further, the specific steps of Step 1 include: Step A1: Set the sine function, and cyclically calculate the values of the sine function according to the frequency list, time range, and step size of the required multi-frequency heterodyne structured light; Step A2: Superimpose the component signals at different frequencies to form the initial multi-frequency heterodyne coded structured light; Step A3: Adjust the frequency, time range, and modulation amplitude of the initial multi-frequency heterodyne coded structured light to obtain different multi-frequency heterodyne coded structured lights with specific spectral characteristics, time domain characteristics, and amplitude characteristics; Step A4: Write the multi-frequency heterodyne coded structured light into the projector, and irradiate the surface of the countersunk hole with the multi-frequency heterodyne coded structured light through the projector to form a modulated image with a specific pattern and coding sequence; Step A5: Use a camera to collect the modulated image.

[0009] To better implement the present invention, further, the specific steps of Step 2 include: Step B1: Use multiple cameras to collect modulated images from different perspectives, and perform filtering on the modulated images to enhance the extraction accuracy of subsequent phase information; Step B2: Perform Fourier transform on the light intensity information in the modulated images from different perspectives to obtain the sine phase component and cosine phase component of the modulated images, and accumulate the sine phase component and cosine phase component to calculate the phase matrix; Step B3: Calculate the modulation degree of the modulated images using a modulation degree calculation function based on the sine phase component and cosine phase component; Step B4: Set a modulation degree threshold and create a mask matrix, and filter the components in the phase matrix with a modulation degree lower than the modulation degree threshold through the modulation degree threshold and the mask matrix to obtain the wrapped phase.

[0010] To better implement the present invention, further, the modulation degree calculation function is specifically: ; where: B represents the modulation degree; N represents the number of phase shift steps; k represents the k-th phase shift step, k = 0, 1,..., N - 1; I k represents the intensity of the k-th phase shift.

[0011] To better implement the present invention, further, step 3 specifically includes: Step C1: For the modulated images collected from different perspectives, use a multi-frequency phase algorithm to combine the phase information at different frequencies; Step C2: Use sine gratings of several different frequencies to perform phase difference processing on the combined phase information, so that the phase difference signal can cover the entire field of view; Step C3: Based on the phase difference signal, solve the absolute phase distribution information of the modulated images, and perform heterodyne operation on the wrapped phases at different frequencies to obtain the absolute phase of the countersunk hole surface.

[0012] To better implement the present invention, further, step 4 specifically includes: Step D1: Identify and match the pixel points located at the same countersunk hole position under multiple camera perspectives, and aggregate all the pixel points located at the same countersunk hole position into a set of matching pixel points; Step D2: Calculate the parallax of each pixel point in the set of matching pixel points to obtain the pixel offset of each pixel point in different modulated images; Step D3: Based on the pixel offset, use triangulation to measure the depth information of the countersunk hole surface, and obtain the three-dimensional point cloud data of the countersunk hole surface based on the depth information.

[0013] To better implement the present invention, further, the three-dimensional point cloud data in step 4 is filtered to eliminate abnormal pixel points that deviate from the matching pixel point set by an excessive amount.

[0014] To better implement the present invention, further, the absolute phase includes the actual absolute phase and the ideal absolute phase, and the actual absolute phase and the ideal absolute phase are normalized to the range of [0, 2π].

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects: The present invention uses an efficient automatic calibration algorithm to determine the internal and external parameters of the camera, designs and generates a specific coded structured light to irradiate the surface of the countersunk hole, forming a light spot with a specific pattern and coding sequence; performs heterodyne operation on the wrapped phase outside multiple frequencies to obtain the absolute phase information of the countersunk hole surface; then performs multi-view stereo matching on the modulated image based on the structured light multi-view imaging to obtain a set of matching pixel points located at the same countersunk hole position, calculates the disparity between the matching pixel point sets to measure the depth information of the countersunk hole surface, and obtains the three-dimensional point cloud data of the countersunk hole surface based on the depth information; reconstructs the three-dimensional point cloud data to obtain a complete three-dimensional point cloud model of the countersunk hole, and obtains the size information of the countersunk hole based on the three-dimensional point cloud model; the present invention has the characteristics of high precision, speed and stability, realizes the high-precision and high-efficiency detection of the countersunk depth, and further realizes the automatic assembly of large thin-walled parts, improving the efficiency and reducing the labor cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic flow chart of the steps of the present invention; Figure 2 is a schematic diagram of the three-dimensional point cloud model of the countersunk hole. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] Example 1: A method for quickly obtaining the point cloud of a countersunk hole based on coded structured light in this embodiment irradiates the surface of the countersunk hole with structured light having a specific code to obtain a modulated image, calculates the wrapped phase using the light intensity information in the modulated image, performs heterodyne operation on the wrapped phases at different frequencies to obtain the absolute phase, performs multi-view stereo matching on the modulated image based on the absolute phase to obtain a set of matching pixel points located at the same countersunk hole position, calculates the disparity between the matching pixel point sets to measure the depth information of the countersunk hole surface, and obtains the three-dimensional point cloud data of the countersunk hole surface based on the depth information; processes the three-dimensional point cloud data to obtain a three-dimensional point cloud model of the countersunk hole, and obtains the size information of the countersunk hole based on the three-dimensional point cloud model.

[0018] As Figure 1 shown, it specifically includes the following steps: Step 1: Generate multi-frequency heterodyne coded structured light with specific spectral characteristics, time-domain characteristics, and amplitude characteristics. Use the multi-frequency heterodyne coded structured light to irradiate the surface of the countersunk hole, and collect the modulated image using a camera. Step 2: Perform Fourier transform on the light intensity information in the modulated image to obtain the wrapped phase. Step 3: Use the multi-frequency heterodyne algorithm to unwrap the wrapped phase and obtain the absolute phase. Step 4: Perform multi-view stereo matching on the modulated images from different perspectives to obtain a set of matching pixel points at the same countersunk hole position. Calculate the disparity between the sets of matching pixel points to measure the depth information of the countersunk hole surface, and obtain the three-dimensional point cloud data of the countersunk hole surface based on the depth information. Step 5: Reconstruct the three-dimensional point cloud data to obtain the three-dimensional point cloud model of the countersunk hole as shown in Figure 2 and obtain the dimensional information of the countersunk hole based on the three-dimensional point cloud model.

[0019] Among them, Step 1 specifically includes: Step A1: Set the sine function, and cyclically calculate the values of the sine function according to the frequency list, time range, and step size of the required multi-frequency heterodyne structured light. Step A2: Superimpose the component signals at different frequencies to form the initial multi-frequency heterodyne coded structured light. Step A3: Adjust the frequency, time range, and modulation amplitude of the initial multi-frequency heterodyne coded structured light to obtain different multi-frequency heterodyne coded structured lights with specific spectral characteristics, time-domain characteristics, and amplitude characteristics. Step A4: Write the multi-frequency heterodyne coded structured light into the projector, and irradiate the multi-frequency heterodyne coded structured light onto the surface of the countersunk hole through the projector to form a modulated image with a specific pattern and coding sequence. Step A5: Use the camera to collect the modulated image.

[0020] Among them, Step 2 specifically includes: Step B1: Use multiple cameras to collect modulated images from different perspectives, and perform filtering on the modulated images to enhance the extraction accuracy of subsequent phase information. Step B2: Perform Fourier transform on the light intensity information in the modulated images from different perspectives to obtain the sine phase component and cosine phase component of the modulated images, and accumulate the sine phase component and cosine phase component to calculate the phase matrix. Step B3: Calculate the modulation degree of the modulated image based on the sine phase component and cosine phase component using the modulation degree calculation function. Step B4: Set the modulation degree threshold and create a mask matrix, and filter the components in the phase matrix with a modulation degree lower than the modulation degree threshold through the modulation degree threshold and the mask matrix to obtain the wrapped phase.

[0021] Among them, step 3 specifically includes: Step C1: For the modulated images collected from different perspectives, the multi-frequency phase algorithm is used to combine the phase information at different frequencies; Step C2: Use sine gratings with several different frequencies to perform phase difference processing on the combined phase information, so that the phase difference signal can cover the entire field of view; Step C3: Based on the phase difference signal, solve the absolute phase distribution information of the modulated image, and perform heterodyne operation on the wrapped phases at different frequencies to obtain the absolute phase of the countersunk hole surface.

[0022] Among them, step 4 specifically includes: Step D1: Identify and match the pixel points located at the same countersunk hole position under multiple camera perspectives, and gather all the pixel points located at the same countersunk hole position into a set of matching pixel points; Step D2: Calculate the parallax of each pixel point in the set of matching pixel points to obtain the pixel offset of each pixel point in different modulated images; Step D3: Based on the pixel offset, use the triangulation method to measure the depth information of the countersunk hole surface, and obtain the three-dimensional point cloud data of the countersunk hole surface based on the depth information.

[0023] Furthermore, filter the three-dimensional point cloud data in step 4 to remove the abnormal pixel points that deviate from the set of matching pixel points by an excessive amount.

[0024] Furthermore, the absolute phase includes the actual absolute phase and the ideal absolute phase, and the actual absolute phase and the ideal absolute phase are normalized to the range of [0, 2π].

[0025] Embodiment 2: A method for quickly obtaining the countersunk hole point cloud based on coded structured light. This embodiment further optimizes on the basis of Embodiment 1, and uses structured light with a specific code to quickly measure the countersunk hole, specifically: System calibration: Place the calibration plate on the workbench, and the binocular camera collects the calibration plate image. Use an efficient automatic calibration algorithm to quickly and accurately determine the internal and external parameters of the camera.

[0026] Design coded structured light: Use C++ to design and generate coded structured light, and this structured light irradiates the countersunk hole surface through a specific coding method.

[0027] Collect modulated images: Use the projector to project the generated coded structured light onto the countersunk hole surface, and use the camera to collect the modulated images.

[0028] Calculating the wrapped phase using light intensity: By analyzing and processing the light intensity information in the acquired modulated images, the wrapped value of the phase, i.e., the unwrapped phase information, is calculated.

[0029] Unfolding the phase using the multi-frequency heterodyne principle to obtain the absolute phase: When the light is reflected back from the object surface, these codes are modulated. After capturing and analyzing these coded images, the wrapped phases at different frequencies are subjected to heterodyne operation to obtain the absolute phase information.

[0030] Stereo matching to search for corresponding points and obtaining depth information using parallax: The pixel points at the same countersunk hole position are identified and matched under the two viewpoints of the left and right cameras. By calculating the parallax between these matching points, i.e., their pixel offsets in different images, and then converting it into the actual three-dimensional space depth through triangulation technology.

[0031] Filtering out abnormal points: Processing the point cloud data and performing filtering operations to remove these outliers or noises. In this specific step, the points that do not conform to the actual characteristics of the countersunk hole surface are filtered out.

[0032] Point cloud processing to generate the countersunk hole point cloud: After the previous data processing and depth information acquisition, the final point cloud processing will be carried out. This includes reconstructing and organizing the data after filtering out the outliers to form a point cloud model of the countersunk hole surface, and fitting the relevant shapes of the countersunk hole through point cloud software to obtain the dimension information.

[0033] Finding the corresponding points of the left and right pixels in binocular vision using phase value constraints and epipolar constraints, and determining the internal and external parameters of the camera relying on an efficient automatic calibration algorithm; According to the designed structured light, collecting the modulated images of the countersunk hole obtained after being irradiated by the structured light at different viewpoints, and calculating the wrapped value of the phase using the light intensity information in the acquired modulated images; Based on the above-mentioned wrapped phase value, by taking the difference of the phases of multiple sine gratings with different frequencies, the principal value of the phase with a small period is converted into the phase difference with a large period, so that the phase difference signal covers the entire field of view, and then the absolute phase distribution information of the entire modulated image is obtained according to the phase difference signal. And performing heterodyne operation on the wrapped phases at different frequencies to obtain the absolute phase information of the countersunk hole surface.

[0034] Based on the modulated images from different perspectives collected, binocular stereo matching is performed to identify and match the pixel points located at the same counterbore position to form a set of matching pixel points. The depth information of the counterbore surface is measured by calculating the disparity between the pixel points in the set of matching pixel points, and then the three-dimensional point cloud data of the counterbore surface is quickly obtained. During the process of processing the three-dimensional point cloud data, the three-dimensional point cloud data is filtered to remove abnormal pixel points or isolated points that deviate greatly from the set of matching pixel points. Finally, the three-dimensional point cloud data is processed, including data reconstruction, sorting, and organization, to generate a complete three-dimensional point cloud model of the counterbore, and the size information of the counterbore is obtained based on the three-dimensional point cloud model.

[0035] In the camera calibration stage, an efficient automatic calibration algorithm is used, specifically including: Camera calibration covers steps such as data acquisition, feature extraction, parameter derivation, and result evaluation. Image data corresponding to world coordinates and camera coordinates is collected. Corner points in the image are extracted using image processing techniques, and their positions in the world coordinate system are determined. Based on the spatial position information of the corner points, the internal and external parameters of the camera, including focal length, distortion coefficient, camera pose, etc., are derived through an optimization algorithm. Finally, the calibration results are evaluated to verify their accuracy and reliability to ensure that the camera parameters can meet the actual application requirements.

[0036] Design and generate coded structured light, which is irradiated onto the counterbore surface through a specific coding method to form light spots with specific patterns and coding sequences, specifically including: Determine the parameters required to generate structured light with a specific code, including frequency, time range, step size, and modulation amplitude, etc. Use the sine function to generate coded structured light with multi-frequency heterodyne. Set the number of steps of phase shift to N , then the phase shift formula for the structured light to generate fringes is as follows: ; where: A represents the average intensity, B represents the modulation intensity, represents the target phase distribution, represents the phase shift amount at the k-th step.

[0037] As shown in the phase shift formula, according to the required frequency list, as well as the time range and step size, the values of the sine function are calculated cyclically, and the signals of each frequency component are superimposed to form coded structured light with multi-frequency heterodyne. Adjust the parameters such as the required frequency, time range, step size, and modulation amplitude to generate structured light with different characteristic codes. By adjusting these parameters, the spectral characteristics, time-domain characteristics, and amplitude characteristics of the coded structured light are controlled. The generated coded structured light is written into the projection system and then irradiated onto the counterbore surface to form a pattern with specific patterns and coding sequences for subsequent visual detection processes.

[0038] The images modulated by the coded structured light are collected at different viewing angles, and the phase wrapping value is calculated using the light intensity information in the collected modulated images, including: The modulated images obtained by coded structured light illumination are collected at different viewing angles, and the light intensity information in these modulated images is used to perform Fourier transform steps to calculate the phase wrapping value. By simultaneously analyzing multiple equations and performing unwrapping calculations, the following formula is obtained: ; Filtering is performed on each modulated image to enhance the extraction of phase information. Then, the sine phase component and cosine phase component of each modulated image are calculated according to the angle formula of Fourier transform, and the sine phase component and cosine phase component are accumulated into the corresponding matrix. Subsequently, the phase matrix is calculated by calling the phase function of OpenCV using the accumulated value. At the same time, based on these sine phase components and cosine phase components, the modulation calculation function is established as follows: ; Where: B represents the modulation degree; N represents the number of phase shift steps; k represents the kth phase shift step, k=0,1,…N-1; I k represents the intensity of the k-th phase shift.

[0039] The modulation calculation function is used to calculate the modulation, and a mask matrix is created according to the preset modulation threshold to filter the part of the phase matrix with a modulation lower than the threshold. Finally, the processed phase matrix is returned, which contains the phase information of the modulated image modulated by the coded structured light.

[0040] The phase is expanded using the multi-frequency heterodyne principle to obtain the absolute phase, including: For the modulated image corresponding to the coded structured light collected at each viewing angle, the phase information at different frequencies is combined using a multi-frequency phase calculation method. The phase information is extracted through heterodyne operation, and the phase is expanded to obtain the absolute value. This step ensures the accuracy of the phase information while maintaining high efficiency.

[0041] The other parts of this embodiment are the same as those of Embodiment 1, and thus will not be described in detail.

[0042] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A rapid acquisition method for countersunk hole point cloud based on coded structured light, characterized in that, The countersunk hole surface is irradiated with structured light having a specific encoding to obtain a modulated image. The wrapped phase is calculated using the light intensity information in the modulated image. The absolute phase is obtained by performing heterodyne operations on the wrapped phases at different frequencies. Based on the absolute phase, stereo matching is performed on the matching pixel point sets located at the same countersunk hole position from multiple perspectives, and the disparity between the matching pixel point sets is calculated to measure the depth information of the countersunk hole surface. Based on the depth information, the three-dimensional point cloud data of the countersunk hole surface is obtained; After processing the three-dimensional point cloud data, a three-dimensional point cloud model of the countersunk hole is obtained, and the size information of the countersunk hole is obtained based on the three-dimensional point cloud model.

2. The method for quickly obtaining the countersunk hole point cloud based on coded structured light according to claim 1, characterized in that, Specifically, it includes the following steps: Step 1: Generate multi-frequency heterodyne encoded structured light with specific spectral characteristics, time domain characteristics, and amplitude characteristics. Use the multi-frequency heterodyne encoded structured light to irradiate the surface of the countersunk hole, and use a camera to collect the modulated image; Step 2: Perform a Fourier transform on the light intensity information in the modulated image to obtain the wrapped phase; Step 3: Use the multi-frequency heterodyne algorithm to unwrap the wrapped phase and obtain the absolute phase; Step 4: Perform multi-view stereo matching on the modulated images from different perspectives to obtain the matching pixel point sets located at the same countersunk hole position, calculate the disparity between the matching pixel point sets to measure the depth information of the countersunk hole surface, and obtain the three-dimensional point cloud data of the countersunk hole surface based on the depth information; Step 5: Reconstruct the three-dimensional point cloud data to obtain a complete three-dimensional point cloud model of the countersunk hole, and obtain the size information of the countersunk hole based on the three-dimensional point cloud model.

3. A rapid acquisition method for countersunk hole point cloud based on coded structured light according to claim 2, characterized in that, The specific content of Step 1 includes: Step A1: Set the sine function, and cyclically calculate the values of the sine function according to the frequency list, time range, and step size of the required multi-frequency heterodyne structured light; Step A2: Superimpose the component signals at different frequencies to form the initial multi-frequency heterodyne encoded structured light; Step A3: Adjust the frequency, time range, and modulation amplitude of the initial multi-frequency heterodyne encoded structured light to obtain different multi-frequency heterodyne encoded structured lights with specific spectral characteristics, time domain characteristics, and amplitude characteristics; Step A4: Write the multi-frequency heterodyne encoded structured light into the projector, and irradiate the multi-frequency heterodyne encoded structured light onto the countersunk hole surface through the projector to form a modulated image with a specific pattern and coding sequence; Step A5: Use a camera to collect the modulated image.

4. A method for rapidly obtaining the countersunk hole point cloud based on coded structured light according to claim 2, wherein, The specific content of Step 2 includes: Step B1: Use multiple cameras to collect modulated images from different perspectives, and perform filtering processing on the modulated images to enhance the extraction accuracy of subsequent phase information; Step B2: Perform a Fourier transform on the light intensity information in the modulated images from different perspectives to obtain the sine phase component and cosine phase component of the modulated image, and accumulate the sine phase component and cosine phase component to calculate the phase matrix; Step B3: Calculate the modulation degree of the modulated image based on the sine phase component and cosine phase component using the modulation degree calculation function; Step B4: Set the modulation degree threshold and create a mask matrix, and filter the components in the phase matrix with a modulation degree lower than the modulation degree threshold through the modulation degree threshold and the mask matrix to obtain the wrapped phase.

5. A method for rapidly obtaining the countersunk hole point cloud based on coded structured light according to claim 4, characterized in that, The specific modulation degree calculation function is: ； Where: B represents the modulation degree; N represents the number of steps of phase shift; k represents the k-th phase shift step number, k = 0, 1, … N - 1; I k represents the intensity of the k-th step of phase shift.

6. The method for rapidly obtaining the countersunk hole point cloud based on coded structured light according to claim 2, characterized in that, The specific content of Step 3 includes: Step C1: For the modulated images acquired from different perspectives, the multi-frequency phase algorithm is used to combine the phase information at different frequencies; Step C2: Sine gratings with several different frequencies are used to perform phase subtraction on the combined phase information, so that the phase difference signal can cover the entire field of view; Step C3: Based on the phase difference signal, the absolute phase distribution information of the modulated image is calculated, and the wrapped phases at different frequencies are subjected to heterodyne operation to obtain the absolute phase of the countersunk hole surface.

7. A method for rapidly obtaining the countersunk hole point cloud based on coded structured light according to claim 2, characterized in that The specific steps of step 4 include: Step D1: Identify and match the pixel points located at the same countersunk hole position under multiple camera perspectives, and collect all the pixel points located at the same countersunk hole position into a set of matching pixel points; Step D2: Calculate the parallax of each pixel point in the set of matching pixel points to obtain the pixel offset of each pixel point in different modulated images; Step D3: Based on the pixel offset, the depth information of the countersunk hole surface is measured by triangulation, and the three-dimensional point cloud data of the countersunk hole surface is obtained based on the depth information.

8. A method for rapidly obtaining the countersunk hole point cloud based on coded structured light according to any one of claims 2-7, characterized in that, Filter the three-dimensional point cloud data in step 4 to remove the abnormal pixel points that deviate from the set of matching pixel points by more than the standard.

9. A method for quickly obtaining the countersunk hole point cloud based on coded structured light according to any one of claims 2-7, characterized in that, The absolute phase includes the actual absolute phase and the ideal absolute phase, and the actual absolute phase and the ideal absolute phase are normalized to the range of [0, 2π].

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