Data error correction method of motion capture system and storage medium

Abstract

The invention discloses a data error correction method of a motion capture system and a storage medium. The method comprises the following steps: capturing a frame data set through the motion capture system; sequentially arranging the corresponding relations between all the data points of the next frame and the data points of the previous frame in the frame data set, selecting the corresponding relation most conforming to the judgment standard from each group of corresponding relations, and adjusting the point positions of the data points of the next frame and the point positions of the data points of the previous frame according to the corresponding relations. Wherein the data points are spatial position information of reflective mark points in the motion capture system; according to the method, the missing data points of each frame are counted in sequence from the second frame of the frame data set, and the data points of the missing data points corresponding to the point positions of the previous frame are supplemented to the frame, so that technical personnel do not need to manually repair wrong data in the frame data set, and the processing efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the field of motion capture, and in particular to a data error correction method and a storage medium for a motion capture system. Background Art

[0002] Motion capture technology is a technology that obtains the motion trajectory of a specific point of a target object. Currently, the commonly used methods are mainly machine vision and marking. The machine vision method is to obtain the image of the moving target through a camera (usually a depth camera or multi-eye vision) and perform motion extraction. The marking method is to mark the points that need to be monitored. There are generally two types of active marking points and reflective marking points. Active marking points are marking points that will actively emit light, and different marking points will flash at different frequencies and phases. This marking method can distinguish different marking points. Reflective marking points are made of light materials to make labels, and infrared rays are emitted by cameras. The labels reflect infrared rays and are received by multiple (three or more) cameras, so that the position of the reflective marking points can be located.

[0003] In the process of collecting reflective markers, there will be two kinds of "small errors" that need to be corrected later, namely point loss and data misalignment. Point loss means that after the reflective marker is blocked (that is, it cannot be guaranteed that three or more cameras can capture the position of the flash marker at the same time), the system will not be able to determine the specific position of the flash marker in space, and the recorded data will show that the marker is missing. Data misalignment means that during the recording process, the position information of the same sequence is not the same marker. In most cases, misalignment occurs with point loss. This is because when recording data, after multiple points are lost, the collection point reappears and is re-recognized by the system. There is a certain probability that the system will record its position information in the wrong place, that is, under other collection points, then the position information that should be here will appear in other locations.

[0004] The above two problems seriously affect the post-processing of motion capture data. When the number of points is small and the acquisition time is short, manual repair methods can be used. However, the motion capture sampling rate is 60Hz, and the number of points in actual use often exceeds 10 points, or even more than 20 points. The length of the time series and the possible misaligned combinations far exceed the ability of pure manual repair, and the efficiency is low. Summary of the invention

[0005] To achieve the above-mentioned purpose and other related purposes, the present invention discloses a data error correction method for a motion capture system, comprising: The frame data set is obtained by capturing the motion capture system; The corresponding relationships between all the data points of the next frame and the data points of the previous frame in the frame data set are arranged in sequence, and the corresponding relationship that best meets the evaluation criteria is selected from each group of corresponding relationships. The position of the data points of the next frame is adjusted with the position of the data points of the previous frame according to the corresponding relationship, where the data points are the spatial position information of the reflective marker points in the motion capture system; Starting from the second frame of the frame data set, the missing data points of each frame are counted in turn, and the data points of the previous frame corresponding to the missing data points are supplemented to the frame.

[0006] Furthermore, the method further comprises: The adjusted frame data set is sorted using multinomial interpolation.

[0007] Furthermore, the step of using a multinomial interpolation method to sort the adjusted frame data set includes: Traverse the data points of each frame in the frame data set, and compare the data points of each frame with the data points of the corresponding points in the previous frame; If the spatial position coordinates of a data point at a certain point in N consecutive frames do not change, the data corresponding to the data point at that point in the above N frames are repaired using a multinomial interpolation method, where N is a preset frame number threshold.

[0008] Furthermore, the data can be repaired by using the direct method, Lagrange interpolation method or Newton interpolation method.

[0009] Furthermore, the preset frame number threshold range is 3 to 5 frames.

[0010] Further, the step of sequentially arranging the correspondences between all the data points of the next frame and the data points of the previous frame in the frame data set, selecting the correspondence that best meets the evaluation criteria from each group of correspondences, and adjusting the positions of the data points of the next frame and the data points of the previous frame according to the correspondences includes: From the first frame and the second frame, all corresponding relationships are obtained. The corresponding relationship is a one-to-one correspondence between the position of each data point in the next frame and the position of each data point in the previous frame. The total number of corresponding relationships is W=A f e , where e is the total number of reflective markers and f is the number of data points in the next frame; Randomly select w results from W combinations, and calculate the mean and variance of the distance between each data point in the next frame and each data point in the previous frame in each result; The corresponding relationship with the smallest sum of mean and variance is taken as the corresponding relationship that best meets the evaluation criteria.

[0011] Furthermore, the method for calculating the distance between two data points is: Among them, (x1, y1, z1) and (x2, y2, z2) are the coordinates of two data points in the preset spatial coordinate system.

[0012] On the other hand, the present invention further provides a computer-readable storage medium having a computer program stored thereon, which implements the above method when executed by a processor.

[0013] By adopting the above technical solution, the frame data set is first captured by the motion capture system, and then the frame data set is processed by the nearest distance intersection judgment to repair the problem of data misalignment. Then, the frame data set is processed by forward interpolation or polynomial interpolation to repair the problem of missing data points. This eliminates the need for technicians to manually repair erroneous data in the frame data set, thereby improving processing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. The accompanying drawings are used to better understand the present solution and do not constitute a limitation of the present disclosure. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements, among which:

[0015] Figure 1 The present invention is a flowchart of a method for correcting data errors in a motion capture system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0017] Reference Figure 1 , an embodiment of the present invention provides a data error correction method for a motion capture system, comprising the following steps: S1: The frame dataset is captured by the motion capture system.

[0018] Specifically, the frame data set is A={A1, A2, ..., A i , ..., A m}, where A i is the set of data points in the i-th frame data captured by the motion capture system, i=1, 2, …, m, and m is the total number of frames captured by the motion capture system.

[0019] Among them, A i ={A i1 , A i 2 , ..., A i j , ..., A i n}, A i j is the jth data point in the i-th frame data, the data point is the spatial position information of the reflective marker point, j=1, 2, ..., n, n is the number of reflective marker points in the motion capture system.

[0020] As mentioned above, due to the occurrence of point loss errors, there may be some A i j The information is empty.

[0021] S2: Arrange the correspondences between all the data points of the next frame and the data points of the previous frame in the frame data set in sequence, and select the correspondence that best meets the evaluation criteria from each group of correspondences, and adjust the positions of the data points of the next frame with the positions of the data points of the previous frame according to the correspondences, where the data points are the spatial position information of the reflective marker points in the motion capture system.

[0022] Specifically, firstly, the data of two adjacent frames are taken out (starting from the first frame and the second frame), and all corresponding relationships are obtained. The corresponding relationship is a one-to-one correspondence between the position of each data point in the next frame and the position of each data point in the previous frame. The total number of corresponding relationships is W=A f e , where e is the total number of reflective markers and f is the number of data points in the next frame; Randomly select w results from W combinations, and calculate the mean and variance of the distance between each data point in the next frame and each data point in the previous frame in each result; The corresponding relationship with the smallest sum of mean and variance is taken as the corresponding relationship that best meets the evaluation criteria.

[0023] The method for calculating the spatial distance between two data points is: Among them, (x1, y1, z1) and (x2, y2, z2) are the coordinates of two data points in the preset spatial coordinate system.

[0024] Through the above technical solution, the position of the next frame of data points is adjusted according to the position of the previous frame. For example, if the result that best meets the evaluation criteria is the same as A1 in A2 1 The closest point is A2 2 , then A2 2 Adjust the data to A2 1position, thus solving the problem of data misalignment.

[0025] S3: Starting from the second frame of the frame data set, the missing data points of each frame are counted in sequence, and the data points of the previous frame corresponding to the missing data points are added to the frame.

[0026] In the above, the forward interpolation method is used to complete the data points with empty data point values, thereby solving the problem of missing data points.

[0027] In another possible embodiment, the method further includes: S4: The adjusted frame dataset is sorted using multinomial interpolation.

[0028] S41: traverse the data points of each frame in the frame data set, and compare the data points of each frame with the data points of the corresponding points in the previous frame.

[0029] S42: If there is a data point whose spatial position coordinates do not change in N consecutive frames, a multinomial interpolation method is used to repair data for the data point corresponding to the point in the above N frames, where N is a preset frame number threshold. The embodiment of the present invention sets the range of N to 3 to 5 frames, preferably 3 frames.

[0030] Specifically, the data can be repaired using the direct method, the Lagrange interpolation method or the Newton interpolation method.

[0031] The steps of direct polynomial interpolation are as follows: Find a k-order polynomial as follows, The (x, y) coordinates of the k points before and after the lost point Can satisfy Among them, r=0, 1, 2,…, s.

[0032] Use what you get Fit the xy coordinates of the defect. The movement in a short period of time can be assumed to be uniform, and the xy coordinates of the missing points can be completed using evenly spaced x coordinates.

[0033] Similarly, for the z-axis direction, find Polynomial, substitute the x coordinate from the previous step to find the specific z coordinate.

[0034] In the case where clear data points are available, using Lagrange interpolation method and Newton interpolation method to repair data is also an existing technology known to those skilled in the art, and will not be described in detail here.

[0035] As mentioned above, when the forward interpolation method is used, the missing point data is directly used with the previous frame data, which will have a certain negative impact on the restoration of the motion trajectory. The use of multiple interpolation methods to restore and repair the missing data can improve the smoothness of the repaired data, thereby improving the effect of repairing the motion capture data.

[0036] An embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the above method is implemented.

[0037] Those skilled in the art will appreciate that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined.

[0038] For the method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the embodiments of the present invention are not limited by the order of the actions described, because according to the embodiments of the present invention, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of the present invention.

[0039] It can be known from the description of the above implementation modes that those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly contributed to the prior art in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes several instructions for enabling a computer device (which can be a personal computer, a server or a network device, etc.) to execute the methods described in the various implementation modes of the present application or certain parts of the implementation modes.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A data error correction method for a motion capture system, characterized in that: include: The frame data set is obtained by capturing the motion capture system; The corresponding relationships between all the data points of the next frame and the data points of the previous frame in the frame data set are arranged in sequence, and the corresponding relationship that best meets the evaluation criteria is selected from each group of corresponding relationships. The position of the data points of the next frame is adjusted with the position of the data points of the previous frame according to the corresponding relationship, where the data points are the spatial position information of the reflective marker points in the motion capture system; Starting from the second frame of the frame data set, the missing data points of each frame are counted in turn, and the data points of the previous frame corresponding to the missing data points are supplemented to the frame.

2. The method according to claim 1, characterized in that The method further comprises: The adjusted frame data set is sorted using multinomial interpolation.

3. The method according to claim 2, characterized in that The step of using a multi-iteration interpolation method to sort the adjusted frame data set includes: Traverse the data points of each frame in the frame data set, and compare the data points of each frame with the data points of the corresponding points in the previous frame; If the spatial position coordinates of a data point at a certain point in N consecutive frames do not change, the data corresponding to the data point at that point in the above N frames are repaired using a multinomial interpolation method, where N is a preset frame number threshold.

4. The method according to claim 3, characterized in that The data can be repaired using direct method, Lagrange interpolation method or Newton interpolation method.

5. The method according to claim 3, characterized in that: The preset frame number threshold range is 3 to 5 frames.

6. The method according to claim 1, characterized in that The step of sequentially arranging the correspondences between all the data points of the next frame and the data points of the previous frame in the frame data set, selecting the correspondence that best meets the evaluation criteria from each group of correspondences, and adjusting the positions of the data points of the next frame and the data points of the previous frame according to the correspondences includes: From the first frame and the second frame, all corresponding relationships are obtained. The corresponding relationship is a one-to-one correspondence between the position of each data point in the next frame and the position of each data point in the previous frame. The total number of corresponding relationships is W=A f e , where e is the total number of reflective markers and f is the number of data points in the next frame; Randomly select w results from W combinations, and calculate the mean and variance of the distance between each data point in the next frame and each data point in the previous frame in each result; The corresponding relationship with the smallest sum of mean and variance is taken as the corresponding relationship that best meets the evaluation criteria.

7. The method according to claim 6, characterized in that The method for calculating the distance between two data points is: Among them, (x1, y1, z1) and (x2, y2, z2) are the coordinates of two data points in the preset spatial coordinate system.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method described in any one of claims 1 to 7 is implemented.

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