阅读说明：本技术 一种刚体配置方法及光学动作捕捉方法 (rigid body configuration method and optical motion capture method ) 是由 杭建伟 许秋子 于 2018-11-29 设计创作，主要内容包括：一种刚体配置方法及光学动作捕捉方法。刚体配置方法包括：确定刚体配置方式数目、计算三维坐标矩阵的奇异值、计算列向量正交程度、优选配置方式进行配置等步骤。由于对刚体上所有标记点做整体考虑,避免了以往遍历所有标记点可能存在位置的情形,使得差异度比较过程得以简化,有利于降低计算量,提高系统的运算效率,不仅适用于标记点数目相同的多个待配置刚体,还适用于标记点数目不同的待配置刚体,并且无需设定限制条件。(rigid body configuration methods and optical motion capture methods, the rigid body configuration method includes determining the number of rigid body configuration modes, calculating singular values of a three-dimensional coordinate matrix, calculating the column vector orthogonality degree, configuring the preferred configuration mode, and the like.)

1, rigid body configuration method, characterized by that, including the following steps:

determining the number of rigid body configuration modes;

performing singular value decomposition on the three-dimensional coordinate matrix corresponding to each rigid body configuration modes to obtain singular values of the three-dimensional coordinate matrix;

calculating the orthogonality degree of the column vectors of the three-dimensional coordinate matrix according to the singular value, and selecting a rigid body configuration mode corresponding to the three-dimensional coordinate matrix with the maximum column vector orthogonality degree as an optimal configuration mode;

and configuring the rigid body to be configured according to the preferred configuration mode.

2. The rigid body configuration method of claim 1, wherein the determining the number of rigid body configurations comprises:

determining the number of rigid bodies to be configured, the total number of mark point positions on each rigid body to be configured and the number of mark points to be configured;

calculating the number of configuration modes formed on each rigid body to be configured through a combination algorithm according to the total number of the mark point positions on each rigid body to be configured and the number of the mark points to be configured;

and determining the number of the rigid body configuration modes according to the number of the configuration modes formed on each rigid body to be configured.

3. The rigid body configuration method according to claim 2, wherein the calculating the number of configuration modes formed by each rigid body to be configured through a combination algorithm according to the total number of the mark point positions on each rigid body to be configured and the number of the mark points to be configured comprises:

for any rigid body with total mark point positions being K and the number of mark points to be configured being L, the number of configuration modes formed on the rigid body is calculated by a combination algorithm and is as follows:

wherein i is the serial number of the rigid body to be configured, L, K is an integer, L is less than K and L is greater than or equal to 3.

4. A rigid body configuration method according to claim 3, wherein said determining the number of rigid body configurations according to the number of configurations formed on each rigid body to be configured comprises:

the total number of rigid body configuration modes is formulated as:

P＝N₁×N₂×…N_i×…N_n

wherein, the subscript N is the number of rigid bodies to be configured, i ∈ {1,2 …, N }, then, N_nRepresenting the number of configuration modes formed on the nth rigid body to be configured;

determining all or parts of the total number of rigid body configuration modes as the number of rigid body configuration modes.

5. The rigid body configuration method according to claim 4, wherein the performing singular value decomposition on the three-dimensional coordinate matrix corresponding to each rigid body configuration modes to obtain singular values of the three-dimensional coordinate matrix comprises:

for each rigid body configuration modes, obtaining the three-dimensional coordinates of each mark point to be configured on each rigid body to be configured according to the rigid body configuration mode;

and constructing a three-dimensional coordinate matrix according to the three-dimensional coordinates of each mark point to be configured on each rigid body to be configured, and calculating the singular value of the three-dimensional coordinate matrix.

6. The rigid body configuration method according to claim 5, wherein the constructing a three-dimensional coordinate matrix according to the three-dimensional coordinates of each mark point to be configured on each rigid body to be configured and calculating singular values of the three-dimensional coordinate matrix comprises:

constructing a three-dimensional coordinate matrix according to the three-dimensional coordinates of each mark point to be configured on each rigid body to be configured:

x, y and z respectively represent coordinate values in each coordinate direction in three-dimensional coordinates, n is the number of rigid bodies to be configured, and k is the maximum number of mark points to be configured in the n rigid bodies;

according to the formula M ═ USV^TCalculating to obtain singular value array S of matrix M_j

S_j＝SVD(M)＝[σ₁σ₂... σ_r]

U, V respectively represents a left singular vector matrix and a right singular vector matrix of the matrix M, SVD is a matrix decomposition function, subscript j is a serial number of a rigid configuration mode, sigma is a singular value, subscript r is the number of the singular value, and r is min { 3xk, n };

singular value array S of three-dimensional coordinate matrix corresponding to all rigid body configuration modes determined by calculation₁、S₂、…S_PWhere P represents the number of rigid body configurations.

7. A rigid body configuration method according to claim 6, wherein for a rigid body to be configured for which the number of marker points to be configured does not reach k, the three-dimensional coordinates of less than k marker points to be configured on the rigid body are set to (0,0, 0).

8. The rigid body configuration method according to claim 6, wherein the calculating the degree of orthogonality of the column vectors of the three-dimensional coordinate matrix according to the singular values and selecting the rigid body configuration mode corresponding to the three-dimensional coordinate matrix with the maximum degree of orthogonality of the column vectors as a preferred configuration mode comprises:

singular value array S for arbitrary _jIf the singular value array S_jThe medium singular value satisfies sigma₁＝σ₂＝...＝σ_rThen the singular value array S is formed_jThe corresponding rigid body configuration is the preferred configuration.

9. The rigid body configuration method of claim 8,

singular value array S for arbitrary _jCalculating the singular value array S_jDegree of orthogonality delta of column vectors of a corresponding three-dimensional coordinate matrix_jThe calculation method comprises the following steps:

calculate S in this way₁、S₂、…S_PDegree of orthogonality delta of column vectors of a corresponding three-dimensional coordinate matrix₁、δ_j、…、δ_PAt each degree of orthogonality δ₁、δ_j、…、δ_PThe rigid body configuration mode corresponding to the maximum value is selected as the preferred configuration mode.

10, optical motion capture method comprising the rigid body configuration method of any of claims 1-9 at , further comprising the steps of:

respectively arranging the configured rigid bodies at a plurality of target positions on a measuring object;

and acquiring the three-dimensional coordinates of the mark points on each rigid body of the measuring object in the motion process so as to perform optical motion capture on the measuring object according to the acquired three-dimensional coordinates.

11. The optical motion capture method of claim 11 wherein said obtaining three-dimensional coordinates of marker points on each rigid body of the measurement object during motion comprises:

acquiring a plurality of two-dimensional images of the measuring object in the motion process, and calculating two-dimensional coordinates of mark points on each rigid body according to the plurality of two-dimensional images;

and calculating the three-dimensional coordinates of the mark points according to the two-dimensional coordinates of the mark points on each rigid body.

12, rigid body configuration device, comprising:

the preset unit is used for determining the number of rigid body configuration modes;

the solving unit is used for carrying out singular value decomposition on the three-dimensional coordinate matrix corresponding to each rigid body configuration modes to obtain singular values of the three-dimensional coordinate matrix;

the calculation unit is used for calculating the orthogonality of the column vectors of the three-dimensional coordinate matrix according to the singular value and selecting a rigid configuration mode corresponding to the three-dimensional coordinate matrix with the maximum column vector orthogonality as a preferred configuration mode;

and the configuration unit is used for configuring the rigid body to be configured according to the preferred configuration mode.

A computer-readable storage medium comprising a program executable by a processor to perform the method recited by any of claims 1-9, wherein the method is recited in any of claims .

Technical Field

The present invention relates to motion capture technology, and more particularly to rigid body configuration methods and optical motion capture methods.

Background

Motion capture technology (Motion capture, referred to as Motion) is that a tracker is arranged at a key part of a moving object, the position of the tracker is captured by a Motion capture system, and data of three-dimensional space coordinates are obtained after the data are processed by a computer. After the three-dimensional space coordinate data is identified by the computer, the method can be applied to the fields of animation production, gait analysis, biomechanics, human-machine engineering and the like. Especially in the field of movie special effects, real person images captured by a plurality of cameras are converted into digital models, actions of actors during performance are captured and recorded, and then the actions are synchronized to virtual characters in a computer, so that the actions of the virtual characters are not different from those of real persons, and vivid and natural effects are achieved.

The common optical motion capture is mostly based on the computer vision principle, theoretically, for points in the space, as long as the points can be seen by two cameras at the same time, the position of the point in the space at the moment can be determined according to images and camera parameters shot by the two cameras at the same moment, and when the cameras continuously shoot at a sufficiently high speed, a three-dimensional motion track of the point can be obtained from an image sequence.

In the conventional optical motion capture system, a motion track of a reflective marker point (marker) is generally required to be acquired to capture and track a target object, in general, a plurality of reflective marker points are configured into rigid bodies, each rigid body is arranged at a certain target part of the target object, and then, when the target object is tracked, the motion states of different target parts are mainly distinguished by identifying different rigid bodies on the target object.

Common rigid body configuration methods are: the initial position of each light reflecting mark point on each rigid body is randomly arranged, then all possible positions of each light reflecting mark are traversed, the sum of the difference degrees between any two rigid bodies is calculated, and the rigid body configuration mode corresponding to the maximum value in the obtained sums is used as the final rigid body configuration scheme. However, the above method needs to traverse all the positions where each reflective marker point may exist, and also needs to calculate the sum of the difference between any two rigid bodies, which results in huge calculation amount and excessive occupation of the processing overhead of the dynamic capturing system.

For example, in the prior art, a method for configuring a high-order point rigid body includes (1) initializing positions of all reflective marker points on each of a plurality of rigid bodies, selecting reflective marker points from reflective markers not determined as target reflective marker points when target positions of the reflective marker points on the rigid bodies are determined, (2) fixing other reflective marker points except the target reflective marker points, and moving the target reflective marker points successively at each vacant position of the rigid body to which the target reflective marker points belong, (3) calculating a rigid body difference between the target reflective marker points at each vacant position according to position information of each reflective marker point, the rigid body difference being a sum of differences between any two rigid bodies of the plurality of rigid bodies, and (4) determining a vacant position corresponding to a maximum value of the rigid body difference as a target position of the target reflective marker point, wherein optimization may be continued by before determining a target position of the reflective marker points using the rigid body configuration method, and further calculation may be carried out by calculation of invalid operations when the target positions of the reflective marker points are determined as necessary, and the target reflective marker points may be subjected to a reduction in the number of the target reflective marker points, which may be caused by a subsequent bad influence of the reflective marker points, which may be caused by a reduction in the target reflective marker points, which may be caused by a subsequent operation which may be caused by a reduction of a large number of reflective marker point.

Disclosure of Invention

In order to solve the above technical problems, the present application provides rigid body configuration methods and optical motion capture methods.

According to , embodiments provide rigid body configuration methods, including the steps of:

determining the number of rigid body configuration modes;

performing singular value decomposition on the three-dimensional coordinate matrix corresponding to each rigid body configuration modes to obtain singular values of the three-dimensional coordinate matrix;

calculating the orthogonality degree of the column vectors of the three-dimensional coordinate matrix according to the singular value, and selecting a rigid body configuration mode corresponding to the three-dimensional coordinate matrix with the maximum column vector orthogonality degree as an optimal configuration mode;

and configuring the rigid body to be configured according to the preferred configuration mode.

The determining the number of rigid body configuration modes comprises:

determining the number of rigid bodies to be configured, the total number of mark point positions on each rigid body to be configured and the number of mark points to be configured;

calculating the number of configuration modes formed on each rigid body to be configured through a combination algorithm according to the total number of the mark point positions on each rigid body to be configured and the number of the mark points to be configured;

and determining the number of the rigid body configuration modes according to the number of the configuration modes formed on each rigid body to be configured.

The method for calculating the number of the configuration modes formed by each rigid bodies to be configured through a combination algorithm according to the total number of the mark point positions on each rigid body to be configured and the number of the mark points to be configured comprises the following steps:

for any rigid body with total mark point positions being K and the number of mark points to be configured being L, the number of configuration modes formed on the rigid body is calculated by a combination algorithm and is as follows:

wherein i is the serial number of the rigid body to be configured, L, K is an integer, L is less than K and L is greater than or equal to 3.

The determining the number of the rigid body configuration modes according to the number of the configuration modes formed on each rigid body to be configured includes:

the total number of rigid body configuration modes is formulated as:

P＝N₁×N₂×…N_i×…N_n

wherein, the subscript N is the number of rigid bodies to be configured, i ∈ {1,2 …, N }, then, N_nRepresenting the number of configuration modes formed on the nth rigid body to be configured;

determining all or parts of the total number of rigid body configuration modes as the number of rigid body configuration modes.

The singular value decomposition of the three-dimensional coordinate matrix corresponding to each rigid body configuration modes to obtain the singular value of the three-dimensional coordinate matrix includes:

for each rigid body configuration modes, obtaining the three-dimensional coordinates of each mark point to be configured on each rigid body to be configured according to the rigid body configuration mode;

and constructing a three-dimensional coordinate matrix according to the three-dimensional coordinates of each mark point to be configured on each rigid body to be configured, and calculating the singular value of the three-dimensional coordinate matrix.

The method for constructing the three-dimensional coordinate matrix according to the three-dimensional coordinates of the mark points to be configured on each rigid body to be configured and calculating the singular value of the three-dimensional coordinate matrix comprises the following steps:

constructing a three-dimensional coordinate matrix according to the three-dimensional coordinates of each mark point to be configured on each rigid body to be configured

X, y and z respectively represent coordinate values in each coordinate direction in three-dimensional coordinates, n is the number of rigid bodies to be configured, and k is the maximum number of mark points to be configured in the n rigid bodies;

according to the formula M ═ USV^TCalculating to obtain singular value array S of matrix M_j

S_j＝SVD(M)＝[σ₁σ₂...σ_r]

U, V respectively represents a left singular vector matrix and a right singular vector matrix of the matrix M, SVD is a matrix decomposition function, subscript j is a serial number of a rigid configuration mode, sigma is a singular value, subscript r is the number of the singular value, and r is min { 3xk, n };

singular value array S of three-dimensional coordinate matrix corresponding to all rigid body configuration modes determined by calculation₁、S₂、…S_PWhere P represents the number of rigid body configurations.

And for the rigid body to be configured, the number of the mark points to be configured does not reach k, setting the three-dimensional coordinates of less than k mark points to be configured on the rigid body as (0,0, 0).

The calculating the orthogonal degree of the column vectors of the three-dimensional coordinate matrix according to the singular value and selecting the rigid body configuration mode corresponding to the three-dimensional coordinate matrix with the maximum column vector orthogonal degree as the optimal configuration mode comprise:

singular value array S for arbitrary _jIf the singular value array S_jThe medium singular value satisfies sigma₁＝σ₂＝...＝σ_rThen the singular value array S is formed_jThe corresponding rigid body configuration is the preferred configuration.

Singular value array S for arbitrary _jCalculating the singular value array S_jDegree of orthogonality delta of column vectors of a corresponding three-dimensional coordinate matrix_jThe calculation method is

Calculate S in this way₁、S₂、…S_PDegree of orthogonality delta of column vectors of a corresponding three-dimensional coordinate matrix₁、δ_j、…、δ_PAt each degree of orthogonality δ₁、δ_j、…、δ_PThe rigid body configuration mode corresponding to the maximum value is selected as the preferred configuration mode.

According to a second aspect, exemplary embodiments provide optical motion capture methods, including the rigid body configuration method of above, further including the steps of:

respectively arranging the configured rigid bodies at a plurality of target positions on a measuring object;

and acquiring the three-dimensional coordinates of the mark points on each rigid body of the measuring object in the motion process so as to perform optical motion capture on the measuring object according to the acquired three-dimensional coordinates.

Acquiring a plurality of two-dimensional images of the measuring object in the motion process, and calculating two-dimensional coordinates of mark points on each rigid body according to the plurality of two-dimensional images;

and calculating the three-dimensional coordinates of the mark points according to the two-dimensional coordinates of the mark points on each rigid body.

According to a third aspect, example embodiments provide rigid body configuration devices, comprising:

the preset unit is used for determining the number of rigid body configuration modes;

the solving unit is used for carrying out singular value decomposition on the three-dimensional coordinate matrix corresponding to each rigid body configuration modes to obtain singular values of the three-dimensional coordinate matrix;

the calculation unit is used for calculating the orthogonality of the column vectors of the three-dimensional coordinate matrix according to the singular value and selecting a rigid configuration mode corresponding to the three-dimensional coordinate matrix with the maximum column vector orthogonality as a preferred configuration mode;

and the configuration unit is used for configuring the rigid body to be configured according to the preferred configuration mode.

According to a fourth aspect, embodiments provide computer readable storage media, including a program executable by a processor to perform the method of any of and of the second aspects.

The beneficial effect of this application is:

, the claimed method introduces matrix algorithm for solving singular decomposition to show the characteristics of each rigid configuration mode, which is beneficial to extracting important characteristics of each rigid configuration mode from mathematical perspective, and introduces a process for calculating the orthogonality degree of three-dimensional coordinate matrix column vectors in the rigid configuration method to quantify the difference of rigid configuration modes corresponding to the orthogonality degree of each column vector, so as to conveniently judge the advantages and disadvantages of each rigid configuration mode according to the quantified result, thereby obtaining the preferred configuration mode capable of making the maximum difference between each rigid, and the claimed method for configuring rigid configurations integrally considers all mark points on the rigid, so that the process for comparing the difference degrees is simplified, which is beneficial to reducing the calculated amount and improving the operational efficiency of the system, and the fourth aspect, which is not only suitable for the number of rigid configuration points, but also is suitable for limiting the number of rigid configuration points to be configured, and is suitable for multiple rigid configuration mark points to be configured, and has high value.

Drawings

FIG. 1 is a flow chart of a rigid body configuration in the embodiment;

FIG. 2 is a flow chart for determining rigid body configuration;

FIG. 3 is a flow chart for solving a singular value array;

FIG. 4 is a flow chart of a method for optical motion capture in the embodiment;

FIG. 5 is a flow chart of a rigid body configuration device in the example.

Detailed Description

In the following detailed description, the invention is described in conjunction with the accompanying drawings in , where like elements in different embodiments have been given like element numbers associated with them, in which case many details will be described to better understand the present application, however, those skilled in the art will readily appreciate that some of the features may be omitted or replaced with other elements, materials, methods, and in some cases, operations associated with the present application are not shown or described in the specification, which is necessary to avoid overwhelming the core of the present application and to avoid unnecessary detailed description of the associated operations, which will be fully apparent to those skilled in the art based on the description in the specification and general knowledge in the art.

Additionally, the various orders in the specification and drawings are for clarity only to describe certain embodiments and are not meant to be a required order unless otherwise specified where a certain order must be followed.

The ordinal numbers used herein to describe the components, such as "," "second," etc., are used solely to distinguish between the items described and do not have any sequential or technical meaning.

The invention of the technical scheme of the application is that the existing rigid body configuration method is mostly considered from the configuration mode of a single rigid body, a certain mark point (marker) or a certain rigid body is fixed firstly, then other rigid bodies are determined by traversing the mark point, although the existing method can achieve the effect of large difference degree between the rigid bodies, the problems of complicated process, large calculation amount and multiple limiting conditions exist, and the application situation of rigid body configuration cannot be met.