JP2003058904A - Three-dimensional data processor, program, recording medium and three-dimensional data processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide technology by which reproducibility of the shape regarding a thin part of a three-dimensional object can be enhanced in the case of integrating a plurality of pieces of three-dimensional shape data in volume system. SOLUTION: In the case of integrating pieces of three dimensional shape data F1, F2 acquired by measuring the three-dimensional object by performing an arithmetic operation of distance potentials of pieces of the shape data F1, F2 by every boxel of a three-dimensional coordinate system, a representative measuring direction H3 to be stored, for example, in the boxel Vu is calculated by synthesizing vectors weighted according to distance from pieces of the three- dimensional shape data F1, F2 to the boxel Vu regarding the respective measuring directions H1, H2 of the three dimensional data F1, F2. And the three- dimensional shape data F2 having the measuring direction H2 excessively out of the representative measuring direction H3 is excluded from an integrated object to the three-dimensional shape data F1 regarding the boxel Vu. The reproducibility of the shape regarding the thin part of the three-dimensional object can be enhanced by performing such a processing to other boxels as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional coordinate system that integrates a plurality of three-dimensional shape data acquired by three-dimensional measurement by performing a predetermined integration process on a plurality of voxels arranged in a three-dimensional coordinate system. Data processing technology.

[0002]

2. Description of the Related Art A three-dimensional object is measured by a three-dimensional shape measuring device.
When integrating a plurality of three-dimensional shape data obtained by measuring a (subject) from multiple directions, a volume-based shape integration method can be used to generate three-dimensional shape data for the entire circumference of a three-dimensional object.

Regarding the above volume method, A Volume
tric Method for Building Complex Models from Range
Images (B.Curless and M.Levoy, In Proceedings of ACM
SIGGRAH '92, 1996). This method is shown in Figure 1.
As shown in FIG. 6, a partial spatial distance potential field (hereinafter referred to as “section potential”) such as “glue margin” is set in the three-dimensional space around the shape data Q1 and Q2,
The shape integration is performed using this segmented potential. Due to the segmented potential formed in a part of such a space, it is possible to avoid an excessive influence of mutual distance potentials set for each shape data in shape integration.

[0004]

However, in the shape integration method utilizing the above-mentioned segmented potential, for example, a plurality of three-dimensional shape data obtained by measuring thin surfaces (thin portions) in substantially opposite directions are integrated. In this case, there is a problem that the reproducibility is lowered. The thin portion refers to a portion having a sufficiently small thickness (depth) in the three-dimensional object to be measured, and a specific example regarding the reduction in reproducibility of the thin portion will be described below.

As shown in FIG. 16, measurement directions E1 and E2
When two pieces of shape data J1 and J2 observed from are integrated, in the section W corresponding to the thin portion, the shape data J1,
Since J2 approaches, the sectional potentials Q1 and Q2 overlap and exert an excessive influence on each other. In this section W, there is a high possibility that the shape data J1 and J2 will be generated as one surface Jw by the shape integration, and the reproducibility of the shape will deteriorate.

The present invention has been made in view of the above problems, and relates to a thin portion of a three-dimensional object when a plurality of three-dimensional shape data obtained by measuring the three-dimensional object is integrated using a volume method. It is an object of the present invention to provide a three-dimensional data processing technique capable of improving shape reproducibility.

[0007]

In order to solve the above-mentioned problems, the invention according to claim 1 performs predetermined integration processing on a plurality of voxels arranged in a three-dimensional coordinate system,
A three-dimensional data processing device that integrates a plurality of three-dimensional shape data acquired by three-dimensional measurement, (a) based on the respective measurement orientation of the plurality of three-dimensional shape data, for each of the plurality of voxels. Setting means for setting a representative measurement direction, (b) for each of the plurality of voxels, three-dimensional shape data relating to the measurement direction deviating from the plurality of three-dimensional shape data by a predetermined angle or more with respect to the representative measurement direction. Integration means for excluding the predetermined integration processing.

According to a second aspect of the present invention, in the three-dimensional data processing apparatus according to the first aspect of the invention, the setting means performs (a-1) predetermined vector combination for each of the measurement directions. , A means for calculating the representative measurement orientation.

According to a third aspect of the present invention, in the three-dimensional data processing device according to the second aspect of the invention, the predetermined vector composition represents each of the plurality of three-dimensional shape data in the three-dimensional coordinate system. It is a vector composition that is weighted according to the distance from the shape to the voxel.

According to a fourth aspect of the present invention, in the three-dimensional data processing apparatus according to the first aspect of the invention, the setting means performs (a-2) principal component analysis for each of the measurement directions. Means for calculating the representative measurement direction, (a
-3) to the representative measurement direction, and the information of the composite vector weighted according to the distance from each shape to the voxel representing the three-dimensional shape data in the three-dimensional coordinate system for each of the measurement direction And a means for calculating the representative measurement direction.

According to the invention of claim 5, the three-dimensional data processing apparatus is installed in a computer built in the three-dimensional data processing apparatus, so that the three-dimensional data processing apparatus is according to any one of claims 1 to 4. It is a program that functions as a three-dimensional data processing device.

Further, the invention according to claim 6 relates to the invention according to any one of claims 1 to 4, wherein the three-dimensional data processing device is installed in a computer built in the three-dimensional data processing device. It is a recording medium in which a program for functioning as a three-dimensional data processing device is recorded.

Further, the invention of claim 7 is a cubic system for integrating a plurality of three-dimensional shape data acquired by three-dimensional measurement by performing a predetermined integration process on a plurality of voxels arranged in a three-dimensional coordinate system. Original data processing method,
(a) based on each measurement direction related to the plurality of three-dimensional shape data, a setting step of setting a representative measurement direction for each of the plurality of voxels, (b) for each of the plurality of voxels, the plurality of three-dimensional An integration step of excluding three-dimensional shape data relating to a measurement direction that deviates from the representative measurement direction by a predetermined angle or more from the shape data and performing the predetermined integration process.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION <Main Part Configuration of Three-Dimensional Data Processing Device> FIG. 1 is a diagram showing a main part configuration of a three-dimensional data processing device 1 according to an embodiment of the present invention.

The three-dimensional data processing apparatus 1 is constructed as a personal computer, for example. The three-dimensional data processing device 1 includes a processing unit 10 having a box shape,
It has an operation unit 11 and a display unit 12 composed of, for example, a CRT.

The processing unit 10 has a drive 101 into which the recording medium 9 such as an optical disk is inserted.

The operation unit 11 has a mouse 111 and a keyboard 112, and receives an input operation to the three-dimensional data processing apparatus 1 from an operator.

FIG. 2 is a diagram showing functional blocks of the three-dimensional data processing apparatus 1.

The processing unit 10 of the three-dimensional data processing apparatus 1 is
Input / output I connected to the operation unit 11 and the display unit 12
/ F13 and a control unit 14 electrically connected to the input / output I / F13. Further, the processing unit 10 includes the control unit 1
4 and the input / output I / F 16
It has and.

The input / output I / F 13 is an interface for controlling data transmission / reception between the operation unit 11 and the display unit 12 and the control unit 14.

The storage unit 15 is configured as a hard disk, for example.

The input / output I / F 16 is an interface for inputting / outputting data to / from the recording medium 9 via the drive 101.

The control unit 14 has a CPU 141 and a memory 142, and is a part that controls the operation of the three-dimensional data processing apparatus 1 in a centralized manner. Memory 14 of this control unit 14
2 can store program data recorded in the recording medium 9 via the input / output I / F 16. As a result, the stored program can be reflected in the operation of the three-dimensional data processing device 1.

Further, the control unit 14 can perform a process of integrating a plurality of three-dimensional shape data. For example, as shown in FIG.
That is, the three-dimensional object 3 acquired by measuring (observing) from multiple directions
The multi-viewpoint three-dimensional shape data corresponding to the partial shape can be integrated to generate the three-dimensional shape data around the three-dimensional object 3.

Before explaining the operation of the three-dimensional data processing apparatus 1, the principle of integration of the above-mentioned three-dimensional shape data, in particular, the principle of shape integration by the volume method will be described.

<Principle of integration of three-dimensional shape data> FIG. 4
FIG. 3 is a diagram for explaining a three-dimensional shape representation by a volume method.

According to the volume method, the quadrangular pyramid Ca represented by the boundary representation method in FIG. 4 (a) has a plurality of voxels arranged in a three-dimensional coordinate system as shown in FIG. 4 (b). :
Volume element) Vx. As described above, in the shape representation by the volume method, an arbitrary shape is represented by stacking a large number of voxels Vx having a minute volume. Further, by giving an attribute value according to data processing to this voxel Vx, various data processing using this attribute value becomes possible.

FIG. 5 is a diagram for explaining an attribute value given to a voxel.

The voxel Vx is a three-dimensional shape measuring device 2
The polygon group Pm, which is three-dimensional shape data measured by the sensor Sn (see FIG. 3), is located at a distance Lo along the measurement direction Do of the sensor Sn, and the distance value related to this distance Lo is It can be used as an attribute value of the voxel Vx.

When a plurality of voxels Vx in which distance values are stored as attribute values in this way are distributed in a three-dimensional space,
A distance potential (field) can be formed. This distance potential will be described below.

FIG. 6 is a diagram for explaining the distance potential.

FIG. 6A is a diagram showing a cross section of a three-dimensional shape Ko represented by a polygon group or the like. This shape Ko
On the other hand, as shown in FIG. 6B, the measurement direction Do (FIG. 5)
The direction Da of the distance potential corresponding to is set, and voxels having the attribute value of the distance from the shape Ko are three-dimensionally arranged in this direction Da. As a result, as shown in FIG. 6C, for example, a contour surface K1 having a distance potential of +0.5 and a contour surface K2 having a distance potential of −0.5 centering on the shape Ko serving as the boundary itself. It is possible to form a scalar potential field with a distance having.

FIG. 7 is a diagram for explaining the integration of the three-dimensional shape data using the distance potential.

Two partial shapes KA and KB shown in FIG.
When integrating with respect to the overlapping section Pa, as described above, the partial potentials VA and VB are converted into distance potential fields VA and VB. Next, as shown in FIG. 7B, after the partial shapes KA and KB are aligned, the distance value Vo integrated is generated by, for example, adding the distance values stored in each voxel. (Fig. 7
(c)). Then, for example, a curved surface having a distance potential of 0 is extracted by a scalar isosurface extraction method such as the Marching Cubes method, and when this is expressed by a boundary expression such as a polygon, the integrated three-dimensional image shown in FIG. The shape KC can be generated. By the above method, a plurality of three-dimensional shape data can be properly integrated.

The operation of the three-dimensional data processing apparatus 1 using the above-described three-dimensional shape data integration method will be described below. In this operation, the process of extracting the three-dimensional shape data to be excluded from the integration is performed in advance so that the integration process for each voxel is not performed on the three-dimensional shape data that should not be integrated.

<Operation of the three-dimensional data processing apparatus 1> FIG.
3 is a flowchart illustrating an operation of integrating three-dimensional shape data in the three-dimensional data processing device 1. This operation is automatically executed by the control unit 14.

In step S1, a plurality of polygon meshes (three-dimensional shape data) which are boundary expression data are input. Specifically, the multi-viewpoint polygon mesh data acquired by the three-dimensional shape input device 2 shown in FIG. 3 is input to the three-dimensional data processing device 1 through, for example, the recording medium 9 or the like. The position information of the three-dimensional shape input device 2 when each polygon mesh data is measured is also input.

In step S2, as shown in FIG. 7B, the input polygon meshes are aligned.
Here, the plurality of polygon meshes are aligned based on the position information of the three-dimensional shape input device 2 with respect to the subject 3.

In step S3, a plurality of aligned polygon mesh data are integrated. This operation will be described in detail below.

FIG. 9 is a flow chart for explaining the integration of polygon mesh data corresponding to the above step S3.

In step S11, as shown in FIG. 7A, each polygon mesh data is converted into data expressing a shape by volume method (hereinafter, simply referred to as "shape data"). That is, it is converted into a distance potential centered on each polygon mesh.

In step S12, the representative measurement orientation is set for each voxel arranged in the three-dimensional coordinate system. The calculation of the representative measurement orientation will be described below.

FIG. 10 is a diagram for explaining the calculation of the representative measurement orientation in voxels. Note that FIG. 10 shows the three-dimensional space two-dimensionally for convenience, and the lattice in the drawing shows each voxel.

The shapes FA and FB of the three-dimensional coordinate system are polygon meshes measured from the measurement directions EA and EB, respectively. Here, the representative measurement direction of the voxel Vt of interest is
It is calculated by performing weighting according to the distance value between the target voxel Vt and each shape FA, FB, and combining the vectors corresponding to each measurement direction EA, EB. Below,
A specific procedure will be described.

First, as shown in FIG. 11, from the center Cv of the voxel Vt of interest to the measurement surface of the shape FA, the measurement direction E
The distance value LA, which is the length measured in the direction of A, and the distance value L from the center Cv of the voxel Vt of interest to the measurement surface of the shape FB.
Find B and.

Next, for example, the functions GA and G shown in FIG.
Distance value L based on B (horizontal axis is distance value, vertical axis is weighting coefficient)
The weighting factors corresponding to A and LB are acquired. This function G
In A and GB, the weighting factor has a peak value at a distance value of 0, and the larger the absolute value of the distance value, namely, the voxel Vt of interest.
And the three-dimensional shape are separated from each other, the weighting coefficient decreases.

Then, as shown in FIG. 13, the measurement direction E
A vector HA obtained by multiplying A by a weighting coefficient and a measurement direction E
A vector HB obtained by multiplying B by a weighting factor is combined, and this combined vector HC is used as the representative measurement direction. In this case, since the distance value LA is smaller than the distance value LB due to the characteristic of the above function, the weighting coefficient becomes large, and the absolute value of the vector HA becomes larger than the absolute value of the vector HB. That is, the direction of the synthetic vector HC that is the representative measurement direction is dominant because the measurement direction EA of the shape FA has a large influence.
In other words, in a voxel close to the shape plane, the measurement direction to which the shape plane belongs is adopted as the representative measurement direction.

The calculated representative measurement direction is stored in the target voxel Vt together with the information of the distance potential, but the representative measurement direction is similarly calculated for the voxels other than the target voxel Vt, and the information is stored. It will be. Note that this representative measurement orientation is information that needs to be held only during shape integration processing, but does not need to be held thereafter.

Returning to FIG. 9, the description will be continued.

In step S13, it is determined for each voxel whether or not there is shape data for the representative measurement direction calculated in step S12 and the measurement direction deviated by a predetermined angle, for example, 120 degrees or more. Here, if there is shape data in a measurement direction that deviates from the representative measurement direction by a predetermined angle or more, the process proceeds to step S14, and if there is no such shape data, the process proceeds to step S15.

In step S14, the shape data of the measurement direction deviated from the representative measurement direction in step S13 by a predetermined angle or more is excluded from the integration target. Specifically, when the shapes F1 and F2 of the three-dimensional coordinate system shown in FIG. 14 are integrated, the shape data F having a measurement direction H2 deviated by 120 degrees or more from the representative measurement direction H3 stored in the voxel Vu.
2 is excluded from the integration target for the shape F1.

In step S15, the integration processing of the distance potentials excluding the shape data excluded from the integration target is performed for each voxel (see FIG. 7C).

In step S16, as shown in FIG. 7D, the zero isosurface of the distance potential is extracted to generate a polygon mesh which is a boundary expression. The generated polygon mesh becomes integrated three-dimensional shape data.

By the operation of the three-dimensional data processing apparatus 1 described above, shape data that deviates from the representative measurement orientation and a predetermined angle or more for each voxel is excluded from the integration target, so that the reproducibility of the shape in the thin portion of the three-dimensional object is improved. it can.

Regarding the integration processing of three-dimensional shape data, the integration of two pieces of three-dimensional shape data has been described, but the three pieces of three-dimensional shape data M1 to M shown in FIG.
The same processing is performed when integrating 3 as well.

In the case of integrating the three-dimensional shape data M1 to M3 measured from the measurement directions N1 to N3, the representative measurement direction is calculated for each voxel similarly to the integration of the two curved surfaces. For example, regarding the calculation of the representative measurement direction of the voxel Vp of interest, as shown in FIG.
Vectors R1 to R3 that are weighted according to the distance to each shape surface for 3 are obtained, and a composite vector Rt that combines these three vectors R1 to R3 is set for the representative measurement direction.

For the voxel Vp of interest, the measurement direction N3 deviating from the representative measurement direction Rt by 120 degrees or more.
The shape data M3 that belongs to is excluded from the integration target. That is, in the target voxel Vp, the integration processing of the distance potential of the shape data M1 and the distance potential of the shape data M2 is performed.

As described above, if one piece of information on the representative measurement direction calculated in consideration of the distance of each shape is added to each of a plurality of voxels, the shape data to be integrated can be selected. As a result, even when integrating a large number of shape data,
Since the shape data that should not be integrated can be excluded before the integration processing for each voxel based on the information for the representative measurement, it is possible to uniformly perform the integration processing of the distance potential for each voxel for all the shape data.

It is not essential to collectively calculate the distance potential for all the shape data, and the distance potential calculation may be performed only for a necessary portion.

<Modification> ⊙ Principal component analysis may be used to calculate the representative measurement orientation in the above embodiment. That is, after the representative measurement direction is calculated by performing the principal component analysis on the measurement direction of each of the three-dimensional shape data, for example, FIG.
The sign of the representative measurement direction obtained from the information of the combined vector weighted according to the distance value between the voxel and each shape using the functions GA and GB shown in FIG. To calculate. Accordingly, since the representative measurement direction is obtained by using the principal component analysis, the representative measurement direction can be calculated with high accuracy.

For the representative measurement orientation in the above embodiment, it is not essential to calculate by vector synthesis,
For example, the measurement direction to which the shape data closest to the voxel belongs may be the representative measurement direction. In this case, the accuracy of the representative measurement direction is reduced, but the representative measurement direction can be easily determined.

The potential expression in the above embodiment is not limited to the scalar value expression but may be the vector expression.

[0063]

As described above, according to the inventions of claims 1 to 7, the representative measurement direction is set for each of a plurality of voxels based on each measurement direction of a plurality of three-dimensional shape data, For each of a plurality of voxels, a predetermined integration process is performed by excluding, from the plurality of three-dimensional shape data, the three-dimensional shape data related to the measurement direction deviating from the representative measurement direction by a predetermined angle or more. As a result, the reproducibility of the shape in the thin portion of the three-dimensional object can be improved.

In particular, according to the second aspect of the invention, since the representative measurement direction is calculated by performing a predetermined vector combination for each measurement direction, the representative measurement direction can be set with high accuracy.

Further, in the third aspect of the invention, the predetermined vector composition is vector composition which is weighted according to the distance from each shape representing a plurality of three-dimensional shape data in a three-dimensional coordinate system to a voxel. , The representative measurement direction can be set more accurately.

Further, in the invention of claim 4, the representative measurement direction calculated by performing the principal component analysis for each measurement direction and the three-dimensional shape data for each measurement direction are expressed in the three-dimensional coordinate system. The representative measurement direction is calculated based on the information of the combined vector weighted according to the distance from each shape to the voxel. As a result, the representative measurement direction can be set accurately.

[Brief description of drawings]

FIG. 1 is a diagram showing a main part configuration of a three-dimensional data processing apparatus 1 according to an embodiment of the present invention.

FIG. 2 is a diagram showing functional blocks of a three-dimensional data processing apparatus 1.

FIG. 3 is a diagram for explaining acquisition of multi-viewpoint three-dimensional shape data for a three-dimensional object.

FIG. 4 is a diagram for explaining three-dimensional shape representation by a volume method.

FIG. 5 is a diagram for explaining an attribute value given to a voxel.

FIG. 6 is a diagram for explaining a distance potential.

FIG. 7 is a diagram for explaining integration of three-dimensional shape data using a distance potential.

FIG. 8 is a flowchart illustrating an operation of integrating three-dimensional shape data in the three-dimensional data processing device 1.

FIG. 9 is a flowchart illustrating integration of polygon mesh data.

FIG. 10 is a diagram for explaining calculation of a representative measurement direction in voxels.

FIG. 11 is a diagram for explaining a distance value used to calculate a representative measurement direction.

FIG. 12 is a diagram for explaining weighting used to calculate a representative measurement orientation.

FIG. 13 is a diagram for explaining calculation of a representative measurement direction by vector combination.

FIG. 14 is a diagram for explaining an example of shape integration using a representative measurement orientation.

FIG. 15 is a diagram illustrating an example of shape integration regarding three pieces of shape data.

FIG. 16 is a diagram illustrating integration of three-dimensional shape data according to a conventional example.

[Explanation of symbols]

1 Three-dimensional data processing device 2 Three-dimensional shape measuring device 14 Control unit H1, H2, N1, N2, N3 For measurement For H3, Rt representative measurement Vt, Vu, Vp Voxels of interest

Claims (7)

[Claims] 1. A three-dimensional data processing apparatus for integrating a plurality of three-dimensional shape data acquired by three-dimensional measurement by performing a predetermined integration process on a plurality of voxels arranged in a three-dimensional coordinate system. , (A) setting means for setting a representative measurement orientation for each of the plurality of voxels based on the respective measurement orientations related to the plurality of three-dimensional shape data, (b) for each of the plurality of voxels, the plurality of tertiary 3D data, characterized in that the original shape data excludes 3D shape data relating to a measurement direction that deviates from the representative measurement direction by a predetermined angle or more and performs the predetermined integration processing. Processing equipment. 2. The three-dimensional data processing device according to claim 1, wherein the setting unit calculates the representative measurement direction by (a-1) performing a predetermined vector combination for each of the measurement directions. A three-dimensional data processing device comprising: 3. The three-dimensional data processing apparatus according to claim 2, wherein the predetermined vector composition is performed according to a distance from each shape representing the plurality of three-dimensional shape data in the three-dimensional coordinate system to a voxel. A three-dimensional data processing device, characterized in that vector synthesis is performed by weighting. 4. The three-dimensional data processing device according to claim 1, wherein the setting means includes: (a-2) means for calculating a representative measurement direction by performing a principal component analysis on each of the measurement directions. , (A-3) the representative measurement direction, and of the composite vector weighted according to the distance from each shape to the voxel representing the three-dimensional shape data in the three-dimensional coordinate system for each of the measurement direction Means for calculating the representative measurement orientation based on information, and a three-dimensional data processing apparatus. 5. The three-dimensional data processing apparatus is made to function as the three-dimensional data processing apparatus according to any one of claims 1 to 4 by being installed in a computer incorporated in the three-dimensional data processing apparatus. A program characterized by that. 6. The three-dimensional data processing apparatus is made to function as the three-dimensional data processing apparatus according to any one of claims 1 to 4 by being installed in a computer built in the three-dimensional data processing apparatus. A computer-readable recording medium on which a program for recording is recorded. 7. A three-dimensional data processing method for integrating a plurality of three-dimensional shape data acquired by three-dimensional measurement by performing a predetermined integration process on a plurality of voxels arranged in a three-dimensional coordinate system. , (A) a setting step of setting a representative measurement orientation for each of the plurality of voxels based on the respective measurement orientations related to the plurality of three-dimensional shape data, (b) for each of the plurality of voxels, the plurality of tertiary An integration step of excluding three-dimensional shape data relating to a measurement direction deviating from the representative measurement direction by a predetermined angle or more from the original shape data, and performing the predetermined integration process. Processing method.