JPH0668766B2 - Three-dimensional measuring device for line segments using accumulated frame count information - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] A line segment three-dimensional measuring apparatus using accumulated frame count information for measuring a direction or the like of a line segment forming a three-dimensional image in a three-dimensional space. The aim is to prevent the extraction of direction information from being disturbed by the reflection of the metal surface that appears in some frames, and the imaging means that captures a stereoscopic image for each frame while moving the imaging position. Line segment extraction means for performing spherical projection and spherical mapping of the obtained image to extract line segment mapping points representing line segments forming a stereoscopic image, and mapping based on the line segment mapping points extracted by the line segment extraction means A mapping function generating means for generating a function, a mapping memory for storing the mapping function generated by the mapping function generating means, and an accumulating memory for counting the number of times of the frame in which the mapping function is drawn for each pixel. A cumulative threshold for updating the count value of the cumulative memory corresponding to the pixel for which the mapping function is drawn for each frame by reading the contents of the mapping memory, and a predetermined threshold using the updated cumulative memory contents. Filter means for filtering the segment direction information by filtering with the value.

[Industrial application field]

The present invention relates to a three-dimensional measuring device for line segments, which uses information on the cumulative number of frames to measure the direction of a line segment in a three-dimensional space that forms a stereoscopic image.

For example, when operating a robot in a place where human entry is dangerous, such as a nuclear reactor, in order to operate the object of the work with the robot manipulator,
It is necessary to measure the distance to the target and the posture of the target. It is necessary that such measurement can be performed quickly and accurately.

[Conventional technology]

In order to perform such stereoscopic measurement, a camera provided on the robot side performs spherical projection of an object, and the projection image is subjected to mapping processing to obtain various three-dimensional image information such as presence / absence of line segment, direction of line segment, Techniques for extracting the distance to a line segment are known, and are disclosed in, for example, JP-A-59-184973 and JP-A-60-21.
There is a proposal such as the 8183 publication.

A method of measuring the direction of a line segment in a three-dimensional space using a spherical map will be described below with reference to FIGS. 6 and 7.
As shown in FIG. 6, line segment L is spherically projected onto a spherical surface to obtain arc L '. Each point P ₁ , P ₂ , P ₃ ... Of the line segment L is an arc L '
Let the points projected above be P ₁ ′, P ₂ ′, P ₃ ′ ...
Draw a great circle (corresponding to the equator when each point is the north pole) l ₁ , l ₂ , l ₃ ... on the sphere with P ₁ ′, P ₂ ′, P ₃ ′… as the center.

As a result, a line segment mapping point S (hereinafter referred to as S point) at which a plurality of great circles l ₁ , l ₂ , l ₃ ... The point S is representative of the straight line segment L, and indicates that the straight line segment L exists.

Next, the position of the camera is moved in an arbitrary linear direction by a constant interval ΔC, a line segment is photographed at each moving point, and the point S is extracted. Here, one image obtained at each photographing point will be referred to as an image of each frame. FIG. 7 shows this state. In this figure, instead of moving the camera, the camera is placed at the center of the sphere and the line segment L is
It is shown as being moved relative to L ₁ , L ₂ , L ₃ . Corresponding to these line segments L ₁ , L ₂ , L ₃ ... S of S ₁ , S ₂ , S ₃ ...
It is assumed that points have been extracted.

When a plurality of S points obtained in this way are further spherically mapped to draw a great circle corresponding to each S point S ₁ , S ₂ , S ₃ ..., the direction mapping point SS (hereinafter , Called SS point)
Is required. The direction of the vector connecting the center 0 of the sphere and this SS point represents the direction of the line segment L.

In order to measure the three-dimensional azimuth of a line segment in this way, image data over several frames is used. That is, a great circle with the S point of each frame as a pole is drawn, and after drawing for all frames, the SS point is obtained as the convergence point of the great circle and the three-dimensional azimuth is measured.

As a method of extracting the SS point as the great circle convergence point, a method of narrowing down the peak point (convergence point) in consideration of the density of the S point is known. That is, when drawing a great circle with the S point as a pole, the density information of the S point is also entered, and after drawing for all frames, the peak point where the added value of the density is a peak is extracted as the SS point. It is a thing. The density at the S point is a value that increases with the length of the line segment or its clarity, and is a parameter that represents the "probability" of the existence of the line segment.

[Problems to be Solved by the Invention]

The conventional method that considers the density of the S point in the extraction of the SS point has an effect on the density data such as the length of the line segment, and is an effective method for processing a clean and clear image. .

On the other hand, if a metal surface or the like is reflected in the image and the light ray is strongly reflected by specular reflection or the like, the line segment is extracted with a very strong density. Such an image appears only on the screen of a part of a large number of frames, but its density is so large that it becomes a false image that is not to be measured and the image that is actually measured is desired. It confuses and interferes with the extraction of image contours.

Therefore, an object of the present invention is to prevent the extraction of the directional information from being disturbed even by the reflection of the metal surface appearing in a part of the frames in the measurement target image.

[Means for Solving the Problems]

FIG. 1 is a principle block diagram according to the present invention. The three-dimensional measuring apparatus according to the present invention includes an imaging unit 11 that captures a stereoscopic image for each frame while moving the imaging position, and the imaging unit 11
A line segment extracting means 12 for extracting a line segment mapping point S representing a line segment forming the stereoscopic image by spherical projection and spherical mapping of the image obtained in (3), and a line extracted by the line segment extracting means 12 Mapping point S
A mapping function generating means 13 for generating a mapping function based on, and a memory having a memory area corresponding to each of the pixels into which the spherical surface is divided into a plurality of pixels, the mapping function generating means 13 being generated by the mapping function generating means 13. A mapping memory 14 that stores the presence or absence of a mapping function for each frame and each pixel, a memory 15 having an area for writing information of the number of frames in which the mapping function exists for each pixel obtained by dividing the spherical surface into a plurality of pixels, and the mapping memory
The contents of 14 are read out in frame units, the memory updating means 16 for incrementing and updating the information of the number of frames of the memory 15 corresponding to the pixels with the mapping function, and the contents of the updated memory 15 And a filter means 17 for extracting line segment direction information by performing a filtering process for selecting a value larger than the threshold value and a value larger than the threshold value.

[Action]

An image pickup means 11 picks up a stereoscopic image for each frame to obtain an image, and a line segment extraction means 12 extracts a line segment mapping point S from this image. Then, the mapping function generating means 13 generates a mapping function based on the extracted mapping point S, and writes this in the mapping memory 14 for each frame.

The cumulative memory updating means 16 reads the contents of the mapping memory 14 frame by frame, and for a certain frame, increments and updates the contents of the pixels of the cumulative memory 15 corresponding to the pixels for which the mapping function is drawn. This operation is performed over all frames.

As a result, if the mapping function is drawn for a certain pixel over a plurality of frames, the count value of the contents of the cumulative memory 15 is increased by the number of frames in which the mapping function is drawn.

When the update of the cumulative memory 15 is completed, the filter means 17 filters the contents of the cumulative memory 15 by thresholding the contents with a predetermined threshold value. That is, a certain number of frames is set as a predetermined threshold value, and the contents of the cumulative memory 15 that do not reach this number of frames are deleted. As a result, as the contents of the cumulative memory 15, only the pixels in which the mapping function appears more times than the set threshold number of frames remain. If the direction mapping point SS of the line segment is extracted based on the result of this filter processing, the direction information can be extracted from the viewpoint of using the number of frames as a parameter.

False images such as reflections on a metal surface are rarely seen over many frames. On the other hand, we want to extract line segments with low density that are seen over many frames. Filtering is very effective.

As a result, it is possible to accurately measure the actual image while removing the influence of the false image that appears only in some frames, such as the reflection on the metal surface.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram showing the overall configuration of a three-dimensional measuring apparatus as an embodiment of the present invention. In FIG. 2, the apparatus of the present embodiment is roughly configured to include a camera device 1, a contour extracting unit 2, a host computer 3, a line segment extracting unit 4, a three-dimensional azimuth measuring unit (matching processor) 5, and the like. It

The camera device 1 is configured so as to take an image of an object to be photographed at each photographing position while moving at predetermined intervals in an arbitrary linear direction, and thereby obtain images of a plurality of frames of the object to be photographed. . The number of shooting positions is, for example, 10
Positional degree is selected.

The image captured by the camera device 1 is input to the contour extraction unit 2. The contour extraction unit 2 extracts the contour of the object to be photographed in the photographed image by a known method and supplies it to the line segment extraction unit 4.

The host computer 3 is a multi-bus 30, CPU 31, command interface 32, data interface 33, DMA controller 3
4. It is configured to include the command interface 35, etc., and controls the operation of each unit.

Line segment extraction unit 2 has internal bus 40, controller board 4
1, front stage interface 42, contour extraction unit interface 43, buffer memory board 44, WCS control board 45, 77 mapping boards 46 (# 0) to 46 (# 76), bus monitor board 47, data monitor board 48, rear stage The interface 49 and the like are included, and based on the contour data transferred from the contour extraction unit 2, an S point that represents a straight line segment that constitutes the contour of the object to be photographed, and is extracted for each frame by a known method. Then, the S point data is given to the three-dimensional azimuth measuring unit 5.

The three-dimensional azimuth measuring unit 5 includes an internal bus 50, a controller board 51, a front interface 52, and a buffer memory board.
53, WCS control board 54, 77 mapping boards 55 (# 0) ~ 55
(# 76), bus monitor board 56, data monitor board 57,
It is configured to include the latter-stage interface 58 and the like.

This three-dimensional azimuth measuring unit 5 includes 77 mapping boards 55.
(# 0) to 55 (# 76) is a parallel computing computer that executes parallel computing. The controller board 51 receives commands from the host computer 3, interprets them, and executes them on other boards on the three-dimensional azimuth measuring unit 5. It has the function of issuing commands.
The interfaces 52 and 58 are boards for transmitting and receiving data such as S points. The WCS control board 54 has a mapping board 55 (#
0) to 55 (# 76) for updating micro programs. The buffer memory 53 is a board for temporarily storing data, and the data monitor board 57 is a board for displaying and monitoring the data.

A detailed configuration example of the mapping boards 55 (# 0) to 55 (# 76) is shown in FIG. In FIG. 3, 61 to 64 are communication interface units, 65 is a great circle ROM, 66 is a luminance ROM, 67 is a command latch, 68 is an auxiliary code latch, 69 and 70 are adjacent interfaces, 71 is an address calculator, and 72 is an address calculator. Data calculator, 73 is mapping plane R
AM.

The mapping boards 55 (# 0) to 55 (# 76) have eight mapping surfaces. Each side is referred to as the bank B ₁ ~B _8. Bank designation is RA
This is done using the address of M.

Two arithmetic units 71 and 72 are mounted on this mapping board, and the address arithmetic unit 71 is an arithmetic unit for calculating the address of the mapping RAM 73. The data calculator 72 is connected to the data port of the mapping plane RAM 73 and processes data.

The luminance ROM 66 is a look-up table when the grayscale data is used as the mapping function. The command latch 67 is a register that holds an execution command issued from the controller board 51. The auxiliary code latch 68 is a register that holds the auxiliary code in the execution command issued by the controller board 51. Adjacent interfaces 69 and 70 are communication circuits for transferring data between adjacent boards.

The operation of the apparatus of this embodiment will be described below with reference to the drawings.

The overall flow of processing by the apparatus of this embodiment is shown in FIG. 4, and the line segment direction measurement processing procedure in FIG. 4 is shown in FIG.

First, the overall operation will be described with reference to FIG. The camera device 1 photographs the object while sequentially moving the photographing position (here, 10 positions), and the image data IM ₀ for 10 frames
~ IM ₉ is obtained. These image data IM _{0 to} IM ₉ are processed by the contour extraction unit 2 (step S),
As a result, contour data PD _{0 to} PD ₉ for 10 frames are obtained.

These contour data PD _{0 to} PD ₉ are further processed by the line segment extraction unit 4 to obtain 10 points of S point data SD _{0 to} SD _{9 of} each frame in total. S point data SD _{0 for} these 10 frames
~ SD ₉ is further input to the 3D bearing measurement unit 5,
Here, the line segment direction measurement processing is performed according to the procedure of FIG. 5 described later, and as a result, S point data SD _{0 to} SD ₉ of 10 frames are obtained.
Are integrated to obtain SS point data SSD consisting of SS point information indicating the direction of the line segment.

The line segment direction measurement processing procedure will be described below with reference to FIG. First, in the present embodiment, a mapping plane SP for writing a mapping function and a one-plane accumulation plane IP for binary accumulation of the mapping function are prepared.

First, the contents of the cumulative plane IP and the mapping plane SP are cleared (steps S12, 13). Next, the contents of the first frame of the S point data SD _{0 to} SD ₉ , that is, the contents of the S point data SD ₀ are read, a great circle with the read S point as a pole is generated, and this great circle is generated. Is written in the mapping plane SP (step S14). This operation is performed for all S points in the S point data SD ₀ (steps S14, S15).

When the writing of the great circle to the mapping plane SP for all S points of the S data SD ₀ is completed, then the contents of the mapping plane SP are scanned for all pixels, and if the great circle is present, the The content of the pixel of the cumulative plane IP corresponding to the pixel is incremented by 1 (step S16).

When this operation is completed for the S point data SD ₀ of the first frame, the same operation as described above is repeated for the S point data SD ₁ of the second frame, and the operation is repeated for the last frame S point data SD ₉ Repeat until (Steps S13 to S1
7).

As a result, the contents of each pixel of the cumulative plane IP are
The value is counted up by the number of frames in which a great circle exists for the pixel.

The SS points are extracted by using the contents of this cumulative plane IP as a frame number filter by the number of frames (step S1
8). That is, for example, "5" is set as the threshold value depending on the number of frames, and among the pixels of the mapping result in which the density is taken into consideration, only the pixels of the cumulative plane IP having a value of "5" or more are left and set as the SS point. The cumulative value of the pixel of is erased. As a result, the influence of the high-density S point, which is limited to only some frames, as a false image due to reflection on the metal surface is eliminated.

As a result, the obtained SS points are stored in the SS point data SSD. This makes it possible to extract the information indicating the direction of the line segment.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to this invention, the extraction of a line segment direction is not obstructed by the false image, such as the reflection of the metal surface which appears in some frames in the measurement target image, and the direction information can be extracted accurately. Like

[Brief description of drawings]

FIG. 1 is a block diagram showing the principle of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, FIG. 3 is a detailed block diagram of a mapping board in FIG. 2, and FIG. Fig. 5 shows the overall processing by Fig. 5, Fig. 5 is a flow chart showing the line segment direction measurement processing in Fig. 4, Fig. 6 is an explanatory view of a conventional S point extraction method, and Fig. 7 is a conventional SS. It is explanatory drawing of the extraction method of a point. In the figure, 1 ... Camera device 2 ... Contour extraction unit 3 ... Host computer 4 ... Line segment extraction unit 5 ... Three-dimensional azimuth measurement unit 30 ... Multi-bus 31 ... Central processing unit (CPU) 32, 35 …… Command interface 33 …… Data interface 34 …… DMA controller 41 …… Controller board 42, 52 …… Front stage interface 43 …… Contour extraction unit interface 44 …… Buffer memory board 45, 54 …… WCS control board 46, 55 …… Mapping board 47,56 …… Bus monitor board 48,57 …… Data monitor board 49,58 …… Post-stage interface

Claims (1)

[Claims] 1. An image pickup means (11) for picking up a stereoscopic image for each frame while moving a photographing position, and a spherical projection and spherical image projection of the image obtained by the image pickup means (11) to obtain the stereoscopic image. And a line segment extraction means (12) for extracting a line segment mapping point (S) that represents a line segment constituting the line segment, and a mapping function based on the line segment mapping point (S) extracted by the line segment extraction means (12). A mapping function generating means (13) for generating, and a memory having a memory area corresponding to a pixel obtained by dividing the sphere into a plurality of pixels for each frame, and the mapping function generating means (13) generating the mapping function. A mapping memory (14) that stores the presence or absence of a function for each frame and each pixel, and a memory that has an area for writing information on the number of frames in which the mapping function exists for each pixel obtained by dividing the spherical surface into a plurality of pixels (1
5) and the contents of the mapping memory (14) are read out in frame units,
Memory updating means (16) for incrementing and updating the information on the number of frames of the memory (15) corresponding to the pixels with the mapping function, and from the content of the updated memory (15), A three-dimensional measuring apparatus comprising: a small value as a threshold value, and a filtering means (17) for performing a filtering process for selecting a value larger than the threshold value and extracting line segment direction information.