JPS6174076A - Segment pattern preparing system - Google Patents

Abstract

PURPOSE:To compress segment pattern data which becomes necessary in a high-speed polygonal approximation by reversing the later direction of travel from right to left when necessary and expressing a shape of two segment patterns with the data for one piece, in accordance with the direction of travel at the first crossover point. CONSTITUTION:A control part 100 controls a flow of the necessary processing to respective parts and an area characteristic is extracted by an area characteristic extracting 110 and an area characteristic memory 111. Here, a segment pattern is expressed by a two-dimensional arrangement of 3Xn, and this is stored in a memory 115 as pattern data. The second attached letter value of arrangement corresponds to an n number of points on a segment pattern expressed by a point row and the first attached letter corresponds to three directions of travel in respective points, namely, turning to the left, going straight and turning to the right. A flag, which shows with on and off that to compress a shaft symmetrical pattern, the point row is already turned to the right or to the left or continues to go straight only, is installed, and by limiting the direction turned first to one side, only one side of shaft symmetrical patterns is made and the data are compressed to half.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a line segment pattern creation method used in a component recognition device using image processing. The present invention relates to a line segment pattern creation method suitable for performing a process of approximating a sequence of points) with line segments at high speed.

[Background of the invention]

Conventionally, it has been proposed to perform component recognition by approximating a component pattern into a polygon for the purpose of high-speed and flexible image processing. At this time, all line segment patterns are stored and the sides of the polygon are extracted at high speed by comparing the contour point sequence of the part with this. Regarding this,
For example, in the Proceedings of the National Conference of the Institute of Electrical Engineers of Japan published on March 10, 1988 [15, paper number 134G], parts recognition is performed by line segmentation pattern matching.

However, in such conventional methods, the line segment pattern data used in line segmentation processing includes all straight line patterns within a certain length, resulting in a large memory size, which poses a problem in terms of downsizing and economical equipment. Met.

[Purpose of the invention]

The purpose of the present invention is to solve the above-mentioned problems of the conventional art, to compress line segment pattern data necessary for high-speed polygonal approximation, and to provide a line segment pattern creation method that can be executed even by a small-scale image processing device. Our goal is to provide the following.

[Summary of the invention]

The line segment pattern is axially symmetrical in pairs. When viewed as a traveling direction series, the left and right sides are reversed at each corresponding point. Therefore, in the present invention, by holding only one of the two line segment patterns and reversing the subsequent direction of movement from side to side according to the direction of movement at the first bending point, the shape of the two line segment patterns is divided into one part. The data is expressed as follows.

[Embodiments of the invention]

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

FIG. 1 is a block diagram showing an embodiment of an image processing apparatus according to the present invention.

Here, 100 is a control unit that controls the flow of required processing for each unit described below. r: J1 to 104 are related to preprocessing, 101 is an input control unit, 102
is an image memory, +05 is a preprocessing unit, and 104 is an area information memory. 105 and 106 are related to contour extraction processing; 105 is a contour extraction unit; and 106 is a contour memory. Reference numerals 107 to 109 relate to line segmentation processing; 107 is a line segmentation processing unit; 115 is a line segment pattern memory; 108 is a line segmentation information memory; and 109 is a dictionary pattern memory. 110 and 111 are related to region feature extraction processing, 110 is a region feature extraction unit, 111
is the region feature memory. Reference numerals 112 to 114 are related to pattern matching processing, and 112 is a common area extraction unit, 113 is a common area memory, and 114 is a recognition processing unit.

First, input image data is digitized and binarized using a predetermined threshold value by the input control unit 101, and then input and stored in the image memory 102 as grayscale image data and binary image data.

In the image data stored in the image memo 1J102, the preprocessing unit 105 first determines which area on the image is to be the target object area, and then the position information of the representative point of that area is stored in the area information memory 104. be done.

Next, the contour extraction unit 105 determines a search start point based on the position information of the representative point, sequentially searches for contour pixels in the specified area on the image, and stores, for example, the center coordinate value in the contour memory 106. let

Based on the center coordinate values, the line segmentation processing unit 107 approximates the line segment by tracing the point sequence representing the center of the contour pixel one by one and comparing it with the line segment pattern data preset in the line segment pattern memory 115. and the end point of the line segment,
That is, the coordinates of each vertex obtained by approximating the area to a polygon are sequentially stored in the line segmentation information memory 10B. The line segment r prefix is transferred to the dictionary pattern memory 109 when a dictionary pattern is registered.

In addition, the region feature extraction unit 110 & extracts features of the specified region (for example, area 1 center of gravity, principal axis of inertia, maximum length 1 perimeter, etc.) from the contents of the line segmentation information memory 108,
11 to be memorized. When registering a dictionary pattern, its characteristic information is stored in the dictionary pattern memory 109.

Furthermore, the common area extracting unit 112 extracts the currently input pattern (stored in the line segmentation information memory 108) and the dictionary pattern (stored in the dictionary pattern memory 109) so that the characteristics of both After converting the coordinates on the input cover pattern side so that they match (for example, so that the barycenter coordinates match or the principal axis of inertia directions match), the common area (seed shape) of both patterns is similarly converted to a vertex. It is obtained as a column and recorded in the common area memory 113.

Finally, the 1 recognition processing unit 114 calculates the area of the common area (seed figure), calculates the ratio of this to the area of the dictionary pattern or input pattern, and if the value exceeds a predetermined value, both patterns are It is determined that there is a match and the recognition result is output.

If the two patterns do not match and there are multiple dictionary patterns, the second. The matching process with the fifth dictionary pattern is repeated in the same way. Note that the recognition processing unit 114 calculates the position of the input cover turn from the relative position before conversion of both matching patterns.

Posture information is also output.

In the above series of image processing, the main part of the present invention is
Next, a method of creating a line segment pattern used in the line segment pattern memory 115 and processing using the same will be described.

The polygonal approximation performed by the line segmentation processing unit 107 is a process in which the outline of the target image area is traced, and when a series of continuous outline points can be regarded as a straight line, both end points thereof are set as the vertices of the polygon.

As shown in Figure 2, there are two ways to think about contour lines: (A) and (B), where the center of a contour pixel is the contour line, and (C), where the boundary line between area pixels and background pixels is the contour line. There are two ways (D), and the adjacency state of continuous contour points is as follows:
4-connection (B), (D) considering only vertical and horizontal adjacency,
There are two ways, 8-connection (A) and (C), which take diagonal adjacency into consideration. Therefore, for contour tracing, (A) to (D
) There are four methods in total. However, among these, 8 boundaries are connected (
C) is meaningless because it does not uniquely correspond to the pixel value.

In each case, the direction of tracking is shown in Figure 2 (cL).

There are possibilities as shown in (α・), (A), and (Li). Hereinafter, a case will be described in which a contour line is traced using boundary 4 connection (D).

An example of a contour point sequence is shown in FIG. Each contour point has its own direction of movement, as indicated by the arrow in the figure, and the shape of the contour line is represented by a column of this direction of movement. If a restriction is placed on the length, the sequence of points that are considered to be line segments under certain conditions □ becomes a finite number of sequences in the direction of travel. The condition for considering a line segment is, for example, that a maximum permissible distance from the center line is determined, and a line segment is a point sequence in which all points satisfy this value. Since the number and length of line segment patterns are finite, all line segment patterns can be created artificially.

FIG. 4 shows an example of a representation format of a line segment pattern and polygon approximation using the same.

The line segment pattern is represented by a 5×2 two-dimensional array as shown in FIG. 4(α)K, and this is stored in the memory 115 as pattern data. The second subscript value of the array corresponds to the points on the line segment pattern represented by the dot sequence, and the first subscript value corresponds to the three directions of travel at each point, namely, left turn, left turn,
Supports going straight and turning right. The contents of the array element are the number, ie, the pointer, of the next point when the direction of movement is determined at a certain point. For example, when the direction of travel is determined to be a right turn at the starting point °0", the number of the next point when traveling in that direction is indicated as °187". However, since there is a restriction that the point sequence can be regarded as a straight line, all five traveling directions are not always allowed at each point. An end mark END is written in the element corresponding to the prefecture direction, and when this is detected while tracing the contour, the detected point is regarded as the end point of the line segment, and this is the apex of the polygon. and register. In Fig. 4(b), at the starting point S of the line segment, tracking starts from the starting point 102 of the → minute pattern, the end mark END is detected at point E, this point 533° is set as the vertex of the polygon, and the line segment Return the pattern pointer to the starting point "01" and begin tracing a new line segment. In the figure, the number of each point is the point number of the line segment pattern.

Next, the procedure of polygon approximation using this line segment pattern will be explained using FIG. 5 and taking FIG. 4 as an example. In polygonal approximation, contour points are traced one by one, and at the same time, a line segment pattern is traced by selecting the ink according to the direction of movement at each point. First, the tracing starting point, for example, Fig. 4 (b ) are registered as the first vertices of the polygon, and the line segment pattern pointer is set to "0" for initialization (step 501).

Thereafter, the processes of steps 501 to 507 are repeated. First, the traveling direction at the tracking start point SK is determined (step 502). Here, a method for determining the traveling direction will be explained using FIG. 5.

In FIG. 5, it is assumed that pixel A is included in the component area. First, it is checked whether pixel B is included in the component area, and if it is not included, the traveling direction is set to be a right turn. Next, it is checked whether pixel B is included in the component area, and if it is not included, the moving direction is set to move forward, and if it is included, the moving direction is set to be a left turn. To determine whether a pixel is included in the component area,
There are various methods, for example, for a binary image, the contour memory 1
It can be determined whether the value read from 06 is 1# or "0#."

Next, referring to the slot pointed to by the pointer of the line segment pattern, the next pointer is selected according to the direction of movement (step 505). For example, in the case of FIG. 4, the area of pointer "0" is referred to, and in this case, since the direction of travel is a right turn as shown in FIG. 4(b), the next pointer 1187'' is selected.

If the next pointer is the end mark END (step 5o4), the contour point at that point is newly registered in the line division information memory 108 as the vertex of the polygon, and the pointer is returned to °0'' (step 505). .

Next, proceed to the next contour point according to the traveling direction (step 506), and check the end condition, for example, whether or not the contour has been circled once and returned to the tracking start point S.Step 507
), steps 502 to 507 are repeated until the termination condition is satisfied.

For example, when tracing the contour line shown in Figure 4 (6) according to the line segment pattern data shown in Figure 4 (α), start from pointer "01" and follow the direction of travel (right turn) to the next voice/pointer.
Proceed to '187'. After that, move on to the next contour tracking,
Determine the direction of travel (straight ahead) and select the pointer 1315". From then on, tracking is performed in the same way until the end mark END is reached.
When a pointer indicating ``3'' is detected, the pointer at that time is
53# is registered as the vertex. Then, the coordinate position at this time is calculated based on the coordinate of the starting point and stored in the memory 108.

However, as shown in Figure 4 (α), the first bending point of a pair of axially symmetric line segments is a right turn (or left turn).
Since there is only one side limited to , 7 lags are maintained in this loop, and after the first break point appears on the contour point sequence, when that break point is a left turn (right turn), the line segment pattern is Use left and right reversed. Since the line segment pattern shown in FIG. 4 (α) is constant data, it can be created offline and later loaded with the program. Therefore, there is no need to perform high-speed processing during creation.

In addition, since the contents of line segment patterns are not related to the processing procedure of polygon approximation, operations such as adjusting the roughness of polygon approximation can be programmed by replacing line segment patterns created using various straight line criteria. This can be easily done without changing the hardware or hardware.

Next, a procedure for creating a line segment pattern as shown in FIG. 4(α) will be explained. The line segment pattern is represented by a 5×1 array. The second subscript corresponds to each point on the construction line segment pattern, and the first
The subscript tS corresponds to the direction of movement at each point. The content is a pointer or end mark END that indicates the next point when the direction of travel is determined at each point. Therefore, a line segment pattern is a set of slots in which the allowed traveling directions at each point are written on the condition that the line is a straight line.

To create line butter y, at each point in the line pattern soil, add new points according to the five directions of movement,
It is determined whether the point sequence obtained by adding this is a straight line. If it is not a straight line, create an end mark, if it is a straight line, create a new slot corresponding to the added new point, write that number as a pointer, and repeat the same process for the new point.

Continue this process until the length of the line segment reaches the allowable value.

For this basic procedure, a method known as the vertical method in the state-space search method can be used. (described on pages ~56)
The above is the basic idea of creating a line segment pattern. The flow of processing will be explained below using FIG. 6.

The line segment pattern is represented by an array T. Let C be a counter that indicates how far a line segment pattern is used. Also,
In order to compress axially symmetrical patterns, a flag is set to indicate whether the point sequence has already bent to the right or left, or whether it continues to move straight ahead, and this flag is set to indicate whether the point sequence has already bent to the right or left, or whether it continues to move straight. Create only one pattern and compress the data by half.

First, as shown in FIG. 6 (α), the point sequence and counter are initialized. For example, the first two points of the point sequence are (owO>
and (+, 0). As a result, the line segment pattern is limited to one of the four rotationally symmetric patterns, and the data is compressed.

Leave the flag turned off. Also, clear the counter to 0.

Next, for the point (1,0) and the O-th slot of the line segment pattern, a point sequence extension process (step 602) is performed in which the point sequence is extended in five directions of travel (left turn, straight ahead, right turn) to determine a straight line. Let's do it. The point sequence extension process further includes the next point sequence extension process, and the extension is repeated one after another until the permissible length is reached. Details of the point sequence extension process will be explained with reference to FIG. 6(b). Note that FIG. 6(h) is a diagram showing the subroutine of step 602 in FIG. 6(α).

First, as shown in FIG. 6Cb), a point to be processed is specified by P. This pointer P is a local variable within the point sequence extension process, and is fixed to the value of C at the beginning of the point sequence extension process (step 611). The value of C itself changes during processing. Next, the counter and the black column length are incremented (steps 612 and 615), and a new point is added assuming that the direction of travel is a left turn. That is, pointer entry processing (step 614) is performed. This pointer entry process is shown in Figure 6 (C
), pointer entry processing is performed only if the flag is on (steps 621 to 625), and if it is off, an end mark END is written (step 627).

This limits the direction of the first bending point to the right. Next, the traveling direction is set to go straight, and pointer entry processing is performed this time regardless of the flag (step 615). Next, the direction of travel is set to right, a new point is added, the flag is turned on, and pointer entry processing is performed (step 616). That is, after turning right even once, the flag is turned on.

Next, each pointer entry process shown in FIG. 6(b) will be explained in detail with reference to FIG. 6(C). FIG. 6(C) is a diagram showing the subroutines of steps 614, 615, and 616 in FIG. 6(b). First, extend the point sequence (
Step 622), it is determined whether the length of the point sequence exceeds a tolerance value (Step 625). - If the second result is exceeded, an end mark is entered (step 627),
If not, it is determined whether the point sequence to which the new point has been added is a straight line (step 625). If it is not a straight line, an end mark is written (step 627). Any judgment criteria may be used as necessary. For example, a method is used in which the center line of a series of points is drawn using the least squares method and a maximum allowable value is set for the distance from this to each point. If it is a straight line, the counter C is incremented to create a new slot, this cuff/value is written as a pointer, and (step 62
5) For this new point, perform the point sequence extension process shown in Figure 6(b) and increment the length of the point sequence (
step 626). In this way, a line segment pattern as shown in FIG. 4(α)K is created. That is, the pointer entry process is performed by incrementing the counter from the pointer @0''', and if the first turning point is on the left, an end mark is written, and the pointer entry process in the case of straight travel is continued up to the allowable value.

Thereafter, pointer entry processing for right turns and roughly left turns is performed within the allowable values.

The line segment pattern created in this way includes all point sequences that are considered to be straight lines under certain standards, and does not include double point sequences of the same shape. As shown in α) and (b), there are parts C and D that have the same shape. When a part of the same shape includes the end point of a line segment, the point sequence data corresponding to that part will have double equivalent data, and by representing one of them and erasing the others, Data can be compressed.

The procedure will be explained using FIG. The part to be erased always includes the end point of the line segment, that is, the slot containing the end mark in all five directions, so go back and erase unnecessary parts from this line (.

First, as shown in FIG. 8(cL), the line segment pattern array is scanned to find the end point, and erasure marks are written in all but the first point (2) (step 801).

Next, perform point sequence integration processing by scanning the line segment pattern array and erasing all but one point containing ■ (
Step 802).

The point sequence integration process will be explained in detail using FIG. 8(b). First, pointer J to be sampled is designated. Then, the next sample I is cleared (step 811). Next, the line segment pattern is scanned to find points including J, and a point sequence erasing process is performed in which erasing marks are written on all points except the first point I (step 812). Next, if point I exists (step 813), a similar point sequence integration process is performed for point ■ (step 814).

Finally, erase all slots marked with erasure marks, pack the data, and exit (step 803).
.

By performing the above processing, the direction of the first breaking point of the line segment pattern is limited to the right, and when comparing with the actual point sequence, if the first breaking point of the point sequence is on the left, then By reversing the direction of movement, the line segment pattern memory 115 can be compressed in half.

〔Effect of the invention〕

As described above, according to the present invention, while taking advantage of polygon approximation processing in an image processing device, the required memory size can be significantly reduced, and the image processing device can be made smaller and more economical.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of an image processing device used in the present invention, FIG. 2 is a diagram for explaining a contour tracing method in polygon approximation processing, and FIG. Figure 4 is a diagram showing an example of line segment pattern expression format and polygon approximation, Figure 5 is a flowchart showing the procedure of polygon approximation, Figure 6 is a flowchart of line segment pattern creation processing, FIG. 7 is a diagram showing an example of line segment patterns having common parts, and FIG. 8 is a flowchart of data compression processing in which common parts of line segment patterns are removed.・・Image memory, +
05...-Preprocessing unit, [4... Area information memory, +O
S...Contour extraction unit, 106...Contour memory, 107
...Line segmentation processing unit, 108...Line segmentation information memory, 109...Dictionary pattern memory, 11Q...Region feature extraction unit, 111...Region feature memory, 112...
- Common area extraction unit, 115... common area memory, 11
4... Recognition processing unit, 100... Control unit, 115...
・Line segment pattern memory. 1st paper note 2 (A) (8)
(C) (D) (α)
(-e-) (d) Rod 3 picture) Note + figure 5 evening figure 4 accent 2 figure (ta) 74 figure mo 7 figure 8 figure (/:1.) Zutte γ♂ O3 to

Claims (1)

[Claims] Polygon approximation of the part image is performed by comparing the contour point sequence of the part image with data stored in a line segment pattern memory that stores various line segment patterns required for line segment approximation, and the vertex coordinates of the polygon are calculated. In an image processing device that performs recognition processing based on columns, one of the various line segment patterns that is axially symmetric is stored in a line segment pattern memory, and contour points are When matching against columns,
If the direction of the first bending point of the point sequence is reversed, the subsequent direction of movement is reversed and compared with data stored in the line segment pattern memory.