JPH0571992B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recognition circuit for characters, figures, etc., and more particularly to a circuit for calculating the moment of a closed loop region in a bit pattern obtained by scanning a drawing or the like.

In image processing, characters and figures are often recognized. At this time, first-order or higher-order moments are determined in order to determine the center of gravity position and shape of characters and figures. For example, first-order moments M ₁₁ , M ₁₂ and second-order moments M ₂₁ ,
M ₂₂ and M ₂₃ are given by the following formula.

M ₁₁ = 〓 ^(x,y) ∈ ^R x M ₁₂ = 〓 ^(x,y) ∈ ^R y M ₂₁ = 〓 ^(x,y) ∈ ^R x ² M ₂₂ = 〓 ^(x,y) ∈ ^R xy M ₂₃ = 〓 ^(x,y) ∈ ^R y ² (1) In equation (1), R is the graphic area in the closed loop, and (x,
y) is the coordinate of the internal bit. The area S is determined by equation (2).

S= 〓 ^(x,y) ∈ ^R 1 (2) From the values obtained as above, the position of the center of gravity of the figure, and the variance V are obtained by equation (3).

=M ₁₁ /S, =M ₁₂ /S V = (M ₂₁ +M ₂₃ ) /S - (-2 x + -2 y) (3) Also, the shape of the figure is an ellipse, and the oblateness is h. In this case, it can be written as V/S=1+h ² /4πh (4), so the flatness can be determined from these values.

Conventionally, in order to find the moment of a graphical area in such a closed loop, the bit pattern is raster scanned and the coordinate values of the pixels included in the closed loop and their square values or products are accumulated to find the cumulative total. was. However, in the conventional method, pixel 1
It takes time to calculate each item one by one,
Another disadvantage is that when the closed loop region for which the moment is to be determined is complicated with other closed loop regions, it takes time and effort to separate the regions.

An object of the present invention is to provide a moment calculation circuit that can quickly and easily calculate moments in a closed loop region.

The present invention is based on the moment Σx ⁱ y ^j of a region R surrounded by a closed loop drawn on the drawing (Σ is the sum of all pixel positions (x, y) belonging to the region R, i, j
is an integer), the moment calculation circuit includes a pattern memory for storing a bit pattern obtained by scanning a drawing, etc., a write/read circuit that controls writing to and reading from the pattern memory, and a moment calculation circuit for storing the bit pattern obtained by scanning a drawing, etc. An edge trace section that traces the edges of the closed loop region in the bit pattern that has been created, and the coordinates (x,
One or more units that calculate the cumulative moment value _y 〓 ^y ′ ⁼¹ x ⁱ y′ ^j or _x 〓 ^x ′ ⁼¹ x′ ⁱ y ^j from y) and integrate the obtained value with a sign determined by the tracing direction The present invention is characterized in that it is comprised of a moment accumulator, and a control section for controlling each of the circuits.

Further, the present invention provides a moment Σx ⁱ y ^j of a region R surrounded by a closed loop drawn on the drawing (Σ is the sum of all pixel positions belonging to the region R, (x, y),
i, j are integers), the moment calculation circuit includes a pattern memory for storing a bit pattern obtained by scanning a drawing, etc., a write/read circuit that controls writing to and reading from the pattern memory, and a moment calculation circuit for calculating the bit pattern obtained by scanning a drawing, etc.; The distance from the reference line is obtained from the coordinates (x, y) of the current position of the trace point obtained from the edge trace section that traces the edge of the closed loop region in the bit pattern stored in the memory, and the edge trace section. An area accumulator that integrates the area with a sign determined by the tracing direction, and a moment cumulative value _y 〓 ^y ′ ⁼¹ x ⁱ y′ ^j or _x 〓 ^x ′ ⁼¹ from the coordinates (x, y) of the current position of the above trace point. It is composed of one or more moment accumulators that calculate x' ⁱ y ^j and integrate the obtained values with a sign determined by the trace direction, and a control section for controlling each of the circuits. Features. By importing the moment value and area obtained by the present invention into an external computer, etc., and performing simple calculations such as equations (3) and (4), the center of gravity position, shape parameters, etc. of the figure can be calculated. It is possible to obtain.

The moment calculation circuit of the present invention traces around one edge of a closed loop region, uses the direction of the trace as a sign for integration, and calculates x,
Accumulate the moment cumulative value calculated from the y coordinate. In other words, trace points are aligned with a predetermined straight line, for example, X
For example, when the direction of the trace when projected onto the axis is in the positive direction, the cumulative moment value is added to the cumulative value, and when the direction of the trace is in the opposite direction, the above product is subtracted from the cumulative value, and the trace completes one revolution. The integrated value of time is taken as the moment of the closed loop region.

Next, the principle of the present invention will be explained with reference to the drawings.

FIG. 1 is a diagram showing a closed loop in a bit pattern for explaining the operation of the moment calculation circuit of the present invention. The closed loop region can have any shape, but
The case of the illustrated shape will be explained as an example. In the figure, point P ₁ is the rightmost point of region R, and point P ₂ is the rightmost point of region R.
The leftmost point of the convex region in the middle, point P ₃ is the rightmost point of the concave region, point P ₄ is the leftmost point of region R, points P _I , P _J ,
P _K and P _L are points on the edge with the same X coordinate value x _I ,
The point P _T is the top point of the region R that is found first by raster scanning or the like. Moment calculation is performed as follows. In the explanation, the trace starting point is the topmost point of the region R, and the direction of the trace is clockwise, and the correspondence between the trace direction and the sign of the integration is positive when it is in the positive direction of the X axis, and negative when it is in the negative direction. point
Since the section from P ₄ to point P ₁ is traced in the positive direction of the X-axis, the moment cumulative value described later is added to the integrated value in this section, and the section from point P ₁ to P ₂ is traced in the negative direction of the X-axis. Therefore, in this section, the moment cumulative value is subtracted from the cumulative value, and from point P ₂ to point P ₃
Since the interval is traced in the positive direction, add the point
Since the section from P ₃ to point P ₄ is traced in a negative direction, it is subtracted, and this operation is continued until the trace goes around the region R.

The cumulative moment value differs depending on the order of the moment to be found, but for the five types of moments shown in equation (1), the contribution of a line segment of length y drawn from each point (x, y) to the X axis is Since it only needs to be accumulated, it becomes as shown in equation (5).

ΔM ₁₁ (x, y)= _y 〓 ^y ′ ⁼¹ x=xy ΔM ₁₂ (x, y)= _y 〓 ^y ′ ⁼¹ y′=1/2y(y+1) ΔM ₂₁ (x, y)= _y 〓 ^y ′ ⁼¹ x ² =x ² y ΔM ₂₂ (x, y)= _y 〓 ^y ′ ⁼¹ xy′=1/2xy(y+1) ΔM ₂₃ (x, y)= _y 〓 ^y ′ ⁼¹ y′ ² = 1/6y(y+1)(2y+1) (5) In this way, for example, when the X coordinate value is x _I , the moment cumulative value _{ΔM ij (} x _I , y _I ) (here, i and j represent the subscripts _1, 2, etc. of ΔM in equation (5)) and the cumulative moment value ΔM _ij (X _I , y _L ) at the point P _L is calculated as the difference. subtract, add the cumulative moment value ΔM _ij (x _I , y _K ) at point P _K , and subtract the cumulative moment value ΔM _ij (x _I , y _J ) at point P _J , so
After all, the moment cumulative value between point P _I and point P _J and point P _K
The contribution to the moment of the minute area in the region _XI in the region R, which is the cumulative value of the moment between and the point _PL , is added to the cumulative value. Since this is done over the entire area, it can be seen that the integrated value of the moments is the moment of the area. Note that the area S can be obtained by performing the same integration as above on the y-coordinate itself instead of the cumulative moment value ΔM _ij , and is
7512 "Area calculation circuit" is already known. By incorporating the area calculation circuit into the present invention,
It is possible to construct a device that easily obtains the feature values of a figure as shown in equations (3) and (4).

FIG. 2 is a block diagram showing an embodiment of the present invention including an area calculation circuit, which includes a control section 1, a pattern memory 2, an R/W circuit 3, an edge trace section 4, and an area accumulation circuit. 5 and a moment accumulator group 6. The edge trace section 4 includes a start point register 41, a current point register 42, a direction detection circuit 43, and a comparison circuit 44. The operation is as follows. Information processing equipment such as a computer (not shown)
sends the bit pattern to the pattern memory 2 via the signal line 101 and stores it. The information processing device further sends the coordinate values of the trace start point P _T to the start point register 41 and current point register 42 in the edge lace section 4 via the signal line 102, and stores them. The information processing device then sends a moment calculation command signal to the signal line 103.
It is sent to the control unit 1 via. When the control unit 1 receives the moment calculation command signal, it sends a clear signal to the area accumulator 5 and the moment accumulator group 6 (three in FIG. 2) via the signal line 104 to set each integrated value to 0.
and clear the trace signal to signal line 1.
05 to the R/W circuit 3. R/W circuit 3
When receiving the trace signal, receives the coordinate value of the current trace point from the current point register 42 via the signal line 106, and stores this as a memory address via the signal line 107 in the pattern memory 2.
The pattern data in the vicinity of the trace point, for example, the pattern data of 3×3 pixels centered on that point, is read out from the pattern memory 2 via the signal line 107 and sent to the edge trace section 4 via the signal line 108. The signal is applied to the direction detection circuit 43 inside. The direction detection circuit 43 determines the direction of the trace from the pattern data, and outputs a plus sign when the trace direction is in the positive direction of the X-axis, a minus sign when the trace direction is in the negative direction, and a direction perpendicular to the X-axis. In this case, 0 is sent to the area accumulator 5 and the moment accumulator group 6 via the signal line 110. The area accumulator 5 receives the y-coordinate value of the trace point from the current point register 42 via the signal line 111, and sends the sign to the signal line 110.
When the signal is received from the direction detection circuit 43 via the direction detection circuit 43, it is integrated. Further, the moment accumulator group 6 receives the x, y coordinate values of the trace point from the current point register 42 via the signal line 111, and receives the sign from the direction detection circuit 43 via the signal line 110, and receives the moment cumulative value. is calculated as shown in equation (5) and integrated. In other words, when the sign is positive, y
The coordinate value or moment cumulative value is added to each currently stored integrated value, and when the sign is negative, it is subtracted from the integrated value. When the sign is 0, no integration operation is performed. Thereafter, the count point register 42 in the edge trace section 4 receives the trace direction from the direction detection circuit 43 via the signal line 109, and uses the direction value to calculate the current contents and the coordinates of a new trace point corresponding to that direction. Update to value.

A comparison circuit 44 in the edge trace section 4 obtains the coordinate value of the trace start point from the start point register 41 via the signal line 112, and obtains the coordinate value of the current trace point from the count point register 42 via the signal line 111. , the two values are compared, and if they match, a match signal is given to the control section 1 via the signal line 113, and if they do not match, a mismatch signal is given to the control section 1.

The control unit 1 checks the signal line 113, and if it is a mismatch signal, sends the trace signal again to the R/W circuit 3, causing the above operation to be executed again. When the trace point returns to the trace start point after going around the closed loop region, the comparison circuit 44 sends a coincidence signal to the control unit 1 via the signal line 113. The control unit 1 detects this, completes the calculation of the area of the closed loop region and each moment, and confirms that the calculated area is obtained via the signal line 114 and the calculated moment is obtained via the signal line group 115. This is notified to the information processing device via the signal line 103, and the information is inputted.

As described above, according to the moment calculation circuit of the present invention, there is no need to raster scan and accumulate deviations from the moment of the pixel calculated from the coordinate values for each pixel included in the closed loop area, and Even if the closed-loop region is complicated, there is no need to perform separation processing, and the moment of the closed-loop region can be calculated quickly and easily by simply tracing the edges of the closed-loop region once.

In the above explanation, the trace starting point is the top point of region R, the trace direction is clockwise, and the correspondence between the trace direction and the sign of integration is positive for the positive direction of the X axis, and positive for the negative direction. Although the explanation is given as minus when, the above is not limited to the above, in general, the trace starting point may be any point on the edge, the direction of the trace may be counterclockwise, and the reaction between the direction of the trace and the sign of the integration is as follows: When projected onto an arbitrary straight line, if it is in a certain direction (positive or negative), it should be defined as plus, and if it is in the opposite direction, it should be defined as minus. Then, when the integration result is negative, the absolute value may be output.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a closed loop region in a bit pattern, and FIG. 2 is a block diagram showing one embodiment of the present invention. In the figure, 1...control unit, 2...pattern memory, 3...R/W circuit, 4...edge trace unit, 5...area accumulator, 6...moment accumulator group, 41 ...start point register,
42...Current point register, 43...Direction detection circuit, 44...Comparison circuit.

Claims (1)

[Claims] 1. Region R surrounded by a closed loop drawn on the drawing
moment Σx ⁱ y ^j (Σ is the sum of all pixel positions (x, y) belonging to region R, i, j is i=
j = an integer other than 0), the moment calculation circuit includes a pattern memory for storing a bit pattern obtained by scanning a drawing, etc., a write/read circuit that controls writing to and reading from the pattern memory, and An edge trace section that traces the edges of the closed loop region in the bit pattern stored in the pattern memory, and a moment cumulative value _y 〓 ^y ′ ⁼ from the coordinates (x, y) of the current position of the trace point obtained from the edge trace section. ^{1 X i y} ′ ^{j or} _x ^〓 A moment calculation circuit comprising: a control section for controlling the moment; 2 Region R surrounded by a closed loop drawn on the drawing
moment Σx ⁱ y ^j (Σ is the sum of all pixel positions (x, y) belonging to region R, i, j is i=
j = an integer other than 0), the moment calculation circuit includes a pattern memory for storing a bit pattern obtained by scanning a drawing, etc., a write/read circuit that controls writing to and reading from the pattern memory, and The distance from the reference line is obtained from the coordinates (x, y) of the current position of the trace point given by the edge trace section that traces the edge of the closed loop region in the bit pattern stored in the pattern memory, and the edge trace section. An area accumulator that integrates the area with a sign determined by the tracing direction, and a moment cumulative value _y 〓 ^y ′ ⁼¹ x ⁱ y′ ^j or _x 〓 ^x ′ ⁼¹ from the coordinates (x, y) of the current position of the above trace point. It is composed of one or more moment accumulators that calculate x' ⁱ y ^j and integrate the obtained values with a sign determined by the trace direction, and a control section for controlling each of the circuits. Characteristic moment calculation circuit.