JPS6246901B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image contour tracking processing method, and more particularly to an image contour tracking processing method for smoothly tracing the outline of a digital figure without being affected by small cracks or defects in the digital figure. It is.

The principle of this type of conventional system will be explained with reference to FIG. Figure 1A shows when contour tracking is started; in the figure, 1 is the figure on the digital mesh, 2 is the starting point pixel of contour tracing, a, b,
c, d, e, f, g, and h are pixels adjacent to the starting point pixel 2, respectively. Figure 1B shows contour tracking as the first
This is a step up from Figure A, where 3 is the tracked contour pixels, a', b', c', d', e', f', g'
，
h' are pixels adjacent to the contour pixel 3, respectively.
Note that the direction from a certain pixel to an adjacent pixel of that pixel will be represented by numbers from "1" to "8" as shown in FIG.

To explain the operating principle of Fig. 1, first, Fig. 1A
, an appropriate boundary pixel 2 seen from above of figure 1
Specify. Regarding adjacent pixels in eight directions centering on this boundary pixel 2, counterclockwise from direction "3", that is, pixels c, d, e, f, g, h,
It is checked whether these pixels are part of figure 1 in the order of a and b, and the first pixel among these pixels that is considered to be part of figure 1 becomes the outline pixel. In the case of the figure, pixel f is a contour pixel. The contour tracing direction viewed from the contour tracing start pixel 2 at this time is stored. In the case of the figure, the contour tracking direction is direction "6". Next, regarding FIG. 1B, centering on the contour-tracked pixel 3 (same as pixel f in FIG. 1A),
Value "1" in the direction opposite to the contour tracking direction memorized above.
Starting from the direction in which . In the figure, the contour tracking direction is “6”
Starting from pixel c' in the direction "3" which is the opposite direction "2" and adding 1, examine d', e', f', g', h', a', b' in order,
f′ becomes the contour pixel. The contour tracing direction at this time is memorized and the process moves to the next stage of contour tracing. By repeating the above operations, the outline of the figure is traced, but a drawback of this method is that continuous line figures input using an image input device such as a facsimile input device may If the cut occurs due to input accuracy, etc., the contour tracing will enter the back side of the line figure from the cutting point of the line figure. Therefore, there were problems such as the inability to process closed area detection.

In order to eliminate these drawbacks, the present invention uses a window of an appropriate size and traces the contour of a figure while checking whether the figure exists within the window.The drawings will be explained in detail below. do.

FIG. 4 shows the configuration of an embodiment of the present invention. In the figure, 4 is a digital image memory;
5 is a contour vicinity point tracking device, and 6 is a digital image memory. To explain this operation, for a figure stored in the digital image memory 4, a contour vicinity point tracking figure that circumscribes the figure while maintaining a constant pixel width interval is obtained by the contour vicinity point tracking device 5. The contour vicinity point tracking figure is stored in the digital image memory 6. Next, regarding the contour neighboring point tracking figure stored in the digital image memory 6,
A near-contour point tracking figure that inscribes the figure at intervals of the above-mentioned pixel width is obtained by the near-contour point tracking device 5, and the obtained near-contour point tracking figure is stored in the digital image memory 4. The figure stored in the digital image memory 4 becomes the contour tracing figure of the original figure.

FIG. 5 shows the principle of an embodiment of the contour vicinity point tracking device shown in FIG. In the figure 1
is the figure on the digital mesh, 7 is the starting point pixel of contour neighboring point tracking, A, B, C, D, E, F, G,
H is a pixel adjacent to the starting point pixel 7, respectively.
FIG. 5B shows the contour neighboring point tracking advanced by one step from the state shown in FIG. 5A. F′、G′、
H' is a pixel adjacent to the contour neighboring point 8, respectively. Note that the same tracking direction as in FIG. 2 is defined here.

To explain the operating principle of FIG. 5, first, a window is prepared that is larger in size than an undesired crack or defect occurring in the figure whose outline is to be traced. In the figure, a 3×3 pixel square window is used as an example. In FIG. 5A, the center point of the window is set so that the window touches a part of the upper side of the figure 1, the center point is set as the starting point pixel 7 for tracking points near the outline, and the initial value of the tracking direction is set as " 7”. For adjacent pixels in 8 directions centered on this starting point pixel 7, counterclockwise from the pixel in the opposite direction of the initial value of the tracking direction, that is, the direction "3", that is, in the figure, pixels C, D, E, F, G, H, Move the "center point of the window" (in the case shown, the point corresponding to pixel 7) in the order of A and B to check whether the part of figure 1 is included in the window. When the part of figure 1 is included in the window, the center pixel of the window is set to 1 with pixel 7 as the center.
The pixel whose position is moved back by one in the clockwise direction becomes a new point near the contour. In the case of the figure, since figure 1 is included when pixel F is centered, pixel E
becomes the new contour neighborhood point. The contour vicinity point tracking direction viewed from the starting point pixel 7 of contour vicinity point tracking at this time is stored. In the case of the figure, the contour vicinity point tracking direction is direction "5". Next, regarding FIG. 5B, regarding adjacent pixels in eight directions centered on pixel 8 (same as pixel E in FIG. 5A), which has become a new contour neighborhood point, in the opposite direction to the contour neighborhood point tracking direction described above. Starting from the pixel of
Move the center point of the window in the order of A', B', C', D', E', F', G', H' and check whether the part of figure 1 is included in the window. The center pixel of the window when the part of figure 1 was initially included in the window is moved back by one position clockwise with pixel 8 as the center, and the pixel becomes a new point near the contour. In the case of the figure, pixel F' is near the new contour. The direction of contour vicinity point tracking at this time is memorized. In the case of the figure, the tracking direction of points near the contour is direction "6". Using these new points near the contour and their tracking directions, we move on to the next step of tracking points near the contour. By repeating the above operations, points near the outline of the figure are tracked.

FIG. 6 shows an embodiment of a method for tracking points near the outline of a figure. In the figure, 4 is a digital image memory, 9 and 10 are registers, 11 is an adder, 12 is a register, 13 is an octal counter, 14 is a function generator, 15 is an adder, 16 is a register, 17 is a window circuit, 18 is a register, 19 is a subtracter, 2
0 is a gate, 21 is a register, and 22 and 23 are output terminals.

To explain this operation, the window center coordinates (x ₀ ,
y ₀ ) and the initial value of the tracking direction (in the embodiment shown in FIG. 5, the initial value of the tracking direction is direction "7") are input into registers 9 and 10, respectively. Here, regarding the x and y axes, the horizontal right direction in FIG. 5 is the x axis, and the vertical upward direction is the y axis. The tracking direction input to the register 10 is added with the numerical value "4" stored in the register 12 by the adder 11, and the output of the adder 11 is set in the octal counter 13. The contents of octal counter 13 are input to function generator 14 . Here, the function generator 14 generates the following function. In other words, if the direction D is a variable, the position coordinates of the pixel (x,
As the displacement added to y), the displacement (fx(D), fy(D)) is expressed as (fx(1), fy(1)) = (1, 0) (fx(2), fy(2)) = ( 1, 1) (fx(3), fy(3)) = (0, 1) (fx(4), fy(4)) = (-1, 1) (fx(5), fy(5)) = (-1, 0) (fx(6), fy(6)) = (-1, -1) (fx(7), fy(7)) = (0, -1) (fx(8), fy(8)) = (1, -1). The output of the function generator 14 is added to the position coordinates (x ₀ , y ₀ ) stored in the register 9 by the adder 15 , and the output (x ₀ +fx(D), y ₀ +
fy(D)) is stored in register 16. register 1
6 is input to the window circuit 17, which creates a window centered at the coordinates given by the register 16 on the digital image memory 4 in which the figure to be contour traced is stored. It detects whether or not a part of the figure is included in the window, and outputs "YES" if it is included, and outputs "NO" if it is not included. At the start stage of tracking points near the contour, the output of the window circuit 17 is always “NO”.
This becomes the output. The “NO” output of the window circuit 17 activates the octal counter 13 and outputs the octal counter 1.
``1'' is added to the contents of 3. The added contents of the octal counter 13 are input to the function generator 14, and the function generator 14 calculates (fx (D+1), fy (D+
1) Output. This output is added to the contents of register 9 (x ₀ , y ₀ ) by adder 15 , and the output of the adder (x ₀ +fx (D+1), y ₀ +fy (D+1)) is stored in register 16 . At this time, the contents stored in register 16 at the previous stage (x ₀ + fx(D), y ₀
+fy(D)) is transferred to register 18. The contents of the register 16 are input to the window circuit 17 as the new center coordinates of the window, and the window circuit 17 creates a window on the digital image memory 4 and detects whether a part of the figure is included within the window. If a part of the figure is not included in the window, the window circuit 17 outputs "NO", activates the octal counter 13, adds 1 to the content of the octal counter 13, and then repeats the same procedure to create a new window. A window is provided, it is detected whether a part of the figure is included, and the above operation is repeated. If the output of the window circuit 17 is "YES", the window circuit 17 operates the subtracter 19 and the gate 20. Subtractor 19 is octal counter 1
The numerical value "1" stored in the register 21 is subtracted from the contents of 3, and the tracking direction of the point near the contour is outputted to the output terminal 22. Also, the gate 20 is the register 18
The window center coordinates stored one cycle before are outputted to the output terminal 23, and this output becomes the coordinates of the point near the traced contour. The tracking direction and the coordinates of the point near the contour obtained at the output terminals 22 and 23 are input to the registers 10 and 9, respectively, and new tracking of the point near the contour is started.

As explained above, according to the present invention, the outline of a figure is detected using a window with a certain size. Contour tracking can be performed without

[Brief explanation of the drawing]

Figure 1 is a diagram explaining the principle of the conventional contour tracking method, Figure 2 is a diagram explaining the definition of adjacent directions of pixels, Figure 3 is a diagram explaining the drawbacks of the conventional method, and Figure 4 is an example of an embodiment of the method of the present invention. 5 is a diagram illustrating the principle of an embodiment of the contour vicinity point tracking system, and FIG. 6 is a block diagram of an embodiment of the contour vicinity point tracking device shown in FIG. 4. 1...Figure part, 2...Start pixel of contour tracking, a,
b, c, d, e, f, g, h...adjacent pixels, 3...tracked contour pixels, a', b', c', d', e', f', g
′、
h'... Adjacent pixel, 4... Digital image memory, 5...
Contour vicinity point tracking device, 6...Digital image memory, 7...Start point pixel for contour vicinity point tracking, A, B,
C, D, E, F, G, H...adjacent pixels, 8...point pixels near the tracked contour, A', B', C', D', E',
F', G', H'...Adjacent pixels, 9...Register, 10...
Register, 11... Adder, 12... Register, 13
...octal counter, 14...function generator, 15...adder, 16...register, 17...window circuit, 1
8...Register, 19...Subtractor, 20...Gate, 2
1...Register, 22...Output terminal, 23...Output terminal.

Claims (1)

[Claims] 1. An image contour tracking processing method that includes a digital image memory and a means for forming and scanning a digital window of a predetermined size on the digital image memory, and traces the contour of a digital figure on the digital image memory. A contour vicinity point tracking unit is provided for positioning the center of the digital window at a plurality of points within a predetermined range centering on the vicinity points of the contour, and revolving the digital window around the vicinity points, An image contour tracking processing method, characterized in that the digital window detects the digital figure during revolution of the window, thereby moving the position of the neighboring point.