JPH0145665B2 - - Google Patents

Description

Detailed description of the invention: Technical field to which the invention pertains If the sum of the logical "1" (or "0") parts of the binary signal of an image obtained by raster scanning is calculated for each horizontal scan, A projection distribution of the binarized image in the horizontal scanning direction (referred to as the X direction) is obtained. The present invention relates to a circuit for quickly obtaining a similar projection distribution in the vertical direction (referred to as the Y direction) of an image at the same time as the projection distribution in the X direction.

Prior art and its problems Figure 1 shows the scanning direction of the screen of an industrial television camera (hereinafter simply referred to as a camera), which is not shown in the figure.
1 is a screen, 2 is a horizontal (X direction) scan, and 3 is a vertical direction (Y direction) in which the horizontal scan 2 is repeated. Further, FIG. 2 shows an example of a projection distribution, where 4 is a binarized image composed of pixels obtained by binarizing an image signal, 5 is a pattern, and 5A is the pattern 5.
5B is the vertical projection distribution of the pattern 5.

Conventionally, in order to obtain the projection distribution in the vertical direction (Y direction) orthogonal to the horizontal scanning direction (X direction), pixel data obtained from the binary image signal output from the camera is temporarily stored in memory in the order of scanning. , When the scanning of one screen is completed, the data arranged in the Y direction is sequentially read out and processed.

However, this method requires a memory for storing one screen of images, and a memory for each X coordinate (the position of pixels counted in the X direction. The Y coordinate will be defined in the same manner from now on) Having the X coordinate of Y
It is necessary to read out the pixel data arranged in the direction, and the processing time for this is substantially the same as the scanning time of one screen by a camera. In industrial pattern recognition, it is necessary to perform calculation processing for each screen of images that change from moment to moment, but the fundamental problem is that the processing takes time.

Purpose of the invention and its main points As described above, the present invention does not require a memory to store pixel data for one screen, and moreover, the projection distribution in both the horizontal X and vertical Y directions is simultaneously determined at the end of scanning one screen. The purpose is to solve the above problems by completing the following steps.

The key point of the present invention is that in addition to a horizontal projection data memory that stores horizontal projection data for each Y coordinate for one screen, there are two memories accessed by a horizontal address counter, each with an odd numbered First and second vertical projection data memories whose input/output states are switched by even-numbered horizontal synchronizing signals are provided, and the first or second vertical projection data memory is provided for each point of the X coordinate of each horizontal scan. Take out the vertical projection data at the address corresponding to the X coordinate from one of the vertical projection data memories designated for output, integrate the newly scanned pixel data at the X coordinate, and input the integrated value. A vertical pixel preset counter is provided as an input to the address of the other designated vertical projection data memory.

Embodiments of the Invention Next, embodiments of the present invention will be described with reference to FIGS. 3 to 8. The same reference numerals in the figures indicate the same or corresponding parts.

First, the definition of projective distribution will be explained with reference to FIG.
7 is a pixel obtained by binarizing the image signal, and 8 is the coordinate of each pixel in the horizontal X scanning direction, which is expressed as 1, 2...i...M for each pixel according to the scanning order. Similarly 9
is the coordinate of each pixel in the vertical Y direction, and is expressed as 1, 2, . . . j . . . N for each pixel in the order of scanning. 10 is the X coordinate i,
Pixel data P(i, j) of a pixel at Y coordinate j is represented. The scanning order is 1 horizontal X scan (i=1, 2,
...M), j advances by one. At this time, the vertical projection distribution in the vertical Y direction is expressed by the following formula.

_N 〓 ^j=1 P(i, j) (i=1, 2,...M) p(i, j)=“0” or “1” However, in the above equation, “0” means that there is no projection distribution detection such as the background. The target pattern portion "1" is also the target pattern portion.

Similarly, the horizontal projection distribution in the horizontal X direction is shown below.

_M 〓 ⁱ⁼¹ P(i, j) (j=1, 2, . . . N) Next, the vertical Y projection distribution detection circuit will be explained based on FIG. 4 and with reference to FIGS. 5 and 6. Vertical projection data memory 14 (hereinafter referred to as YA memory), vertical projection data memory 15 (hereinafter referred to as YB memory)
The address 35 given to terminal A of corresponds to the X coordinate explained in FIG. The horizontal address counter 11 is cleared at the beginning of each horizontal scan by a horizontal synchronizing signal (hereinafter referred to as *HSYC signal) 22 applied to terminal CR, and is cleared by a clock signal (hereinafter referred to as CLK signal) 21 applied to terminal CK. It counts and outputs an address corresponding to the scanning position (X coordinate) of the horizontal scanning to the terminal Q as the scanning progresses. Note that the CLK signal 21 is a clock pulse signal whose timing coincides with updating of pixels, that is, coordinates. The output of the horizontal address counter 11 is a DMA inversion signal (*DMA) 3 as described later.
8 is applied to the terminal and is closed during the projection pattern extraction period, through the YA memory 14.
and address input 3 to terminal A of YB memory 15.
5 (same symbols (14, 15-A) in FIG. 5B).

Frequency divider circuit 16 *HSYC signal 22 at terminal CK
is input, the frequency is divided by 1/2, and the frequency is output to terminal Q. In other words, timing chart Figure 5 A
As shown in the figure, the frequency-divided signals 31 (16-Q) and 32 (16
-) are output from terminal Q, respectively. The frequency-divided signals 31 and 32 are inverted from each other. In FIG. 4, the frequency-divided signals 31 and 32 are subjected to NAND conditions by a clock inversion signal (hereinafter referred to as *CLK signal) 39, which is obtained by inverting the CLK signal 21 by a NOT element 28, and a NAND element 27, and their outputs are respectively Read/write signals to the terminals of YB memory 15 and YA memory 14 (A34 (15-
WR), 33(14-)).
That is, as shown in FIG. 5A, the frequency-divided signals 31, 3
When 2 is “1” *Synchronized with CLK signal 39,
*CLK signal is “1”, that is, CLK signal is “0”
*CLK when the write signal is stable and when the frequency division signals 31 and 32 are "0".
A read signal is given regardless of signal 39. Therefore, when projection data is written into either the YA memory 14 or the YB memory 15, the other outputs (reads) the projection data.

In FIG. 4, the data selector 17 receives the frequency-divided signal 32 (16-) at its terminal, and outputs data (data readout) among the outputs given to the terminals A and B from the D/I terminal of the YA memory 14 or YB memory 15. ) mode and output it. This output is the terminal D of the vertical pixel preset counter (hereinafter referred to as preset counter) 18.
is given as a preset value. On the other hand, the terminal CK of the preset counter 18 receives a binary image signal (hereinafter referred to as DATA) 23 (same reference numeral in FIG. 5B) currently being scanned and a CLK signal 21 (same reference numeral in FIG. 5B).
The pixel data signal of the coordinates currently being scanned (FIG. 5 B36 (18
−CK)) is given. In this way, the preset counter 18 is set to the preset value.
If DATA23 is “1”, it is counted up by +1 in synchronization with CLK signal 21, and DATA23
If the value is "0", the preset value is held as it is, and the preset value is updated in an integrated manner. The preset value thus integrated and updated is supplied as input data from the output terminal Q of the preset counter 18 to the D/I terminal of the YA memory 14 or the YB memory 15 which is in the write mode via the memory input buffer 19. be remembered. In other words, the movement of the vertical projection data in the above read/write operations of the YA memory 14 and YB memory 15 is as shown by the dotted line WA or WB in FIG. The vertical projection data is
The integration is updated for each address and sequentially written to the YB memory 15. Similarly, the vertical projection data read from the YB memory 15 is integrated and updated and written to the YA memory 14. /Write operations are swapped for each horizontal scan.

On the other hand, the shift register 40 receives a projection pattern extraction period signal (hereinafter referred to as
(written as DMA signal) 37 (However, this DMA signal 37 is a DMA inverted signal (hereinafter written as *DMA signal)
38 is inverted by the NOT element 28.
They are also shown with the same reference numerals in FIG. 6A. ) as input, and *
The HSYC signal 22 (same symbol in FIG. 6A) is used as a synchronization signal, and the signal 41 delayed by one horizontal scanning period with respect to the DMA signal 37 (same symbol in FIG. 6A (40-QA))
Outputs to terminal QA. Signal 4 of this terminal QA section
1 and the CLK signal 21 is taken by the NAND element 27, and the preset counter 18
The preset value load signal "0" is applied to the terminal LD of the screen, but the DMA signal 37 in the first horizontal scanning period of screen scanning, that is, in FIG.
Since the signal 41 is "0" only during the period T1 after the rise of the signal, the load signal becomes "1" and loading (writing) of the preset value to the preset counter 18 is prohibited. Therefore, during the period T1, the YA memory 14 or the YB memory 15
The vertical projection data (the preset value) accumulated before the period T1, which is on the side to be read during the period T1, is not read, and the preset counter 18 starts counting anew from 0. In this case, the preset counter 18 sends a clear signal to the terminal CR.
The DMA signal 37 is applied and cleared before the projection pattern extraction period starts, that is, when the DMA signal 37 is "0", and counting is performed only during the period when the DMA signal 37 is "1". In this way, one of the YA memory 14 and the YB memory 15 stores information accumulated in the Y direction with the same X coordinate for each X coordinate (i=1, 2,...M) in the previous horizontal scan. The number of pixels of pixel data "1" is stored as integrated vertical projection data, and on the other hand, each pixel data during the current horizontal scan is integrated and updated to the integrated vertical projection data and newly stored.

Therefore, as shown in FIG. 7, upon completion of the K-th horizontal scan (that is, the position where the Y coordinate is K),
Read data 29 is stored in the YA memory 14 or YB memory 15 used for reading during the horizontal scanning period, and write data 30 is stored in the YA memory 14 or YB memory 15 used for writing. That is, by scanning up to the K-th scan, the sum of image data of "1" appearing in the vertical direction up to that point is obtained for each X-coordinate position. The written data 30, that is, the integrated vertical projection data, can be expressed by the following equation in the same manner as described above.

_K 〓 ^j=1 (i, j) (i=1, 2,...M) (1) P (i, j) = “0” or “1” Therefore, once the scanning for one screen is completed, the above ( 1) The formula is as follows, _N 〓 ^j=1 P(i, j) (i=1, 2,...M) Each position (X coordinate) of horizontal scanning (i=1, 2,...
A vertical projection distribution consisting of vertical projection data _N 〓 ^j=1 P (i, j) obtained by vertically projecting the pixel data for each M) is obtained.

In the above explanation, the projection distribution detection of the logic "1" part of the binarized image was described, but if an inverted signal is given as the binarized image signal (DATA) 23, the image part of the logic "0" It will be easy to see that a projective distribution can be detected.

Now, during the period when the DMA signal 37 is "0", that is, the projection pattern is not extracted by screen scanning, the corresponding
DMA signal 37 to CPU address bus buffer 13
and the terminals of the CPU data bus buffer 20, the CPU (not shown) can access the YA memory 14 and the YB memory 15 via the address bus AB24 and the CPU address bus buffer 13, and the vertical projection data is the CPU
YA memory 14, YB memory 1 via data bus DB25 and CPU data bus buffer 20.
5. The CPU data bus buffer 20 is a bidirectional buffer, and data can be written to the YA memory 14 and YB memory 15, and the vertical projection data can also be processed from the CPU side.

Next, a detection circuit for detecting a projection distribution in the horizontal X direction, which operates in parallel with the operation for detecting the vertical projection distribution, will be described based on FIG. 8 and with reference to FIGS. 5 and 6. In other words, the vertical address counter 49 receives the vertical synchronization signal (*VSYC) 44 at the start of screen scanning.
is applied to the terminal CR and cleared, then the terminal
Horizontal synchronization signal (*HSYC) 22 given to CK
is counted, and an address corresponding to the coordinate in the vertical Y direction is output to terminal Q. This address is a DMA inversion signal (*
Memory address buffer 4 by DMA) 38
7 is closed, it is applied to the horizontal projection data memory 48. On the other hand, horizontal pixel counter 45
is cleared by the horizontal synchronization trailing edge signal (*HSYCR) 43 (same symbol in FIG. 6B) applied to the terminal CR for each horizontal scan, and then applied to the terminal CK via the AND element 26. Binarized pixel signal
Pixel data signal 36 which is AND of DATA23 and CLK signal 21 (same symbol (45-CK) in Figure 5B)
are counted and integrated in synchronization with the CLK signal 21. 1
After the horizontal scanning is completed, the integrated value of the pixel data signal 36 for one horizontal scanning, that is, the horizontal projection data in the X direction at the Y coordinate of the horizontal scanning is transferred to the horizontal projection data memory 4 via the memory input buffer 46.
8, the horizontal synchronization leading edge signal (*HSYCF) applied to the terminal of the horizontal projection data memory 48
42 (same reference numeral in FIG. 6B).

In this way, after one screen has been scanned, one screen's worth of horizontal projection data for each horizontal scan (each Y coordinate) is stored in the horizontal projection data memory 48, and is stored in the CPU as in the case of the vertical projection data described above. Therefore, by accessing from address bus AB24 and CPU address bus buffer 13, data is read via CPU data bus buffer 20 and data bus DB25. Note that the horizontal projection distribution in the horizontal X direction at this time is expressed by _M 〓 ⁱ⁼¹ P(i, j) (i=1, 2, . . . N) using the same formula as above.

Effects of the Invention As detailed above, according to the present invention, the horizontal projection data for each Y-coordinate and the vertical projection data for each X-coordinate are updated and accumulated up to the coordinate point in synchronization with the scanning of the screen. While storing the values, it is possible to obtain the complete horizontal and vertical projection distribution for one screen at the same time as the scanning of that screen is completed, eliminating the need for memory to store one screen's worth of binarized images as in the past. First, the processing time required to read and process data from this memory, which is equivalent to scanning one screen, can be reduced. Therefore, it is possible to significantly improve the processing speed, which is a problem in conventional pattern recognition, and it can greatly contribute to improving the performance of various measurements, positioning and handling by robots, etc., which are applications of pattern recognition.

[Brief explanation of drawings]

Figure 1 is a diagram showing the scanning direction of the screen, Figure 2 is a diagram illustrating an overview of the horizontal and vertical projection distribution of a binarized image, and Figure 3 is the relationship between pixel data and coordinates on one screen. FIG. 4 is a block diagram showing the configuration of the vertical projection data detection circuit, and FIG.
Figure 6 is a timing chart showing the timing of some signals in Figures 4 and 8. Figure 7 is a timing chart showing the timing of some signals in Figures 4 and 8. Figure 7 is during screen scanning. FIG. 8 is a block diagram showing the configuration of a detection circuit for horizontal projection data. Code explanation 11...Horizontal address counter, 1
4, 15... Vertical projection data memory, 18... Vertical pixel preset counter, 49... Vertical address counter, 48... Horizontal projection data memory, 45... Horizontal pixel counter.

Claims (1)

[Claims] 1. A horizontal address counter that sequentially outputs addresses corresponding to the horizontal coordinates of pixels for each horizontal scan;
two memories accessed by the horizontal address counter, first and second vertical projection data memories whose input/output states are switched by odd-numbered and even-numbered horizontal synchronization signals, respectively; For each horizontal coordinate scan, the first
Or, extract the vertical projection data at the address corresponding to the horizontal coordinate from one of the memories designated for output among the second vertical projection data memories, integrate the newly scanned pixel data at the horizontal coordinate, and then integrate the data. a vertical pixel preset counter that inputs the value to the address of the other vertical projection data memory specified by the input; a vertical address counter that sequentially outputs an address corresponding to the vertical coordinate of the pixel for each vertical scan; and; A horizontal projection data memory accessed by the vertical address counter; Accumulating the pixel data of the vertical coordinate for each horizontal scan, and storing the accumulated value as horizontal projection data in the horizontal projection data memory. A horizontal pixel counter inputting the vertical coordinate to the address; and a projection distribution detection circuit for an image.