JPS5942907B2 - character recognition device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a character recognition device, for example, a character recognition device including kanji, which compares graphic information obtained by scanning a character to be recognized with pattern information read out from a standard character storage memory. Based on the discrepancy information obtained and weighted by the weighting circuit, the graphic information of the character to be recognized and the pattern information of the standard character are combined into a pattern'.
The present invention relates to a character recognition device that recognizes the recognition target characters through matching processing.

Conventional character recognition methods employ a pattern matching method in which graphic information of a character to be recognized is compared with pattern information of a standard character prepared in advance to recognize the character to be recognized.

In the conventional pattern matching method described above, in order to deal with the positional shift of the recognition target character with respect to the standard character during matching, weighted pattern information is used as the pattern information of the standard character. Recognition is taking place. However, since the weighted pattern information needs to be stored in memory in advance as at least 2 or 3 bits of information, the required memory capacity is large, and the recognition target characters are similar but different characters. In Σ recognition, although it is only necessary to have weighted values only for meshes with mismatches, it is not always necessary to provide weighted values for all meshes, including matching meshes. It's not an effective measure. The present invention aims to solve the above-mentioned problems, and the character recognition device of the present invention compares graphic information obtained by scanning a recognition target character with pattern information of a standard character by pattern matching processing. In the character recognition device that recognizes the recognition target character, the standard character storage memory stores the standard character as binary pattern information corresponding to the black mesh and white mesh of the standard character, and the standard character storage memory. a weighting circuit that weights the mismatched mesh obtained by comparing the graphical information of the character to be recognized with the pattern information read from the character;
The weighting circuit includes a mismatched mesh extraction section for extracting the mismatched mesh, and a comparison section that compares the mesh surrounding information between the graphic information of the recognition target character corresponding to the mismatched mesh and the pattern information of the standard character. , is configured to weight the mismatched mesh based on the comparison result, and is configured to perform pattern matching between the graphic information of the recognition target character and the pattern information of the standard character based on the weighted mismatch degree. It is characterized by

This will be explained below with reference to the drawings. FIGS. 1A and 1B are explanatory diagrams showing scanning patterns of two similar examples of recognition target characters;
Figure 2 shows one of the scanning windows generally composed of m x n meshes.
Example, FIG. 3 is an explanatory diagram showing the discrepancy caused by comparing FIGS. 1A and b, FIG. 4a is an enlarged view of part A shown in FIG. 3. Enlarged views of A and b in FIG. 1 correspond to section A shown in FIG. 3, FIG. 5 a is an enlarged view of section B shown in FIG. FIG. 1A and FIG. 1B are enlarged views, and FIG. 6 shows a circuit diagram of one embodiment of the present invention.

In the figure, Wa represents a scanning window composed of a 3×3 mesh for scanning characters to be recognized, and Wb similarly represents a standard character scanning window. In the following, we will take as an example the case of recognizing similar but different characters "king" and "tama" shown in Figure 1 a and b, respectively. This will be explained as a standard character stored in the character storage memory. The binary graphic information pattern (hereinafter referred to as the input pattern) obtained by scanning the recognition target character "King" is shown in FIG. Binary information pattern (
(hereinafter referred to as standard pattern) is shown in FIG. 1b. In the figure, [
1" represents a black mesh, and "0" represents a white mesh. In addition, FIG. 3 shows that the input pattern shown in FIG. 1a and the standard pattern shown in FIG. Exclusive OR results are shown for the contents of meshes A22 and B22, respectively, of the pattern and the pattern within the [ball] scanning window Wb. That is, the areas surrounded by solid lines in parts A and B shown in FIG. 3 indicate areas where the input pattern and the standard pattern do not match, and the areas surrounded by dotted lines indicate common areas, respectively. (・Ma 4th
Consider a situation in which the scanning windows Wa and Wb are made to correspond to the centers A22 and B22 of the scanning windows Wa and Wb, respectively, at the positions shown in FIGS. 4b and 4c corresponding to A1 in FIG.

At this time, mesh A22 is logic "1" and mesh B2
2 is logic "O", the exclusive OR of meshes A22 and B22 becomes logic "1", and it can be seen that a mismatch occurs in the mesh between the manual pattern and the standard pattern corresponding to mesh A1. In the case of the present invention, when such a mismatched mesh is detected, it is assumed that there is a mismatch of at least a weight of "1" between the two patterns.Then, it is determined whether or not the mismatch has an even larger weight. It is checked as follows. That is, when the result of the exclusive OR of the centers A22 and B22 of the scanning windows Wa and Wb is logical "1", the inner ring of the centers A22 and B22 of the scanning windows Wa and Wb is For example, in the example shown in FIG. 4, the side of the scanning window Wb on the side of the logic "O" is examined.In this case, the OR result for each mesh Bll to B33 of the scanning window Wb is logical "1". , the mismatched mesh A, is found to be adjacent to the common area of the two patterns indicated by the dotted line in FIG. For example, the same operation as above is performed for the portion B shown in FIG. 3, that is, the mismatched mesh B1 shown in FIG. 5a. and B22, if we take the OR for each mesh Al, through A33 in the scanning window Wa on the logic "O" side, the result of the OR will be logic [0].This means that the mismatched mesh B1 is This indicates that the two patterns are not adjacent to the common area surrounded by the dotted line in FIG. In the embodiment, a weight of [2] is added and it is assumed that there is a mismatch with a weight of [3].In this way, the mismatched mesh is determined depending on whether or not the mismatched mesh is adjacent to the common area of both patterns. In other words, the weighting of the mismatching degree of adjacent mismatched meshes such as mesh A1 is kept low, and the mismatching weight of mismatched meshes that do not exist adjacently like mesh B1 is kept low. By increasing the weighting of degree, it is effective to distinguish between similar but slightly different characters to be recognized.Next, a circuit according to an embodiment of the present invention shown in FIG. 6 will be described.

In the figure, 1 is a memory for storing standard patterns, 2 to 7
is a shift register, 8 is an exclusive OR circuit, 9, 10, 15, and 16 are AND circuits, 11, 13, and 17 are OR circuits, 12 and 14 are inverting circuits, 18 is an adder circuit, 19 is a register, and 20 is a Each shows a judgment circuit. In FIG. 6, the input pattern and the standard pattern are sequentially transferred one bit at a time to shift registers 2 to 4 and 5, respectively.
While the input is being input to terminals 7 to 7, the terminals shown (All) are connected.
By examining the outputs appearing at A33 and Bll to B33, the scanning windows Wa and W can be determined in a known manner.
Creates the same state as when scanning by b. Then, only when the logics of the output A22 of the shift register 3 and the output B22 of the shift register 6 are different, that is, when it is determined that there is a mismatched mesh in the comparison between the input pattern and the standard pattern, the exclusive OR circuit 8 is logic [
1" and sends the weight "2 logic" information to the adder circuit 18 first. At this time, among the outputs A22 and B22 of the shift registers 3 and 6, based on the output of the OR circuit 11 or 13 that outputs the peripheral information of the mesh on the logic [0] side (. is sent to the adder circuit 18, and the weight "2" sent from the exclusive OR circuit 8 is
The information is added in an adder circuit 18. In this manner, the degree of mismatch of the mismatched mesh is weighted by adding peripheral information of the mismatched mesh, and added in the addition circuit 18. Each mismatched mesh is sequentially weighted by the above-described means, and the weighted mismatch information for each mismatched mesh is sent to the adder circuit one after another via the register 19 until scanning of one recognition target character is completed. In step 18, the total value of the mismatch information is cumulatively added together with the one-character scanning end signal, and is sent to the determination circuit 20, where the character to be recognized is identified. Note that FIG. 6 will be specifically explained using an example. Taking the case shown in FIG. 4 as an example, scanning windows Wa and Wb shown in FIG.
Mesh information corresponding to I to B33 is taken out as outputs from output terminals All to A33 of shift registers 2 to 4 and output terminals Bll to B33 of shift registers 5 to 7, respectively.The above outputs Outputs from the output terminal A22 of the shift register 3 and the output terminal B22 of the shift register 6 are taken out and sent to the exclusive OR circuit 8 as shown in the figure.The output of the terminal A22 is logic "1", The output of the above terminal B22 is logic “O”
, therefore, the output of the exclusive OR circuit 8 becomes logic "1",
The output of the exclusive OR circuit 8 is sent to the adder circuit 18, where the weight "2 times" is added. On the other hand, the above terminals A22 and B
22, each terminal B of the shift registers 5 to 7 on the terminal B22 side, that is, on the standard pattern side, indicates the output of logic "O"
The output of the illustrated OR circuit 13 to which the outputs of ll to B33 are sent is logic "1", and the AND circuit 9 is turned on, but the output of the OR circuit 13 is set to logic "O" by the inverting circuit 14.
”, the output of the AND circuit 16 becomes logic “O”. Further, the output of the illustrated AND circuit 10 is a logic [
Therefore, the output of the AND circuit 15 becomes logic "0", and the inputs of the OR circuit 1r both become logic "0", so the output of the OR circuit 17 becomes logic "0", and the output of the adder circuit 18 becomes logic "0".
will not be added in . Therefore, the inconsistency value of the inconsistency mesh A1 in the example shown in FIG. Next, taking the case shown in FIG. 5 as an example, as explained in the example of FIG. 4 above, the output logic [0] of the terminal A22 of the shift register 3 and the output logic "1'' is sent to the exclusive OR circuit 8, and the output of the exclusive OR circuit 8 becomes logic ``1''. Therefore, the output of the exclusive OR circuit 8 is sent to the adder circuit 18, and the weight [28'' is added thereto as in the example of FIG. 4 above. On the other hand, the above terminals A22 and B
Terminals Al of shift registers 2 to 4 on the terminal A22 side, that is, on the input pattern side, which shows the output of logic "0" among 22
The outputs of I to A33 are respectively sent to the OR circuit 11,
The output of the OR circuit 11 becomes logic "O", and the inverting circuit 1
2 and the logic "1" is sent to the AND circuit 15. Also, exclusive OR circuit 8 and shift register 6
If the output of terminal B22 is logic "1", it is AND circuit 1.
0, and the output logic "1" of the AND circuit 10 is sent to the AND circuit 15. The AND circuit 15 outputs the output logic [1] of the inversion circuit 12 and the output logic [1] of the AND circuit 10. and outputs logic [1], OR circuit 1
The output of 7 becomes logic "1". The output logic [1] of the OR circuit 17 is added as a weight "21" in the adding circuit 18. Therefore, the output of the exclusive OR circuit 8 and the output of the OR circuit 17, that is, the weights "2" and "21"
are added in the adding circuit 18, and the mismatch degree value of the mismatch mesh B1 in the example shown in FIG. 5 becomes "3". In this way, the mismatched mesh A1 in the example of FIG.
” In addition, each mismatched mesh is automatically weighted, such as the mismatched mesh B1 in the example shown in FIG. The cumulative addition is carried out in the adding circuit 18 sequentially through the register 19 until the scanning of one character to be recognized is completed, and the summation value of the degree of discrepancy is sent to the judgment circuit 20 together with the one character scanning end signal, and the total value of the character to be recognized is An identification is made. As explained above, according to the present invention, the standard pattern stored in the memory is prepared as a binary pattern, so the memory becomes simple and inexpensive, and mismatched meshes can be extracted in terms of performance. Since the mismatched mesh is automatically weighted in accordance with the surrounding information of the mismatched mesh, it is particularly effective in distinguishing between similar but slightly different recognition target characters. .

[Brief explanation of the drawing]

1A and 1B are explanatory diagrams showing scanning patterns of two similar examples of characters to be recognized; FIG. 2 is an example of a scanning window generally composed of an m×n mesh; and FIG. An explanatory diagram showing the discrepancy caused by comparing A and b. Fig. 4 a is an enlarged view of part A shown in Fig. 3, and Figs. 4 B and c are the first part corresponding to part B shown in Fig. 3. Figures A and b are enlarged views, Figure 5 a is an enlarged view of part B shown in Figure 3, Figures 5 B and c are enlarged views of Figure 1 A and b corresponding to part B shown in Figure 3, respectively; FIG. 6 shows a circuit diagram of one embodiment of the present invention.

Claims (1)

[Scope of Claims] 1. In the character recognition device that recognizes the recognition target character by comparing graphic information obtained by scanning the recognition target character and standard character pattern information through pattern matching processing, A standard character storage memory that stores standard characters as binary pattern information corresponding to the black mesh and white mesh of the standard character, and a graphic of the character to be recognized based on the pattern information read from the standard character storage memory. The weighting circuit is provided with a weighting circuit that weights the mismatched meshes obtained by comparing the information, and the weighting circuit is provided with a mismatched mesh extracting section that extracts the mismatched meshes, and the weighting circuit that weights the mismatched meshes obtained by comparing the information. It is configured to include a comparison unit that compares mesh peripheral information between the graphic information and the pattern information of the standard character, and is configured to weight the mismatched mesh based on the comparison result, and based on the weighted mismatch degree, the recognition target The pattern between the graphic information of the character and the pattern information of the above standard characters.
A character recognition device configured to perform matching. 2 The weighting circuit applies weighting based on the graphic information pattern of the character to be recognized on the side where the mismatched mesh is a white mesh or the surrounding information of the mesh corresponding to the mismatched mesh of the standard character information pattern. A character recognition device according to claim 1, characterized in that the character recognition device is configured as follows.