JPS6246039B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a character extraction method for cutting out each character from a character string including numbers, symbols, etc. written on a form.

Conventionally, in handwritten character recognition, it has been very difficult to separate each character from each character string, so a limit frame has been set up for each character and the person is asked to fill in the space. However, setting a limit frame is extremely inconvenient when designing forms, and there is a desire to simplify forms as much as possible.

On the other hand, there is also a demand for the development of a character recognition device that can similarly separate characters without a restriction frame.

Therefore, it is an object of the present invention to solve the above-mentioned problems and provide a character separation method that can sufficiently separate characters even without a limiting frame. In a character extraction method for cutting out characters one by one from a plurality of written characters, a histogram creation circuit detects a change in distance to each character in a vertical direction from one frame to another; A detection circuit that detects that the change in distance from each frame to each character obtained by the histogram creation circuit has changed by a predetermined value or more; and at least the distance in the column direction of the frame at the change point from each frame detected by the change point detection circuit. 1 change point within
and a combination detection circuit for detecting as one set,
This can be achieved by a character extraction method characterized in that characters are extracted based on each set of change points.

The present invention will be explained below with reference to the drawings.

FIG. 1 shows an embodiment of the character cutting method of the present invention.

In the figure, 1 is a video observation unit, 2 is a video buffer, 3 is a histogram creation circuit, 4 is a change point detection circuit, 5 is a change point memory buffer, 6 is an extraction point determination circuit, 7 is a combination search circuit, and 8 is a character extraction position determination circuit. The circuit and 9 indicate a character recognition section, respectively.

Further, FIGS. 2 to 8 show the processing status of each part in FIG. 1.

Characters written in a line within a strip-shaped frame of one fixed width on a form are read by a video observation unit 1 such as an optical reader and stored in a video buffer 2.

Therefore, in the video buffer 2, characters written in a line between the strip-shaped frames A and B are stored as shown in FIG. However, the frame may be in a readable state or may be determined virtually.

The video thus stored in the video buffer 2 is sequentially read out in the column direction of frames A and B and input to the histogram creation circuit 3.

As shown in Figure 3, the histogram creation circuit 3 sequentially detects the distance to a character in the vertical direction from frame B to frame A (or the distance to frame A if the character does not collide) in the column direction. As shown in FIG. 4, the distances to the characters in the vertical direction are similarly sequentially detected in the column direction from frame A to frame B, and this detected information is sequentially sent to the change point detection circuit 4. In the change point detection circuit 4, the distance from each frame A, B to the character changes by a predetermined value or more (this distance is determined from the height of each input character).
The detected points are sequentially detected as shown as B ₁ to B ₃ and A ₁ to A ₁₁ in FIGS. 3 and 4, and the memory address and distance of each change point are stored in the change point memory buffer 5. Stored separately by distance from frames A and B.

The memory address of the changing point of each frame and the distance from each frame stored in the changing point memory buffer 5 are input to the extraction point determining circuit 6.

In the extraction point determination circuit 6, if there are multiple change points on each frame A and B within a predetermined distance (this distance is determined from the expected width of a character and is smaller than the expected width of at least one character) ), leave the one with the smallest distance to the character at each change point and delete the other change points. The change point after the change and the distance to the character are sent to the combination detection circuit 7. (For example, from A ₄ , A ₅ , and A ₆ in FIG. 5, only A ₄ remains.) That is, as shown in FIG. 5, the distances from the points of change and the characters from the frames A and B are input.

However, FIG. 5 is a virtual diagram to make the explanation easier to understand, and in reality, the memory address of the change point and the distance to the character are sent.

The combination detection circuit 7 detects a combination of a change point from frame A and a change point from frame B.

In other words, in the combination detection circuit, for example, the fifth
If the point of change from frame B shown in the figure is within a predetermined distance in the column direction from the point of change from frame A, this is detected as one combination.

In this case A ₁ , and B ₁ , A ₂ and B ₂ , A ₄ and B ₃ , A ₇
and B ₅ , A ₉ and B ₆ , and A ₁₁ and B ₈ .

After determining the combination in this manner, a flag is added to the determined change point of the combination in a manner that allows correspondence, and the flag is sent to the character cutout position determination circuit 8 together with the contents of the extraction point determination circuit 6.

The character cutting position determination circuit 8 instructs the video buffer 2 to cut out characters as follows.

When cutting out this character, there are four cases in which the change points and distances from each frame A and B and their relationships are as follows, and the following processing is performed.

a. When the distance from each change point of the combination determined by the combination detection circuit 7 to the character is added up to be longer than the width of the frame (see FIG. 6).

b If it becomes shorter, contrary to a (see Figure 7).

c When the change points of the combinations determined in the same way as a and b above are at the same position in the column direction (fifth
For figures A ₁ and B ₁ , A ₄ and B ₃ , A ₁₁ , B ₈ ).

d A change point where there is no combination in the combination detection circuit 7 (see FIG. 8).

In the case of above a, as shown in Fig. 6, the upper frame A
If the distance to the lower frame B is Y, the distance from the change point from frame A to the character is y ₁ , and the distance from the change point from frame B to the character is y ₂ , then the center point y _s
is y _s =y ₁ −y ₂ +Y/2, and the position of the change point of upper frame A is x ₁ and lower frame B
If the position of the change point is x ₂ , then from frame A to y _2s
Separate the characters at x ₁ position, x ₂ from y _s to frame B
A memory address is instructed to the video buffer 2 so as to separate at the position.

Therefore, it is possible to separate and cut out characters in the form shown in FIG. 62.

In the case of b above, addresses are given to the video buffer 2 so that frames A to Y-y ₂ are separated by x ₁ , and frames (Y-y ₂ ) to frame B are separated by x ₂ , as shown in Fig. 7-1. By instructing, characters can be separated and cut out as shown in FIG. 72.

In case c above, an address is given to the video buffer 2 to unconditionally separate the characters between each change point, and the characters are separated and cut out.

In the case of d above, the characters are separated by cutting vertically from the point of change from one frame A, as shown in FIG.

In this way, the character cutting position detection circuit 8
A character extraction address is instructed to the video buffer 2, and each character extracted is sent to the character recognition section 9 for character recognition.

As described above, the present invention makes it possible to easily cut out characters one by one without setting a limit frame for each character on a form, and thus allows the person filling in the form to write freely on a form that does not require a limit frame. This simplifies the form design and also makes it easier for the character recognition device to cut out characters, thereby improving the recognition rate.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the character extraction method of the present invention, and FIGS. 2 to 8 show the processing steps of each part in FIG. is a histogram creation circuit, 4 is a change point detection circuit, 5 is a change point memory buffer, 6 is an extraction point determination circuit, 7 is a combination detection circuit, 8 is a character cutting position determination circuit, 9
indicate character recognition units, respectively.

Claims (1)

[Claims] 1 In a character extraction method in which a plurality of characters written in a line within a band-shaped frame of a certain width on a form are read and characters are cut out one by one from the plurality of read characters, one frame is cut out from the other. a histogram creation circuit that detects changes in the distance to each character in the vertical direction toward the frame and changes in the distance to each character in the vertical direction from the other frame toward one frame;
a change point detection circuit for detecting that the distance from each frame to the character obtained by the histogram creation circuit has changed by more than a predetermined value; a combination detection circuit that detects as one set a pair of change points in which the distance between the change point and the second change point detected on the other frame side is within a predetermined distance at least in the column direction; A character cutting method characterized in that a character cutting position is determined in accordance with the positions of the pair of change points.