JPH0474754B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a character recognition method for reading and recognizing characters.

As a character recognition method, there is a method in which characters on a medium are read and sampled, and each character is sequentially recognized from the data. However, this method recognizes each character sequentially from only sampling data, so if there is dirt between the characters on the medium, the dirt will be mistaken as part of the character and character recognition will be interrupted. The characters may end up being unrecognizable or misread.

The present invention uses analog circuit means to prevent characters from being unrecognizable or misreading due to dirt on the medium, etc., and when the start point of a read character is detected and the end point of the read character is detected before a set time elapses, the character is The purpose of this invention is to provide a character recognition method that does not perform recognition.

The present invention will be described in detail below with reference to the drawings.

The structure of the present invention will be explained with reference to FIG. The signal is scanned and read in the horizontal direction by the analog/digital conversion circuit 2, and converted from analog to digital by the analog/digital conversion circuit 2. Further, the analog circuit means 5 detects the start point and end point of each read character from the character reading output from the character reading means 1, and the character start point signal from the analog/digital conversion circuit 2 is detected by the analog circuit means 5. The storage means 3 stores the data of each read character. The recognition means 4 recognizes the read characters based on the data in the storage means 3. The timer means 6 is operated by a character start point signal from the analog circuit means 5, and measures a predetermined set time smaller than the time corresponding to the minimum character width among the plurality of character widths. The control means 7 detects that the end point of the read character is detected by the analog circuit means 5 before the timer means 6 measures the set time, and prevents the recognition means 4 from performing character recognition.

FIG. 2 shows an embodiment of the invention.

This embodiment is an example of reading and recognizing magnetic ink characters from a medium such as a card such as a check on which magnetic ink characters E13B are recorded at regular intervals in the horizontal direction. The magnetic ink characters on the card are detected by transporting the card at a constant speed by scanning the card in the lateral direction of the characters with the magnetic head 11 at a fixed position. The output of the magnetic head 11 is amplified by an amplifier 12, noise is removed by a low-pass filter 13, and an analog/digital conversion circuit 14 operates with a signal from a central processing unit (CPU) 15 to perform sampling and digitization. is created and stored in random access memory (RAM) 16. Further, the output signal of the amplifier 12 is integrated by an integrating circuit 17, binarized at a constant level by a waveform shaping circuit 18, and inverted to become a negative rectangular wave. The time constant of the integrator circuit 17 is set so that the falling and rising edges of the negative rectangular wave from the waveform circuit 18 correspond to the starting and ending points of any magnetic ink character. and the termination point are detected by the integrating circuit 17 and the waveform shaping circuit 18. Here, the JIS standard E13B is shown in Figure 4~
These are 14 types of magnetic ink characters that are recorded on a medium in the shape shown in , and are selectively recorded on the medium in a horizontal row at regular intervals. This magnetic ink character is read from the rear side by being scanned and read in the horizontal direction by the magnetic head 11,
The character reading signal from the magnetic head 11 is output as a differential waveform indicating the amount of magnetic change in the lateral direction of the magnetic ink character as shown in FIGS. When this character reading signal is equally divided horizontally into 8 blocks, the positive peak always appears in the first block, and the last peak appears in any of the 5th to 8th blocks in the latter half. The magnetic ink characters are composed of four different character widths. This character reading signal is integrated by the integrating circuit 17, binarized at a certain level by the waveform shaping circuit 18, and inverted to become a negative rectangular wave, and this rectangular wave exists for the character width of the character reading signal. .
The integrating circuit 17 and the waveform shaping circuit 18 detect the time when the character reading signal exceeds a certain level as the starting point, and output it from the waveform shaping circuit 18 as the falling edge of a negative rectangular wave. The waveform shaping circuit 1 detects the time of drop as the termination point.
8, it is output as a rising edge of a negative rectangular wave. For example, in the magnetic ink character shown in FIG. 4, the character reading signal, the output signal of the integrating circuit 17, and the waveform shaping circuit 1
The negative square wave from 8 is as shown in FIG.
Furthermore, E13B has four types of character widths, and the minimum character width is 1.321 mm. Soft timer (CPU15
The time of the built-in timer) 19 is set to a value smaller than the time width of the output rectangular wave of the waveform shaping circuit 18 for characters with the minimum character width, but considering the ink stains on the card, the time width of the above time width is set to 1 If it is about /3, there is no problem in practice. CPU15, RAM1
6. Read-only memory (ROM) 20 and input/output ports (omitted in the figure for simplicity) constitute a microcomputer, and the CPU 15 executes the following operations using a program as shown in Fig. 3 stored in the ROM 20. Perform processing like this. The CPU 15 receives the rectangular wave from the waveform shaping circuit 18, and its falling and rising edges are given as a character start point signal and a character end point signal.When the CPU 15 detects the falling edge of the rectangular wave, it sets the set time to the soft timer 19. At the same time as starting the detection operation, the analog/digital conversion circuit 14 is operated to sample the read signal and store the data in the RAM 16. If the rectangular wave from the waveform shaping circuit 18 rises and a character end point signal is given before the timer 19 detects the set time, it is determined that this is not a character reading but a dirt reading, and the analog/
The digital conversion circuit 14 is stopped, sampling of the read signal is stopped, and the character recognition program is not executed. Therefore, if the time from the start point to the end point of each character reading signal is less than the set time of the soft timer 19 (the set time smaller than the time corresponding to the minimum character width of E13B), character recognition will not be performed. Even if there is a stain or the like whose length is shorter than the time corresponding to the set time of the soft timer 19 between each character on the medium, this stain will not make it impossible to recognize the character or cause the character to be read incorrectly. When the timer 19 detects the set time before the rectangular wave from the waveform shaping circuit 18 rises and the character end point signal is given, it determines that this is a character reading and instructs the analog/digital conversion circuit 14 to operate. The reading signal continues to be sampled. Thereafter, when the rectangular wave from the waveform shaping circuit 18 rises and a character end point signal is applied, the analog/digital conversion circuit 14 is stopped and a character recognition program is entered to recognize the read character based on the data in the RAM 16.

As described above, in the character recognition method according to the present invention, if the ending point of the read character is detected before a set time has elapsed after the analog circuit means detects the start point of the read character, character recognition is not performed. Therefore, even if there is dirt or the like between the characters on the medium, it is possible to prevent the characters from being unrecognizable or misreading due to the dirt, etc., thereby increasing the character recognition rate and the efficiency of character recognition.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the configuration of the present invention, Figure 2 is a block diagram showing the configuration of the present invention.
The figure is a block diagram showing one embodiment of the present invention, and FIG. 3 is a flowchart showing a program of the same embodiment.
FIG. 4 is a diagram showing each character of E13B and the read signal waveform, and FIG. 5 is a timing chart of the above embodiment. DESCRIPTION OF SYMBOLS 1... Character reading means, 2... Analog/digital conversion circuit, 3... Storage means, 4... Recognition means, 5... Analog circuit means, 6... Timer means, 7... Control means.

Claims (1)

[Claims] 1 A plurality of characters on a medium whose character width is specified as one of multiple types of character widths and which are arranged horizontally at a predetermined interval are scanned and read in the horizontal direction by a character reading means, and are read as sampling data. A character recognition method that stores and recognizes read characters based on the stored sampling data,
analog circuit means for detecting the start point and end point of each read character from the character reading output from the character reading means; a timer means for timing a predetermined set time smaller than the time corresponding to the minimum character width; an analog/digital conversion circuit to which the character reading output from the character reading means is input; and each reading from the analog/digital conversion circuit. a memory means for starting the storage of character data by the character start point signal; a recognition means for recognizing the read character based on the data in the memory means; and a recognition means for recognizing the read character based on the data in the memory means; and control means for detecting that the terminal point of the character has been detected by the analog circuit means and for not causing the recognition means to perform character recognition.