JPH03122786A - Optical character reader - Google Patents

Abstract

PURPOSE:To obtain a proper character reading result by preparing a dictionary for executing the character recognizing processing of a partial character pattern in each contact/extruded state, and when a character is contacted/extruded with/from a frame, executing its character recognizing processing by using the dictionary. CONSTITUTION:A character recognizing circuit 13 executes the character recognizing processing of a character pattern detected by a character segmenting circuit 12 in each character based upon a reference pattern stored in the dictionary memory 14. The memory 14 stores reference patterns for recognizing the character patterns of characters entered so as not to be contacted/extruded with/from respective character entering frames and reference patterns for recognizing partial character patterns (patterns existing in the character entering frames) due to contact/extrusion in each contacted/extruded state with/from each character entering frame. Even when a character entered in the character entering frame is contacted/extruded with/from the frame, its proper character reading result can be obtained.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention is an optical character reader for reading characters written in a non-dropout color character writing frame provided on a form. Regarding equipment.

(Prior Art) Generally, in an optical character reading device that reads characters written on a form, characters are read within a frame provided on the form indicating a position where characters are written. If the frame (character entry frame) that indicates the character entry position provided on the form is printed with a black frame (non-dropout color), the characters written in the character entry frame may touch the frame. , the condition for writing characters is that they do not protrude.

In recent years, optical character reading devices are increasingly used to read forms on which characters are recorded by ordinary people, such as the payment notice slip shown in FIG. However, since the characters are filled in by ordinary people,
It is very common for characters to touch or extend beyond the character entry frame. Even if such characters are not entered correctly, the character recognition process will continue to be performed. For this reason, the character recognition rate may drop significantly for characters that are not accurately written within the character entry frame. In particular, a major problem arises if numerical and character data such as account numbers and amounts on payment notification slips are misread.

(Problem to be Solved by the Invention) As described above, if the characters written in the character entry frame provided on the form touch or protrude from the frame, the character recognition rate decreases. There was a problem with this.

The present invention has been made in view of the above points, and it is possible to obtain suitable character reading results even when the characters are written in the character entry frame or touch or protrude from the frame. The purpose of the present invention is to provide a possible optical character reading device.

[Configuration of the Invention (Means for Solving the Problems) The present invention provides contact/extrusion state detection means for detecting a state in which characters written in a character entry frame of a form are in contact with or protrude from the character entry frame; A character pattern detection means for detecting a partial character pattern existing within the character writing frame excluding the touching/protruding portion of the character whose contact/protrusion has been detected by the contact/protrusion state detection means; A dictionary storage means for storing standard character patterns used in character recognition processing for partial character patterns formed by contacting and protruding from the character entry frame, and a contact/protrusion state detection means for each of the plurality of characters. character recognition that reads out a signature pattern stored in a dictionary storage means and performs character recognition processing on the partial character pattern detected by the character pattern detection means according to the state of contact or protrusion of the character with respect to the character entry frame; The apparatus is configured to include a processing means.

Furthermore, the contact/protrusion state is indicated by the number of characters touching/protruding in each direction of the character entry frame in the up, down, left, and right directions, and the standard pattern corresponds to the number of contact/protrusion in each direction of the character entry frame in the up, down, left, and right directions. The information is stored in the dictionary storage means.

(Operation) According to this configuration, for characters written in contact with or protruding from the character entry frame, a character written in contact with or protruding from the character entry frame that is different from the general standard character pattern stored in the dictionary storage unit is used. Character recognition processing is performed using a specific standard character pattern. In addition, standard character patterns for characters that touch or protrude are stored in the dictionary storage section for each character to be read, so partial character patterns formed by touching or protruding from the character entry frame are stored in the dictionary storage section for each character to be read. , even if the characters are similar to other characters, it is possible to at least prevent them from being misread (rejected).

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a functional part that performs character recognition processing in an optical character reading device according to the same embodiment. In the figure, +1 is a line buffer for storing a binary pattern of character lines and items read optically from a form. A character cutting circuit 12 and a character recognition circuit 13 are connected to the line buffer H. The character recognition circuit 12 detects a character pattern for one character from the character line-equity binarized pattern stored in the line buffer II. The character recognition circuit 13 performs character recognition processing for each character on the character pattern detected by the character cutting circuit I2, based on the symbol pattern stored in the dictionary memory 14. The dictionary memory 14 contains standard patterns for recognizing character patterns of characters written without touching or protruding from the character entry frame, as well as partial character patterns due to contact or protrusion (existing within the character entry frame). (patterns) are stored for each state of contact with or protrusion from the character entry frame.

Next, the operation of this embodiment will be explained.

Here, it is assumed that a form as shown in FIG. 2 is to be subjected to character reading processing. First, the form shown in FIG. 2 is optically scanned using a scanner device or the like to detect the form image.

When a form image is detected, an image of an area (line) targeted for character reading processing is detected based on preset reading control information. Note that a description of the processing executed based on the reading control information will be omitted. Second
In the case of the form shown in the figure, the line image of the data line (the line where the account number and amount are entered) is detected and transferred to the line buffer 11 via the data line A in the figure. When one line of image data is transferred to the buffer 11, the line is sent from a circuit (not shown) (for example, a control circuit that controls the entire device) to the character cutting circuit 12 via the control line B in the figure. A character cutting start signal is given. When the character cutting circuit 12 receives a character cutting start signal,
The line buffer 11 is scanned through the data line C in the figure to detect a character pattern for one character. The character cutting circuit 12 detects character patterns in the following manner. First, from the image pattern for one line stored in the line buffer 11, as shown in FIG. Based on this, extract the character entry frame. The character entry frame can be determined in the X direction and Y direction.
In each histogram in the direction, is the histogram value greater than or equal to a certain slice level, and is the coordinate of the histogram within the error range of the pitch (for example, given by reading control information) that indicates the pre-assumed frame size? It depends on whether or not. When the extraction of the character entry frame is completed, the character cutting circuit 12 calculates the number of character patterns (character lines) that intersect (contact) with each of the upper, lower, left, and right character entry frame lines (the number of touching/protruding clips). Obtain as shown in the figure. Here, the number of clips touching and protruding from the left side character frame line is (L), and similarly, the number of clips on the right side (R), the upper side (T), and the lower side (B). FIG. 4 shows an example in which the number "0" protrudes from the left character frame line. The method of detecting the number of touching/protruding clips is, for example, by scanning one bit inside each character entry frame line (on the character side) and changing it from a white bit (for example, "0") to a black bit (for example, 1). Find the number of change points.In Figure 4, CI.

A change from white to black is detected at C2,
The number of change points -2 is the number of clips (L) that touch and protrude from the left side character entry frame line. In this way, the number “0” shown in FIG.
The number of clips in contact and protrusion is (L)-2, (R)
-0, (T)-0, (B)-0. Next, the character cutting circuit 12 removes the pattern of the character entry frame and extracts a character pattern (partial character pattern) located within the character entry frame. The character pattern (partial character pattern) thus obtained is sent to the character recognition circuit 13 via the data line C.
will be forwarded to. However, for character patterns that do not touch or protrude from the character entry frame, normal character patterns will be transferred.

In addition, the character cutting circuit 12 transfers the number of clips that touch and protrude in the character entry frame to the character recognition circuit 13 as additional information of the partial character pattern (character pattern), and also starts character recognition processing via the signal line D. Outputs a recognition start signal that instructs. When the character recognition circuit 13 receives the recognition start signal from the character cutting circuit 12, the character recognition circuit 13 selects each of the character patterns (partial character patterns) input via the data line C to be read, which are stored in advance in the dictionary memory 14. Character recognition processing is performed by comparing characters with standard patterns.

In the dictionary memory 14 used for character recognition processing, dictionary entry points are set and mark patterns are stored, as shown in FIG. FIG. 5 shows the entry points of a dictionary used to recognize character patterns of numbers. That is, in the dictionary memory 14,
For each character to be read, a dictionary entry point is set for each set of the number of clips that touch and protrude from each character entry frame line (contact/protrude state), and a standard pattern corresponding to the contact/protrusion state is stored. be done.

For example, a recognition dictionary for recognizing the character pattern of the number "0" is a dictionary for patterns that do not touch or protrude from the upper, lower, left, or right character entry frames (L-0, R-O, T-0, B-
0), Dictionary for a pattern (pattern as shown in Figure 4) that protrudes only on the left side character entry frame line with the number of clips -2 (L-2, R-0°T-0, B-0), Bottom side Pattern dictionaries (L-0°R-0, T-0, B-2) that protrude only from the character entry frame line with the number of clips -2, and other pattern dictionaries that do not satisfy the above conditions (L-*, R-*
.

T-*, B-*). Similarly, for other characters, a dictionary is constructed for each possible contact/protrusion state of each character.

The character recognition circuit 13 reads from the dictionary memory 14 the dictionary (standard pattern) indicated by the dictionary entry point corresponding to the number of contact/protrusion clips input as additional information of the character pattern (partial character pattern) to be recognized, and Recognize characters by matching them with patterns. When the character recognition result (character code) is thus obtained, the character recognition circuit 13 outputs this recognition result to the data line E. Furthermore, when character recognition for one character is completed, the character recognition circuit 13 transmits the following information via the signal line F.
A single character recognition circuit signal is output to the character cutting circuit 12.

As a result, the character cutting circuit 12 starts cutting out a character pattern to be subjected to the next character recognition process from the image stored in the line buffer 11.

Thereafter, similar processing is repeated to cut out character patterns (partial character patterns) existing within each character entry frame and perform character recognition processing.

Here, an example of character recognition processing will be described.

The character pattern in the character entry frame (a) in Figure 2 extends beyond the lower frame line by the number of clips = 2 (see Figure 3), so by removing the frame pattern when cutting out characters, Figure 6 This results in a partial character pattern as shown in (a). Such a partial character pattern can also be recognized as the number "6" if the dictionary memory 14 stores a dictionary for character patterns in which the lower part of the character pattern is missing. In addition, since the character pattern in the character entry frame in Figure 2 (b) extends beyond the left side frame line by the number of clips - 3, the frame pattern is removed when cutting out characters, resulting in the character pattern shown in Figure 6 (b). It becomes a partial character pattern. This partial character pattern is similar to the number "3", but it is processed for character recognition using the dictionary (prepared as a dictionary for the number "8") with the number of clips to the left character frame minus 3. , it is possible to at least reject it and prevent it from being misread as the number "3" (provided that the dictionary for the number "3" does not have a dictionary for the number of clips to the left character frame - 3).
. Similarly, the character pattern in the character entry frame in Figure 2 (c) becomes a partial character pattern as shown in Figure 6 (c) by removing the frame pattern, but it is necessary to prepare a dictionary for this partial character pattern. This can prevent the number from being misread as the number "7". It should be noted that the partial character pattern in the character entry frame in FIG. 2(d) does not have any other characters that are easily confused with other characters due to the lip as shown in the figure. Therefore, there is no need to prepare a dictionary specifically for partial character patterns obtained by clipping, and the character recognition circuit can be implemented using a dictionary for the numeral "5".

Similarly, even if the number "3" is clipped to the left character frame, there is no other character that can easily be mistaken for another character, so
Character recognition processing may be performed using a QX-like dictionary for the number "3". As a result, when performing character recognition on the partial character pattern of the number "8" that extends beyond the left side frame line by the number of clips minus three, the dictionary for the number "3" is not selected.

In this way, the direction of contact and protrusion to the character entry frame,
By preparing a recognition dictionary (standard pattern) used for character recognition processing for partial character patterns in several clips, the characters written on the form can be displayed in the character entry frame (
Even if the character touches or protrudes from a non-dropout color (such as a black frame), the recognition dictionary for partial character patterns is used to deal with this, so at least misreading can be prevented.

Furthermore, conventionally, character entry frames have been printed using dropout colors because it is difficult to cut out character patterns that touch or protrude from character entry frames using non-dropout colors. However, in the present invention, recognition processing can be executed for partial character patterns that touch or protrude from the character entry frame. Therefore,
Since the character entry frame does not necessarily have to be in a dropout color, there is no need to use a specific light source corresponding to this, and it is possible to detect the image of the form and perform character recognition using a single light source.

[Effects of the Invention] As described above, according to the present invention, a dictionary is provided for performing character recognition processing on character patterns (partial character patterns) of characters written in contact with or protruding from a character entry frame provided on a form. Prepared for each contact/extrusion condition,
Even if the characters touch or protrude from the frame, suitable character reading results can be obtained by performing character recognition processing using this dictionary.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a functional part that performs character recognition processing in an optical character reading device according to an embodiment of the present invention, and FIG. 2 is a diagram showing an example of a form to be subjected to character reading processing. Figure 3 is a diagram for explaining the process of character entry frame extraction, Figure 4 is a diagram for explaining the process of calculating the number of clips in which a character pattern touches and protrudes from the character entry frame, and Figure 5 is a diagram for explaining the process of character entry frame extraction. FIG. 6 is a diagram showing the correspondence between the number of touching/protruding clips and dictionary entry points, and FIG. 6 is a diagram showing an example of a partial character pattern. 11...Line buffer, 12...Character extraction circuit, I3...Character recognition circuit, 14...Dictionary memory first
figure

Claims (2)

[Claims] (1) In an optical character reading device that reads characters written in a character entry frame provided on a form, the state in which characters written in the character entry frame of the form are in contact with or protrude from the character entry frame a contact/protrusion state detection means for detecting a contact/protrusion state detection means; and a partial character pattern existing within the character entry frame excluding the contact/protrusion portion of the character whose contact/protrusion has been detected by the contact/protrusion state detection means; For each of the plurality of characters to be read, a standard character pattern used for character recognition processing of a partial character pattern formed by contacting or protruding from a character entry frame is detected. a dictionary storage means for storing data for each state; and a standard pattern stored in the dictionary storage means is read out according to a contacting/protruding state of a character with respect to the character writing frame detected by the contacting/protruding state detecting means. , character recognition processing means for performing character recognition processing on the partial character pattern detected by the character pattern detection means. (2) The contacting/protruding state is indicated by the number of characters touching/protruding in each of the up, down, left, and right directions of the character entry frame, and the standard pattern is the number of contacting/protruding characters in each of the up, down, left, and right directions of the character entry frame. 2. The optical character reading device according to claim 1, wherein each character is stored in said dictionary storage means in correspondence with each other.