JPS63120387A - Optical character reader - Google Patents

Abstract

PURPOSE:To use a handy type reader by deciding whether each character of a character line of a identifying object exists within a prescribed range of a visual field of an image sensor or not, and outputting a result of read only in case when a deciding condition is satisfied. CONSTITUTION:A character of one digit portion of a screen memory 8 is segmented to a memory 10 by a segmenting circuit 9, and X coordinate information of its segmenting position is sent to a position deciding part 16. Also, at the time of segmenting one character each from the memory 10 by a segmenting circuit 11, Y-coordinate information of the segmenting position is sent to a deciding part 16. The deciding part 16 decides whether the positions of segmented characters are contained within a prescribed range in the X direction and the Y direction, respectively, or not, and in case when all the characters of the character line are contained in a visual field of an image sensor 6, a result of read which is read by a character identifying circuit 13 is outputted from an output control part 14.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is an optical character reading device, particularly an optical character reading device that reads characters by holding a scanner and applying it to a line where characters are written on a price tag or the like. , relates to a hand-held optical character reader.

<Conventional technology> At supermarkets, department stores, etc., POS (Point of Use) collects sales information for each item and manages inventory.
5ales) system is widespread. As an OCR that can be used in this POS system, there is a hand-held optical character reader that can read characters within its field of view simply by placing a scanner on the paper to be read (for example, Japanese Patent Application No. 6O-79082 ). FIG. 4 shows a typical configuration of a hand-held optical character reading device.

In the optical character reading device shown in FIG.
Holding the scanner 1, place the image input port of the scanner 1 on the paper 3 on which the reading handwriting is written, and press the push button switch 19 to read the characters and symbols written on the paper 3. The paper 3 is, for example, a price tag on which information for a POS system is written. Such a scanner 1 includes a light source 4 that irradiates light onto a sheet of paper 3, a lens system 5 that forms an image of the sheet of paper 3, and an image that forms an image of characters to be read on the sheet of paper 3 by the lens system 5. It houses a sensor 6 and an image sensor drive circuit 7 that binarizes and outputs an analog signal, which is an output signal of the image sensor 6, for each pixel of the image sensor. A binarized image signal of the image of the sensor 6 is output from the image sensor drive circuit 7 to the screen memory 8 of the character recognition device main body 20.

The screen memory 8 stores the entire binarized image data within the field of view of the image sensor 6.

FIG. 5 (al) shows how a character image is projected into the field of view of the image sensor 6, which is stored in the screen memory 8 and has a width (3)×vertical size of pxq pixels.

The character recognition circuit 1 identifies the characters and symbols stored in the screen memory 8.
3 identifies characters one by one, 1 from screen memory 8.
It is necessary to sequentially extract data for characters. - The finger extraction circuit 9 sequentially shifts data corresponding to mXqii!j pixels, which is the processing capacity of the single character extraction circuit 11, from the screen memory 8 pixel by pixel in the X direction, as shown in FIG.
, b2... bS... Take out single digit memo IJ 1
Store at 0. - The character cutting circuit 11 stores data ji! corresponding to mXn pixels, which is the processing capacity of the character identification circuit 13, from a portion of the memory 10 as shown in FIG. clpc2
. . CS . . . are taken out and stored in the single character memory 10.

As shown in FIG. 5 (bl), the - finger extraction circuit 9 extracts data from the screen memory 8 from X=1 to X=m, Y=1 to Y=q shown in FIG. , - transferred to the digit memory 10.

- The character cutting circuit 11 looks at the contents of the one-digit memory 10 as shown in FIG. Transfer to the one-character memory 12.

The data transferred to the single character memory 12 is the character identification time g8.
At step 13, identification is performed for each character cut out. In the same way, the position to be taken out from the screen memory 8 is sequentially shifted, and
=2. C2 is stored in the single character memory 12 in response to 3, 4...
,C,,C.

. . . Character identification is performed by the character identification circuit 13 every time.

FIG. 6 shows how to determine the range when transferring data from the -digit memory 10 to the single character memory 12. First, calculate the horizontal OR for each row of the partial memory 10 as shown in FIG. , if there is no black pixel, the logical sum of each pixel in one row is calculated.The range of data transfer from the 1-digit memory 10 to the 1-character memory 12 is the 6th
As shown in Figure Cal, if the horizontal OR becomes black from Tamaruba Y;13, then Y=1 including the upper margin of the character.
1 to n pixels.

Through the above processing, characters and symbols included in the field of view pxq of the image sensor 6 are read.

On the other hand, the format match determination unit 15 uses the circuit 13 for each character m.
A format check is performed from the output of Part 14 character identification circuit 1
The nine reading results of No. 3 are stored in format units and output in format units. In other words, it is impossible to apply the scanner 1 to the paper 3 so that the character line to be read on the paper 3 is always exactly within the field of view of the image sensor 6 using a hand-held optical character reading device as shown in FIG. Often difficult. If a part of a character line protrudes from the field of view of the image sensor 6 and the number of digits is insufficient due to the protruding character, the format check unit 21 checks the format match determination unit 15 and the output control unit 14.
Accordingly, it is determined that the formats do not match, and the author is notified that the image cannot be read, and is instructed to reapply the scanner 1.

<Problems that the invention is unlikely to solve> In a hand-held optical character reading device as shown in Fig. 4, in order to perform a format l-check, a format is determined in advance before operation of the optical character reading device. It is necessary to register it in the format matching determination section 15.

There are also limits to the types of formats that can be registered.

Therefore, depending on the purpose, it may be desirable to use a free format without setting a format.

However, in the case of conventional hand-held optical character reading devices, a format check is used to determine whether the scanner has been properly applied to a character line, so it cannot be put to practical use without a format check. In this way, conventional hand-held optical character readers cannot be used in free format.

The present invention has been made in view of the problems of the prior art, and detects when a character image to be read formed on an image sensor protrudes from the edge of the field of view in the X and Y directions of the image sensor. Therefore, it is an object of the present invention to provide an optical character reading device that outputs the result of character identification only when there is no misalignment.

Means for Solving Problems> The configuration of the optical character reading device according to the present invention includes a two-dimensional image sensor on which a character image to be read is formed, and a two-dimensional image sensor on which a character image to be read is formed; In a hand-held optical character reading device having a character recognition section for reading each character in an image, the vertical direction (
a position detection means for detecting the position (y, x) in the Y direction) and the horizontal direction (X direction), and detecting whether the Y coordinate and the X coordinate of each character are within predetermined ranges. It is characterized by comprising a position determination section and an output control section that outputs the reading result of the character identification section only when the Y and X coordinates of all characters are within the predetermined range. be.

Function> The position detecting means and the position determination section determine whether the X and Y coordinates of the character read by the character identification section are within a predetermined range, and the character is located outside the predetermined range. In some cases, the identification results of the character identification section are not output, and the identification results are output only when the results are within respective predetermined ranges.

Embodiment An embodiment of an optical character reading device according to the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention.

In Figure 1, a scanner 1, paper 3, light source 4, lens system 5,
Image sensor 6, image sensor drive circuit fIs7, screen memory 8, -digit extraction circuit 9, -digit memory 10, -character extraction circuit 1], -character memory 12, character identification circuit 1
3. The output control section 14 is the same as that shown in FIG.

However, in this embodiment, when the single digit cutting circuit 9 cuts out one digit worth of characters from the screen memory 8 into the single digit memory 10, the X coordinate which is the cutting position is used as the X position information of the cut character and the position of the character position check unit 22 is used. It is output to the determination section 16.

Furthermore, when the character cutting circuit 11 cuts out each character from the single-digit memory 10, it outputs the Y coordinate of the cutting position to the position determining section 16 as the Y coordinate 912 of the cut character.

The position determination unit 16 receives information on the X coordinate of the character cutting position from the single digit cutting circuit 9 and information on the Y coordinate of the character cutting position from the single character cutting circuit 11, and determines the position of the cut out character in the X direction. If it is not within the predetermined range, the character identification circuit 13 identifies the characters including those that have been determined so far and are within the predetermined range. The output control unit 14 is controlled so that the result is not output, or when the result is within a predetermined range, the recognition result of the character recognition circuit 13 is output.

A configuration diagram of an example of the position determining section 16 is shown in FIG. -X of the character cutting position cut out by the digit cutting circuit 9
The coordinate signal is sent to a comparison circuit 6 that determines a predetermined range in the X direction.
1.62 to the respective B and A terminals.

The value of X sin is input to the A terminal of the comparator $61. Also, the comparison circuit 62 has the X waxD value input to the B terminal. A comparison circuit 61 that determines whether the X coordinate of each cutout character exists within a predetermined range in the X direction.
62, X min≦X ≦X maw
The relationship (1) is examined, and if X +iin > X, the comparator circuit 61 outputs a signal 1 outside the predetermined range. Further, if X1uX<X, the comparison circuit 62 outputs a signal 1 outside the predetermined range.

Regarding the Y direction: -The signal of the Y coordinate of the character cutting position cut out by the character cutting circuit 11 is sent to the respective B and A terminals of comparators @63 and 64 that determine a predetermined range @J in the Y direction. It has been entered. The value of Yai n is input to the A terminal of the comparator circuit 64. The value of Y wax is input to the B terminal of the comparison circuit 64. In the comparison circuits 63 and 64 that determine whether or not the Y coordinate of each cutout character exists within a predetermined range in the Y direction, YllILn≦Y≦Y +max f2)
The relationship is examined, and if YlllIn>Y, the comparator circuit 63 outputs a signal 1 outside the predetermined range. If Y wax < Y, the comparison circuit 64 outputs a signal 1 outside the predetermined range.

As above, comparators 61, 62p 63, 64X win
S X≦X a! ax fl)Ymin
5Y≦Y wax (21 is determined,
When this condition is not met, one of the input lines of the OR gate 65 becomes 1, and the output of the OR gate 65 becomes 1, which is input to the AND gate 66. At that time, if the signal indicating the character output timing indicating that the character has been read from the character identification circuit 13 is input to the other terminal of the AND gate 66, the output from the AND gate 66 will be output from the outside of the range 1.
is output to the output control unit 14, and the output control unit 14 does not output the reading results of the character identification circuit 13, including those that have been determined to be within the range.

Conversely, only when the relationship between equations (1) and (2) is satisfied for all characters in one character line, the output control unit assumes that all the character lines to be read are within the field of view of the image sensor 6. The result of reading a character line by the character identification circuit 13 stored in 14 is output.

Here, X+min determines the range of character positions.

For example, the values of X l1laxSY win, Y auix are determined as follows. X win,,X +a
The value of aχ is related to the width W of adjacent characters to be identified.

(b) If the identified character line in the X direction does not include a blank character ('-), the position of the identified character and the X coordinate of the identified character and the left and right edges of the field of view of the image sensor 6 are cut off. If the distance is at least one character width W from the character line, it is determined that the adjacent characters in the character line do not protrude outside the right edge of the visual field.

Therefore, if the width of one character is W, then X l1lin = W
(3) becomes.

Further, if the X coordinates of the extracted characters are not separated by p+1-m-W or more, it is determined that adjacent characters in the character line do not protrude outside the right edge of the visual field. Therefore, X yaax= p + 1- m W f
41.

Here, p: the number of pixels in the field of view in the X direction of the image sensor 6, the number of pixels in the X direction for cutting out the m knee character, and the number of pixels in the width of the W knee character.

Further, assuming that the identified X-direction character line contains at most one blank character, X + ainSX l1lax is as follows.

X win = 2 W (5)
X wax = p + 1- m -2W
(6) becomes.

(b) The value of Yna group, Y age Suppose there is no. Therefore Y m1n-h / 3 (7)
Y wax = q + 1-n-h/3
(8).

Here, q = number of pixels in the field of view in the Y direction of the image sensor, Pixels in the Y direction for n-knee character extraction number, h knee character height pixels, It is.

FIG. 3 shows an example of the relationship between the character line to be read and the field of view of the image sensor.

What is shown in FIG. 3(a) is an example in which a part of the character line protrudes in the X direction and the Y direction, respectively. According to the optical character reading device according to this embodiment, the expression (1) is not satisfied at the cutout position x of the character 3 in the character line. Furthermore, equation (2) is not satisfied at the cutting position Y of character 6 in the character line, and therefore no reading result is output. In such a case, the optical character reading device determines that the character cannot be read and prompts the operator to re-operate the character using conventional means such as an audible alarm or flashing light. This allows the operator to operate the scanner 1 again and reliably read the object to be read.

Moreover, what is shown in FIG. 3 (bl) is an example in which all characters in a character line are included in the field of view of the image sensor, and in this case, equation (1) and (2) are used for all characters in the character line.
) is satisfied. Therefore, the reading result read by the character identification circuit 13 is outputted from the output control section 14.

<Effects of the Invention> According to the optical character reading device according to the present invention, it is determined whether or not each character in a character line to be identified exists within a predetermined range of the field of view of the image sensor, and when the determination condition is satisfied. Since only the reading results are output, a free-format handheld optical character reading device has become possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an optical character reading device according to the present invention, and FIG.
FIG. 3 is a diagram showing an example of the relationship between the field of view of an image sensor and a character line to be identified; FIG. 4 is a diagram showing a configuration of a conventional optical character reading device; Figure 5 is a diagram explaining the line of read characters of the Song Dynasty that is imaged in the field of view of the image sensor and the extraction of these characters, and Figure 6 is an explanation of how to determine the extraction width when extracting one character from a partial memory. It is a diagram. In the drawing, 1 is a scanner, 3 is paper, 4 is a light source, 5 is a lens system, 6 is an image sensor, 7 is an image sensor drive circuit, 8 is a screen memory, 9 is a partial cutting circuit, lθ1 and a partial memory, 11 is a character cutting circuit, 12 is a character memory, 13 is a character identification circuit, 14 is an output control section, 16 is a position determination section, 20 is a character identification device main body, 22 is a character position check section, 61, 62, 63, 64 is a comparator, 65 is O
R gate, 66 (YANr) gate.

Claims (1)

[Claims] In a hand-held optical character reading device having a two-dimensional image sensor on which a character image to be read is formed, and a character identification unit for reading each character in the image to be read formed within the field of view of the image sensor. , the vertical (Y direction) and horizontal (X direction) positions of each character in the image to be read are determined by (Y
, An optical character reading device comprising an output control section that outputs the reading result of the character identification section only when the character identification section is within the predetermined range.