JPS63118893A - Optical character reader - Google Patents

Abstract

PURPOSE:To prevent the same character string from being read several times by providing a means which does not identify a character when a character area lies outside the visual field and when the character area is positioned in the vicinity of the upper and lower ends of the visual field of an image sensor and making the image sensor scan a next area. CONSTITUTION:A new line detection circuit determines the position of the character from signals SET and END transmitted from a scan position detection circuit 29, compares the position with a one determined by signals SET and END transmitted by next scan, and judges that the character string is at the outside of the visual field once with the aid of a signal CLEAR or the changing amount (the number of picture elements) of the character position. If so, the circuit 10 transmits a signal NEW to an identification circuit 11. At the time of receiving a signal NWT from the scan position detection circuit 29, an identification stop circuit 12 stops the identification circuit 11 from recognizing, and controls the circuit 11 so as to again retrieve an output signal from the image sensor 6. By a new line detection circuit 10 when it reads out character strings overflowing from the visual field, the movement of a scanner 1 from top to bottom and vice versa is sufficient.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides the ability to scan characters, symbols, etc. (hereinafter, only characters will be described as a representative, but not all symbols can be used) by scanning paper with a hand-held scanner. The present invention relates to an optical character reading device for reading (similar).

[Conventional technology]

At supermarkets, department stores, etc., POS (Point of Sale) collects sales information for each item and manages inventory.
f5aies) system is widespread. This POS
Systems often use hand-held optical character readers.

This hand-held optical character reading device was developed in
There is one that reads one character at a time, as shown in 9-6418. In order to further improve the operability, as disclosed in Japanese Patent Application No. 61-41474 filed by the present applicant, a field of view for one line is provided, and the scanner can be read simply by placing it on a character string.

[Problem that the invention seeks to solve]

In order to improve operability, optical character reading devices with a field of view for one line read one line of data simply by placing the scanner on the character string, but when reading multiple lines of data, the scanner is moved from top to bottom. Since it is read by moving to the same line, it is necessary to determine whether it is the same line or a new line. If it is the same line, 1
Instead of reading the same data over and over again, you need to read it when a new row comes. However, in the conventional method, there was a problem in that it was not sufficient to determine whether the same line was a new line, and the same line was read multiple times.

This point will be explained based on the optical character reading device shown in FIG. 3 (from Japanese Patent Application No. 61-4147 mentioned above).

In the figure, reference numeral 1 denotes a scanner, which reads characters written on paper 3 by simply placing it on the paper 3 with hand 2. The paper 3 is, for example, a price tag on which information for a POS system is written. 4 is a light source, 5 is a lens system,
Reference numeral 6 denotes an image sensor, which requires a field of view of at least one line of characters written on the paper 3; in this case, the field of view is one line horizontally and about three times as long as one character vertically. 7
is a control/binarization circuit that converts an analog signal, which is an output signal of the image sensor 6, into binary signals corresponding to a character area and a background area, respectively, and sends the signals to a memory 8. memory 8
A binarized signal of the entire field of view of the image sensor 6 is stored in .

Recognition processing is performed from the binarized signals stored in the memory 8, but only the binarized signals in which the characters are correctly within the visual field!
! I'm trying to process it cognitively. That is, FIG. 4 shows an example in which the image sensor 6 scans and binarizes the image, and this figure shows a case where characters are correctly included in the field of view 17. Fifth
The figure shows a case where scanning is performed with characters protruding from the field of view 17.

Note that in FIG. 4.5, some vertical lines indicating pixel divisions are omitted.

The scanning position detection circuit 9 determines whether or not to perform recognition processing. l111, the scanning position detection circuit 9 operates in parallel with storing the binary signal into the memory 8,
Almost at the same time as the storage of the binarized signal into the memory 8 is completed, it is determined whether or not to perform recognition processing.

Furthermore, when performing recognition processing, the scanning position detection circuit 9 determines the recognition area so that only the area where characters are present is recognized, without processing the entire field of view.

An example of a specific configuration of the scanning position detection circuit 9 is shown in FIG. 6. As shown in FIG.
The determination circuit 22 includes a ROM 25 & a register 26.

Each row OR circuit 21 performs an OR operation for each row between the pixels at the second position approximately in the center of the horizontal body of the field of view of the image sensor 6 (19 in FIG. 4, from the Bt column to the Bu column). When the control/binarization circuit 7 sends a binary signal as shown in FIG. At the same time, the logical sum of the binarized signals in each row from the Bt column to the Bu column is calculated by each row logical sum circuit 21.

To further comment, the register 24 is first cleared, and when the signal in the Bt column of the L1 row is input to the OR gate 23, it is stored in the register 24, and when it is repeated up to the Bu column, the logical sum operation of the L1 row is This is because the result is stored in register 24.

When the logical sum up to the Bu column is determined, the contents of the register 24 are sent to the determination circuit 22, and at the same time, the register 24 is cleared. As a result, the result of the logical sum from the L1 row to the t and p rows is sent to the determination circuit 22. From the result of the logical sum for each row, it can be determined whether or not there is a binarized "black" in each row.

The configuration and operation of the determination circuit 22 to which a signal representing the result of the logical sum is supplied are as follows.

That is, the signal representing the result of the logical sum of each row in the determination circuit 22 is input to the ROM 25, and the contents read from the ROM 25 are stored in the register 26. Since the state a'a transition indicating a change in the black and white state is encoded and written in R0M25, the logic of the 0th order row is stored in the register 26, which stores the black and white state up to that row. Signals from the register 24 indicating the sum result and the register 26 indicating the previous state are input to the ROM 25, and the signal of the new state is stored in the register 26. ROM25 has SET, E
Codes corresponding to ND and CLEAR signals are written. When the signal SET changes from white to black, E
ND has black (equivalent to the height of the letters) II! This is output when the color changes to white.
The character position is up to the line D. On the other hand, the bottom row t,
When the signal SET and signal END are not output up to p rows, a CLEAR signal is output to the control circuit 16, and the control circuit 16 clears the memory 8. In this way, subsequent recognition processing is not performed, and a new input signal is acquired by scanning again.

The new line detection circuit 10 determines the character position from the signals SET and END sent from the scanning position detection circuit 9, and compares it with the character position determined by the SET and END signals sent in the next scan, and determines the amount of change in the character position (in pixels). number) or signal CLEA
A judgment is made based on whether the character string has protruded once from the field of view 17 using R, and if it is determined that a new character string exists, a signal NEW is sent to the identification circuit 11. After the signal NEW is sent, the next recognition process is performed.

With this new line detection circuit 10, when reading a character string with more lines than the field of view, it is only necessary to move the scanner 1 from top to bottom or from bottom to top.

The identification circuit 11 recognizes characters one by one from the binary signal stored in the memory 8, and a description thereof will be omitted.

However, when the scanner 1 stops at the position where the character string is at the edge of the field of view as shown in Fig. 7, the signal NEW is output,
SET and END are output without being output, and it determines that the character is in the field of view, performs recognition processing, and the same character string is regarded as a new line, over and over again! ! There was a drawback in recognition processing. In FIG. 7, since part of the 30 pixels in the Ll row, which is the bottom row, is a text area, the output of the image sensor 6 is at a slightly different level between "white" and "black".

Therefore, when binarized at a certain moment, it becomes "white",
Moreover, in the next binarization, it becomes "1 black".

If it becomes "white", the bottom row L1 is "white" and the next.

1 black" from the line, it is determined that the character is within the field of view, but it is determined that the character is out of the field of view, and the signal NEW is output.The signal NEW may or may not be output. Another problem is that even though the scanner 1 is stationary, the same character string is regarded as a new character string and the same character string is read over and over again.

The present invention aims to solve the above problems.

[Means for solving problems]

The present invention does not output the signal NEW when the character string is out of the field of view and when the character string is correctly within the field of view, stops the recognition process, and scans the image sensor again. By adding a means to perform this, it is possible to prevent the same character string from being read over and over again.

〔Example〕

An embodiment of the invention is shown in FIG. Scanning position detection circuit 29
When outputting the signal NWT from the identification stop circuit 12
is to stop the recognition processing operation in the identification circuit 11 and control the output signal from the image sensor 6 to be taken out again. The rest is the same as the conventional example shown in FIG. 3, so the explanation will be omitted.

FIG. 2 is a configuration diagram of the scanning position detection circuit 29, and the 0 judgment circuit 32, which is almost the same as the scanning position detection circuit 9 in FIG. Output.

The logical sum of Ll, which is the bottom row of the visual field, is 0 (all “white”) and the second row from the top) to logical sum 1 (“black” exists)
is continuous between pixels equivalent to a character or the bottom row L
The signal NWT is generated when the logical sum 1 of p is continuous from the second row from the bottom (Lp~■) to the top between pixels corresponding to the number of characters.
Take out only.

Other than that, when changing from "white" to "black", SET 5 "black" continues and when changing to "white", END.

The CLEAR signal when "black" is continuous from the top row and "black" is continuous from the bottom row is the same as the conventional one. Each row OR circuit 31, OR gate 33, register 34, ROM
35, register 36 includes each row OR circuit 21 in FIG.
Since they are the same as the OR gate 23, register 24, ROM 25, and register 36, their explanation will be omitted.

In the above explanation, the signal NWT output was described for "white" on the top and bottom rows and "black" from the next row, but not only on the top and bottom rows, but also on 2 or 3 rows from the top and bottom, etc. The signal NWT is also output when it is "white" in multiple lines and "black" from the next line, and the signal 5ETSE indicating the character position is output.
The ND may be set in the middle of the field of view.

Further, it can be used not only when the field of view is for one line but also when the field of view is for multiple lines.

(Effects of the Invention) The present invention is an image sensor that has a field of view for at least one line, and can read multiple lines by moving the scanner up and down.
Furthermore, even when reading a character string at the edge of the field of view, the same character string is not read multiple times, so characters can be read correctly even when the scanner is stationary. Therefore, an optical character reading device with very good operability can be realized.

[Brief explanation of the drawing]

Figure 1 is a block diagram of an embodiment of the present invention, Figure 2 is a block diagram of a scanning position detection circuit of the present invention, Figure 3 is a block diagram of a conventional example, and Figures 4 and 5 are of the image sensor. FIG. 6 is a block diagram of the scanning detection circuit, and FIG. 7 is an explanatory diagram conceptually showing the inside of the visual field. 1...Scanner, 2...Hand, 3
...Paper, 4...Light source, 5
... Lens system, 6 ... Image sensor, 7 ... Control/binarization circuit, 8 ...
...Memory, 9.29...Scanning position detection circuit, 10...New line detection circuit, 11...Identification circuit, 12...Identification stop Circuit, 19... Pixel for calculating the logical sum in the scanning position detection circuit, 2L31... Each row logical sum circuit, 22.32... Judgment circuit, 23.33... ...Or Gate, 24.34...Register, 25.35...
...ROM, 26.36...Register. Patent applicant: Sumitomo Electric Industries, Ltd. Agent: Kama 1) Text 2 Figure 5

Claims (1)

[Claims] A hand-held optical character reading device that scans and reads characters, symbols, etc. with an image sensor having a field of view for at least one line, which includes a binary circuit that converts an output signal of the image sensor into a binary signal; A memory for storing the binary signal output from the conversion circuit, and a scanning position detecting means for determining whether the character area is within the field of view of the image sensor based on the binary signal, and two stored in the memory. The scanning position detecting means identifies the character area when it is within the field of view of the image sensor. When the character area protrudes from the top and bottom edges of the image sensor, it is regarded as a transition to the next character string, and when the character area is located near the top and bottom edges of the image sensor's field of view, identification processing is performed. , an optical character reading device characterized in that it performs the next scan of an image sensor without regarding it as a transition to the next character string.