JPH061503B2 - Optical reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Field of Industrial Application The present invention relates to a hand-held optical reader that scans characters, symbols, etc. by holding a scanner equipped with an image sensor composed of a plurality of photoelectric conversion elements. .

(2) Prior art and problems to be solved by the invention When reading characters, symbols, etc. written on a paper sheet using an optical reading device, the image sensor is fixed so that the characters, etc. can be correctly entered within the sensor visual field. As long as the image sensor is mechanically moved at a constant speed, it is sufficient to use an inexpensive one-dimensional image sensor having a plurality of photoelectric conversion elements arranged as an example as the image sensor. However, when you use a scanner with a built-in image sensor in your hand to scan characters on paper, or when you use a fixed scanner, the speed of movement of the paper, that is, the direction of movement and the speed of movement are not constant. However, there is a drawback in that the device becomes expensive, because the two-dimensional image sensor in which the photoelectric conversion element group is arranged in a plurality of rows and columns must be used. There are cases where two one-dimensional image sensors or two rows of image sensors are used for the purpose of low cost, but when moving a scanner with a built-in image sensor from left to right or from right to left, the moving direction There was a defect that the data was erroneously detected, resulting in erroneous data. FIG. 2 shows an example of a conventional device, which is a configuration of a hand-held hand scanner 6 using two one-dimensional image sensors 4 and 5. The light source 2 irradiates a paper on which characters, symbols, etc. are written, and the reflected light from the paper 1 is imaged on the image sensors 4 and 5 via the lens system 3. The output signals of the image sensors 4 and 5 are binarized into "white" and "black" (not shown).

FIG. 3 is a diagram for explaining the moving direction of the hand scanner 6. The moving direction of the hand scanner 6 is determined when either one of the image sensors 4 and 5 first detects a part of a character, that is, "black". In FIG. 3 (a), since the image sensor 5 detects "black", the hand scanner 6 has an arrow (7).
It is considered to be moving in the direction of. Since the hand scanner 6 is moved by hand, the moving speed of the hand varies from person to person, and even the same person changes with each operation. Therefore, the image sensors 4 and 5 that sample and scan at a constant cycle.
Then, the number of times of scanning differs due to the different moving speed of the hand, and the scanned characters are not constant. For this reason,
The moving speed of the hand scanner 6 is calculated as follows. The moving speed V of the hand scanner 6 is defined as the interval between the image sensors 4 and 5 and t from the time when “black” is detected by one of the image sensors 4 and 5 to the time when “black” is detected by the other. Becomes V = / t.

When the moving speed V is obtained, the image sensor (4 in FIG. 3 (b)) in which “black” is detected later is changed so that the sampling period corresponds to the speed V, and scanning is performed. The method is such that scanning is performed at the same sampling cycle as before, and the data obtained by scanning is corrected and processed by a method such as speed normalization. According to such a method, the processing is performed based on the data obtained by scanning either one of the image sensors 4 and 5, that is, the image sensor that has detected "black" later, so that the processing is performed when the moving direction is reversed. It was necessary to switch the image sensor for scanning the data.
However, if the moving direction is erroneously determined due to noise or the like, the image sensor for scanning the data to be processed is erroneously switched and the processed data is taken in.
Further, even if it is found that the moving direction is wrong in the middle of the process, the hand scanner has a drawback that it cannot read the data correctly since it has passed through characters and the like. For example, FIG. 4 shows a process of misrecognizing the moving direction of the hand scanner 6.

It is assumed that the hand scanner 6 is actually moving in the direction of arrow 8. However, if "black" is first detected by the image sensor 4 by the noise 10, the movement direction of the hand scanner 6 is processed as the direction of the arrow 9, and the image sensor 5 detects "black" of the character 11 until it is detected. The moving speed V is calculated from the time of and the data scanned by the image sensor 5 is taken in. For this reason, there is a drawback that the number of scans is erroneous and the reading cannot be performed correctly.

The present invention solves the above-mentioned drawbacks of the prior art by using an inexpensive one-dimensional image sensor or at least three rows of image sensors, and even if the hand scanner is moved in the wrong direction at first, An object of the present invention is to provide an inexpensive optical reading device that can be correctly read even if corrected.

(3) Means for Solving the Problems The present invention is provided with at least three rows of image sensors, and the image sensors located on both sides are the first and second image sensors, and are located between the first and the second. And a scanner for counting the number of scanning clocks from the detection of black by the first or second image sensor to the detection of black by the third image sensor. The first image sensor or the second image that detects the first black by storing the binarized symbol of the third image sensor by measuring the relative movement speed with the character / symbol and normalizing it It is characterized in that the sensor is configured to determine the moving direction with respect to characters and symbols.

(4) Action When "black" which means a character line segment first appears in either the first or second image sensor, it is determined whether the moving direction of the scanner is the right direction or the left direction. Alternatively, the relative movement speed of the scanner is calculated by counting the number of scanning clocks from the appearance of the “black” on the second image sensor to the appearance of the “black” on the third image sensor located in the middle. Measurement is performed, and data such as characters and symbols is read by the third image sensor to perform identification processing.

(5) Example FIG. 1 is a diagram illustrating the configuration of an optical reading apparatus of the present invention.

Reference numeral 21 is a sheet on which characters and symbols are written, 20 is a scanner, and the scanner 20 includes a lamp 22, a lens 23, an image sensor (a) 24, an image sensor (b) 25, and an image sensor (c) 26. Has been done. Light is emitted onto the paper 21 by the lamp 22, and the reflected light is passed through the lens 23 to the image sensor (a) 24, the image sensor (b) 25,
An image is formed on the image sensor (c) 26. Image sensor
(a) 24 and image sensor (b) 25, image sensor
(c) 26 is a one-dimensional image sensor in which photoelectric conversion elements are arranged in a line. Instead of the image sensor (a) 24, the image sensor (b) 25, and the image sensor (c) 26, one two-dimensional image sensor having photoelectric conversion elements arranged in three rows may be used. Paper 21 or scanner 2
The paper 21 can be scanned by moving either 0 horizontally. In the embodiment, the scanner 20 is a hand-held optical reader that is manually moved. Image sensor
(a) 24 and image sensor (c) 26 and image sensor
(b) 25 and the image sensor (c) 26 are installed at a distance of, for example, 1 to 1.5 mm, which is close to the width of characters and symbols. Output signals from the image sensor (a) 24, the image sensor (b) 25, and the image sensor (c) 26 are sent to amplification circuits 27, 28, 43, respectively, and amplified, and then binarized circuits 29, 30, 44. Sent to. Binarization circuits 29, 30,
The area 44 is divided into two areas, a paper area "white" and a character area "black". In the description, “black” is “1” and “white” is “0”. The black detection circuits 31, 32 and 45 detect whether or not the scanned image sensor (a) 24, image sensor (b) 25, and image sensor (c) 26 include "black". This can be easily achieved by obtaining the black logical sum of the signals corresponding to each photoelectric conversion element binarized by the binarization circuits 29, 30, and 44 for each of 25 and 26. The detection of the moving direction will be described. When the black detection circuits 31 and 32 first detect “black”, the black flag (b) 33 or the black flag (a) 34 is set, and the paper 2
1 or the moving direction of the scanner 20 is determined. An output signal of the black detection circuit 31, a signal obtained by inverting the output signal of the black flag (b) 33 by the inverter 40, and the black flag (a)
AND gate 38 obtains the logical product of the output signal of 34 and the signal inverted by inverter 41, and when "1", the black flag
(b) Set “1” to 33. Black flag (b) 3 and black flag (a) 34 are not set, and black flag (b) 3 is detected only when "black" is detected by black detection circuit 31.
Since "1" is set in 3, it should be considered that "1" is set in the black flag (b) 33 when "black" first appears in the image sensor (b) 25. You can

Similarly, the output signal of the black detection circuit 32 and the black flag (b) 33
Of the output signal of the black flag (a) 34 and the inverted signal of the output signal of the black flag (a) 34 are obtained by the AND gate 39, and when "1", "1" is set to the black flag (a) 34. As a result, the image sensor (a) 24 is initially set to “black”.
When "1" appears, "1" is set to the black flag (a) 34. Depending on whether "1" is set to the black flag (b) 33 or the black flag a34,
Image sensor (b) 25 or image sensor (a) 24
You can see if "black" first appeared in. Direction detection circuit 3
6 indicates the paper 21 or the scanner 2 depending on which of the output signals of the black flag (b) 33 and the black flag (a) 34 is "1".
Determine the moving direction of 0.

FIG. 5 is an example thereof, and it is assumed that the scanner 20 has moved in the direction of arrow 51 because "black" appears in the image sensor (b) 25. This is the same as the conventional method.

Next, detection of the moving speed of the scanner 20 will be described.
The counter 35 counts the number of scanning clocks from the first appearance of "black" in the image sensor (b) 25 or the image sensor (a) 24 to the appearance of "black" in the image sensor (c) 26. That is, the counter 35 takes the logical sum of the output signals of the black flag (b) 33 and the black flag (a) 34 by the OR gate 42, and after the output signal of the OR gate 42 becomes “1”, the image sensor (c ) 26 is "black"
Is detected, that is, the number of scanning clocks until the output signal of the black detection circuit (c) 45 becomes "1" is counted. The contents of the counter 35 are sent to the speed detection circuit 37. The speed detection circuit 37 detects the moving speed of the paper 21 or the scanner 20 from the count number of the counter 35.

When the scanner 20 moves as shown by the arrow as shown in FIG. 5, first, as shown in FIG. 5 (a), the image sensor (b) 25
"Black" appears on the screen, and the black flag (b) 33 is set.
Next, as shown in FIG. 5 (b), “black” is put on the image sensor (c) 26.
When the scanning clock period is t and the scanning clock count number is n, the time T until T appears is T = nt.

When the distance between the image sensor (a) 24 and the image sensor (c) 26 and the distance between the image sensor (b) 25 and the image sensor (c) 26 is L, the moving speed V is V = L / T = L / n- The moving speed can be calculated by t 1.

Next, the acquisition of character data for identification will be described. Image sensor (a) 24 or image sensor (b)
A black flag indicating whether "black" appears first in 25
When "1" is set in (a) 34 or black flag (b) 33, the binary data from the opposite image sensor is fetched. The output signal of the binarization circuit 44 of the image sensor (c) 26 is input to the normalization circuit. The normalization circuit 46 normalizes the binarized data from the analog signal obtained as a result of scanning by changing the number of scans for scanning one character according to the moving speed of the scanner 20 or the paper 21.
The number of times of scanning one character is made substantially the same. At this time, the means for detecting the moving speed of the scanner and normalizing the binarized data are realized by known means according to the invention described in, for example, Japanese Patent Publication No. 58-9985 or Japanese Patent Publication No. 58-9884. You can

The optical reading device of the present invention includes the normalizing circuit 46 to the memory 4
Binarized data is stored in 7. The data stored in the memory 47 is reversed right and left depending on the moving direction of the scanner 20 and the paper 21. Therefore, when identifying the scanned character, the address switching circuit 48 converts the address of the memory 47 by the signal sent from the direction detection circuit 36, reads the data from the memory 47, and the identification circuit 49. Identify. As the identification circuit 49, the same circuit can be used regardless of the relative movement direction of the scanner and the paper.

With such a configuration, even if the moving direction changes, it is possible to identify using the same identifying circuit 49. The identification circuit is not particularly limited and can be realized by, for example, the method described in JP-A-54-16133. Further, as shown in FIG. 6, there is noise 53 in addition to the characters 54. First, the image sensor (a) 24 detects the noise 53, and even when it becomes "black", the image sensor (c) that captures data Image sensor before "black" appears in 26
When the character 54 “black” is detected in (b) 25, the previously set black flag (a) 34 is cleared and the black flag (b) 33 is set to “1” to change the moving direction. it can.

Furthermore, the image sensor (c) 2
Even if the data is taken into the memory 47 in step 6, the image sensor (c) 26, which takes in the data, can continue to take in the data and change the moving direction to carry out the identification process.

(6) Effects In the optical reading device of the present invention, at least three inexpensive one-dimensional image sensors or three or more photoelectric element rows in a two-dimensional sensor array are used, and one or one row in the center thereof is used. The direction of movement of the paper or scanner is determined by scanning and capturing data as well as the first appearance of "black" on either side of the image sensor. Furthermore, the moving speed is calculated from the number of scanning clocks from the appearance of "black" in one of the image sensors in both rows to the appearance of "black" in the image sensor in the center row, and the data to be imported is normalized. It can be converted. Therefore, even if the moving direction is mistaken for the first time due to noise, the direction can be changed correctly, and an inexpensive optical reading device with less influence of noise is realized.

[Brief description of drawings]

FIG. 1 is an embodiment of the present invention, FIG. 2 is an example of a conventional hand scanner, FIGS. 3 (a) and 3 (b) are explanatory diagrams of speed calculation, and FIG. 4 is a diagram showing the influence of conventional noise. 5 (a) and 5 (b) are explanatory views of the moving direction and moving speed detection of the present invention, and FIG. 6 is a diagram showing the influence of noise in the present invention. 1 ... Paper, 2 ... Lamp, 3 ... Lens, 4, 5 ... Image sensor, 6 ... Hand scanner, 7, 8, 9 ... Arrow, 10
... noise, 11 ... characters, 20 ... scanner, 21 ... paper,
22 ... Lamp, 23 ... Lens, 24 ... Image sensor
(a), 25 ... Image sensor (b), 26 ... Image sensor
(c), 27, 28, 43 ... Amplifier circuit, 29, 30, 44
... Binarization circuit, 31, 32, 45 ... Black detection circuit, 33,
34 ... Black flag, 35 ... Counter, 36 ... Direction detection circuit, 37 ... Speed detection circuit, 38, 39 ... AND gate,
40, 41 ... Inverter, 42 ... OR gate, 46 ... Normalization circuit, 47 ... Memory, 48 ... Address switching circuit, 4
9 ... Identification circuit, 51 ... Arrow, 53 ... Noise, 54 ... Character.

Claims (1)

[Claims] 1. An optical reading device for moving a scanner equipped with a plurality of rows of image sensors relative to a read character / symbol, among the plurality of rows of image sensors.
The image sensors located on both sides are first and second image sensors, the image sensor located between the first and second image sensors is a third image sensor, and the first or second image sensor is provided. The number of scanning clocks from the detection of black by the sensor to the detection of black by the third image sensor is counted, and the scanning character
Means for normalizing the number of scans by measuring the relative movement speed with respect to a symbol, means for storing the binarized signal of the third image sensor, and the first image sensor for detecting the first black Alternatively, an optical reading device comprising means for determining a moving direction with respect to the read character / symbol by the second image sensor.