JPH08161423A - Illuminating device and character reader - Google Patents

Abstract

PURPOSE: To apply the device for reading OCR characters as well by turning the readable rate of embossed characters to 100% by turning on/off plural light sources individually while including light sources for regular reflection in the plural light sources. CONSTITUTION: Luminous fluxes at three parts between broken lines are luminous fluxes to be regularly reflected at three embossed character strings of 1st, 2nd and 3rd embossed lines 7, 8 and 9 respectively. When reading the 1st embossed line 7, the light source for emitting the luminous flux to be regularly reflected at that part is selectively turned on and the light sources for generating the other luminous flux are turned off. When reading the 2nd and 3rd embossed lines 8 and 9, the light source for emitting the luminous flux to be regularly reflected at each part is similarly selectively turned on respectively, and the light sources for emitting the other luminous fluxes are turned off. Thus, the image of an embossed character string on a card 2 is photographed by a CCD camera 4 and a video signal is outputted from the CCD camera 4 to an image processor 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device and a character reading device using the lighting device. In particular, the present invention relates to a lighting device and a character reading device suitable for reading embossed characters and OCR characters used in various cards such as magnetic cards, IC cards, employee cards, and credit cards.

[0002]

2. Description of the Related Art Conventionally, an embossed character is often imaged by a method of detecting diffuse reflected light, like the OCR character. For example, Japanese Patent Application Laid-Open No. 4-276884 discloses such an optical system. Irradiate light from an oblique direction,
The image sensor captures the light reflected in the vertical direction. However, the embossed characters are often attached to the printed portion of the card, such as the tint block and the design, so they are affected by the printing of the tint block and the design. In such cases, this method is applied. I couldn't. Therefore, in order to avoid the influence of the printing of the tint block, the pattern, etc. attached to the card, as shown in FIG. 8, the rubber belt 23 that moves according to the card conveyance is pressed against the embossed portion 22 of the card 21 to form the embossed character. Illuminate the rubber belt floating on the
A method of reading with the optical sensor 25 from above was considered.

However, even in the conventional method shown in FIG. 8, the readability of embossed characters is about 90%, and there are cases where the characters cannot be read or are erroneously read. In addition, dirt on the card,
There were problems such as scratches. The present invention is intended to solve the above problems, and an object of the present invention is to provide an illumination device and a character reading device that can make the readability of embossed characters 100% and can also be applied to the reading of OCR characters. .

[0004]

The above object can be achieved by the present invention described below. That is, according to the present invention, a plurality of light sources arranged in a matrix including a light source for specular reflection arranged at a position where a projected light ray is specularly reflected in a specular reflection detection character and is incident on an image sensor, and the plurality of light sources are individually arranged. The lighting device is composed of a switch means for turning on and off. Further, the present invention is an illuminating device including a diffuse reflection light source arranged at a position where a projected light ray is diffusely reflected in a diffuse reflection detection character and is incident on an image sensor. Further, the present invention provides the lighting device, a lighting control means for controlling the switch means, a holding means for holding a detection target in which a detection character is recorded, and an image sensor for capturing the detection target to obtain an image signal. A character reading device comprising: an image processing unit that receives the image signal, performs image processing, and determines a character.

[0005]

According to the illuminating device of the present invention, the plurality of light sources arranged in rows and columns includes the light source for specular reflection arranged at a position where the projected light rays are specularly reflected in the specular reflection detection character and are incident on the image sensor, Switch means for individually turning on and off the plurality of light sources. Therefore, by turning on the light source for specular reflection by the switch means and turning off the other light sources, only the light specularly reflected in the specular reflection detection character enters the image sensor. When the regular reflection detection character is an embossed character, the image sensor captures the shadow of the embossed character. Further, since the light that is specularly reflected is the light that is reflected on the surface of the card substrate, it is not affected by the printing of a tint block, a pattern, or the like. According to the lighting device of the present invention,
It includes a light source for diffuse reflection arranged at a position where the projected light ray is diffusely reflected in the diffuse reflection detection character and is incident on the image sensor. Therefore, by turning on the diffuse reflection light source by the switch means and turning off the other light sources, only the light diffusely reflected in the diffuse reflection detection character enters the image sensor. When the diffuse reflection detection character is an OCR character, the OCR character is imaged by the image sensor.

Further, according to the character reading device of the present invention, the holding means holds the detection object on which the detected character is recorded, the illuminating device illuminates the detected character, and the lighting control means illuminates the switch means of the illuminating device. Is controlled, and accordingly, appropriate illumination is given to each detected character, and other unnecessary images that interfere with detection are not input to the image sensor. Then, the image processing means inputs the image signal and performs image processing to identify the character.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing the construction of a character reading apparatus of the present invention. In FIG. 1, 1 is a lighting head that is a portion of the lighting device that emits light, 2 is a card with embossed characters, 3 is holding means for fixing the card at a detection position, and 4 is a CCD camera of a sensor that detects an image. Reference numeral 5 denotes an image processing apparatus for digitizing a video signal of a CCD camera, performing image processing for reading, and discriminating characters. Reference numeral 6 denotes a power supply device for supplying power to an illumination head of an illumination device and each light source of the illumination head. The lighting controller includes an interface portion between a switch means for turning off the light and a lighting control means for controlling the switch means. Further, 7 is an embossed first line which is an area of the first line embossed character string on the card 2, 8 is an embossed second line which is an area of the second line embossed character string on the card 2, and 9 is a card It is the second line of embossing, which is the area of the embossed character string on the second line above 2. Reference numeral 10 is a mirror image of the illumination head 1 when the surface of the card 2 is regarded as a mirror.

The operation of the configuration shown in FIG. 1 will be described. The light beam projected by the illumination head 1 reaches the surface of the card 2 held by the holding means 3 and is reflected there to form a CCD.
It reaches the light receiving part of the camera 4. On the surface of the card 2, embossed character strings of three areas of the embossed first line 7, the embossed second line 8, and the embossed third line 9 are attached. The embossed character string, the lighting head 1, and the CCD camera. 4, the light beam projected by the illumination head 1 is specularly reflected on the embossed character string and reaches the light receiving portion of the CCD camera 4 as shown in FIG. That is, when the surface of the card 2 is regarded as a mirror, the lighting head 1
The mirror image 10 of the illumination head, which is a mirror image of, is arranged on the straight line connecting the embossed character string and the CCD camera 4, as indicated by the broken line in FIG.

In FIG. 1, four broken lines are shown. The light fluxes in the three portions between the broken lines are light fluxes that are specularly reflected in the three embossed character strings of the embossed first line 7, the embossed second line 8, and the embossed third line 9, respectively. . When reading the first row 7 of embossing, the light source that emits a light beam that is specularly reflected there is selectively turned on, and the light sources that emit other light beams are turned off. Similarly, when reading the second row 8 of embossing and the third row 9 of embossing, the light source that emits a light beam that is specularly reflected at each portion is selectively turned on, and the light sources that emit other light beams are turned off. Such lighting / extinguishing control is performed based on the control signal output from the image processing device 5.
Is performed by turning on a specific light source among the plurality of light sources arranged in a matrix in the lighting head and extinguishing the others.

As described above, the image of the embossed character string on the card 2 is photographed by the CCD camera 4 and the image signal is C
It is output from the CD camera 4 to the image processing device 5. CCD
The camera 4 depends on the resolution of the camera and the length of the embossed character string, but when a standard (for example, NTSC broadcasting standard) video camera is used, two cameras are used. The shooting range is determined so that both cameras image simultaneously. When reading characters on a card, a resolution of about 0.4 points (0.14 mm) is required. The image processing device 5 converts the video signal into digital image data and stores it in the frame memory of the image processing device 5. The frame memory has 512 × 5 pixels
12 or 640 × 480 and a data length of about 8 bits are used. When using two CCD cameras 4, two frame memories are naturally used and stored in each frame memory.

First, the image processing apparatus 5 performs preprocessing on the image data stored in the frame memory. As preprocessing, processing such as shading correction processing, isolated point (noise) removal processing, smoothing, edge enhancement processing, etc. is performed as necessary. Next, the image processing device 5 performs binarization processing on the image data subjected to the preprocessing. The binarization processing is performed, for example, by taking a histogram of the image data and setting a value between the peaks of the histogram as a threshold value. This is because the image of the embossed character string to be picked up is formed by two parts, a bright part of the specular reflection light and a dark part which is not specularly reflected at the edge part of the convex part of the embossed character, and thus is generally formed. This is because each pixel value of the image data is biased into two parts. When the shooting conditions are constant, a predetermined threshold value can be set and binarization can be performed as a simpler method.

Next, the image processing device 5 cuts out characters from the binarized image data. Since the position of the embossed character or the embossed character string attached to the card 2 is determined, the cutting process can be performed by extracting the position of the edge of the card from the image data. In order to perform it with higher accuracy, a histogram is projected by projecting image data limited to the area of the embossed character string to be read onto the axis in the direction of the embossed character string, and the break of data on that axis, that is, the break between characters and characters is calculated. Extract and correct. Next, the image processing device 5 performs pattern matching processing on the cut out image data and the typeface dictionary registered in advance in the image processing device 5. The character code with the best matching is selected and stored as read data for embossed characters. With respect to other characters that have been cut out, the image processing device 5 controls the illumination controller 6 to shoot the embossed character string of the next line, and the above operation is performed for all embossed characters to finish reading. . The combination of the data read by the two CCD cameras 4 specifies a series of character strings from the common character and the number of characters included in the character string.

Next, the illumination device of the present invention will be described in more detail. FIG. 2 is a front view of the illumination head portion of the illumination device of the present invention. In FIG. 2, 11 is an LED (Light Emit)
tingDiode; a plurality of LED elements 11 are arranged in a matrix as shown in the figure.
Reference numeral 12 is a cable for supplying electric power to the LED element 11. LEDs arranged in rows and columns as shown in FIG.
The element 11 can be divided into five groups up to. Is a group of LED elements 11 in the top row, is a group of LED elements 11 in the row below it, is a group of LED elements 11 in the row further below, and is an LED element 11 in the row further below Is a group of LED elements 11 in the bottom row.

And are used for reading OCR characters, and when reading OCR characters,
Others (-) are turned off (see FIG. 5). Alternatively, it is used for reading embossed characters on the first embossed line, and is turned on when reading embossed characters on the first embossed line, and the others (, to) are turned off (see FIG. 4). Alternatively, it is used for reading embossed characters on the second line of embossing, and is turned on when reading embossed characters on the second line of embossing, and the others (,,,) are turned off. Alternatively, it is used for reading embossed characters on the third embossed line, and is turned on when the embossed characters are read on the third embossed line, and the others (~,) are turned off.

The cable 11 supplies electric power to the LED elements 11 belonging to these five groups.
One conductor single wire and a common ground (or return) conductor single wire can be used. In addition, if the number of groups is very large, or if it is desired to control the turning on / off of the LED elements 11 individually, the cable 11 should be 2
The power line can be composed of a book (plus and minus) or three (plus, minus and ground), and a plurality of signal lines for control signals. LED in the latter case
A circuit for controlling lighting and extinction of light, and a lighting control portion including a switching element such as a triac or a thyristor are provided on the back side where the LED elements 11 are arranged in a matrix.

In general, a CCD camera is highly sensitive to red light and an LED element that emits red light has a high brightness. Therefore, the LED element 11 used in the present invention has red light (wavelengths of 770 nm, 680 nm, etc.). ) Emitting LE
D element is preferred. In this case, it is more preferable to use a filter that allows only the red light to pass through the CCD camera 4 since it is less likely to be affected by ambient light. The LED element 11 includes a lens element and a lens element, but any element can be used in the present invention. When the LED element 11 with a lens having a strong directivity is used in the case of detection by regular reflection light, the selectivity (illuminates only the area to be illuminated and does not illuminate the other areas) is improved. However, when the LED element 11 with a lens having a strong directivity is used, unless the direction of the optical axis of the LED element 11 is aligned with the direction of the broken line shown in FIG. . Further, when the diffused reflected light is used for detection, if the LED element 11 having a small directivity and having no lens is used, uniform illuminance is easily obtained on the card 1. However, the selectivity is reduced.

Next, a card as a character reading target will be described. FIG. 3 is a diagram showing an example of a card in which embossed characters and OCR characters are recorded. In FIG. 3, 7 is the first line of the embossed character and 13 is the OCR character. Specifically, for example, the embossed characters of the card have the following characteristics according to the JIS specification. Typeface: 7B Character type: English letters, numbers "0" to "9", symbols "-""."
"/""("")" Embossed character position; Arbitrary position on 1st to 3rd lines Maximum number of characters: 19 characters / line Further, for example, the OCR character of the card has the following characteristics according to the specification of JIS. Typeface: Arbitrary character size; 8 points or more Character spacing: Minimum 0.4 points or more Character type: Alphabet, numbers "0" to "9", symbol "-""."
"/""("")" OCR character position; within 25 mm from the bottom edge of the card Any position 5 mm or more from the card edge Maximum number of characters: 20 characters

Next, the imaging systems for embossed characters and OCR characters will be described in comparison. FIG. 4 is a schematic diagram showing an imaging system when reading embossed characters. As shown in FIG. 4, only the LED for the first row of embossing of the lighting head 1 is turned on, and the light beam projected by the LED is specularly reflected in the area of the first row of embossing of the card 2, and the specularly reflected light is the CCD. The image is taken by the camera 4. Further, FIG. 5 is a schematic diagram showing an image pickup system at the time of reading an OCR character. As shown in FIG.
Only the OCR character LED of the lighting head 1 is turned on, and the light beam projected by the LED is diffusely reflected in the area of the OCR character of the card 2, and the diffuse reflected light is the CCD.
The image is taken by the camera 4.

FIG. 6 is a diagram showing a portion of image data (before clipping processing) obtained by picking up the image of the card 2 in the image pickup system shown in FIG. 4 and binarizing it in the image processing apparatus 5. In FIG. 6, reference numeral 14 is binary image data of embossed characters. As shown in FIG. 6, the background of the embossed character is white because of the strong regular reflection light; “1”, and the light at the edge of the embossed character is black because the regular reflection light does not reach the CCD camera 4. It is "0". In this way, extremely clear image data of embossed characters can be obtained. FIG. 7 is a view showing a cross section perpendicular to the direction of the embossed line of the embossed portion of the card. In FIG. 7, 15 is an edge portion of the embossed wire, 16 is a peripheral portion of the embossed wire, and 17 is a central portion of the embossed wire. As shown in FIG. 7, the edge portion 15 of the embossed line is a dark portion because the angle at which the specularly reflected light does not reach the CCD camera 4 is a dark portion.
The central portion 17 of the embossed line is a bright portion because it is the angle at which the specularly reflected light reaches the CCD camera 4.

[0020]

As described above, according to the illumination device and the character reading device of the present invention, the image of the embossed character imaged by the CCD camera is extremely clear, and the readability of the embossed character can be 100%. it can. Moreover, OCR
It can also be applied to reading characters. Further, according to the lighting device of the present invention, the plurality of light sources arranged in a matrix includes a regular reflection light source arranged at a position where the projected light ray is regularly reflected in the regular reflection detection character and is incident on the image sensor. Switch means for individually turning on and off a plurality of light sources. Therefore, the specular reflection light source can be turned on by the switch means and the other light sources can be turned off.
By doing so, only the light specularly reflected in the specular reflection detection character is incident on the image sensor. When the regular reflection detection character is an embossed character, the edge of the embossed character becomes a shadow and can be captured by the image sensor. Further, since the light that is specularly reflected is the light that is reflected on the surface of the card substrate, it is not adversely affected by the printing of a tint block, a pattern, or the like.

Further, according to the illuminating device of the present invention, the diffused reflection light source is arranged at a position where the projected light beam is diffusely reflected in the diffuse reflection detection character and is incident on the image sensor. Therefore, by turning on the diffuse reflection light source by the switch means and turning off the other light sources, only the light diffusely reflected by the diffuse reflection detection character can enter the image sensor. When the diffuse reflection detection character is an OCR character, the OCR character can be imaged by an image sensor.

Further, according to the character reading apparatus of the present invention, the detection target on which the detected character is recorded is held by the holding means, the detected character is illuminated by the lighting device, and the switch means of the lighting device is illuminated by the lighting control means. Is controlled, and accordingly, appropriate illumination is given to each detected character, and other unnecessary images that interfere with detection are not input to the image sensor. Then, the image processing means can input the image signal and perform image processing to identify the character.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a character reading device of the present invention.

FIG. 2 is a front view of an illumination head portion of the illumination device of the present invention.

FIG. 3 is a diagram showing an example of a card on which embossed characters and OCR characters are recorded.

FIG. 4 is a schematic diagram showing an image pickup system when reading embossed characters.

FIG. 5 is a schematic diagram showing an imaging system when reading an OCR character.

6 is a diagram showing a portion of image data (before cutout processing) obtained by picking up an image of the card 2 in the image pickup system shown in FIG. 4 and binarizing it in the image processing apparatus 5;

FIG. 7 is a view showing a cross section perpendicular to the direction of the embossed line of the embossed portion of the card.

FIG. 8 is an explanatory diagram illustrating a conventional embossed character reading method.

[Explanation of symbols]

 1 Lighting Head 2 Card 3 Holding Means 4 CCD Camera 5 Image Processing Device 6 Lighting Controller 7 Embossing 1st Line 8 Embossing 2nd Line 9 Embossing 3rd Line 10 Lighting Head Mirror Image 11 LED Element 12 Cable 13 OCR Character 14 Embossed Character Binary image data 15 Edge of embossed line 16 Center part of embossed line

Claims (3)

[Claims] 1. A plurality of light sources arranged in a matrix including light sources for specular reflection arranged at positions where a projected light ray is specularly reflected by a specular reflection detection character and is incident on an image sensor, and the plurality of light sources are individually provided. An illuminating device comprising: switch means for turning on and off. 2. The illumination device according to claim 1, further comprising a diffuse reflection light source arranged at a position where the projected light beam is diffusely reflected by the diffuse reflection detection character and is incident on the image sensor. 3. The lighting device according to claim 1, a lighting control means for controlling the switch means, a holding means for holding a detection target on which a detected character is recorded, and an image obtained by picking up the detection target. A character reading device comprising an image sensor for obtaining a signal and an image processing unit for inputting the image signal and performing image processing to determine a character.