JPH01155487A - Uneven character reader - Google Patents

Abstract

PURPOSE:To accurately read a character irrespective of the position of the character, a groove width and the like by block the reflecting light beams of a plane part in a substance to be read and providing a light-blocking means which does not block the reflecting light from a projecting part or a recessed part. CONSTITUTION:Light beams from a light source 13 irradiate on a plastic card 10 as the substance to be read, and a light-receiving sensor 16 receives the reflecting light beams. A shading plate 14 is arranged in the middle of the light source 13 and the sensor 16 and near the card 10. Consequently, the reflecting light beams in the plane part 11 of the card 10 are blocked by the shading plate 14, and they are not inputted to the sensor 16. In the recessed part (or the projecting part), the reflecting light beams are not blocked in the shading plate but are inputted to the sensor 16. Since the sensor 16 is positioned where a positive reflecting light beams from the card 10 are not made incident on, it receives an irregular reflecting light beams and the light beams which have been reflected several times. With monitoring the output of the sensor 16, the character and the like by the recessed part or the projection part can be read.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a reading device for reading embossed characters formed on a flat surface of plastic, metal, or the like.

[Conventional technology]

FIG. 2 shows the configuration of a conventional reading device disclosed in, for example, Japanese Patent Laid-Open No. 144884/1984. In the figure, 1 is an object to be read, such as a plastic card, and the object 1 has a character 1 figure etc. engraved (embossed) in the form of a concave or convex portion on a flat surface of the object 1. Lamps 3A to 3D on which letters are engraved (formed as four parts) sequentially illuminate the object 1 from four different diagonal directions. A television camera 2 photographs the object 1 illuminated by lamps 3A to 3D.

4 is a binarization circuit, which binarizes the output of the television camera 2. A switch 5 sequentially switches and outputs the output of the binarization circuit 4 when illuminated by the lamps 3A to 3D to the memories 6A to 6D. 7 is or gate,
The outputs of the memories 6A to 6D are output to the memory 8.

When the lamp 3A is illuminated, an image of the characters engraved on the object 1 is photographed by the television camera 2. The signal corresponding to the image at this time is binarized by the binarization circuit 4, input to the memory 6A via the switch 5, and stored. The image stored at this time includes lamp 3A.
Shadows appear in areas where the light cannot reach.

Similarly, the image when illuminated by lamp 3B is memory 6B, the image when illuminated by lamp 3C is memory 6C, and the image when illuminated by lamp 3D is memory 6.
D, respectively. These images are also shadowed by the corresponding lamps.

The outputs of the memories 6A to 6D are added together via the OR gate 7 and input to the memory 8. Therefore, the memory 8 stores an image in which the shadows formed by the respective lamps are combined.

[Problem that the invention seeks to solve]

Since conventional devices require illumination from four directions, a switch 5 and an OR gate 7 are required.
The disadvantage is that the device becomes larger and the cost becomes higher. Furthermore, when the groove width of the engraved character is large, the shadow caused by the illumination does not spread over the entire width of the groove, so that only a binarized image of the peripheral portion of the groove can be obtained. Furthermore, depending on the position of the characters, each lamp may not be illuminated under the same conditions, making it impossible to obtain a correct binarized image.

Therefore, the present invention aims to realize a device that can correctly read characters regardless of the position of each character, groove width, etc. with a simple configuration.

[Means for solving problems]

The concavo-convex character reading device of the present invention includes a light source that generates light that irradiates an object to be read having characters, figures, etc. formed with concave or convex portions formed on a flat surface, and a light source that emits light to be irradiated on an object to be read, which has characters, figures, etc. formed of concave or convex portions on a flat surface, and reflections from the convex or concave portions of the object to be read. A light shielding means arranged to pass the light to the opposite side of the light source and blocking reflected light on the flat surface, and a light shielding means arranged on the opposite side of the light source to prevent specularly reflected light from the object to be read from entering the light shielding means. The apparatus is characterized by comprising a light receiving means disposed at a position to receive reflected light from the object to be read.

[Effect]

Light generated by the light source is irradiated onto an object to be read, such as a plastic card, and the reflected light is received by the light receiving means. Characters, figures, symbols, etc. are engraved in the form of concave or convex portions on the flat surface of the object to be read. A light shielding means is arranged between the light source and the light receiving means and near the object to be read. Reflected light on flat parts is blocked by the light blocking means and is not input to the light receiving means (or even if it is input, the amount of attenuation is large); reflected light on convex or recessed parts is not blocked by the light blocking means and is not input to the light receiving means. Ru.

Since the light receiving means is arranged at a position where specularly reflected light from the object to be read does not enter, it receives diffusely reflected light, light reflected multiple times, and the like.

Therefore, by monitoring the output of the light-receiving means, it is not only possible to read characters, figures, etc. caused by concave or convex portions, but also to prevent deterioration in reading performance due to more light than necessary entering the light-receiving means. Can be done.

〔Example〕

FIG. 1 shows the configuration of a reading device according to the present invention. In the figure, 10 is a plastic card as an object to be read, and characters (including figures, symbols, etc.) are engraved on the flat surface 11 of the card 10 by four parts 12. 13 is an LED array as a light source, which generates light to irradiate the card 10.

Reference numeral 14 denotes a light-shielding plate as a light-shielding means, and its tip is disposed close to (or in contact with) the flat portion 11 of the card 10 . Reference numeral 15 denotes a focusing rod lens array as a light condensing means arranged on the opposite side of the LED array 13 with respect to the light shielding plate 14, and one focal point is at the tip of the light shielding plate 14 (the flat part 11 of the card 10 ), the other focal point is located near the light receiving element array 17 of the light receiving sensor 16.

The light output from the LED array 13 illuminates the card 10 linearly in a direction perpendicular to the plane of the paper, and the light receiving element array 17 is similarly arranged linearly to receive the reflected light. Although the number of arrays corresponds to the resolution to be achieved, for example, five light receiving elements can be arrayed per 1+mm.

When reading the card 10, the card 10 is moved to the left in the figure (in the direction of arrow A) at a constant speed by a roller or the like (not shown). The light receiving element array 17 is sequentially scanned at regular time intervals in accordance with the moving speed of the card 10.

As shown in FIG. 1(a), when the LED array 13 illuminates the flat surface 11 of the card 10, the tip of the light shielding plate 14 is close to (or may be in contact with) the card 10. The reflected light from the plane portion 11 is blocked by the light shielding plate 14 and is not input to the light receiving sensor 16 as a light receiving means, or even if it is input, the amount of attenuation is large.

On the other hand, when the recess 12 is illuminated as shown in FIG. 1(b), a gap is formed between the light shielding plate 14 and the card 10. In order to sufficiently secure this gap, the light shielding plate 14 (at least its tip) is formed to be sufficiently smaller than the width of the recess 12 (for example, to a width of 0.2 mm). Therefore, the light reflected by the concave portion 12 is transmitted to the focusing rod lens array 1.
The light is focused by 5 and incident on the light receiving element array 17 .

Therefore, the light-receiving sensor 16 outputs a signal at a higher level in the portion where the recessed portion 12 is formed than in the flat portion 11, so that characters can be read by monitoring the output of the light-receiving sensor 16.

Incidentally, the recessed portion 12 is formed at an angle α (usually 3
An inclined surface 21 inclined by 5° to 45°) and a flat part 11
and a parallel bottom surface 22. The LED array 13 has an angle β (for example, 6
0°) is larger than the angle α of the inclined surface 21 with respect to the flat portion 11. Therefore, it is possible to prevent a dark portion (shadow) from being generated within the recess 12 where no light is irradiated.

In addition, the light receiving sensor 16 (and the convergent rod lens array 15) is configured such that the specularly reflected light from the plane part 11 is not incident, that is, the angle γ between the optical axis and the plane part 11 is equal to the angle (π - β). (in the example, β≠π/2, whereas γ=π12
).

Therefore, the light that the light receiving sensor 16 receives is the light that has been diffusely reflected at the recess 12 or the light that has been reflected multiple times.

The intensity of these lights is smaller than that of specularly reflected light.On the other hand, both the front and back surfaces of the card 10 are glossy and are formed to reflect light well, so the intensity of specularly reflected light is smaller than that of specularly reflected light. Often extremely large. Therefore, if the specularly reflected light is made to directly enter the light receiving sensor 16 via the convergent rod lens array 15, the light receiving sensor 16 may receive more light than the saturation exposure amount, and the reading function may deteriorate.

At this time, the image of the LED array 13 is also formed on the light receiving sensor 16, and the variation in its output characteristics may increase significantly.

By not receiving specularly reflected light, the occurrence of such a phenomenon is prevented, and accurate reading becomes possible.

〔effect〕

As described above, according to the present invention, the light reflected on the concave portion or the convex portion is received and the light reflected on the flat portion is blocked, so that characters can be accurately written with a small, simple, and inexpensive structure. becomes possible to read. In addition, since the light reflected from the concave or convex portions is received, even if there are letters printed on the flat surface, there is little risk of misdetecting them as concave or convex portions.Furthermore, the light receiving means specularly reflects Since it is arranged so as not to receive light, deterioration in reading performance can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the configuration of the reading device of the present invention, and FIG.
FIG. 1 is a block diagram showing the configuration of a conventional reading device. 1. Object to be read 2... Television cameras 3A to 3D... Lamp 4... Binarization circuit 5... Switches 6A to 6D... Memory 7... OR gate 8... -Memory 10...Plastic card 11...Flat part 12...Concave part 13...LED array 14...Light blocking plate 15...Focusing rod lens array 16...Light receiving sensor 17... Light receiving element array 21... Slanted surface 22... Bottom Patent applicant Oki Electric Industry Co., Ltd.

Claims (1)

[Scope of Claims] A light source that generates light to irradiate an object to be read, which has characters, figures, etc. formed with concave or convex portions on a flat surface thereof; a light shielding means disposed to pass the light to the opposite side of the light source and to block the reflected light on the flat surface; What is claimed is: 1. A textured character reading device comprising: a light receiving means disposed at a position where light does not enter the object, and receives reflected light from an object to be read.