JP2007018038A - Embossed letter reading method and image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately read an embossed letter string formed on a credit card by a shadow method. <P>SOLUTION: An embossed letter reader 1 has: a first contact image sensor 12 illuminating a surface 3 of the card 2 carried by a card carrying mechanism 11 from a first direction inclined to a carrying direction by about 45 degrees, and reading a surface image; and a second contact image sensor 13 illuminating it form a second direction inclined to the opposite side to the carrying direction by about 45 degrees, and reading the surface image. The embossed letter reader 1 processes the read image in an image processing part 20, extracts a shadow of an outline of each emboss letter of the emboss letter string 4 of the card surface 3, and identifies each the embossed letter. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an embossed character reading method capable of accurately reading an embossed character formed on the surface of a card such as a credit card by a shadow method. The present invention also relates to an image reading apparatus capable of reading a card surface image that can accurately extract the shadow of each embossed character.

  A card such as a credit card or a bank card is formed with an identification number string (hereinafter referred to as an embossed character string) made up of numerals, English characters, and the like by embossing. As such an embossed character string reading mechanism, an optically reading method is known instead of a method (imprint) of mechanically copying the embossed character string. As an optical reading method, a shading method is known in which the surface of a card on which an embossed character is formed is illuminated from an oblique direction, and the shadow of the embossed character generated thereby is read by an image sensor such as a CCD camera. A method of reading unevenness information by the shadow method is disclosed in Patent Document 1.

In order to cut out the outlines (shadows) of the embossed characters taken by the shading method from the card background by image processing and to recognize each embossed character accurately based on this, the shadows representing the contours of each embossed character are partially It is necessary to illuminate the surface of the card so that it is formed without any loss. For this reason, in Patent Document 1, the embossed characters are illuminated from different directions at different timings, and the embossed characters are identified from the synthesized image obtained by synthesizing the images obtained at each timing. Also, an embossed character is identified from a combined image obtained by reading an image with the card facing the single light source in different directions and combining the read images. Furthermore, the embossed character is identified from the composite image obtained by combining the images in which the light source is moved to different positions and the card is illuminated.
JP-A-5-62012

  An object of the present invention is to propose an embossed character reading method capable of accurately identifying an embossed character by acquiring card surface images illuminated from different directions with a simple configuration.

  Another object of the present invention is to propose an image reading apparatus capable of reading a card surface image on which a shadow corresponding to the contour of each embossed character is formed with a simple configuration.

In order to solve the above problems, the present invention provides an embossed character reading method for reading an embossed character string formed on the surface of a card by a shadow method.
The card is conveyed in the direction in which the embossed character strings are arranged or in a direction perpendicular to the arrangement direction,
Using an image sensor unit comprising a plurality of light emitting elements and a plurality of light receiving elements, illuminating the surface of the card being conveyed, and reading the surface image of the card,
Extract the shadow of each embossed character that makes up the embossed character string from the read surface image, recognize each embossed character based on each shadow,
As the image sensor unit, using at least first and second image sensor units disposed opposite to the surface of the card to be conveyed,
When viewed from a direction perpendicular to the surface of the card to be conveyed, the first image sensor unit has either an arrangement direction of the embossed character strings or a direction orthogonal to the arrangement direction with respect to the surface of the card. The second image sensor unit emits illumination light from a first direction that is inclined with respect to the second direction, and the second image sensor unit is inclined with respect to both the arrangement direction of the embossed character strings and the direction orthogonal to the arrangement direction. It is characterized by irradiating illumination light from the direction.

  Here, in a card such as a credit card or a bank card, an embossed character string formation area, an embossed character font, and the like are determined according to the standard. The embossed character string generally extends in the long side direction of the card, and each embossed character is arranged so as to be up and down in the short side direction of the card. The embossed character font basically includes an embossed character string arrangement direction and an outline portion extending in a direction orthogonal to the arrangement direction, and an outline portion extending in a direction different from these directions. Yes.

  Therefore, when illumination is performed from both sides of the embossed character string arrangement direction, shadows of the contour portions extending in the embossed character string arrangement direction in the embossed character are not formed. Similarly, when illumination is performed from both sides in a direction orthogonal to the arrangement direction, shadows of outline portions extending in a direction orthogonal to the arrangement direction of the embossed character strings in the embossed characters are not formed.

  In the present invention, illumination is performed from a direction inclined in both the arrangement direction of the embossed character strings (for example, the card long side direction) and the direction orthogonal to the alignment direction (for example, the card short side direction). Therefore, it is possible to reliably form a shadow of the embossed character outline extending in the arrangement direction of the embossed character string (for example, the card long side direction) and the direction orthogonal to the arrangement direction (for example, the card short side direction).

  Next, in the present invention, such illumination and photographing from different directions are performed using an image sensor unit. For example, a line sensor using a contact image sensor called a contact image sensor (CIS) can be used. Therefore, it is possible to reliably read the shadow corresponding to the contour portion of the embossed character with a compact and simple configuration.

  Here, the first and second directions may be directions that are approximately 180 degrees different, i.e., opposite directions.

  In addition, in order to allow each image sensor unit to illuminate the card from the first direction and the second direction, each image sensor unit is provided with the arrangement direction of the embossed character strings of the cards being conveyed and the arrangement. What is necessary is just to arrange | position so that it may become a direction inclined with respect to any of the directions orthogonal to a direction.

  Instead, the first and second image sensor units are arranged in a direction orthogonal to the card transport direction, the direction of each light emitting element in the first image sensor unit is the first direction, and the first The direction of each light emitting element in the two-image sensor unit may be the second direction.

Next, the present invention provides an image reading apparatus for reading an embossed character string formed on the surface of a card by a shading method.
A card transport mechanism for transporting the card in the direction in which the embossed character strings are arranged or in a direction perpendicular to the direction in which the cards are arranged;
A plurality of light emitting elements for illuminating the surface of the card being conveyed, and an image sensor unit comprising a plurality of light receiving elements for reading a surface image of the card,
The image sensor unit includes at least first and second image sensor units,
When viewed from a direction perpendicular to the surface of the card to be conveyed, the first image sensor unit has either an arrangement direction of the embossed character strings or a direction orthogonal to the arrangement direction with respect to the surface of the card. The second image sensor unit emits illumination light from a first direction that is inclined with respect to the second direction, and the second image sensor unit is inclined with respect to both the arrangement direction of the embossed character strings and the direction orthogonal to the arrangement direction. It is characterized by irradiating illumination light from the direction.

  Here, the first direction and the second direction are opposite directions.

  In addition, each image sensor unit, when viewed from a direction perpendicular to the surface of the card, is either in the direction in which the embossed character strings formed on the card to be conveyed or in the direction orthogonal to the direction in which the cards are arranged. It is also characterized by being arranged so as to be inclined.

Furthermore, the first and second image sensor units are arranged in a direction orthogonal to the card conveying direction when viewed from a direction perpendicular to the surface of the card,
The direction of each light emitting element in the first image sensor unit is the first direction, and the direction of each light emitting element in the second image sensor unit is the second direction.

  In the present invention, a plurality of image sensor units are used to incline the surface of a card to be conveyed with respect to both the arrangement direction of the embossed character strings and the direction orthogonal to the arrangement direction. Illuminating from the direction, the image on the surface of the card is read. Therefore, since a shadow image corresponding to the contour of each embossed character can be obtained with certainty, the embossed character can be accurately identified.

  An example of an embossed character reading device for a credit card to which the present invention is applied will be described below with reference to the drawings.

(overall structure)
FIG. 1A is a schematic configuration diagram showing the main part of the embossed character reading apparatus of this example, and FIG. 1B is an explanatory diagram showing its planar configuration. The embossed character string reader 1 of this example is for reading an embossed character string 4 formed on the surface 3 of a card 2 such as a credit card by a shading method.

  The embossed character reader 1 has a card transport mechanism 11 that transports a card 2 to be read in a horizontal state with its surface 3 up in the long side direction (the direction in which the embossed character strings 4 are arranged). First and second contact image sensors (CIS) 12 and 13 which are line sensors are arranged immediately above the transport path of the card 2 transported by the card transport mechanism 11. The first and second contact image sensors 12 and 13 illuminate the surface 3 of the card to be conveyed and read an image of the surface 3 of the card. The images read by the contact image sensors 12 and 13 are supplied to the image processing unit 20, where the shadows of the embossed characters are cut out, and the embossed characters are identified based on them.

  In the first and second contact image sensors 12 and 13, for example, a light emitting element 14 such as an LED and a light receiving element 15 such as a photodiode or a phototransistor are arranged in parallel, and the card surface 3 is emitted from the light emitting element 14. In order that the reflected light of the illuminated illumination lights L1 and L2 is received by the light receiving element 15, a reflection optical system component (not shown) composed of a lens array or the like is disposed between them. The configuration is built in the elongated unit case 16.

  The first and second contact image sensors 12 and 13 are arranged in parallel to the card surface 3 at a constant interval, and when viewed from a direction perpendicular to the card surface 3, the card is conveyed. It is inclined about 45 degrees with respect to the direction. In other words, light is emitted in a direction inclined by about 45 degrees with respect to both the long side direction (the arrangement direction of the embossed character strings 4) and the short side direction (the direction orthogonal to the arrangement direction of the embossed character strings 4) of the card 2. The element 14 and the light receiving element 15 are arranged. Further, in the first contact image sensor 12, the light emitting element 14 is disposed on the upstream side in the card feeding direction, whereas in the second contact image sensor 13, the light emitting element 14 is disposed on the downstream side in the card feeding direction. Has been placed. When the card transport mechanism 11 reverses the transport direction, the upstream side and the downstream side of each light emitting element 14 are also reversed.

  The conveyance for reading the image of the card 2 by the card conveyance mechanism 11 may be performed only once from one direction. Moreover, you may reciprocate by changing conditions, such as changing the light quantity of the light emitting element 14 of the 1st and 2nd contact image sensors 12 and 13. FIG.

  As described above, in the first contact image sensor 12, when viewed from the direction perpendicular to the card surface 3, the illumination light L1 from the light emitting element 14 is tilted about 45 degrees with respect to the card transport direction. The card surface 3 is illuminated from the direction. On the other hand, in the second contact image sensor 13, the illumination light L2 from the light emitting element 14 travels on the card surface 3 from the second direction inclined about 45 degrees with respect to the card transport direction from the opposite side, which is about 180 degrees different. Illuminate.

  FIG. 2 is an explanatory diagram showing the specifications of the card 2 that is the reading target of the apparatus 1 of this example. When the card 2 is a credit card, the standard is defined by ISO / IEC7810 as shown in FIG. 2 (a), and the middle position of the card surface 3 has a maximum of 19 characters as shown in FIG. 2 (b). Is defined as an embossed region 4a. As shown in FIG. 2C, the font of the embossed characters formed in the embossed area 4a is also defined by the standard, and for example, Farrington 7B is used. This font F is basically composed of vertical segments and horizontal segments extending in the vertical direction and the horizontal direction. The embossed character string 4 extends in the card long side direction X (the direction in which the embossed character string 4 is arranged), and each embossed character goes up and down in the card short side direction Y (the direction orthogonal to the direction in which the embossed character string 4 is arranged). It is formed as follows.

  Next, the operation of the embossed character reading device 1 of this example will be described. The card 2 to be read is set in the card transport mechanism 11 and transport is started in the long side direction (the arrangement direction of the embossed character strings 4). The surface 3 of the card 2 to be conveyed is illuminated by the first and second contact image sensors 12, 13. The first contact image sensor 12 illuminates the front surface 3 of the card from a first direction inclined about 45 degrees with respect to the transport direction from the card feeding direction side. The image of the surface 3 of the card in a state illuminated from the first direction is read by the first contact image sensor 12. On the other hand, the second contact image sensor 13 illuminates the surface 3 of the card from the second direction on the opposite side, and the image of the surface 3 of the card in the state illuminated from the second direction is the first. 2 is read by the contact image sensor 13.

  As described above, the outline of the embossed character is a segment portion extending in the long side direction of the card (alignment direction of the embossed character string 4) and the short side direction (direction orthogonal to the aligned direction of the embossed character string 4). It is basically composed of The illumination light from the first and second directions is inclined with respect to both the long side direction (the direction in which the embossed character strings 4 are arranged) and the short side direction (the direction orthogonal to the direction in which the embossed character strings 4 are arranged). Illumination light from the selected direction. Therefore, the shadow of the contour portion in the orthogonal direction in the embossed character is reliably formed. Further, if the read images of both contact image sensors 12 and 13 are combined, the long side direction (the direction in which the embossed character string 4 is arranged) and the short side direction (the direction orthogonal to the direction in which the embossed character string 4 is arranged) It is also possible to reliably extract a shadow image of the contour portion of the embossed character extending in a different direction. Therefore, if the apparatus 1 of this example is used, each embossed character can be accurately identified by the shading method.

  Moreover, in this example, the shadow image corresponding to the outline of each embossed character can be reliably read by a simple configuration in which the two contact image sensors 12 and 13 are arranged to be inclined with respect to the card conveying direction.

  Note that embossed characters are recognized by so-called pattern matching. The image processing unit 20 stores data having the position and characteristics of the image for each embossed character. The acquired image and these data are compared, and as the number of similarities increases, it can be identified as a character with higher reliability.

(Other embodiments)
In the above example, two sets of image sensor units are inclined. Instead, these image sensor units can be arranged in a direction orthogonal to the card conveying direction. For example, when the card 2 is conveyed in the long side direction (the direction in which the embossed character strings 4 are arranged), the image sensor unit may be arranged in the short side direction (the direction perpendicular to the direction in which the embossed character strings 4 are arranged). it can. In this case, the optical axis direction of the built-in light-emitting element and light-receiving element is any of the card long side direction (alignment direction of the embossed character string 4) and the short side direction (direction orthogonal to the alignment direction of the embossed character string 4). These elements may be arranged so as to be inclined in the first and second directions.

  For example, as shown in FIG. 3, the first and second image sensor units 12 </ b> A and 13 </ b> A are arranged in a direction orthogonal to the card 2 transport direction when viewed from a direction perpendicular to the front surface 3 of the card 2. The direction of each light emitting element 14 in the first image sensor unit 12A (the direction of the main optical axis of the emitted light) is the first direction 14a, and the direction of each light emitting element 14 in the second image sensor unit 13A is the second direction. The direction 14b may be used.

  Next, in the above example, two sets of image sensor units are used, but three or more sets of image sensor units may be used. For example, as shown in FIG. 4, a pair of image sensor units 21 and 22 arranged in a direction inclined about 45 degrees on one side with respect to the conveying direction of the card 2 and a direction inclined about 45 degrees on the opposite side. It is also possible to use a pair of image sensor units 23 and 24 arranged in the same manner. Each pair of image sensor units 21, 22 and 23, 24 may be set so that the illumination direction is on the opposite side, for example, as in the case shown in FIG. 1.

  In the above example, the card is a target in which the arrangement direction of the embossed character strings matches the long side direction and the direction orthogonal to the arrangement direction matches the short side direction. However, the present invention can be similarly applied to a card in which an embossed character string is formed in other states. Further, the present invention can be similarly applied to a card having a shape other than a rectangle.

It is a schematic block diagram of the embossed character string reader to which this invention is applied. It is explanatory drawing which shows the specification of the credit card of reading object. It is explanatory drawing which shows another example of an arrangement | sequence of an image sensor. It is explanatory drawing which shows another example of an arrangement | sequence of an image sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Embossed character reader, 2 card | curd, 3 card | curd surface, 4 embossed character string, 11 card | curd conveyance mechanism, 12, 13, 21-24 Contact image sensor, 14 Light emitting element, 15 Light receiving element, 16 Case, 20 Image processing part , L1 illumination light (first direction), L2 illumination light (second direction)

Claims (8)

In the embossed character reading method of reading the embossed character string formed on the surface of the card by the shadow method,
The card is conveyed in the direction in which the embossed character strings are arranged or in a direction perpendicular to the arrangement direction,
Using an image sensor unit including a plurality of light emitting elements and a plurality of light receiving elements, the surface of the card to be conveyed is irradiated with illumination light from the light emitting elements, and a surface image of the card is read by the light receiving elements,
Extracting the shadow of each embossed character constituting the embossed character string from the read surface image, recognizing each embossed character based on each shadow,
As the image sensor unit, using at least first and second image sensor units disposed opposite to the surface of the card to be conveyed,
When viewed from a direction perpendicular to the surface of the card to be conveyed, the first image sensor unit has either an arrangement direction of the embossed character strings or a direction orthogonal to the arrangement direction with respect to the surface of the card. The second image sensor unit emits illumination light from a first direction that is inclined with respect to the second direction, and the second image sensor unit is inclined with respect to both the arrangement direction of the embossed character strings and the direction orthogonal to the arrangement direction. An embossed character reading method characterized by irradiating illumination light from the direction. In claim 1,
The embossed character reading method, wherein the first direction and the second direction are opposite directions. In claim 1 or 2,
Each image sensor unit is arranged so as to be inclined with respect to both the arrangement direction of the embossed character strings formed on the card to be conveyed and a direction orthogonal to the arrangement direction. Embossed character reading method. In claim 1 or 2,
The first and second image sensor units are arranged in a direction orthogonal to the card conveying direction,
The direction of each light emitting element in the first image sensor unit is the first direction,
An embossed character reading method, wherein the direction of each light emitting element in the second image sensor unit is the second direction. In an image reading apparatus for reading an embossed character string formed on the surface of a card by a shadow method,
A card transport mechanism for transporting the card in the direction in which the embossed character strings are arranged or in a direction perpendicular to the direction in which the cards are arranged;
A plurality of light emitting elements for illuminating the surface of the card being conveyed, and an image sensor unit comprising a plurality of light receiving elements for reading a surface image of the card,
The image sensor unit includes at least first and second image sensor units,
When viewed from a direction perpendicular to the surface of the card to be conveyed, the first image sensor unit has either an arrangement direction of the embossed character strings or a direction orthogonal to the arrangement direction with respect to the surface of the card. The second image sensor unit emits illumination light from a first direction that is inclined with respect to the second direction, and the second image sensor unit is inclined with respect to both the arrangement direction of the embossed character strings and the direction orthogonal to the arrangement direction. An image reading apparatus that irradiates illumination light from the direction of. In claim 5,
The image reading apparatus according to claim 1, wherein the first direction and the second direction are opposite directions. In claim 5 or 6,
Each image sensor unit, when viewed from a direction perpendicular to the surface of the card, with respect to either the arrangement direction of the embossed character strings formed on the card to be conveyed or the direction orthogonal to the arrangement direction The image reading apparatus is also arranged so as to be inclined. In claim 5 or 6,
The first and second image sensor units are arranged in a direction perpendicular to the card conveying direction when viewed from a direction perpendicular to the surface of the card,
The direction of each light emitting element in the first image sensor unit is the first direction, and the direction of each light emitting element in the second image sensor unit is the second direction. apparatus.

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