JPH0830833A - Authenticity determination method - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an excellent authenticity determination method capable of determining a forged or altered recording medium. In a true / false judgment method for judging authenticity of a recording medium having an optical layer having optical information on a base material, a phase of memory means for storing information correlating with the optical information and the optical information A true / false judgment method, wherein the number of relationships is calculated, and when the correlation coefficient is larger than a predetermined value, the recording medium is judged to be true. [Effect] Since the authenticity determination method of the present invention can determine a forged or altered recording medium, it is possible to prevent fraud,
Excellent security performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for judging authenticity of a recording medium.

[0002]

BACKGROUND OF THE INVENTION Cards used for boarding tickets, commuter passes, credit cards, prepaid cards, etc. have a magnetic layer for recording various information on a base material such as paper or plastic. Have However,
There has been a problem of fraudulent acts of forging or altering and using these cash-exchangeable cards.

Therefore, a recording medium that is difficult to forge or alter and a recording medium newly provided with optical information for determining the authenticity of the medium are known. However, there are also malicious acts of fraud in which the composition of optical information is known and forged.

An object of the present invention is to provide an excellent authenticity determination method capable of determining a forged or altered recording medium.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an authenticity determination method for determining authenticity of a recording medium having an optical layer having optical information provided on a base material, and storing information correlated with the optical information. Is a true / false determination method characterized in that the correlation coefficient between the memory means and the optical information is calculated, and if the correlation coefficient is larger than a predetermined value, the recording medium is determined to be true.

[0006]

According to the authenticity determination method of the present invention, the correlation coefficient between the optical information provided on the optical layer and the information stored in the memory is within a predetermined range. When the information is similar, the recording medium is identified as true. judge. That is, since the optical information can be compared with the information stored in the memory, the security performance is excellent.

[0007]

EXAMPLES Examples will be described below, but the present invention is not limited thereto. FIG. 1 is a block diagram showing the configuration of an embodiment of a determination mechanism used in the authenticity determination method of the present invention. FIG. 2 shows a sectional view of a recording medium used in the present invention. FIG. 3 shows an example of optical information formed on the optical layer. FIG. 4 is a waveform of a signal obtained from the optical layer shown in FIG.

The determination mechanism used in the authenticity determination method is a detection mechanism for detecting optical information provided on the recording medium 100,
External memory 70 for recording information that correlates with the optical information
0, it has a calculation mechanism for obtaining a correlation coefficient between the optical information provided in the recording medium 100 and the information stored in the external memory 700.

The detection mechanism for detecting the optical information of the recording medium 100 is a light emitting element 200 for irradiating the recording medium 100 with light.
And a light receiving element 300 that detects reflected light and converts it into a signal
, An amplifier 400 for amplifying a signal, and an A / D converter 500 for A / D converting the signal. Light emitting element 2
00 and the light receiving element 300 scan the optical information (not shown) provided on the recording medium 100.

The arithmetic unit for obtaining the correlation coefficient is a CPU 600 for executing the arithmetic processing, a RAM (random access memory) 610 for storing the above-mentioned converted signal, and a ROM (read only) for storing the procedure for obtaining the correlation coefficient. Memory) 620. The external memory 700 stores information correlated with optical information. In this embodiment, the value correlated with the value of the standardized reflection density shown in FIG. 3 described later is stored.

A sectional view of the recording medium 100 is shown in FIG. In the recording medium 100, an optical layer 20 having optical information is formed on a polyester film substrate 10 having a thickness of 188 μm. The optical layer 20 includes an infrared reflection layer 21 and an infrared absorption layer 2
And 2. The infrared reflective layer 21 was made of titanium oxide ink and had a layer thickness of 2 μm. The infrared absorbing layer 22 was made to have a layer thickness of 1 μm using an ink containing carbon black.

An ink composed of a black dye, a color developer, and a near-infrared transmitting dye is applied on the infrared absorption layer 22 to have a thickness of 6 μm.
The concealing layer 30 is formed. The hiding layer 30 is the optical layer 20.
Hide. A protective layer 40 is formed by coating a solution of UV curable acrylic resin on the concealing layer 30 in a thickness of 2 μm.

FIG. 3 shows an example of optical information provided on the optical layer 20. In the present embodiment, the optical information is composed of a plurality of units in which the optical information changes stepwise with a predetermined reflection density difference. In the figure, the value described in the unit is a value obtained by normalizing the reflection density. Further, although each unit is rectangular in the drawing, it is not necessary to be rectangular, and the boundary line of each unit may be a curve.

FIG. 4 is a waveform of a signal obtained from the optical layer shown in FIG. 3 when the diameter of the optical system is substantially equal to the unit width. The vertical axis represents the value obtained by normalizing the reflection density, and the horizontal axis represents the scanning position when the optical system scans in the direction of the arrow in FIG.

The authenticity determination mechanism shown in FIG.
After the detecting mechanism detects the optical information of 00, the optical information is stored in the RAM 610. CPU600 is ROM62
According to the procedure stored in 0, the correlation coefficient between the optical information and the information recorded in the external memory 700 is obtained.

According to the present invention, the recording medium is determined to be true when the correlation coefficient obtained from the above-mentioned calculation mechanism is larger than a predetermined value. Specifically, for example, the predetermined value is 0.7,
When the value of the obtained correlation coefficient is 0.8, it is determined that the recording medium is true, that is, the recording medium is not forged.

After all the optical information of the recording medium 100 is detected by the detection mechanism, it is stored in the RAM 610. The stored values are the points corresponding to the peaks and valleys of the signal waveform shown in FIG. The ROM 620 obtains the reading intensity of the optical information stored in the RAM 610, the standardized average value Xa of reflection densities and the average value Ya of the information recorded in the external memory 700 in this embodiment. Further, the ROM 620 is the RAM 6
The correlation coefficient between the reading intensity Xi of the arbitrary optical information stored in 10 and the value Yi stored in the external memory 700 corresponding to the optical information is obtained according to the following formula 1.

[0018]

(Equation 1) In this authenticity determination method, for example, the method described below can be used. In the first method, an address is assigned to each of a plurality of recording media, and similarly, an address is also assigned to a standardized value of reflection density stored in an external memory that correlates with optical information of the recording media. A recording medium having a matching address and a correlation coefficient between the two that is equal to or larger than a predetermined value is set to be true. In this method, the optical information provided on the recording medium and the information stored in the external memory are 1
Correspond to one by one. The addresses provided on the recording medium may be recorded on the magnetic layer by newly providing a magnetic layer in the configuration described in FIG.

In the second method, a standardized value of one kind of reflection density is stored in an external memory, and a recording medium having an optical layer having a correlation coefficient with a predetermined value or more is made true. In this method, one piece of information stored in the external memory corresponds to different optical information provided on a plurality of recording media.

In the first method, the predetermined value referred to in the present invention is preferably a correlation coefficient of "1" obtained from the optical information provided on the optical layer and the information recorded in the memory. The value may be slightly smaller than "1" in consideration of the reading error of the optical system for reading the optical information. The predetermined value referred to in the second method is preferably such that the correlation coefficient has a certain width, but if the width is increased, forged optical information may be determined to be true, and therefore, for example, 1 to 0. It may be set during 7.

In the above embodiment, the memory is provided as an external memory different from the CPU main body, but the CPU main body or ROM may be used. In the present invention, the position is not limited as long as it has a memory for storing information correlated with optical information.

[0022]

According to the authenticity determination method of the present invention, since a forged or altered recording medium can be determined, fraudulent activity can be prevented and security performance is excellent.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a determination mechanism used in the authenticity determination method of the present invention.

FIG. 2 shows a sectional view of a recording medium used in the present invention.

FIG. 3 shows an example of optical information formed on an optical layer.

FIG. 4 is a waveform of a signal obtained from the optical layer shown in FIG.

[Explanation of symbols]

 10 Base Material 20 Optical Layer 21 Infrared Reflecting Layer 22 Infrared Absorbing Layer 100 Recording Medium 200 Light Receiving Element 300 Light Emitting Element 600 CPU 610 RAM 620 ROM 700 External Memory

Claims (1)

[Claims] 1. A true / false judgment method for judging the authenticity of a recording medium having an optical layer having optical information provided on a base material, wherein the memory means stores information correlating with the optical information and the optical information. The true / false determination method is characterized in that the recording medium is determined to be true when the correlation coefficient is determined and the correlation coefficient is larger than a predetermined value.