JP3363848B2 - Judgment method for paper sheets - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a method for judging the authenticity of paper sheets such as banknotes and securities. 2. Description of the Related Art As a method of judging the authenticity of a bill, a magnetic sensor arranged at a predetermined position while scanning a bill to be inspected,
By a feature amount detection sensor such as an optical sensor, the feature amount of the inspection target bill is sampled in the scanning direction,
There is known a method of comparing the obtained sampling data with reference data created in advance to determine the authenticity of the banknote to be inspected. However, in the case of low-quality bills such as US dollars, the position of the feature detected by the sensor in the printing section of the bill to be inspected is shifted due to printing misalignment. In particular, when there is a printing shift in a direction orthogonal to the scanning direction of the inspection target banknote, there is a problem that if the reference data created based on the banknote without the printing shift is used, it is not possible to make an accurate authenticity determination. . SUMMARY OF THE INVENTION The present invention is directed to a paper which enables accurate authenticity determination even when a sheet to be inspected has a printing deviation in a direction orthogonal to the scanning direction. An object of the present invention is to provide a method for determining the authenticity of leaves. A paper sheet authenticity determination method according to the present invention creates a plurality of reference data in accordance with a print shift amount in a direction orthogonal to a scanning direction of a paper sheet. While scanning a sheet to be inspected, a characteristic amount is detected by a characteristic amount detection sensor provided at a predetermined position to generate characteristic amount data, and an image of a predetermined portion of the inspection target is imaged by an image sensor. Based on an image captured by the image sensor, a print shift amount in a direction orthogonal to the scanning direction of the sheet to be inspected is calculated, and reference data corresponding to the calculated print shift amount, It is characterized in that the authenticity of paper sheets to be inspected is determined based on the quantity data. Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show a banknote to be inspected, a sensor for reading the characteristic amount of the banknote to be inspected, and a CCD camera for imaging a corner portion of the banknote to be inspected. In this example, for convenience of explanation, a case will be described in which the number of sensors is one and the sensor is arranged so as to detect the characteristic amount at the center of the width of the bill to be inspected. The banknote 1 to be inspected is put into an inspection device (not shown) and is conveyed in the direction of the arrow. As a sensor for reading the characteristic amount of the banknote 1 to be inspected, for example, a light transmission type sensor including a light projector 21a and a light receiver 21b is provided. The banknote 1 to be inspected is printed except for the peripheral edge. This printing area is indicated by reference numeral 1a. The light transmissive sensors 21a and 21b are connected to the line L in the bill 1.
The light transmittance is detected at the plurality of positions above. By the way, among the banknotes 1 to be inspected, FIG.
In some cases, the print area 1a is shifted in a direction orthogonal to the scanning direction as shown in FIG. Then, the light transmission type sensor 2
The feature amount detection position in the print area by 1a and 21b is different from the position for the banknote in which the printing displacement has not occurred. Therefore, in this embodiment, a plurality of reference data corresponding to the print shift amount dy (see FIGS. 2 and 4) in the direction orthogonal to the scanning direction of the banknote 1 to be inspected are generated in advance. For example, the reference data for the print shift amount as shown in FIG. 4 is the reference data corresponding to the line L on the bill printing unit 1a shown in FIG. In this embodiment, as shown in FIGS. 1 and 2, a CCD image sensor 22 for taking in an image of the corner S of the banknote 1 to be inspected is provided. Based on the corner image captured by the CCD image sensor 22, the print shift amount dy in a direction orthogonal to the scanning direction of the inspection target bill 1 is measured. Then, the reference data according to the measured print shift amount dy is selected. FIG. 3 shows a processing procedure for authenticity determination of a bill. First, by scanning the bill 1 to be inspected, the light transmittance is detected at a plurality of positions on the line L by the light transmitting sensors 21a and 21b (step 1). The image of the corner S of the banknote to be inspected is represented by C
The print deviation amount dy in the direction orthogonal to the scanning direction of the inspection target banknote 1 is calculated based on the image captured by the CD image sensor 22 (step 2). From the reference data group, reference data corresponding to the calculated print shift amount dy is selected (step 3). Based on the light transmittance data detected in step 1 and the reference data selected in step 3,
The authenticity of the inspected banknote 1 is determined (step 4). In the above embodiment, the print shift amount dy in the direction orthogonal to the scanning direction of the banknote 1 to be inspected is calculated based on the image captured by the CCD image sensor 22. The print shift amount dy may be calculated based on an image captured by another image sensor such as a line sensor. Although a light transmission type sensor is used as a sensor for reading the characteristic amount, other sensors such as a light reflection type sensor and a magnetic sensor can be used. According to the present invention, even if a sheet to be inspected has a printing misalignment in a direction orthogonal to the scanning direction, accurate authenticity determination can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view showing a banknote to be inspected, a sensor for reading a feature amount of the banknote to be inspected, and a CCD camera for imaging a corner portion of the banknote to be inspected. FIG. 2 is a plan view of FIG. FIG. 3 is a flowchart illustrating a procedure of a bill authenticity determination process. FIG. 4 is a plan view showing a feature amount detection position for a banknote having a printing shift in a direction orthogonal to a scanning direction. [Description of Signs] 21a Projector 21b Receiver 22 CCD Image Sensor

────────────────────────────────────────────────── (5) References JP-A-63-49897 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G07D ^7/ 00-7/20

Claims (1)

(57) [Claims] [Claim 1] A plurality of reference data corresponding to a print shift amount in a direction orthogonal to a scanning direction of a sheet is created in advance, and the sheet to be inspected is scanned. Meanwhile, feature amount data is created by detecting a feature amount by a feature amount detection sensor provided at a predetermined position, and an image of a predetermined portion to be inspected is captured by an image sensor, and the image captured by the image sensor The amount of printing deviation in the direction orthogonal to the scanning direction of the sheet to be inspected is calculated on the basis of the reference data corresponding to the calculated amount of printing deviation and the feature amount data. A method for judging the authenticity of paper sheets that performs authenticity judgment of leaves.