JPH02171606A - Shape discriminator for sheet paper - Google Patents

Abstract

PURPOSE:To identify abnormality in shape such as a bending at a corner by calculating a specified range of area based on a length in a direction perpendicular to the conveyance of sheet papers to compare the area with a reference area. CONSTITUTION:An LED array 11 of a paper money inspecting unit 10 irradiates the entire surface of a paper money and the light is received with a lens array 13 and a line sensor 12. The line sensor 12 scans the entire surface of the paper money being conveyed with a conveying belt 14 and each time the paper money is conveyed by 1mm, one line of scanning is performed to determine a length perpendicular to a direction of conveyance from data at right and left ends. An output signal of a line sensor 12 is quantized with a processing circuit 15 and sent to a microprocessor 16, which calculates a specified range of area at a corner of the paper money. The results are compared with a reference surface stored in a memory, thereby enabling abnormality judgement in shape such as a bending at a corner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Industrial Application Field) The present invention relates to a paper sheet shape discriminating device for discriminating the shape of banknotes, etc. used in automatic teller machines and the like.

(Prior art) Devices for determining the shape of paper sheets have traditionally been used in automatic deposit machines, etc., and conventional devices scan the entire paper sheet with a line sensor. The area is compared with the original area of the paper sheet to detect folded corners and damage.

However, when the entire paper sheet is scanned by a line sensor, the leading and trailing edges of the sheet may partially block the scanning line of the line sensor, resulting in the scanning signal at the leading and trailing edges of the sheet. becomes unstable.

Therefore, for example, the length in the direction perpendicular to the conveyance direction is 160 mm.
When a line sensor scans a paper sheet of 1 mm each time it is conveyed, an area of 160 mm (
It is erroneously determined that the corner of the paper sheet is damaged by 18 mm (the same area as when the corner is damaged by 18 mm).

For this reason, conventional devices have been unable to detect irregularities in the shape of paper sheets, such as folded corners.

(Problems to be Solved by the Invention) The present invention has been made based on the above circumstances, and provides a paper sheet shape discrimination device that can reliably identify abnormalities in the shape of paper sheets, such as folded corners. This is what I am trying to do.

[Structure of the Invention (Means and Effects for Solving the Problems) In order to solve the above-mentioned problems, the present invention includes a light projecting means for irradiating light onto paper sheets, and a light projecting means for irradiating light onto paper sheets, A detection means for detecting light from the light projecting means, which is provided opposite to the light projecting means, and detecting the shape of the paper sheet by blocking the light from the light projecting means by the paper sheet. In the shape discrimination device, there is provided a means for determining the length of a paper sheet in a direction orthogonal to the conveying direction of the paper sheet based on a detection signal from the detection means, and a length of the paper sheet detected by the detection means based on the determination result of the length determination means. and a means for comparing the area calculated by the calculation means with the area within the predetermined range of the corners of the paper sheet.

(Function) The area within a predetermined range of the corner of the paper sheet detected by the detection means is calculated based on the judgment result of the length judgment means, and the area between this calculated area and the predetermined corner of the paper sheet is calculated. Only the corners of paper sheets are determined by comparing the area with the area of the range.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the banknote inspection unit 10 is a unit that is incorporated into an automatic teller machine, etc., and includes an LED array 11 that irradiates light onto the entire surface of the banknote, and a
A line sensor 12 is disposed opposite to the banknotes via the banknote conveyance path, and receives the light from the LED array (1). Further, a lens array 13 is provided between the line sensor 12 and the LED array 11 to guide the light from the LED array 11 to the line sensor 2.

The banknotes are held between the conveyor belt 14 and the LED array 1
1 and the line sensor 12.

As shown in FIG. 2, the line sensor 12 scans the entire surface of the banknote, and when the banknote is conveyed, the LED
The light of the array 11 is blocked and the wound region receives no light, resulting in a dark signal.

The line sensor 12 has a 256-bit detection element, and one line is scanned every time a banknote is conveyed 1 mm. Also, the resolution of the line sensor 12 is 1 line/1
It is mm.

As shown in FIG. 3, the line sensor 12 is driven by a line sensor processing circuit 15, and the output signal of the line sensor 12 is quantized by the line sensor processing circuit 15 and sent to the microprocessor 1B.

The microprocessor 1B determines the shape of the paper sheet based on the scanning signal from the line sensor 12, and the memory 17 temporarily stores detection data for determining the shape of the paper sheet. .

Further, the memory 18 stores in advance software programs and data for determining the shape of paper sheets.

Next, the operation of the above configuration will be explained.

First, when a banknote is conveyed and enters between the LED array 11 and the line sensor 12, the output signal of the line sensor 12 changes, and first, the leading edge is detected as indicated by Al shown in FIG.

Based on the scanning signal, the microprocessor determines that the first time the signal changes is the leading edge of the banknote, and stores the data of the right and left ends of the banknote at this time in the memory.

For the right and left ends of the banknote, determine the number of bits at which the output signal of the line sensor 12 changes from bright to dark or from dark to bright, respectively, and calculate the bit number at each change point as shown in Figure 5. Each scan line is stored in memory.

Each time the banknote is conveyed by 1 mm, it is scanned by the line sensor 12, and each scan signal is sent to the microprocessor to perform the above operations.

Then, when there is no change in the scanning signal and there is no data at the right end or left end, it is determined that the banknote has finished passing over the line sensor 12, and shape determination is started.

Data on the right end and left end are stored for each scanning line, and the length of the banknote in the direction orthogonal to the transport direction is determined.

The microprocessor calculates the difference between the right and left end data to determine the length, and compares the length with the length in the previous scan line and the next scan line.

Then, when the change in length in three consecutive scan lines is within 1 degree, the length in the center scan line is determined to be the correct length, and the length data and the scan line are calculated at the number of times from the tip of the bill. It remembers whether it was a scan or not.

This determination is performed for each scanning line, and if the determined length has already appeared, the number of scans is stored in the memory area of the corresponding length, as shown in Figure 6. Create a histogram of length data as follows.

Then, the frequency of the histogram is checked starting from the longest length, and a length with a frequency of 10 or more is determined to be the length of a banknote. Furthermore, the number of scans of the last scan line in which this length was detected is stored as data: P.

Next, the skew angle of the banknote is determined to determine the shape.

That is, 3 left and right from the center of the 256-bit line sensor.
The 0th bit (El, E2) detects the number of scans in which the leading edge of the banknote was detected.

As shown in Figure 4, if the leading edge is detected at E2 (30th bit on the right) in the next scan after the leading edge is detected at El (30th bit on the left), the line sensor will transport the banknote by 1 mm. Since each scan is performed at a rate of 1 line/mm, it is determined by the following formula.

Skinny angle: -tan (1/60) Once the length and skinny angle of the banknote are determined, as shown in FIG. 7, the position B' of the left end of the banknote in the P-th scan described above is determined.

Next, the position C, which is the same position as B' in the scanning direction, is calculated on a line 20 m+g from the tip A of the bill.

Then, based on the above-mentioned skew angle, the correct left end position C' on the line is C''-(+ (P
-L) * Determined by t a n.

Next, find the position of 20 angles inside this C-, and
`` Find the area S of the banknote area shown by diagonal lines outside D.

That is, the difference between the left end position and the position of D for each scanning line is calculated, and the total sum up to the 20th line is calculated.

The distance from the tip of the banknote to position D is 20m in the conveyance direction.
m, and the distance between C″D is 20 am, so the damage fl
o is determined by "400 - area S".

In this manner, corner folds can be reliably determined by determining only the corner portions of the bill.

In the above embodiment, only the determination of the upper left corner was described, but it goes without saying that the other three corners of the banknote can be similarly determined as to whether or not they are bent.

Further, the above-described length determination and skinny angle determination may be performed during scanning of the line sensor or after the banknote has passed, and the timing of the determination is not limited.

[Effects of the Invention] As described above, according to the present invention, it is possible to reliably identify irregularities in the shape of paper sheets, such as folded corners.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the paper sheet shape discriminating device of the present invention, and FIG.
The figure is a plan view for explaining the scanning area of the device shown in Figure 1, Figure 3 is an electrical block diagram, Figure 4 is a diagram showing the scanning signal of the line sensor, and Figures 5 and 6 are data FIG. 7 is a diagram for explaining the memory state of , and FIG. 7 is a diagram for explaining the effect of shape discrimination.

Claims (1)

[Scope of Claims] A light projecting means for irradiating light onto paper sheets, and a detection means for receiving light from the light projecting means, which is provided facing the light projecting means through the transported paper sheets. In a paper sheet shape discriminating device that determines the shape of a paper sheet by blocking light from a light projecting means by the paper sheet, the paper sheet shape discriminator determines the shape of the paper sheet based on a detection signal from the detection means, in a direction orthogonal to the transport direction of the paper sheet. means for determining the length; means for calculating the area within a predetermined range of the corner of the paper sheet detected by the detection means based on the determination result of the length determination means; 1. An apparatus for determining the shape of a paper sheet, comprising means for comparing the area of the corner of the sheet with the area of a predetermined range of a corner of the sheet.