JPS6320576A - Medium recognizing device - Google Patents

Abstract

PURPOSE:To execute the read of a synthetic pattern of both the surface and the reverse side of a medium and the exact read of a fine pattern, by switching the driving of first and second light sources in accordance with a scanning place on a medium to be recognized, by an image sensor. CONSTITUTION:When the time tG when the front end of a medium 2 would reach the read position of an image sensor 10 is elapsed, the second light source LS2 and an LS1 become ON and OFF, respectively, and read by a transmission system is started. Thereafter, read in a B zone is started, a light source LS2 and the LS1 become OFF and ON, respectively and said read is shifted to the read of a reflecting system, and when the time of t2 is elapsed from a start pulse, the light source LS2 and the LS1 return again to the state of ON and OFF, respectively. Read of a C zone is executed in the same way as that of an A zone, and as for the read of a D zone, only in the time zone (a part 2B) between the time t3 and t4, the light source LS2 and the LS1 become OFF and ON, respectively, the read by the reflecting system is executed, and as for other part, the read by the transmission system is executed. The read operation of an E zone is the same as that of the Z zone.

Description

[Detailed Description of the Invention] Summary of the Invention Characters, symbols, etc. mainly displayed on the front and back sides of a sheet-like medium,
In a device that reads patterns, etc. using an image sensor and recognizes or identifies the medium, minute patterns such as letters and symbols can be detected by detecting reflected light, and other patterns can be recognized by detecting transmitted light. Two reflective light sources and a transmitted light source are provided so that the pattern can be read, and these light sources are switched depending on the scanning location of the image sensor.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medium recognition device that recognizes or identifies a sheet-like medium (for example, a banknote) based on data read by an image sensor such as characters, symbols, patterns, etc.

Patterns such as letters, symbols, patterns, etc. are displayed on both the front and back sides, and devices for recognizing or identifying the medium based on read data of these patterns include a single reflective light source method and a transmitted light source method. In the reflective light source method, light from a light source is projected onto a medium, and the reflected light from the medium is detected by an image sensor. According to this method,
When light is projected onto the front surface of a medium, information on the back surface of the medium cannot be obtained. If it is desired to obtain information on both the front and back sides of a medium, it is necessary to either turn the medium upside down and read it twice, or to place a pair of light sources and image sensors on both sides of the medium. Therefore, problems arise in that the recognition process takes a long time or the device becomes complicated. In the transmitted light source method, a light source is placed on the opposite side of the image sensor across the medium, and light that is emitted from the light source, passes through the medium, and reaches the image sensor is detected.

According to this method, it is possible to read a composite image of patterns expressed on both the front and back sides of the medium. However, this method is not necessarily preferable when it is necessary to accurately read fine patterns such as letters, numbers, and symbols displayed on only one side of the medium. Because-
Characters on the surface.

This is because the patterns on the other side are superimposed on the fine patterns such as numbers and symbols, making it difficult to accurately identify the fine patterns. In the transmission light source method, light passes through the medium, so the detected light also includes noise components from the medium itself, which is another factor that makes it difficult to identify fine patterns.

Summary of the Invention The present invention has a relatively simple configuration and enables relatively high-speed processing, and takes advantage of the advantages of both the reflected light source method and the transmitted light source method described above, and enables processing to be performed on both the front and back sides of the medium depending on the location. An object of the present invention is to provide a medium recognition device that can accurately read composite patterns and fine patterns.

The medium recognition device according to the present invention includes an image sensor arranged so as to face one surface of the medium to be recognized, and an image sensor that projects light onto the one surface of the medium to be recognized in order to recognize the medium by reflected light. 1 light source.

a second light source that projects light onto the other side of the medium to be recognized for medium recognition by transmitted light; The invention is characterized by comprising a light source switching means for switching the driving of the light sources.

The switching timing between the first light source and the second light source is determined by predetermining a location on the medium to be read by the reflection method using the first light source and a location to be read by the transmission method using the second light source. This can be done based on. If the medium is a banknote and there are multiple types such as a 1,000 yen bill, a 5,000 yen bill, and a -10,000 yen bill, the switching timing for each type is stored in memory. When these banknotes are transported, their type may be temporarily determined based on their external dimensions, etc., and control may be performed at the timing of switching the determined type.

According to this invention, compared to the conventional method, it is only necessary to add one light source and provide two image sensors, and two image sensors for the front and back sides are not required, so the configuration does not become too complicated. . Furthermore, since the medium pattern only needs to be read once, the processing time is shorter than in the conventional method in which the medium is reversed and both sides of the medium are read twice.

According to the present invention, when it comes to patterns such as patterns, it is possible to read the composite pattern on both the front and back sides of the medium using the transmission method by driving the second light source. By driving the light source and using a reflection method, it is possible to prevent noise components from being mixed in, and it is possible to read data accurately, although the data is only for two sides.

Description of examples Figure 1 shows an example of the electrical configuration of a medium recognition device.

FIG. 2 shows the arrangement of the image sensor and the light source, respectively.

The medium 2 to be recognized is, for example, a banknote, and is conveyed along the conveyance path 1 in the direction of the arrow. This conveyance path 1 includes feed rollers 3. provided before and after the image sensor 10. Including the ejection roller 2 and the like. Further, a gate sensor GS is provided to detect the front end of the medium 2 entering the reading position of the image sensor 10.

The image sensor IO is arranged on one side of the conveyance path 1 so as to face one side of the medium 2 being conveyed, for example, the surface thereof. The image sensor 10 is, for example, COD, MO
S image sensor, an amorphous medium silicon image sensor. In this embodiment, the image sensor 10 is a line sensor (-dimensional image sensor) including a large number of light source elements arranged in a line in a direction perpendicular to the conveying direction of the medium 2. This is the main scanning direction.The conveyance direction of the medium 2 is the sub-scanning direction, and as the medium 2 is conveyed, it is read and scanned in the sub-scanning direction.Of course, it can be read not only in the main-scanning direction but also in the sub-scanning direction. It is also possible to employ a so-called two-dimensional image sensor including photoelectric elements arranged in the same manner, and if the number of photoelectric elements in the sub-scanning direction is large, conveyance of the medium 2 would be unnecessary.

Two light sources LS1. LS2 (including its drive circuit) is provided. One light source LS1 is.

This is for reading by reflected light, and the light projected from this light source LSI hits the surface of the medium 2 being transported.
It is arranged so that it is reflected there and detected by the image sensor 10, and is provided on the same side of the transport path 1 as the image sensor 10.

The other light source LS2 is for reading by the transmission method, and is connected to the image sensor 1o across the transport path 1 so that the light emitted from this light source Ls2 passes through the medium 2 and is detected by the image sensor 10. It is placed in a position opposite to.

Control of reading, light source switching, etc. in this medium recognition device and the medium recognition device are performed by the CPU 20. This CPU 20 has a ROM 2 that stores the program.
1. R for storing various data such as read data
A M 22 and a timer 23 are connected via various buses (only some of which are shown). The timing circuit 13 is
The clock pulse for the operation of this CPU 20 is
U20 and provides an image clock pulse to image sensor 10. CPU20 again. A start pulse, which is a command to start reading (line scan) in the main scanning direction, is sent to the image sensor l via the I10 port.
Give to O.

A read signal output from the image sensor 10 for each image clock pulse passes through a buffer amplifier 11, is converted into a digital signal by an A/D converter 12, and is input to the CPU 20 via an I10 port 14. The detection signal of the gate sensor GS is also given to the CPU 20 via the I10 port 14. The CPU 20 operates the light source LS1. according to the program. A switching signal for LS2 is generated, and the driving of the light source LSI and LS2 is switched via the I10 port 14. Based on the read data of the image sensor 10, the CPU 20
performs a recognition process on the medium 2. For example, if the medium 2 is a banknote, the reading pattern and the RO to 121 or R
The authenticity and type of banknotes are determined by comparing them with the reference patterns stored in A-122.

The result (medium recognition or identification output) is sent to I10 boat 1.
4 and output.

FIG. 3 shows an example of a pattern expressed on the medium 2 and the switching timing of the light sources LSI and LS2 when this pattern is read by the image sensor IO. A fine pattern such as two numbers and letters is displayed on the surface of the medium 2 at portions indicated by 2A and 2B. These parts 2A.

When reading 2B, the light source LSI is driven (turned on) and 2B is read.
Reading is done by reflection method. A pattern is displayed on the other portions of the medium 2 (including the front and back sides), and when reading this pattern, the light source LS2 is turned on and transmission reading is performed.

In order to control switching between the light sources LSI and LS2, the reading area on the medium 2 is divided into bands A to E in the transport direction. Parts 2A and 2B are included in the B band and D band, respectively. In scanning in the main scanning direction in the B band and D band, the timing at which the two portions 2A and 2B should be read is the time tl, t2... from the start pulse.
It is predetermined as t3°t4. The above various data, i.e. width of A-band to E-band (or conveyance time in sub-scanning direction or number of start pulses) 9 hours t1
~t4 etc. are determined in advance for each type of medium, and RA
It is stored in M22.

Figure 3 shows 5 typical main scanning lines in A-band to E-band.
1-S5, and the switching control timing of the light source LSI and LS2 in the A-band, B-band, and D-band is represented by a time chart.

FIG. 4 shows the flow of reading and light source switching control for the medium shown in FIG.

When the medium 2 is inserted into the transport path 1, its transport starts (step 101). When the front end of the medium 2 is detected by the gate sensor GS (step 102), the timer 23 starts a timing operation. When the time tC during which the front end of the medium 2 will reach the reading position of the image sensor 10 has elapsed (step 103), the second light source LS2 is turned on and the LSI is turned off (step 104), and the start
A pulse is output and reading by the transmission method is started (step 104).

The read signals of the image sensor 10 are sequentially stored in the RAM 22. In the process of conveying the medium 2, the main scanning line S
When scanning reading in the main scanning direction in the A band including 1 is repeated a predetermined number of times in the sub scanning direction (conveying direction),
Reading in the band ends (step 1oe).

After this, reading begins in the B band (step 107).
), when the time tl has elapsed from the output of the start pulse, the light source LS2 is turned off, the LSI is turned on, and the reading starts using the reflection method (steps 108 and 109), and when the time t2 has elapsed from the start pulse, the light source LS2 is turned off and the LSI is turned on. Light source LS2
is on and the LSI is turned off (step 110.
111). Since such switching is repeated for each start pulse, the pattern in the portion 2A in the B band is read based on the reflected light, and the patterns in other portions are read based on the transmitted light. When the entire range of the B-band in the sub-scanning direction has been scanned, reading of the B-band ends (step 112).

Reading the C band is done in the same way as the A band (step 1
13.114), In reading the D band, the light source LS2 is turned off and the LSI is turned on only in the time period between time t3 and t4 measured from the start pulse (part 2B), and reading is performed by the reflection method. The other parts are read using the transparent method (step 1).
15-120). The reading operation for E band is the same as that for A band (steps 121 and 122).

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the electrical configuration of the medium recognition device;
FIG. 2 is a side configuration diagram showing the arrangement relationship between the image sensor and the light source, and FIG. 3 shows an example of a pattern expressed on a medium and the light source control timing for reading this pattern. FIG. 4 is a flow chart showing the flow of reading and light source control. 2... Medium, 10... Image sensor. 20...CPU. LSI: first light source, LS2: second light source. that's all

Claims (1)

[Scope of Claims] An image sensor disposed so as to face one surface of the medium to be recognized; a first image sensor that projects light onto the one surface of the medium to be recognized in order to recognize the medium by reflected light; a light source, a second light source that projects light onto the other side of the medium to be recognized for medium recognition using transmitted light;
A medium recognition device comprising: a light source; and a light source switching means for switching driving of the first light source and the second light source depending on a scanning location on the medium to be recognized by the image sensor.