JPH0363784B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a pattern reading device for paper sheets,
For example, when an object to be detected, such as a banknote, has patterns such as letters or patterns printed on its surface, the pattern of a specific track is read during the transportation process.
The present invention relates to a pattern reading device for paper sheets used for processing operations such as authenticity determination.

FIG. 1 is an illustrative diagram for explaining the principle of a conventional pattern reading device. In the figure, an object to be detected 1 such as a banknote is conveyed in the X direction by a conveyor belt 2 . A single photoelectric sensor 3 is arranged between and above the conveyor belts 2, 2, and the pattern of a specific track 11 on the object 1 is read by this photoelectric sensor 3. Then, this read signal is compared with a pre-stored read pattern and it is determined whether or not they match, thereby determining whether the detected object 1 is a genuine banknote or not. be exposed.

However, in the conventional pattern reading device as shown in FIG. Put it away. Therefore, the photoelectric sensor 3 reads the patterns of other tracks, causing a malfunction in determining authenticity.

In order to prevent this, a method may be considered in which all track patterns included in the displacement width of the detected object 1 are stored in a memory in advance. However,
In this method, when matching reading patterns,
When there is a correspondence with any one of the plurality of patterns, it is determined to be true, and therefore the determination accuracy decreases. Furthermore, if the displacement width of the detected object 1 is predicted to be large, it is necessary to store a large number of track patterns in the memory, which has the disadvantage that the storage capacity of the memory becomes extremely large.

SUMMARY OF THE INVENTION Therefore, the main object of the present invention is to provide a pattern reading device for paper sheets that can solve the above-mentioned problems and that can always read patterns on the same track when reading patterns on a plurality of paper sheets. The goal is to provide the following.

To summarize this invention, a set of image sensors is arranged in a direction crossing the conveyance direction of paper sheets, and each sensor element is sequentially scanned so that a part of the image sensor detects the edge of the paper sheet. When a predetermined time elapses from when a paper sheet is detected to when a predetermined number of sensor elements are scanned, a sampling command is output, and when this sampling command is output, the number of sensor elements being scanned is It is configured to sample the output signal and output a pattern read signal.

The present invention will be described in more detail below along with embodiments shown in the drawings.

FIGS. 2A and 2B are illustrative views showing a pattern reading portion included in an embodiment of the present invention. In the figure, conveyance path guides 4, 4 are provided along the conveyance path of the detected object 1 so as to cover the upper and lower sides of the detected object 1. A light source 3 is provided below the conveyance path guides 4, 4. A condenser lens 6 and an image sensor 7 are arranged above the conveyance path guides 4, 4. The condenser lens 6 is used to form an image of the pattern of the object 1 on the image sensor 7 when the object 1 is illuminated by the light source 3 . The image sensor 7 has a plurality of sensors arranged in a line, as shown in FIG. 2B.

FIGS. 3A to 3C are diagrams for explaining the principle of an embodiment of the present invention. Next, the second A
The principle of an embodiment of the present invention will be explained with reference to the drawings to FIG. 3C. When the object 1 to be detected is conveyed to the normal position of the reading section, the sensor 7a included in the image sensor 7 detects the edge of the object 1 to be detected. Then, the pattern of the track is read by the sensor 7b facing the predetermined track 11 of the object 1 to be detected. The track to be read is located at a predetermined distance from the end of the object 1 to be detected, and a read signal can be output from the sensor 7b corresponding to that position.

Further, when the object 1 to be detected deviates from the transport path to the right side in FIG. 3B, the end of the object 1 to be detected 1 is detected by the sensor 7c. In this case, the track 11 corresponds to the sensor 7d, and a read signal is output from the sensor 7d. Furthermore, the third
As shown in Figure C, when the detected object 1 deviates to the left side of the normal conveyance path, the sensor 7e
Detect the edge of. In this case, the sensor 7f corresponds to the track 11, and a read signal is output from this sensor 7f.

In this way, by outputting a reading signal from a sensor that is a predetermined distance away from the sensor that has detected the edge of the detected object 1, even if the detected object 1 is Even if the tracks are shifted in the same direction, it is possible to always output the read signal from the same track.

FIG. 4 is a schematic block diagram of an embodiment of the present invention, and FIG. 5 is a block diagram of the change detection circuit 13 shown in FIG.
FIG. 6 is a specific block diagram of the sample and hold circuit 15, and FIG. 7 is a specific block diagram of the delay circuit 14.

Next, a specific configuration of an embodiment of the present invention will be described with reference to FIGS. 4 to 7. The oscillator 8 constitutes a clock pulse generating means and generates clock pulses. This clock pulse is applied to the counter 9, the image sensor 7, the change detection circuit 13, and the delay circuit 14.
A reading command signal is given to the counter 9. When the counter 9 receives this read command signal, it provides the image sensor 7 with a read start signal synchronized with the clock pulse. The image sensor 7 has a plurality of sensors arranged in one row as shown in FIG. 2B mentioned above. When the image sensor 7 receives a clock pulse, it sequentially outputs a read signal from each sensor. This read signal is transmitted to amplifier 1
The signal is amplified by 0 and applied to the comparison input terminal of the comparator 12 as well as to the sample and hold circuit 15. A reference voltage V is applied to the reference input terminal of the comparator 12. This comparator 12 outputs a signal when the image sensor 7 detects the edge of the object 1 and the level of the read signal exceeds the reference voltage V. The output signal of the comparator 12 is then given to a change detection circuit 13.

The change detection circuit 13, as shown in FIG.
including. Then, the change detection circuit 13 supplies a sample command signal h to the delay circuit 14 in response to the image sensor 7 detecting the edge of the detected object 1 . The delay circuit 14 is composed of inverters 141 and 143 and a preset counter 142 as shown in FIG. As explained in FIG. 3A, this delay circuit 14 is operated after the image sensor 7 is scanned by the clock pulse a and the sensor 7a detects the edge of the object 1 as shown in FIG. 3A. This is to delay the output signal (sample pulse signal) h of the change detection circuit 13 by the time until the sensor 7b detects the track 11. For this purpose, the sample pulse signal h is passed through an inverter 141 to a preset counter 142.
is applied to the load input terminal of The preset counter 142 is configured such that data corresponding to the delay time can be arbitrarily set. Therefore, when clock pulse a is applied to preset counter 142, it outputs delayed signal i from its output terminal. This delayed signal i is supplied to the sample hold circuit 15.
and the A-D converter 16.

The sample hold circuit 15 includes an FET 151, a capacitor 152, and an operational amplifier 153, as shown in FIG. Then, the read signal output from the amplifier 10 is input to the drain of the FET,
The delay signal g output from the delay circuit 14 is
It is input to gate 151. The delayed signal g is
When input to the FET 151, the read signal c is applied to the capacitor 152 via the source. Charge corresponding to the read signal is accumulated in the capacitor 152. Then, a voltage at a level corresponding to the charge is outputted via the operational amplifier 153. The output signal j of the operational amplifier 153 is given as a read signal to an authenticity determining circuit (not shown).

FIGS. 8 and 9 are waveform diagrams of each part of FIGS. 4 to 7.

Next, the specific operation of one embodiment of the present invention will be described with reference to FIGS. 2A to 9.
An oscillator 8 generates a clock pulse a and supplies it to a counter 9 and an image sensor 7. When the counter 9 receives a reading command signal, the clock pulse a
A start signal b synchronized with is given to the image sensor 7. When the image sensor 7 is given a start signal b and a clock pulse a, it sequentially outputs read signals from each sensor in synchronization with the clock pulse a. Then, when the object 1 to be detected is conveyed by the conveyor belt 2, the sensor 7a detects the end of the object 1, as shown in FIG. 3A, for example. Therefore, the read signal from the image sensor 7 that rises to H level corresponding to the edge of the detected object 1 is transmitted to the amplifier 1.
given to 0. Further, as the image sensor 7 reads the pattern of the detected object 1, the output level of the image sensor 7 changes. Comparator 1
2 compares the read signal with the reference signal V, and when it is determined that the signal that read the edge of the detected object 1 is larger than the reference signal, the H level output signal is sent to the D type included in the change detection circuit 13. flipflop 13
Give it to the D input of 1. Accordingly, the D-type flip-flop 131 synchronizes its H-level signal with the clock pulse a and outputs the next D-type flip-flop 132.
and one input terminal of EXOR gate 133. D-type flip-flop 132 outputs the input H level signal in synchronization with clock pulse a. That is, the D-type flip-flop 13
2 is the detection signal e output from the change detection circuit 13
is applied to the other input terminal of EXOR gate 133 with a delay of one clock pulse period. Therefore,
EXOR gate 133 receives sample gate signal g.
It is applied to one input terminal of AND gate 135. AND
An inverter 134 is connected to the other input terminal of the gate 135.
Clock pulse a is applied via Therefore, AND gate 135 provides sample pulse signal h to delay circuit 14. In the delay circuit 14,
A preset counter 142 delays the sample pulse signal h according to a preset value and provides a delayed signal i to the sample hold circuit 15 and the A/D conversion circuit 16.

The sample and hold circuit 15 samples and holds the input read signal c at the timing when the delay signal i is applied. That is, the sixth
As shown in the figure, when the read signal c is input to the drain of the FET 151 and the delayed signal i is input to the gate thereof, charges corresponding to the read signal c are accumulated in the capacitor 152. In order to hold the charges accumulated until the next sample pulse signal is input to the capacitor 152, a staircase as shown in FIG. 9 is formed at both ends of the capacitor 152 each time a sample pulse signal is applied. An analog hold signal with a waveform appears. This analog hold signal is sent to the A-D converter 16 via the amplifier 153.
given to. The A-D converter 16 converts the analog hold signal f into a digital value in synchronization with the delay signal i, and supplies the digital value to the authenticity determination circuit.

As described above, according to the present invention, the image sensor is arranged so as to intersect with the conveyance direction of the paper sheet, and each sensor element is sequentially scanned, so that the sensor element included in the image sensor is located at the edge of the paper sheet. Since the pattern of the paper sheet is read by a sensor element that is scanned after a predetermined period of time has elapsed after detecting the edge of the paper sheet, even if the paper sheet deviates from the conveyance path, it can be read at a certain distance from the edge of the sheet. Can read patterns on distant tracks. Therefore, if this invention is applied to an authenticity discrimination device, etc., there is no need to previously store the patterns of multiple tracks of paper sheets in a memory, etc., and the storage capacity of the memory can be kept to a minimum. .

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the principle of pattern reading in a conventional pattern reading device. Second
FIG. A and FIG. 2B are illustrative views showing the configuration of a pattern reading section according to an embodiment of the present invention. FIGS. 3A to 3C are diagrams for explaining the principle of the present invention. FIG. 4 is a schematic block diagram of one embodiment of the present invention. FIG. 5 is a concrete block diagram of the change detection circuit shown in FIG. 4. FIG. 6 is a concrete block diagram of the sample and hold circuit. FIG. 7 is a concrete block diagram of the same delay circuit. FIGS. 8 and 9 are waveform diagrams of each part of FIGS. 4 to 7. In the figure, 1 is the object to be detected, 2 is the conveyor belt,
7 is an image sensor, 8 is an oscillator, 9 is a counter, 10 is an amplifier, 12 is a comparator, 13 is a change detection circuit, 14 is a delay circuit, 15 is a sample and hold circuit, and 16 is an AD converter.

Claims (1)

[Scope of Claims] 1. A pattern reading device for reading a pattern recorded on a paper sheet, comprising: a conveyance means for conveying the paper sheet; a plurality of sensor elements arranged in a direction in which the paper sheet is conveyed; a set of image sensors arranged in a direction crossing the paper sheet, at least a part of which detects the edge of the paper sheet, the image sensor is sequentially scanned at a constant period, and each sensor element detects the paper sheet. a scanning means for reading a pattern of the same kind; a predetermined period from when one of the sensor elements of the image sensor detects the edge of the paper sheet until the scanning means scans a predetermined number of sensor elements; a sampling command means for outputting a sampling command signal when a time has elapsed, and an output signal of the sensor element being scanned by the scanning means in response to the sampling command signal being given from the sampling command means; A pattern reading device for paper sheets, comprising a sampling means for sampling and outputting a reading signal of the pattern. 2. The image sensor is configured to output a reading signal of the pattern by being supplied with a pulse signal, and the scanning means includes a clock pulse generating means for generating a clock pulse and applying it to the image sensor. The sampling command means includes: edge detection signal output means for deriving a detection signal in response to any sensor element of the image sensor detecting an edge of the paper sheet; and the detection signal. 2. The paper sheet pattern reading apparatus according to claim 1, further comprising a delay means for delaying the predetermined time by the predetermined time and outputting the sampled signal as the sampling signal. 3. The delay means according to claim 2, wherein the delay means includes a counting means for counting the clock pulses and outputting the sampling signal in response to counting the number of clock pulses corresponding to the predetermined time. Paper leaf pattern reading device.