JP3811213B2 - Reader - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reading device that reads the surface of a reading object such as a coin, medal, or card.
[0002]
[Prior art]
Although the necessity to determine the authenticity of a given article is increasing, this tendency is particularly remarkable in the fields of bank machines and vending machines that handle coins and medals. Conventional coin readers determine the authenticity of a coin based on the size, thickness, and material of the coin, but this determination method sufficiently addresses social problems associated with recent internationalization. It seems to be impossible. That is, many foreigners have entered our country due to internationalization in recent years. Along with this entry, many foreign coins that resemble our own coins flow in and flood, and as a result, counterfeiting that is difficult to discern It is not uncommon for coins to be exercised to significantly hinder economic activity. For example, the 500 yen coin issued by the Japanese government is the most common size in the world, and it is almost impossible to distinguish it from foreign coins such as South Korea and Russia based on the size and thickness of the coin. Can not. Therefore, a recent coin reader uses an illuminator to determine the authenticity of a coin based on the inscription of the coin, more specifically, the figure, number, or character on the exposed surface of the coin. Is given.
[0003]
A conventional reading apparatus is disclosed in Japanese Patent Laid-Open No. 5-89276. In this reading apparatus, the surface of a reading object to be conveyed is imaged by an image pickup device arranged on the upper side, and the authenticity of the reading object is determined from the captured image data.
[0004]
[Problems to be solved by the invention]
However, in the conventional reader, since the reading object is conveyed asynchronously with the image pickup device, at least two fields are required to output a still image of the moving reading object with the image pickup device. Time was needed.
[0005]
A general image sensor operates with a television-type synchronization signal. Since the synchronization signal is generated asynchronously with the conveyance timing of the reading object, the synchronization signal timing and the conveyance timing of the reading object are matched. It was difficult.
[0006]
The present invention solves such a problem, shortens the period from the start of imaging to the output of the captured image, and easily matches the timing of conveying the reading object and the timing of the synchronization signal. It is an object of the present invention to provide a reader that can perform the above-described process.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, a reading device according to the present invention is a reading device that reads the surface of an object to be read that is conveyed along a predetermined conveyance path, and is a capture trigger when the reading object arrives at the imaging area of the conveyance path. , A television-type synchronization signal that is initialized by a capture trigger and starts output, and a read trigger is generated after the capture trigger occurs and within the same vertical blanking interval as the capture trigger A signal output means for outputting a readout signal; an illuminating means for irradiating light on the imaging region of the conveyance path for a predetermined period from when the capture trigger is generated until the readout trigger is generated; and a discarding section and a light receiving section An image pickup means having an electrode portion and a transfer portion, and picking up an image of the surface of the object to be read at the timing of the capture signal and the read signal. A first process of the charge discharged to repeatedly discard unit at predetermined time intervals, and the second process of accumulating the electrode unit charges generated by the light receiving unit, which is accumulated in the electrode unit based on the synchronization signal And a third process for executing the third process for outputting the charge to the transfer unit. The first process that has been executed up to that point is stopped at the acquisition trigger generation timing, and the second process is performed at the acquisition trigger generation timing. The third process is executed at the timing when the read trigger is generated by executing the process.
[0008]
According to the reading apparatus of the present invention, the capture signal and the readout signal are generated by the signal output means. Here, the acquisition signal is a signal that generates an acquisition trigger when the reading object reaches the imaging region. The read signal is a signal for generating a read trigger after the acquisition trigger is generated and within the same vertical blanking interval as the acquisition trigger.
[0009]
In the imaging unit, the first process is executed before the capture trigger is generated, and the charge accumulated in the electrode unit is repeatedly discharged to the disposal unit at regular intervals . Unnecessary charges are swept out by repeating the discharge of the charges, and the S / N ratio of the image picked up by the image pickup means is improved. Next, when a capture trigger occurs, the first process is stopped at this timing and the second process is executed. By executing the second process, the charge generated in the light receiving unit is accumulated in the electrode unit. As a result, an image of light reflected from the surface of the reading object is accumulated as an electric charge in the electrode portion.
[0010]
Furthermore, after this read trigger occurs and at the timing when the vertical blanking interval ends, the third process is executed to output the charge accumulated in the electrode part to the transfer part. The third process ends in one field period (a period until the next vertical blanking interval comes) or one frame period (a period until a plurality of vertical blanking intervals come).
[0011]
In this way, the electric charge is accumulated in the electrode part in the vertical blanking interval, and the electric charge of the electrode part is output to the transfer unit at the timing when the vertical blanking interval is completed, so that the image is picked up after the imaging is started. The period until the output image is output can be one field period or one frame period.
[0012]
In addition, since the synchronization signal is output in synchronization with the capture trigger that occurs when the reading object reaches the imaging region, the conveyance timing of the reading object and the timing of the synchronization signal can be easily matched.
[0013]
Here, it is preferable that an illumination means consists of LED light sources.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments according to the invention will be described with reference to the accompanying drawings.
[0015]
FIG. 1 is a perspective view illustrating a configuration of a reading device 1 according to the present embodiment. The reading device 1 is a device that reads a figure, a pattern, a number, a character, or the like engraved on the surface of a coin A that is a reading object. As shown in FIG. 1, the reader 1 includes a rectangular parallelepiped imaging unit 10, flat plates 20 and 21 attached to opposing peripheral portions on the upper surface of the imaging unit 10, and the imaging unit 10 and the flat plates 20 and 21. And a belt conveyor 30 provided. The upper surface of the imaging unit 10 and the height of the upper surfaces of the flat plates 20 and 21 coincide with each other, and a flat surface is formed as a whole, which is a conveyance path B for conveying coins A. A gap substantially the same as the thickness of the coins A is provided between the conveyance path B and the lower surface of the belt conveyor 30, and the coins A are conveyed through the gaps by driving the belt conveyor 30.
[0016]
As shown in FIG. 2, the imaging unit 10 includes a cubic housing 11 having an upper surface opened and a glass upper plate 12 that covers the upper surface opening. An area sensor 13, an LED 14 for detecting the passage of the coin A, and an LED 15 that is an illumination unit are disposed. The area sensor 13 is attached to a fixed base 16 inside the housing 11 and images the surface of the coin A that passes through the imaging region C of the top plate 12.
[0017]
Here, the area sensor 13 includes a discarding unit, a light receiving unit, an electrode unit, and a transfer unit, and the light receiving unit generates an electric charge by the incidence of light. In addition, the charge generated in the light receiving unit is accumulated in the electrode unit, and the accumulated charge is transferred to the transfer unit or the discard unit. Furthermore, the area sensor 13 has a charge sweeping function such as increasing the level of the overflow drain voltage to eliminate the effect of accumulating charges generated in the light receiving unit.
[0018]
The LED 14 is attached to a fixed plate 17 protruding from the inner side surface of the housing 11 and irradiates light toward the upper surface plate 12. Further, the LEDs 15 are arranged in a ring shape along the inner surface of the upper surface plate 12 and irradiate the coin A passing over the upper surface plate 12 with light for a short time.
[0019]
The belt of the belt conveyor 30 shown in FIG. 1 is provided in the center of the conveyance path B, and the light emitted from the pair of LEDs 14 arranged on both sides of the belt is on both sides of the upper plate 12 and the belt of the belt conveyor 30. Pass through and proceed upwards. A pair of PDs 40 are disposed on the optical path of the irradiation light above the belt conveyor 30, and light that has passed through both sides of the belt of the belt conveyor 30 enters the opposing PDs 40.
[0020]
Next, the reading process of the coin A by the reading device 1 will be described with reference to the schematic diagram of FIG. FIG. 3A shows a state where the coin A is inserted into the gap between the conveyance path B composed of the upper surface plate 12 and the flat plates 20 and 21 and the belt conveyor 30. Light is emitted upward from the LED 14, and the irradiated light passes through both sides of the top plate 12 and the belt of the belt conveyor 30 and enters the PD 40.
[0021]
Next, as shown in FIG. 3B, when the coin A is conveyed along with the movement of the belt of the belt conveyor 30 and the coin A reaches the optical path of the irradiation light of the LED 14, the irradiation light is blocked by the coin A. Accordingly, the amount of light received by the PD 40 is less than a predetermined level. The apparatus determines that the coin A is approaching the imaging area C of the area sensor 13 due to the decrease in the amount of light received by the PD 40.
[0022]
Further, when the coin A is transported and the coin A reaches the imaging area C as shown in FIG. 3C, the irradiation light from the LED 14 that has been blocked by the coin A until then is irradiated again on the PD 40. A signal (details will be described later) for driving the area sensor 13 is output. The imaging area C is irradiated with light from the LED 15, and the coin A that has reached the imaging area C is illuminated. Since this irradiation light is incident on the surface of the coin A from an oblique direction, a shaded image emerges due to the irregularities on the surface of the coin A. By capturing this surface image with the area sensor 13 based on the aforementioned signal, a clear image of the coin A can be obtained.
[0023]
The imaging process of the area sensor 13 will be described with reference to the block diagram of FIG. 4 and the waveform diagram of FIG. The area sensor 13 includes a capture signal (see FIG. 5B), a readout signal (see FIG. 5F), and a discharge signal (see FIG. 5C) generated by the control circuit 50 that is a signal output means. Controlled by. Here, the capture signal is a signal that generates a capture trigger when the coin A reaches the imaging region C. The read signal is a signal for generating a read trigger after the acquisition trigger is generated and within the same vertical blanking interval as the acquisition trigger. Further, the discharge signal is a signal for repeatedly generating a charge discharge trigger before the acquisition trigger is generated and after the read trigger is generated. The read signal and the discharge signal are given to the area sensor 13 via the driver 51, and the area sensor 13 performs processing according to these signals.
[0024]
Further, the control circuit 50 incorporates a capture signal generation circuit 50a for generating a capture signal and a synchronization signal reset circuit 50b. The synchronization signal reset circuit 50b receives the capture signal generated by the capture signal generation circuit 50a, and uses a television system vertical synchronization signal (FIG. 5 (h)) and a horizontal synchronization signal (FIG. 5) at the capture trigger generation timing. (I)) is reset (initialized). These synchronization signals are given to the amplifier 52. Further, the image data (see FIG. 5G) of the surface of the coin A output from the area sensor 13 is given to the amplifier 52, and this image data is amplified by the amplifier 52 and then synchronized with the synchronization signal. Output at timing.
[0025]
The area sensor 13 includes a charge discharging process (first process) for discharging the charges accumulated in the electrode part to the discarding part, and a charge accumulation process (second process) for storing the charge generated in the light receiving part in the electrode part. And a charge output process (third process) for outputting the charge accumulated in the electrode part to the transfer part based on the synchronization signal. The charge accumulation process is performed at the timing when the capture trigger occurs in the capture signal, and the charge output process is performed at the timing when the read trigger occurs in the read signal.
[0026]
Further, the charge discharging process is performed under the control of the discharging signal. That is, before the coin A arrives in the imaging region C, the charge discharge trigger is repeatedly generated in the discharge signal. Therefore, during this period, the charge discharge process is repeated at regular intervals . In addition, when a coin A arrives in the imaging area C, a capture trigger is generated in the capture signal, and the generation of the trigger in the discharge signal is stopped at the generation timing of the capture trigger. Accordingly, the charge discharge processing is also stopped. Furthermore, since the trigger generation in the discharge signal restarts at the timing when the read trigger occurs in the read signal, the charge discharge processing is restarted accordingly.
[0027]
Each process of the area sensor 13 is performed as follows. First, when the irradiation light from the LED 14 is blocked by the coin A and the light reception amount of the PD 40 decreases, the level of the light reception amount signal (see FIG. 5A) given from the PD 40 to the control means 50 decreases. The control means 50 having received this received light amount signal determines that the coin A is approaching the imaging area C of the area sensor 13. When the coin A is further conveyed, the irradiation light from the LED 14 that has been blocked by the coin A until then is irradiated again on the PD 40, and the received light amount level increases. The control circuit 50 to which the received light amount signal is input determines that the coin A has reached the imaging region C, generates an acquisition trigger for the acquisition signal, and stops generating the discharge signal trigger.
[0028]
The discharge signal is input to the area sensor 13, and the area sensor 13 accumulates the charge generated in the light receiving unit in the electrode unit and stops the discharge operation of the charge at every 1H (63.5 μsec) in the electrode unit. Charges are accumulated in the electrode part of the area sensor 13 by accumulating the charge in the electrode part and stopping discharging the charge to the discard part. As a result, an optical image by reflected light reflected from the surface of the coin A by irradiation light from the LED 15 is stored as an electric charge in the electrode part of the area sensor 13 (see FIG. 5E).
[0029]
The LED 15 may be lit for the entire period from the occurrence of the acquisition trigger to the generation of the read trigger (see FIG. 5D), or the read trigger is generated after the acquisition trigger is generated. A predetermined period of time (see FIGS. 5 (j) and 5 (k)) may be lit. Further, the LED 15 may be constantly lit.
[0030]
The control circuit 50 generates a read trigger for the read signal after a predetermined time has elapsed since the acquisition trigger was generated (for example, 10H). The read trigger is given to the area sensor 13, and the area sensor 13 causes the transfer unit to output the charge accumulated in the electrode unit. By this output processing, the image data on the surface of the coin A (see FIG. 5G) is output from the area sensor 13 after the vertical blanking interval (for example, 20H) is completed.
[0031]
In this way, charges are accumulated in the electrode section in the vertical blanking interval, and further, the charge of the electrode portion is output to the transfer section at the timing when the vertical blanking interval is completed, so that imaging is started after imaging is started. The period until the output image is output can be one field period or one frame period.
[0032]
In addition, since the synchronization signal is output in synchronization with the capture trigger that occurs when the coin A reaches the imaging region C, the transfer timing of the coin A and the timing of the synchronization signal can be easily matched.
[0033]
Further, since the period (t ₂ ) during which charges are accumulated in the electrode portion of the area sensor 13 is very short, the irradiation light from the LED 14 is reflected on the surface of the coin A or the inner surface of the upper surface plate 12, and the area sensor 13. However, the incident light is hardly accumulated in the electrode part as an electric charge.
[0034]
In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible. For example, the belt of the belt conveyor 30 is not necessarily limited to a material that transmits light, and a resin or other material may be used. However, when a non-transparent material is used, it is necessary to form a through groove or the like on at least the optical path of the LED 14 so that irradiation light from the LED 14 can be received by the PD 40. The reading object is not limited to the coin A, and may be a medal or a card.
[0035]
【The invention's effect】
As described in detail above, the reading device of the present invention accumulates charges in the electrode section in the vertical blanking interval, and further outputs the charges in the electrode portion to the transfer section at the timing when the vertical blanking interval ends. Therefore, the period from the start of imaging to the output of the captured image can be a very short period such as one field period or one frame period. As a result, for example, in the case of an EIA-compliant television output image, 60 images can be captured per second as a field image, and the number of tasks per unit time is improved.
[0036]
In addition, since the synchronization signal is output in synchronization with the capture trigger that occurs when the reading object reaches the imaging region, the conveyance timing of the reading object and the timing of the synchronization signal can be easily matched.
[0037]
Furthermore, since unnecessary charges are swept out from the electrode portion by executing the third process, the S / N ratio of the image captured by the imaging unit is improved.
[Brief description of the drawings]
FIG. 1 is a perspective view illustrating a configuration of a reading apparatus according to an embodiment.
FIG. 2 is a perspective view showing a cross-sectional structure of an imaging unit.
FIG. 3 is a schematic view showing a coin surface reading process by the reading device of FIG. 1;
FIG. 4 is a block diagram showing a processing circuit for controlling the area sensor.
FIG. 5 is a waveform diagram in a processing circuit for controlling an area sensor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Reading apparatus, 10 ... Imaging unit, 11 ... Housing | casing, 12 ... Top plate, 13 ... Area sensor (imaging means), 14 ... LED, 15 ... LED (illuminating means), 16 ... Fixing stand, 17 ... Fixing plate , 20, 21 ... plane plate, 30 ... belt conveyor, 40 ... PD, 50 ... control circuit (signal output means), 51 ... driver, 52 ... amplifier, A ... coin (reading object), B ... transport path, C ... imaging area.

Claims (2)

In a reading device that reads the surface of an object to be read that is transported along a predetermined transport path,
A capture signal to generate a capture trigger when the read object in the imaging region of the conveying path is reached, the synchronizing signal of the television system to start output the initialized with the capture trigger, the acquisition trigger occurs And a signal output means for outputting a readout signal for generating a readout trigger after and within the same vertical blanking interval as the capture trigger;
Predetermined period during the period from the acquisition trigger occurs until the read trigger occurs, the illuminating means for irradiating light to the imaging area of the conveying path,
An imaging unit having a disposal unit, a light receiving unit, an electrode unit, and a transfer unit, and imaging the surface of the reading object at the timing of the capture signal and the readout signal;
The imaging means repeats the charge accumulated in the electrode unit at a certain time interval and discharges it to the discard unit, and second process accumulates the charge generated in the light receiving unit in the electrode unit And a third process for outputting the charge accumulated in the electrode unit to the transfer unit based on the synchronization signal,
The first process that has been executed until the acquisition trigger is stopped, the second process is executed at the acquisition trigger, and the third process is executed at the read trigger. The reading apparatus characterized by performing the process of. The reading apparatus according to claim 1 , wherein the illuminating unit includes an LED light source .

Images