JPH0833938B2 - Bill validator - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a banknote discriminating apparatus, and more specifically, by detecting the color of a banknote, the denomination and / or authenticity of the banknote can be ensured. The present invention relates to a bill discriminating device that can detect a bill.

PRIOR ART By detecting the color of a banknote, the denomination of the banknote and / or
Alternatively, there is known a bill discriminating apparatus which discriminates authenticity.

For example, Japanese Unexamined Patent Publication No. 62-296292 includes two color detection means for detecting different color components of transmitted light or reflected light of a bill along a longitudinal direction of the bill along a bill conveyance path. A plurality of color sensors are provided, and a time-series change pattern of the ratio of two types of color components photoelectrically detected by these color sensors is obtained, and a reference pattern that is previously obtained and stored for each denomination It proposes a bill discriminating apparatus which discriminates the denomination and / or the authenticity of bills by comparing with

Problems to be Solved by the Invention This bill discriminating apparatus selects two colors from the three primary colors of light, and these two colors are included in transmitted light or reflected light of bills.
The bill is discriminated based on the color component ratio.
Banknotes are given a wide variety of colors to prevent counterfeiting. Therefore, only two specific color components contained in the transmitted or reflected light of the banknote are detected, When comparing the pattern of the series change with the reference pattern to determine the denomination and / or the authenticity of the banknote, the denomination and It was not easy to tell the truth.

That is, for a banknote on which a color having the same spectrum as the background color of the banknote paper is printed, when the transmitted light or the reflected light of the banknote is detected, only a specific color component of the three primary colors of light becomes large. Therefore, by comparing the pattern of the time series change of the ratio of the two colors with the reference pattern,
The distinction is relatively easy, but it is quite different from the spectrum of the three primary colors of light that the background color of the banknote paper has, like a banknote in which the blue background is printed on the banknote paper whose background color is yellow. In the case of a banknote that is printed with a color that has, the difference between each spectrum of the three primary colors of light in the transmitted light or the reflected light of the banknote becomes small, and the spectrum is
It is close to that of an achromatic color, and therefore, the light of two colors among the three primary colors of light, for example, red light and green light, is selectively detected, and a pattern of a time-series change in the ratio of the detected light amounts is calculated.
Even if an attempt is made to determine the denomination and / or authenticity of a banknote as compared with the reference pattern, it is difficult to distinguish it from a counterfeit banknote by black-and-white copying, and the determination cannot be performed with sufficient accuracy.

In particular, the white and black in black and white counterfeit banknotes, i.e., the background and toner of copy paper, are not both white and black in the chromatic sense, but are completely Not achromatic,
Therefore, even if the color detection means is adjusted so that the output of the color detection means becomes zero with respect to the background color of the copy paper in order to determine the counterfeit banknotes by black-and-white copying, It was even more difficult to reliably distinguish a banknote printed with a color having a spectrum completely different from the spectrum of the three primary colors of light from a counterfeit banknote by black-and-white copying.

An object of the present invention is to provide a bill discriminating apparatus capable of surely detecting the denomination and / or authenticity of a bill by detecting the color of the bill.

Another object of the present invention is to provide a bill discriminating apparatus capable of surely discriminating counterfeit bills by black-and-white copying.

Configuration of the Invention An object of the present invention is to provide a bill discriminating apparatus provided with at least two color detecting means for photoelectrically detecting light of different wavelengths in transmitted light or reflected light of a bill, and the at least two colors. Among the detection means, a current correction means for correcting the output current of at least one color detection means, an output current output from the at least one color detection means and corrected by the current correction means, and the other at least two other currents. At least two amplifying means for amplifying the output current output from the color detecting means;
Of the two amplifying means, an amplifying rate adjusting means capable of adjusting the amplifying rate of at least one amplifying means, and a differential amplifying means for differentially amplifying output signals of the at least two amplifying means,
This is achieved by a bill discriminating device equipped with discriminating means for discriminating the denomination and / or the authenticity of the bill based on the output signal of the differential amplifying means.

EFFECTS OF THE INVENTION According to the present invention, it is possible to correct the output current of at least one color detection unit by the current correction unit and adjust the amplification factor of at least one amplification unit by the amplification factor adjustment unit. Since it is possible, by adjusting the correction value of the output current of at least one color detecting means and the amplification factor of at least one amplifying means, the output signal of the differential amplifying means at the time of detecting the counterfeit bill by the black and white copy. Can be set to zero and therefore
It is possible to reliably discriminate counterfeit banknotes by black and white copying, and as a result, it is possible to accurately discriminate banknotes that are close to achromatic color and were difficult to distinguish from counterfeit banknotes by black and white copying in the past. Therefore, the denomination of the bill and its authenticity can be accurately discriminated.

Examples Hereinafter, with reference to the accompanying drawings, examples of the present invention,
Add a detailed description.

FIG. 1 is a block diagram of a bill discriminating apparatus according to an embodiment of the present invention.

Referring to FIG. 1, a bill discriminating apparatus 1 according to an embodiment of the present invention emits light from a light emitting device 2 and a light emitting device 2 that linearly irradiate the surface of a conveyed bill B, and the bill B is The color sensor 3 includes a pair of a green light detecting element 3a and a red light detecting element 3b which photoelectrically detect the reflected light reflected.

The green light detecting element 3a and the red light detecting element 3b have selective sensitivities to the spectrums of the green light and the red light, respectively, and detect only the green component and the red component in the reflected light of the banknote B. Is.

The current correction circuit 4 is a current correction means for correcting the output current I _a green light detecting element 3a, the output current of the corrected green light detecting element 3a than the correction current I _c supplied from the current correction circuit 4 ( I _a + I _c ) and output current of red light detector 3b
An amplifier 5a for converting _Ib into a voltage and amplifying it, respectively.
5b is provided, and further, a differential amplifier 6 that differentially amplifies the output signals of the amplifiers 5a and 5b, and a divider 7 that divides the output signal of the differential amplifier 6 by the output signal of the amplifier 5b are provided. The output signal of the divider 7 is sent to the discriminating means 8 to discriminate the denomination of the bill and discriminate the authenticity. In FIG. 1, 9a and 9b are amplifiers 5a and 5b, respectively.
It is an amplification factor adjusting circuit for adjusting the amplification factor of.

Here, the correction current value I _c supplied from the current correction circuit 4
The amplification factors of the amplifiers 5a and 5b are set so that the output of the differential amplifier 6 becomes zero with respect to the reflected light reflected from the counterfeit bill by the black and white copy. That is, assuming that the amplification factors of the amplifiers 5a and 5b are A _a and A _b and the amplification factor of the differential amplifier 6 is A _d , the output voltage V ₀ of the differential amplifier 6 is V ₀ = A _d {A _a (I _{a + I c) -A b I} b} given by ... (1), if the characteristic coefficient of the divider 7 is M, the voltage V output from the divider 7 is given by the following equation.

V = MV ₀ / A _b I _b = MA _d {A _a (I _a + I _c ) −A _b I _b } / A _b I _b (2) Therefore, the color of the black-and-white copy paper, that is, its ground color The output current of the green light detection element 3a and the output current of the red light detection element 3b when white is detected are I _aw and I
_bw, and the output current of the green light detection element 3a and the output current of the red light detection element 3b when the black of the black and white copy, that is, the color of the toner is detected, are I _ab and I _bb , respectively, A _a (I _aw + I _c ) −A _b I _bw = 0 (3) A _a (I _ab + I _c ) + A _b I _bb = 0 (4) When the output voltage of the divider 7 is satisfied, Since V becomes zero, according to equations (3) and (4), A _a = A _b (I _bw −I _bb ) / (I _aw −I _ab ) ... (5) I _c = (I _aw I _bb −I _bw I _ab ) / (I _bw −I _bb ) ... (6) so that the amplification factor adjusting circuits 9a and 9b provide the amplifier 5a,
The amplification factor of 5b is also corrected by the current correction circuit 4 by the correction current value I _c.
By setting, it becomes possible to set the output voltage V of the divider 7 to be zero when the white and black of the black and white copy are detected.
The output voltage V of the divider 7 is V = MA _d A _b {(I _bw −I _bb ) I _a + (I _aw I _bb −I _bw I _ab ) − (I _aw −I _ab ) I _b } ÷ A _b I _b (I _aw −I _ab ) ... (7).

Here, the ratio of the portion covered by the toner in the black and white copy image in the area corresponding to the color detection pixel area of the banknote B, that is, the toner coverage is x, the output current of the green light detection element 3a The output current I _b of I _a and the red light detection element 3 _b is given by the following equations respectively, and I _a = I _aw (1-x) + x I _ab (8) I _b = I _bw (1-) x) + x I _bb (9) By substituting these equations (8) and (9) into equation (7), V = 0 becomes equal, so that for counterfeit bills by black and white copy The output voltage V of the divider 7 is always zero regardless of the toner coverage ratio x in the black and white copy image in the color detection pixel area of the banknote B.

Therefore, the amplification factor adjusting circuit 9a, 9b by the amplifier 5a,
By setting the amplification factors A _a and A _b of 5b and the correction current value I _c from the current correction circuit 4 so as to satisfy the equations (5) and (6), respectively, it is possible to reliably perform black-and-white copying. It is possible to discriminate counterfeit banknotes, and as a result, the background color is yellow, and it looks like a banknote printed in blue.
The paper is printed with a color that is completely different from the spectrum of the three primary colors of light that the background color of the paper money has, and the difference between the spectra of the three primary colors of light in the reflected light of the banknote is small, and it is achromatic. Since it has a close spectrum, it is possible to accurately determine the denomination of banknotes whose denominations were difficult to distinguish. Can be performed accurately.

Further, the amount of light emitted from the light emitter 2 changes with time, or the green light detecting element 3a and the red light detecting element 3b are changed.
Or amplifier 5a, the characteristics of 5b is, when changes due to aging or temperature changes, the correction current value I _c is the output current I _b of the output current I _a and the red light detecting element 3b of the green light detecting element 3a The output voltage V ₀ of the differential amplifier 6 is output by the divider 7 from the output of the amplifier 5b by the divider 7 because it is relatively small and can be ignored, and normally A _a I _a and A _b I _b change similarly. By dividing by the voltage, these effects cancel each other out, and the change in the output voltage V of the divider 7 can be neglected, and further, the change as described above can be ignored. if occurred, equation (5) and (6) so as to hold, the amplification factor adjustment circuit 9a, 9b by an amplifier 5a, an amplification factor a _a of 5b, the a _b, the correction from the current correction circuit 4 By re-adjusting the current value I _c ,
With black and white copying, it is possible to set the output voltage of the divider 7 to zero for counterfeit banknotes.

As shown in equations (5) and (6), the amplification factor adjusting circuits 9a and 9b set the amplification factors A _a and A _b of the amplifiers 5a and 5b, and the correction current value supplied from the correction current circuit 4 is set. After setting I _c , the banknote B is transported along the transport path 10,
The bill B is linearly scanned by the light emitter 2, the reflected light from the bill B is photoelectrically read by the green light detection element 3a and the red light detection element 3b, and further, the output of the green light detection element 3a. After correcting the current I _a with the correction current I _c supplied from the correction current circuit 4, the corrected output current (I _a + I _c ) of the green light detection element 3 a and the corrected output current I _b of the red light detection element 3 _b are calculated. , Are respectively converted into voltages by the amplifiers 5a and 5b, and are amplified by predetermined amplification factors A _a and A _b . Further, these are differentially amplified by the differential amplifier 6 and the differential amplifier by the divider 7. The output voltage of 6 is the amplifier 5b
After being divided by the output voltage of, the output signal of the divider 7 is sent to the discrimination means 8 to discriminate the denomination and authenticity of the bill B.

A reference pattern for each denomination is stored in advance in the discriminating means 8, and a time-series detection signal pattern which is line-scanned by the light emitter 2 and subjected to the above-described signal processing is stored. The reference patterns are compared with each other, and the denomination of the banknote B is discriminated depending on which reference pattern matches. As described above, since the output voltage output from the divider 7 becomes zero for a counterfeit banknote by black-and-white copying, the detection signal of a counterfeit banknote by black-and-white copying does not match any of the reference patterns. Without, it is possible to reliably identify a counterfeit banknote by black-and-white copying.

According to this embodiment, the correction current value I _c and the amplifier 5a supplied from the correction current circuit 4 are set so that the detection signal of the counterfeit bill by black and white copy is always zero.
Since the amplification factors A _a and A _{b of} 5b are set, it is possible to reliably discriminate counterfeit banknotes by black-and-white copying.Therefore, it is close to achromatic color, and conventionally, it can be distinguished from counterfeit banknotes by black-and-white copying. It becomes possible to accurately discriminate even difficult banknotes, and as a result, it is possible to accurately discriminate the denomination and authenticity of the banknote.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the invention described in the claims, and those modifications are also included in the scope of the present invention. Needless to say.

For example, in the above-described embodiment, the reflected light reflected by the bill B has selective sensitivity to the spectra of green light and red light, respectively, and only the green component and the red component of the reflected light of the bill B are detected. It is detected by the pair of green light detecting element 3a and red light detecting element 3b photoelectrically detected, on the front surface of the photoelectric conversion element, provided with a filter that transmits only the green component and red component in the reflected light, The filter may allow the photoelectric conversion element to detect only light of a specific wavelength.

Further, in the above-mentioned embodiment, respectively, the red light and the green light are selectively detected, but even if the red light and the blue light, the green light and the blue light are selectively detected, May detect red light, green light and blue light.

Further, although the reflected light of the bill B is detected in the above-described embodiment, the light emitter 2 is set to the color sensor 3 with respect to the color sensor 3.
The bill B may be provided on the opposite side of the transport path 10 and the transmitted light of the bill B may be detected instead of the reflected light.

Further, in the above-described embodiment, the output current of the green light detecting element 3a is corrected by the correction current circuit 4. However, even if the output current of the red light detecting element 3b is corrected,
The output currents of the green light detecting element 3a and the red light detecting element 3b may be corrected, and a light detecting means for selectively detecting at least two colors of red light, green light and blue light may be provided. It suffices to provide and correct at least one of the output currents.

Further, in the above embodiment, the amplification factor adjusting circuit 9a,
9b is provided and the amplification factors A _a and A _b of both the amplifiers 5a and 5b are adjusted by these so as to satisfy the equation (5). However, one of the amplifiers 5a and 5b has the amplification factor A _a. Alternatively, it is also possible to adjust only A _b so that the formula (5) is satisfied.

Further, in the above embodiment, the divider 7 is provided,
The amount of light emitted from the light emitter 2 changes with time, or the green light detecting element 3a, the red light detecting element 3b, or the amplifier.
5a, the characteristics of 5b is, when changed by over time or temperature changes, although determination accuracy is attempted to prevent that decrease, amplifiers 5a, the amplification factor of 5b A _a, A _b and corrected current value
It is not always necessary to provide the divider 7 if I _c is appropriately adjusted so as to satisfy the equations (5) and (6), respectively.

Furthermore, although the bill B is scanned in a line shape by the light emitting device 2 in the above-described embodiment, it may be scanned in a dot shape.

According to the present invention, by detecting the color of the bill,
It is possible to reliably determine the denomination and / or the authenticity of the bill.

[Brief description of drawings]

FIG. 1 is a block diagram of a bill discriminating apparatus according to an embodiment of the present invention. 1 ... Banknote discriminating device, 2 ... Light emitter, 3 ... Color sensor, 3a ... Green light detecting element, 3b ... Red light detecting element, 4 ... Correction current circuit, 5a, 5b ... Amplifier, 6 ...... Differential amplifier, 7 …… Divider, 8 …… Discrimination means, 9a, 9b …… Amplification factor adjusting circuit, 10 …… Billage conveyance path.

Claims (3)

[Claims] 1. A bill discriminating apparatus provided with at least two color detecting means for photoelectrically detecting light having wavelengths in transmitted light or reflected light of a bill, and at least one of the at least two color detecting means. Current correction means for correcting the output current of one color detection means, and the output current output from the at least one color detection means, corrected by the current correction means, and output from the other at least two color detection means. At least 2 to amplify output current
One amplification means and among the at least two amplification means,
Based on an output signal of the at least one amplification means, an amplification rate adjustment means capable of adjusting the amplification rate, a differential amplification means for differentially amplifying the output signals of the at least two amplification means, and an output signal of the differential amplification means, A bill discriminating apparatus provided with discriminating means for discriminating the denomination and / or authenticity of the bill. 2. The output signal of the differential amplifying means,
It is characterized in that it comprises divider means for dividing by the output signal of the at least one amplifying means, and the discrimination means discriminates the denomination and / or the authenticity of the bill based on the output signal of the divider means. The bill discriminating apparatus according to claim 1. 3. The at least two color detecting means comprises a green light detecting means for selectively detecting green light and a red light detecting means for selectively detecting red light. ) Or the bill discriminating device according to (2).