JPS6222088B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a color detection device for paper-like objects.

Light is irradiated onto a specific area of a moving regular paper-like object, the transmitted light or reflected light is detected in multiple bands, and this detected amount is compared with the detected amount (reference value) of a standard paper-like object as a reference. The method of inspecting the correctness of paper-like objects using paper is an effective technique for quickly determining the correctness and comparison of printed matter such as train tickets and securities.

FIG. 1 is a diagram showing a signal processing system of a conventional color detection device for conveyed paper-like objects. In the figure, reference numerals 1 ₁ , 1 ₂ , and 1 ₃ are light receivers having different wavelength sensitivities, for example, R, G, and B three-color separation light receivers. These light receivers 1 ₁ , 1 ₂ , 1 ₃ receive the reference light F _R when the detected object to be conveyed is not within the detection field of view, and when the detected object is within the field of view, the light is transmitted through the object. It is configured to receive light or reflected light F _S . 2 ₁ , 2 ₂ , 2 ₃ are amplifiers 3 ₁ , 3 ₂ , 3 ₃ are automatic gain adjustment circuits for each of the above amplifiers, and amplifiers 2 ₁ , 2 ₂ , 2 ₃ are optical receivers 1 ₁ , 1 ₂ , 1 ₃ The outputs v ₁ , v ₂ , v ₃ of are amplified to output signals V ₁ , V ₂ , V ₃ . Reference numeral 4 denotes a timing control circuit which receives a bill edge signal T ₀ from the photoelectric switch 5 for detecting the bill edge of the paper-like object to be detected, and outputs a timing signal T _A of the automatic gain control circuits 3 ₁ , 3 ₂ , 3 ₃ . and outputs an integration timing signal T _G of an integration circuit to be described later.

Automatic gain control circuits 3 ₁ , 3 ₂ , 3 ₃ have T _A =1
The gains of the amplifiers 2 ₁ , 2 ₂ , and 2 ₃ are adjusted so that the output V ₁ = V ₂ = V ₃ = const during the period (the period in which the optical receiver is receiving the reference light F _R ), and T _A During the period when =0 (the period during which the photoreceiver receives reflected light or transmitted light from the object to be detected), the gain adjustment feed and back loop are opened. 6 ₁ , 6 ₂ , 6 ₃
is an integrating circuit which receives signals V ₁ , V ₂ , V ₃ and outputs integral outputs w ₁ , w ₂ , w ₃ . Here, the integration period is a time period determined by the integration timing signal T _G ,
This is the time it takes for the target area of the printed matter to be detected to pass through the detection field of view.

7 is an adder, and 8 ₁ and 8 ₂ are division circuits, S ₁ =w ₁ +w ₂ +w ₃ , u ₁ =w ₁ /s ₁ , u ₂ respectively.
Outputs = w ₂ /s ₁ . 9 ₁ , 9 ₂ , 9 ₃ are comparison circuits, and 10 ₁ , 10 ₂ , 10 ₃ are comparison reference value storage circuits, which store comparison reference values s ₀₁ , u ₀₁ , u ₀₂ detected in advance from standard printed matter. I remember. When the results compared by the comparison circuits 9 ₁ , 9 ₂ , 9 ₃ satisfy a predetermined condition, the output z of the AND circuit 11
outputs a signal "2" indicating that the printed matter to be detected belongs to the standard printed matter, indicating "correct", and outputs a signal "0" indicating "no", indicating that the detected printed matter does not belong to the standard printed matter, if the condition is not met.

In such a color detection device for conveyed paper, it is necessary to prevent a decrease in detection accuracy due to fluctuations in the detection system such as fluctuations in the light intensity of the illumination light source, changes in the sensitivity of the receiver, and fluctuations in the amplifier. Although it is possible to detect and discriminate objects, this conventional method has the following drawbacks and inadequacies.

Precise adjustment of the gain control circuit for each channel is required, and imbalance in adjustment between channels causes a decrease in detection accuracy. Further, fluctuation factors occurring in the automatic gain adjustment circuit itself cannot be removed.

Since the required signal is obtained by integrating the received light signal over a predetermined time, fluctuations in the conveyance speed directly appear as errors in the detection signal.
That is, the error factor of the conveyance speed in the detection signal cannot be removed.

An object of the present invention is to eliminate the drawbacks and deficiencies found in such conventional methods and to provide a highly accurate conveyed paper-like object color detection device.

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

FIGS. 2a and 2b are a schematic configuration diagram and a diagram of a signal processing system of a color detection device for a conveyed paper-like object according to an embodiment of the present invention. In Figure 2 a, 21, 22
is a detection unit that sees different fields of view. 23-28
are light receivers that are located within each detection section and have different wavelength sensitivities. In this embodiment, transmitted light and reflected light are separated into three colors of R, G, and B, and the light is received and detected. Each of the light receivers 23 to 28 is connected to the roller 3
A detection target 48 conveyed in a conveying direction 47 by belts 41 to 46 driven by belts 7 to 40 is detected by a light source 50 in a lamp house 49.
When the detection target 48 is not within the detection field of view, it receives the reference light φ _R , and when the detection target 48 is within the detection field, it receives three channels each of transmitted light and reflected light φ _S of the detection target 48. is configured to do so.

In FIG. 2b, 51 to 56 are amplifiers,
The outputs v ₁ to _{v 6} of the light receivers 23 to 28 are amplified, respectively, and signals V ₁ to _{V 6} are output. 57 to 60 are light receivers for detecting paper edge; light receiver 59 for detecting paper edge;
-60 are irradiated by lamps 78-79, and amplifiers 61-64 illuminate the detection target 4.
Signals TD1 to TD4 are output which are "0" when there is no 8, and "1" when there is. The timing control circuit 65 receives the ticket edge signals TD1 to TD4 and outputs various timing signals necessary for detection processing.

FIG. 3 is a diagram illustrating the integral timing signal T _G output by the timing control circuit 65. In the figure, TD1 becomes "1" when the object to be detected 48 passes through the paper edge detection light receiver 60, and becomes "0" when it does not pass through. Similarly, in TD2, TD3, and TD4, when the detection target 48 passes through the paper end detection light receivers 59, 58, and 57, the above-mentioned signals are output. The period from the rising edge T ₁ of TD1 to the rising edge T ₂ of TD2 is the reference signal integration interval, in which the reference light φ _R is integrated and W _oR (n=
1 to 6) are output. Also, the period between the rising edge T ₃ of TD4 and the rising edge T ₄ of TD3 is an integration period of the transmitted light and reflected light signals from the detection object 48, and the transmitted light and reflected light φ _S of the detection object 48 are integrated into the integrator 66. ~7
1 and outputs W _oS (n=1 to 6).

The multiplexer 72 has 12 types of 6 channels from the integrators 66 to 71 (W _oR , W _oS , n=1 to 6)
signals are switched in a predetermined order by a control signal T _M and output as a signal W.
The analog-digital conversion circuit 73 converts the output W from the multiplexer 72 into a digital signal P using the control signal T _D and converts it into 12 types of signals (W
_oR , W _oS , n=1 to 6) are digital memory 7
4 by the control signal _TBM . The 12 types of integral data stored in the digital memory 74 are
Y _o = (W _oS /W _oR ) x K (n = 1 to 6, K =
const) is input to the AGC calculation firmware 75, which is an arithmetic circuit, and after performing the above-mentioned calculation, is stored in the digital memory 76 as the output _Yo .

Note that the control signal T _M is a control signal for converting 12 types of parallel signals into a serial signal W determined in advance by the multiplexer 72. The control _TBM stores the digital signal P in the digital memory 74 and stores the digital signal P in the digital memory 74.
This is a control signal for outputting to the AGC calculation firmware 75. The control signal T _A is a control signal for calculating the output X from the digital memory 74 by the AGC calculation firmware 75 . The control signal T _RM is a control signal for calculating the output
This is a control signal for storing the output Y from 5 in the digital memory 76 and outputting it to the detection firmware 77. The control signal T _R is a signal for controlling the output of the result from the detection and discrimination firmware 77.

The data stored in the digital memory 76 as described above is transferred to the detection discrimination firmware 77.
If a predetermined condition is met, it will be "1", otherwise it will be "0".
Output to Z.

In the above embodiment, the signal storage and calculation sections 74, 7
Although parts 5 and 76 are constructed from individual electronic circuits, the same purpose can be achieved even if this part is replaced with a functional element such as a microprocessor that has both memory and calculation functions. In the embodiment, there are four photoelectric switches (light receivers) for detecting paper-like objects on the conveyance path.
However, even if 58 and 59 are used together, the object of the present invention can be achieved. Furthermore, in the case where there are multiple detection areas, more photoelectric switches may be provided, and the number of position detection photoelectric switches on the conveyance path is not limited to four.

According to the color detection device for conveyed paper-like objects according to the present invention, it is possible to eliminate the factors of variation in the detection system and the factors of variation in the conveyance speed of the conveyance system without requiring precise adjustment of the output signal for each channel, and to achieve high performance. Color detection of paper-like objects is possible, and its effects will be explained next.

FIG. 4 shows the output signal waveform of the i-th channel in a certain reference state, where the output signal waveform of the optical receiver is v _i (t), and the signal output when receiving the reference light F _R is V _0i . Integration timing determined by the conveyed paper-like material passing sequentially through the light receivers 57 to 60
Let T ₁ , T ₂ , T ₃ , and T ₄ . On the other hand, fluctuations occur in the detection system such as the illumination light intensity, receiver sensitivity, and amplifier gain, and the detection signal becomes α times as large as 1/β.
(However, it is assumed that the time constant of the conveyance speed change is large and there is no change in the conveyance speed in the section T ₁ to _{T 4} in Figure 4.) The output signal waveform of Figure 5 is It becomes like this.

In Figures 4 and 5, the receiver is the reference light F _R
The signal integrated output while receiving the light is V _R0
i and V _Ri , and the signal integrated output while receiving the transmitted light and reflected light of the conveyed paper-like object are expressed by V _S0i and V _Si , respectively, then V _Ri =∫ ^T2 ′ _T1 ′v _i ′(t)dt=∫〓 ^T2 〓 _T
1 αV ₀ dt′ = α, β, V _R0

Claims (1)

[Scope of Claims] 1. An apparatus for detecting the color, etc. of a conveyed paper-like object and comparing it with a pre-stored discrimination reference value, comprising: a light source for irradiating a predetermined area on a conveyance path with reference light; and the paper. a plurality of position detection elements arranged sequentially along the conveyance direction of the paper-like object on a conveyance path of the paper-like object; a plurality of light receivers that receive signal light from the paper-like object; a first means for integrating an output signal of the light receiver that has received the reference light from the light source for a first period determined by the output of the position detection element when the reference light has not passed through a predetermined area; When an object passes through the predetermined area, a second
a second means for integrating the output signal of the light receiver that has received the signal light from the paper-like object for a period of time; and means for calculating the ratio of the integral values obtained by the first means and the second means. A color detection device for a paper-like object, characterized by comprising: