JP2969145B2 - Thickness measurement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A device for processing paper sheets in the field of information processing, wherein the thickness is determined by using a thickness determination device capable of roughly determining the thickness of paper sheets using light transmission data. measurement methods for.

[0002]

2. Description of the Related Art In a paper sheet processing apparatus, the whole paper sheet to be inspected is divided into small areas, and each of the small areas is formed by a plurality of optical sensors and magnetic sensors arranged in an array. After measuring the shading, amplifying the measured value to a desired value, performing A / D (analog to digital) conversion, performing various image processing on the value, and comparing the processed value with dictionary data prepared in advance. Kind of authenticity.

Conventionally, in the above-described paper sheet processing apparatus, as one item for determining the authenticity, a method of determining the thickness of the paper sheet has been used. This is a machine that detects the thickness of a paper sheet by reading the force that a roller placed on the paper conveyance surface pushes upward when the paper sheet is conveyed, converts it into an electric signal, and detects the thickness of the paper sheet. This is a method that uses a typical sensor.

[0004]

However, conventionally, such a mechanical thickness sensor is important in accuracy due to the necessity of detecting the thickness of a sheet in a unit of micrometer due to its structure, and is therefore expensive. There was a problem. In addition, there is also a problem that although not so precise, it is not suitable as an inexpensive device which needs to determine a certain amount of thickness.

Further, there is a possibility that the thickness judgment may be erroneously performed when the roller is jumped by minute dust or the like adhering to the paper sheet or when a part of the paper sheet is bent. It was necessary to judge the thickness value based on the above, and to judge the thickness with reference to the thickness value. Therefore, an object of the present invention is to determine the average value of the thickness of the paper sheet from the amount of transmitted light, so that the determination of the overlapped paper sheet and the paper sheet that has become a thin medium can be slightly performed by hardware. To make it easy to realize.

[0006]

According to the present invention, the following processing steps, that is, each pixel of a paper sheet, is performed by using a thickness determining apparatus provided with a sensor means for measuring light transmission data of the paper sheet. A processing step for obtaining light transmission data, a processing step for amplifying the light transmission data, a processing step for converting the amplified light transmission data from an analog value to a digital value, and only the internal data of the light transmission data of each pixel. A processing step of adding, a processing step of dividing the added value by the total number of pixels to obtain an average value of light transmission data, and applying each of the processing steps to a typical sheet to obtain the average value, and A threshold value and an upper threshold value, a processing step of storing as a dictionary, a processing step of comparing an average value of the light transmission data obtained for the sheet to be subjected to the thickness determination with an average value of the dictionary, and Should be measured Thickness process to determine normal or abnormal stage of leaf thickness measurement method using the thickness determination apparatus comprising is provided.

[0007]

According to the present invention, the data of the amount of light transmission corresponding to each pixel of the paper sheet obtained by the sensor means 101 is obtained, amplified and A / D-converted, and thereafter, by the light transmission data processing means. Average light transmission amount data per pixel of the internal data can be obtained. This data is obtained for a typical sheet, stored as a dictionary having a lower threshold and an upper threshold, and compared with the measured average light transmission amount data, the thickness of the sheet is calculated. Can be determined as normal or abnormal.

[0008]

Block diagram of the thickness measurement apparatus as an embodiment of the embodiment of the present invention is shown in FIG. This apparatus includes a sheet entry sensor 100, a sensor 101, an amplifier 102, an A / D converter.
103, a light transmission data processing unit 104, a dictionary comparison unit 105 as a comparison determination unit, a dictionary data unit 108, a storage unit 106, and a central processing unit 107.

The paper sheet entry sensor unit 100 detects that a paper sheet has been conveyed, and the central processing unit 107 receives this detection signal and activates the sensor unit 101. Sensor unit 101
When the paper passes, light is emitted from one side and transmitted light is received on the other side. The sensor unit 101 is a central processing unit.
Under the control of 107, data is sampled as many times as necessary in accordance with the transport of paper sheets. The sampling is performed for each pixel over the entire sheet.

The sampled data is supplied to an amplifying unit 102
After being amplified by the A / D converter 103 and converted from an analog amount into a digital amount by the A / D converter 103, the light transmission data processor 1
At 04, only the internal data of the paper sheet is added, and the result is divided by the number of added data to obtain light transmission data for each pixel. Next, the dictionary comparison unit 105 selects the dictionary data unit 1
08 and the light transmission data per pixel are compared, and the authentication result of the paper sheet is stored in the storage unit 106. As the dictionary data, for example, a lower threshold and an upper threshold described below are used.

FIG . 3 and FIG. 4 are flow charts showing the processing in the apparatus according to the embodiment in a divided manner, and these figures are connected at point a to constitute one flow chart. At the start of the process, first, the contents N of the register indicating the number of pixels inside the sheet are initialized to 0, and the contents S of the data addition register inside the sheet are initialized to 0. Next, in step 1 (S1), it is determined whether or not the light transmission data (measured value) X is internal data of a paper sheet. If it is not internal data, the process proceeds to step 4 (S4). If it is internal data, N + 1 is set to N (S2), and S + X
Is set to S (S3), and the process proceeds to step 4.

In step 4, it is determined whether or not all data processing has been completed. If not completed, the process returns to step 1, and if completed, the process proceeds to step 5 (S5). In step 5, S ÷ N is calculated to obtain T (light transmission data value per pixel), and the process proceeds to step 6 (S6) to determine whether T is larger than the lower limit threshold of the dictionary data. When T is larger than the lower threshold, the process proceeds to step 7 (S7), and when T is not larger, the process proceeds to step 9 (S9). In step 7, T
Is smaller than the upper limit threshold of the dictionary data. If T is smaller than the upper threshold, step 8 (S
Proceed to 8), and if not small, proceed to step 11 (S11).

In step 8, the storage unit stores that the result of determination by the optical sensor is normal for the thickness. In step 9, it is detected that two or more sheets overlap, and the storage unit stores the result of the determination by the optical sensor that the thickness is abnormal (S10). In step 11, it is detected that the paper sheet is a thin medium, and in step 12, the thickness is determined to be abnormal based on the determination result of the optical sensor, and is stored in the storage unit. Thus, the process ends.

The above-described thickness determination is obtained as a result of focusing on the fact that there is a certain relationship between the thickness and the amount of transmitted light, as shown in FIG. The lower threshold value and the upper threshold value are calculated by statistically processing the distribution of sample results of a large amount of data on paper sheets that can be input.

The present invention can be achieved in a conventional paper sheet authenticity judging apparatus by adding a small function (addition and average value calculation) of a light transmission data processing section to confirm the thickness judgment in the conventional apparatus. Useful for In addition, the amount of transmitted light used in the apparatus according to the embodiment is the same as that of a sheet (watermark,
There are some differences depending on the dark pattern part or the Braille part, etc., but the value of the paper sheet existing part and the part that is not so is about 40-60 (relative value) in the former, but 150 (relative value) in the latter.
As described above, about 80 (relative value) can be set as the threshold value.

In the present invention, the reason why the average value of the amount of transmitted light per pixel is used as a comparison object is that it is possible to detect a chipped sheet in which a part of a sheet is cut off, a completely double sheet, and the like. Conventionally, for a missing ticket, an abnormality is detected by judging the light amount addition value so that the following processing is not performed. In addition, although the transmitted light amount is detected to be small in the two-ply ticket, this has a disadvantage that it cannot be distinguished from the missing ticket.

[0017]

According to the present invention, by judging the average value of the thickness of the paper sheet from the amount of transmitted light, it is possible to determine the overlapped paper sheet and the thin paper sheet hardly. This can be easily performed by adding a small amount of wear. The thickness value obtained by the present invention is a rough value and does not reach the accuracy of a mechanical sensor, but the effect is significantly increased by using both in combination. Since the optical sensor is always used in the conventional device, when the present invention is applied to the conventional device, less hardware is required to be added.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating the principle of the present invention.

2 is a block diagram of a thickness measurement apparatus of the embodiment of the present invention.

FIG. 3 is a partial flowchart showing processing in the apparatus of FIG. 2 together with FIG. 4;

FIG. 4 is a partial flowchart showing processing in the apparatus of FIG. 2 together with FIG. 3;

FIG. 5 is a characteristic diagram illustrating a relationship between a light transmission output value and a thickness of a sheet in a sensor unit used in the apparatus of FIG. 2;

[Explanation of symbols]

 100: paper sheet entry sensor unit 101: sensor unit 102: amplifying unit 103: A / D conversion unit 104: light transmission data processing unit 105: dictionary comparison unit 106: storage unit 107: central processing unit 108: dictionary data unit

Claims (1)

(57) [Claims] 1. A next processing step, that is, a processing step of obtaining light transmission data for each pixel of a paper sheet, using a thickness determination device provided with a sensor means for measuring light transmission data of the paper sheet; Amplifying the light transmission data; converting the amplified light transmission data from an analog value to a digital value; adding only the internal data of the light transmission data of each pixel; Dividing by the total number of pixels to obtain an average value of the light transmission data; applying each of the processing steps to a typical paper sheet to obtain the average value; providing a lower threshold and an upper threshold A processing step of storing the dictionary as a dictionary, a processing step of comparing the average value of the light transmission data obtained for the sheet to be subjected to the thickness determination with the average value of the dictionary, and the thickness of the sheet to be measured is determined by the comparison. Determine whether it is normal or abnormal Processing stage, the thickness measuring method using the thickness determining device having a to.