JPS6320575A - Medium recognizing device - Google Patents

Abstract

PURPOSE:To suppress the increase of an overall read data amount by providing an image sensor in which the arrangement density of a picture element detecting element is different, in the main scanning direction on a medium to be recognized. CONSTITUTION:In a part of an image sensor 10 corresponding to fine pattern regions 2A, 2B on a medium 2 which is to be read by a high resolution, the arrangement density of an element 1 of the image sensor 10 is high. That is to say, it is in a dense arrangement (b group and d group), and in other parts, the arrangement of the element 1 is coarse (a, c and e groups). Also, as for the read of the minute pattern areas 2A, 2B, the internal of a main scanning line is narrow, and in the sub-scanning direction, as well, a read density is increased (B zone and D zone). A read density in the sub-scanning direction to other part is coarse (A, C and E zones), and the read density in the sub- scanning direction can be varied by making the carrying speed of the medium constant and changing the output period of a start pulse S, or making the output period of the start pulse S constant and changing the carrying speed of the medium 2.

Description

DETAILED DESCRIPTION OF THE INVENTION Summary of the Invention A device that recognizes or identifies characters, symbols, patterns, etc. mainly displayed on a sheet-like medium by using an image sensor. The arrangement density of the image sensor's pixel detection elements should be adjusted at least in the main scanning direction on the medium to be recognized, so that fine patterns can be read with high density and other patterns can be read at high speed even with coarse accuracy. It is characterized by being different depending on the scanning location.

BACKGROUND OF THE INVENTION The present invention relates to a medium recognition device that mainly recognizes or identifies a sheet-like medium (for example, paper Wi) based on data read by an image φ sensor such as characters, symbols, patterns, etc.

In conventional media pattern recognition devices, CCD and MO
An S-image red sensor is used. However, in these conventional image sensors, photoelectric elements are arranged at equal intervals. Hence the pattern reading accuracy.

In order to improve recognition accuracy, it is necessary to use an image sensor with a high pixel density. In this case, since the read data length becomes long, it is necessary to increase the memory capacity, and the process for pattern recognition also takes time. If all pattern information on a medium is to be read by a high-density image sensor like the one mentioned above, the higher the pixel density, the longer it will take to read it, and if you want to read it in the shortest possible time, you will need high-speed reading. However, there is a limit to the operating speed of the image number sensor.

Summary of the Invention The present invention provides a medium recognition device that can suppress the increase in the overall amount of read data as much as possible, and that can read data using highly densely arranged photoelectric elements in areas where highly accurate data is required. The purpose is to provide

A medium recognition device according to the present invention is characterized in that it includes an image sensor in which the arrangement density of pixel detection elements is varied at least in the main scanning direction depending on the scanning location on the medium to be recognized.

A pixel detection element is a photoelectric detection element or a part thereof that reads data for one pixel, and the collection of these elements is an image sensor. It is determined in advance according to the selected pattern. For example, a pattern, such as a banknote, is made up of a fine pattern that includes numbers and symbols that must be read accurately, and a pattern that can be read roughly or is better for pattern recognition. In the case where the pixel detection elements are arranged closely in the places where fine patterns are to be read, the pixel detection elements are arranged sparsely in the places where the pattern is to be read.

The reading density may also be varied in the sub-scanning direction.If the image sensor is a so-called two-dimensional image sensor, the density of the pixel detection elements may be varied also in the sub-scanning direction. In the case of a sensor, the reading density in the sub-scanning direction can be varied by changing the conveyance speed of the medium or by changing the output interval (period) of the start pulse that provides the timing to start scanning in the main-scanning direction. Can be done.

According to this invention, a portion of the medium containing important information,
In areas of the image sensor that correspond to areas that require accurate judgment, the pixel detection elements are arranged in a high density to enable high-precision reading, and in other areas, the density of the pixel detection elements is reduced. It is relatively low. therefore,
Since the overall number of pixel detection elements does not need to increase significantly, or can even be reduced compared to conventional methods, it is possible to suppress increases in reading time and processing time, and still achieve high-precision reading of the necessary parts. .

Recognition becomes possible.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 shows an example of the electrical configuration of a medium recognition device. FIG. 2 shows the positions of fine patterns such as characters and symbols on a medium to be recognized, and the main scanning line when reading the pattern on the medium with an image sensor.

It shows the timing of the start pulse of each main scan (in the sub-scan direction) and the distribution of pixel detection elements that are components of the image sensor. Further, FIG. 3 schematically shows an example of the arrangement of pixel detection elements of an image sensor.

Referring to these drawings, the medium 2 to be recognized is, for example, a banknote, and is conveyed in the direction shown by the arrow in FIG. 2 (the direction opposite to the sub-scanning direction). The pattern expressed on medium 2 is a fine pattern of letters, symbols, numbers, etc. (the area is 2A, 2
(shown as B) and a pattern. The fine patterns 2A, 2B are read with high resolution in order to accurately identify them. Other patterns do not necessarily need to be read with high resolution.

The image fist sensor IO is arranged in an example of a medium conveyance path so as to face one side, for example, the surface of the medium 2 being conveyed. Image sensor 10 is, for example, an amorphous-silicon image sensor. In this embodiment, the image sensor lO is a line-shaped (-dimensional) image sensor (line ), the direction in which the 0 pixel detection elements l are arranged is the main scanning direction. The direction in which the medium 2 is conveyed (more precisely, the opposite direction thereof) is the sub-scanning direction, and as the medium 2 is conveyed, it is read and scanned in the sub-scanning direction. Of course, it is also possible to employ a so-called two-dimensional image sensor that includes pixel detection elements arranged not only in the main scanning direction but also in the sub-scanning direction. Transport will not be necessary.

As can be seen from the element density distribution of the image Φ sensor in FIG. 2 and from FIG. - The arrangement density of the elements 1 of the sensor 10 is high, that is, they are densely arranged (groups b and d), and the arrangement of elements 1 is sparse in other parts (a, c, and group e), and also the second group
As can be seen from the start pulse activation timing in the sub-scanning direction in the figure, when reading fine pattern areas 2A and 2B, the interval between the main scanning lines is narrower, and the reading density is also increased in the sub-scanning direction. (B band and D band), and the reading density in the sub-scanning direction for other parts is coarse (A).

C and E bands), the reading density in the sub-scanning direction can be determined by changing the output period of the start pulse S while keeping the conveyance speed of the medium 2 constant, or by changing the conveyance speed of the medium 2 while keeping the output period of the start pulse S constant. By changing
It can be changed. The start pulse S is a signal that instructs the image sensor 10 to start reading in the main scanning direction. Of course, even if the period of the start contest pulse changes, it goes without saying that this period is selected so that one scan in the main scanning direction is completed within - period.However, as mentioned above, If the arrangement density of the elements in the area for reading the areas 2A and 2B on the two-dimensional image sensor is increased, there is no need to change the start pulse period or the conveyance speed.

In FIG. 2, the read output of the image sensor 10 is sent via a multiplexer 12 to a pattern recognition section 13A or a character, symbol, etc. recognition section 13B. 13B by recognition
is for recognizing and processing the read patterns for the fine pattern areas 2A and 2B. For example, by comparing the read patterns with reference patterns stored in advance in the memory, it is possible to recognize characters, etc. make false judgments.

The recognition unit 13A performs matching and identification processing on the pattern patterns in areas other than the areas 2A and 2B. By subjecting the identification outputs of both recognition units 13A and 13B to appropriate logical processing (in the illustrated example, A N D processing by an A N D circuit 14), a final recognition or identification output is obtained.

The timing circuit 11 provides the above-mentioned start pulse S and clock pulses for reading each pixel to the image sensor 10, and also provides the multiplexer 12 with a switching signal for the recognition section. The edge of the conveyed medium 2 is detected by the gate sensor GS, and after a certain period of time after this detection, the first start pulse S is generated.
At the same time, output of clock pulses is started. FIG. 4 shows how the recognition units 13A and 13B are switched.

When reading band A of the medium 2, the recognition unit 13A is selected, and the read signal of the image sensor 10 is sent to the recognition unit 13A.
Enter.

In reading the B band, the recognition unit 13A is selected when scanning the elements a group to C group, but when the scanning by the d group starts, the recognition unit 13A is selected to read the fine pattern area 2B.
3B, and the read signal from the image sensor 10 is sent to the recognition unit 13B via the multiplexer 12.

In group e, the recognition unit 13A is selected again.

When reading C-band and E-band, the read signal is sent to the recognition section 13A.

In the D band, the recognition unit 13B is selected only in the elements of group b for reading the fine pattern area 2A,
A read signal is sent to this recognition section 13B.

The timing of switching from the recognition unit 13A to 13B during scanning by the elements of group b in the D band is determined by the timing circuit 11.
After the output of the star)-pulse S, predetermined times t1 and t2 are measured, and these times t,
This is done by sending a signal from the timing circuit 11 to the multiplexer 12 instructing switching to the recognition unit 13B only during -t2. The same applies to switching during scanning of the d group in the B band.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the electrical configuration of the medium recognition device;
Figure 2 is an explanatory diagram showing the pattern of the medium, the density distribution of the pixel detection elements of the image sensor arranged in the main scanning direction, the reading density in the sub-scanning direction, etc., and Figure 3 is the pixel detection of the image sensor. FIG. 4, which is a diagram showing an example of arrangement of elements, is a time chart showing timing of reading and switching. DESCRIPTION OF SYMBOLS 1... Pixel detection element of image φ sensor, 2... Medium to be recognized, 2A, 2B... 8g thin pattern area, 10... Image sensor. Figure 1

Claims (3)

[Claims] (1) A medium recognition device including an image sensor in which the arrangement density of pixel detection elements is varied at least in the main scanning direction depending on the scanning location on the medium to be recognized. (2) The medium recognition device according to claim (1), further comprising means for varying the detection density in the sub-scanning direction. (3) The medium recognition device according to claim (1), further comprising a switching means for switching and providing the output of the image sensor to at least two pattern recognition means.