JPS63106881A - Optical reader - Google Patents

Abstract

PURPOSE:To shorten a reading time, by performing the read scan of only a specific area by image-forming the required visual field of a read object in the specific of an image sensor, and applying a jump processing with a fast vertical clock on an unrequired area. CONSTITUTION:When the unrequired areas 1-M-1 of the image sensor 1 are scanned, scan are performed with a horizontal clock 11 and the fast vertical clock 13, and for example, jump scan is performed with the horizontal clock of 4MHz and the fast vertical clock of 2MHz. The scan on specific areas M-M+i are performed with the horizontal clock 11 and an ordinary vertical clock 12, and the reading of the image of the read object in the specific areas are performed with, for example, a horizontal clock of 4MHz and an ordinary vertical clock of 10kHz. Thus, assuming that the specific areas of 40-60 columns are present in picture elements columns of 244 in a vertical direction, it is possible to shorten a time required for the read scan of a tag on the image sensor 1 to 1/6-1/4.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention is an optical reading device that optically reads characters or symbols. The present invention relates to an optical reading device that is effective when limited to a certain area.

<Conventional technology> POS systems that collect sales information for each item at supermarkets and department stores and perform inventory management, etc. use a tag (price tag) attached to each item on an image sensor with pixels arranged vertically and horizontally. The image sensor is scanned horizontally and vertically to read the characters or symbols printed on the tag.

<Problems to be Solved by the Invention> In general, the vertical length of characters or symbols printed on tags is the height of one character, and the horizontal length is the length of the character array.・Horizontal dimension is 2 m
m x 57 It becomes elongated like a blur, and the image formed on the image sensor becomes an extremely horizontally elongated image, and there is a large amount of blank space that does not need to be read. Therefore, in order to read such a horizontally long image, (1) it is possible to improve the processing speed by processing such a horizontally long image by creating an image sensor in which pixels are arranged horizontally to match the field of view. It will be done.

(2) There is a method of using a mass-produced image sensor such as one for a video camera so that the horizontal field of view is completely focused on the image sensor, and then cutting out unnecessary parts by post-processing the output signal of the image sensor. .

In the case of (1), it is difficult to form a horizontally long image on a horizontally long image sensor, and part of the image may be missing.

Furthermore, manufacturing such a special image sensor is not versatile and is uneconomical.

In the case of (2), the method of deleting unnecessary parts in post-processing processes the unnecessary parts at the same processing speed as the necessary parts, which slows down the reading speed and causes camera shake when reading by holding the optical reading device in the hand. was also unavoidable.

The present invention has been made in view of such problems, and uses a mass-produced image sensor for a video camera or the like to read out a reading target limited to a specific area, such as an image of a horizontally long character array, at high speed. The purpose is to provide optical reading devices.

Means for Solving the Problems> The configuration of the optical reading device according to the present invention includes an image sensor of the optical reading device, and an optical system that forms an image of the required field of view of the reading target within a specific area of the light receiving area of the image sensor. and a clock generator that generates a horizontal clock for scanning the image sensor, a normal vertical clock, and a high-speed vertical clock; and 2) a normal vertical clock that limits the vertical position of a specific area of the image sensor a decoder that provides position information of a specific area from a vertical counter that inputs a high-speed vertical clock; and a selector that switches between the vertical clock of the clock generator and the high-speed vertical clock in accordance with the output of the decoder and outputs the same to the image sensor. It is characterized by consisting of.

Function: A required field of view of the object to be read is formed on a specific area of the light receiving area of the image sensor of the optical reading device, and when reading the imaged object on the image sensor, a vertical clock is set based on the position information of the specific area of the image sensor. The imaged object is read using a high-speed vertical clock outside a specific area, and using a normal vertical clock outside a specific area.

Embodiment> FIG. 1 shows a configuration diagram of an embodiment of an optical reading device according to the present invention. Figure 2 shows an example of a tag that is attached to each item at a supermarket or department store, where the image is formed on the image sensor part in Figure 1, and Figure 3 shows the part of the tag that needs to be read out on a specific area of the image sensor. FIG. 3 is a diagram showing an optical system for forming an image. FIG. 4 is a plan view of the image sensor.

In this embodiment, instead of using an elongated image sensor specifically for reading tags as an image sensor, for example, a horizontal 3
Using an image sensor with 20×244 vertical pixels, characters or symbols to be read are imaged in a specific area on the image sensor and read at high speed.

In the optical reading device according to the present invention shown in FIG. 1, the image sensor 1 is a general-purpose image sensor widely used in TV cameras and the like. In the present invention, PO8 as shown in FIG.
The characters or symbols on the tag 7 are imaged onto a specific area of the image sensor 1 for use.

According to the optical system shown in FIG. 3, the field of view of the tag 7 illuminated by the illumination 10 is imaged on the image sensor 1 via the mirror 8 and the lens system 9. In this optical system, it is necessary to read extremely long and narrow objects such as characters or symbols on tag 7.
7a is always imaged on a specific area la of the image sensor 1. Tag 7 is unnecessary! The IP7b is imaged at least on the unnecessary area lb of the image sensor 1.

FIG. 4 shows a specific area 1a and an unnecessary area 1b on the image sensor 1. The specific area 1a is vertically scanned by M = M
+ i. The unnecessary area 1b is given as 1 to M-1 and M+i+1 to N by vertical scanning.

The clock generator 2 in FIG. 1 includes a horizontal clock 11 that scans the image sensor 1 shown in FIG. 4, a normal vertical clock 12 that scans a specific area 1a of the image sensor 1, and a high-speed vertical clock 13 that scans an unnecessary area 1b. and occurs.

The vertical counter 4 inputs the normal vertical clock and the high-speed vertical clock, and calculates the vertical coordinates M, M of the specific area 1a in the vertical direction.
+i is counted and output to the decoder 5. The decoder 5 determines the scan area of the image sensor 1 based on the input signal from the vertical counter 4, and if the scan area is an unnecessary area on the image sensor 1, a high-speed vertical clock 13 signal is input to the image sensor 1 and skipped. When performing scanning and scanning a specific area on the image sensor 1, the vertical clock 12 of the selector 6 is normally inputted to the image sensor 1 to read the image of the required field of view on the tag. outputs a switching signal for switching between the four-clock clock and the high-speed vertical clock.

FIG. 5 is a diagram showing the correspondence between the horizontal clock and the vertical clock when the image sensor 1 shown in FIG. 4 switches from scanning an unnecessary area to scanning a specific area.

When scanning unnecessary areas 1 to M-18 of the image sensor 1, the scanning is performed using a horizontal click 11 and a high-speed vertical clock 13. For example, the horizontal clock is 4MHz, and the high-speed vertical clock is 2MHz.
Skipping scanning is performed at MHz, and specific areas M to M +
If i has 7, it is scanned by horizontal clock 11 and normal vertical clock 12. For example, an image to be read in a specific area is read using a horizontal clock of 4 MHz and a normal vertical clock of 10 KHz.

In this way, out of 244 vertical pixel columns with skip scanning,
When the specific area is set to 40 to 60 columns, the time required to read and scan the tag 7 on the image sensor 1 is 1/6 to 1/1 compared to scanning with a fixed vertical clock and horizontal clock that read the entire image sensor. I was able to shorten the time to /4.

<Effects of the Invention> According to the optical reading device according to the present invention, by using a commercially available inexpensive video image sensor, the required field of view of the reading target is imaged within a specific area of the image sensor, and only the specific area can be read and scanned. By skipping unnecessary areas using a high-speed vertical clock, the readout time has been significantly reduced. As a result, we were able to improve the processing speed of the entire system.

Furthermore, according to the present invention, even if the object to be read moves during reading,
Since the reading processing time for one screen is short, there is less screen distortion due to movement, and reading errors are less likely to occur.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an optical reading device according to the present invention, Fig. 2 is a plan view of an example of an object to be read, and Fig. 3 is a block diagram of an optical system that images the required field of view of the object to be read on an image sensor. ,
FIG. 4 is a diagram showing a specific area in which the required field of view of the object to be read is imaged on the image sensor, and FIG. 5 is a diagram showing switching of scanning between the unnecessary area and the specific area of the image sensor. In the drawing, 1 is an image sensor, 2 is a clock generator, 4 is a vertical counter, 5 is a decoder, 6 is a selector,
71.1' tag, 8 is mirror, 9 is lens system, 10 is lighting, 11 is horizontal clock, 12 is normal vertical clock, 1
3 is a high speed vertical clock. Figure 1 Figure 3 Figure 4 Figure 5 Mud meeting ■

Claims (1)

[Scope of Claims] An image sensor, an optical system that images a required field of view of a reading target within a specific light-receiving area of the image sensor, and a horizontal clock, a normal vertical clock, and a high-speed vertical clock that scan the image sensor. a decoder that provides positional information of the specific area from a vertical counter that inputs the normal vertical clock and the high-speed vertical clock that limit the vertical position of the specific area of the image sensor;
An optical reading device comprising: a selector that switches between a vertical clock of the clock generator and a high-speed vertical clock according to an output of the decoder and outputs the same to the image sensor.