JPH0421157Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field of the Invention The present invention relates to an optical reading device for reading marks such as characters, symbols, and bar codes.

Prior Art and Problems Optical reading devices are commonly used as hand scanner type devices for reading marks such as bar codes and characters in POS terminals and the like. Recently, a compatible optical reading device capable of reading both characters, symbols, and bar codes has been proposed, and is disclosed in Japanese Patent Application No. 191670/1989 filed by the present applicant. This compatible device images characters, symbols, or barcodes on an image sensor with a structure in which photoelectric conversion elements are arranged in a planar manner, and scans almost the entire area on the image sensor when reading characters/symbols. Furthermore, when reading a barcode, a part of the area is scanned and read.

However, in this conventional example, the scanning period of the image sensor and the binarization threshold are not changed even if the reading target is different, so there is a problem that increasing the reading accuracy of one will reduce the reading accuracy of the other. . For example, when reading characters and symbols, the scanning period of the image sensor is set to a value as long as possible in consideration of the operation time of the identification circuit connected to the subsequent stage of the binarization circuit. On the other hand, when reading a barcode, the number of scans is counted based on the output signal of a part of the photoelectric conversion element group on the image sensor.
Due to the use of a configuration that determines the white/black bar width,
The performance improves as the scanning period of the image sensor is shortened.

Further, since characters and symbols are often printed in black, while barcodes are often printed in various colors, the contrast between the characters and symbols and the barcode is often different from the background. For this reason, both characters/symbols and barcodes are
It becomes difficult to read high accuracy with the valuation threshold.

Purpose of the invention The present invention was made in view of the problems of the prior art described above, and its purpose is to provide a high-performance compatible optical reader that can read both characters/symbols and barcodes with high precision. The goal is to provide equipment.

Configuration of the Invention The present invention that achieves the above object is configured to change the scanning period and the binarization threshold depending on the type of video to be captured and binarized.

EXAMPLES OF THE INVENTION The present invention will be explained in more detail by way of examples below.

FIG. 1 is a structural block diagram of an optical reading device according to an embodiment of the present invention, which is composed of a hand scanner section 10 and a processing section 20.

In the hand scanner section 10, 11 and 12 are lamps for illuminating the paper 30 on which characters, symbols, or barcodes are drawn; 13 is a lens for forming an image of reflected light from the paper onto the image sensor 14;
14 is an image sensor having a structure in which a group of photoelectric conversion elements are arranged in a planar manner; 15 is an amplifier circuit that amplifies the output of the image sensor; and 16 is an image sensor with a scanning period depending on the type of video to be captured and binarized. This is a switch that changes the binarization threshold.

On the other hand, in the processing section 20, 21 and 22 are binarization circuits, 23 and 24 are scan control circuits, 25 and 26 are identification circuits, and 27 is an output selection circuit.

When reading the barcode 31 drawn on the paper 30, the user presses down the switch 16 provided in the hand scanner section 10. As a result, only the binarization circuit 22 and the scan control circuit 24 become operational. The scan control circuit 24, which is now in an operating state, supplies a scan pulse with a relatively short period to the image sensor 14 in the hand scanner section 10, and the image sensor 14 captures a bar code with a relatively short scan period. The video captured in this way is passed through an amplifier circuit 15 to a binarization circuit 2.
2 and is binarized using a threshold suitable for barcode binarization, the identification circuit 26 identifies the bar width, and this identification result is sent to the output selection circuit 27.
It is output to the outside through .

On the other hand, when characters/symbols are drawn on the paper 30, the user pushes up the switch 16 provided on the hand scanner section 10. As a result, only the binarization circuit 21 and the scan control circuit 23 become operational. The scan control circuit 23 in the operating state supplies the image sensor 14 in the hand scanner section 10 with a relatively long-period scanning pulse determined by taking into account the time required for identification by the identification section 25, and the image sensor 14 performs a comparison. Barcodes are captured with a long scanning cycle. The video captured in this way is input to the binarization circuit 21 via the amplifier circuit 15, and is converted into a binary image using a threshold suitable for binarizing characters and symbols drawn in black and having high contrast with the background. The character/symbol type is identified by the identification circuit 25, and the identification result is output to the outside via the output selection circuit 27.

In the above embodiment, dedicated scanning control circuits and binarization circuits are provided for each of characters/symbols and barcodes, but these are shared and the scanning period and threshold for binarization are changed by switch 16. It is also possible to have a configuration in which:

Effects of the Invention As explained above, the present invention is capable of adjusting the scanning period and the
Since it is configured to change the value threshold, it is possible to realize a compatible optical reading device that can read both characters/symbols and barcodes with high accuracy.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present optical reading device. 10...hand scanner section, 20...processing section,
30...Paper, 11, 12...Lamp for illuminating the paper 30 on which characters/symbols or barcodes are drawn, 13...Lens for forming an image of reflected light from the paper onto the image sensor 14, 14... ...an image sensor having a structure in which a group of photoelectric conversion elements are arranged in a plane, 15... an amplifier circuit that amplifies the output of the image sensor, 16... a scanning period according to the type of video to be captured and binarized. and a switch for changing the binarization threshold, 21, 22...binarization circuit,
23, 24...Scanning control circuit, 25, 26...Identification circuit, 27...Output selection circuit.

Claims (1)

[Claims for Utility Model Registration] An image sensor that includes a group of photoelectric conversion elements arranged in a plane and captures an image by scanning the group of photoelectric conversion elements, and that binarizes the image captured by the image sensor. An optical reading device equipped with a binarization circuit, characterized in that the scanning period and the binarization threshold are changed depending on the type of video to be captured and binarized. .