JPS61233876A - Optical reader - Google Patents

Abstract

PURPOSE:To attain reading corresponding to a color bar code or a dropout color by providing plural lighting light sources having different wavelength regions and switching automatically the light source according to the result of reading. CONSTITUTION:A tungsten lamp 4a and a read LED 4b are provided in a hand scanner 1, a reflected light from a recording body 3 iradiated by one of them is converted into an electric signal by an image sensor 6 via a lens 5, amplified by an amplifier 7 and sent to a recognition processing section 8. A binary-coding section 9 of the section 8 applies binary-coding to the image signal, and after the result is stored once in a pattern buffer 10, it is sent to a character/bar code discrimination section 11 and a character recognition section or a bar code recognition section is activated by the result of discrimination. When a recognition result processing section 14 discriminates it as a proper form, the result is outputted, but when not, a light source switching control section 15 is operated to changeover the light sources for recognition again.

Description

[Detailed description of the invention]

[11 Field of Industrial Application This invention relates to an optical reading device that reads characters and codes such as barcodes using the same image sensor, and has a plurality of illumination light sources having different wavelength regions,
According to the reading result (judgment), it is possible to automatically switch the light source and read in response to color codes, dropout colors, etc. [2] Conventional technology and its problems OCR characters and Optical hand scanners that read barcodes and barcodes using the same image sensor are already well known.For example, according to US Pat. It is supplied to each recognition unit at the same time, and the result of the one that can be identified is output as the reading result.Also, a red LED with a peak value near 660 nm is used as the illumination source of the above hand scanner for characters/barcodes. However, regarding an optical information reading device characterized by identifying blue or green barcodes, Japanese Patent Laid-Open No. 59-243 discloses
Although it is disclosed in Publication No. H, in this case, conventional OCR
It becomes difficult to use dropout colors such as blue or green that were applied with hand scanners, and it is necessary to limit the dropout colors to red to yellow. In practical terms, this is an additional constraint when creating price tags and the like. Next, there is a description in Japanese Patent Application Laid-Open No. 59-33576 regarding an optical information reading device equipped with several light emission means so as to exhibit high brightness in a plurality of different wavelength regions. requires a changeover switch, and when handling a large amount of information, it is unlikely that it will be possible to handle it by operating the switch according to the format of each information entry. Problems in the conventional technology are summarized below.

[3] Problems with the prior art The optical reading device of the prior art that reads both normal characters and barcodes uses a tungsten lamp as a light source, but it is not suitable for blue and border color barcodes. ,
Since the intensity of the reflected light in the wavelength range of 400 to 700 nm is lower than that of infrared light, the output of the photoelectric element due to the reflected light is reduced to about 15% of that of a black bar code, making it impossible to identify it. (See Figure 2) Next, an optical reader using a red LED (intensity peak around 660 nm) can distinguish both blue and green at the same level as black, but on the other hand, if a normal tungsten lamp is used as the light source, dropout colors that can be applied to ruled lines, stroke print position specification frames, etc. cannot be used. (Refer to Figure 3) Furthermore, in the case of a type that is equipped with multiple light sources corresponding to multiple wavelength bands and uses a switch to switch the light sources depending on the object to be read, product information containing a mixture of text and barcodes may be displayed. The operator is forced to repeat the steps shown in the following reference figure 1, which is inappropriate when the operation targets a large number of consecutive product tags. Reference Fig. 1 [4] Means for Solving the Problem The present invention solves the above-mentioned problems, and its configuration will be explained with reference to Fig. 1. 1 is a hand scanner that optically reads information such as characters and barcodes, and covers the information written on the recording medium 3.
The light is irradiated by a light source 4a or 4b, and the reflected light is focused through a lens 5 on an image sensor 6 in which a plurality of photoelectric conversion elements are arranged two-dimensionally, and the signal output is amplified by an amplifier circuit 7. A value conversion unit 9 is used to convert the signal into a white/black digital signal, the signal is stored in a screen buffer 10, and then a judgment circuit 11 determines whether the object to be read is a character or a barcode.
Based on the result, if it is a character, the circuit 12
If it is a barcode, the screen buffer 1 is sent by the circuit 13.
0 is processed, and the recognition result processing unit 14 outputs the circuit 18.
Alternatively, it is determined whether the number of digits, check digits, etc. conform to a predetermined format based on the recognition result sent from the circuit 12, and if so, the recognition result is sent to an external device. do. On the other hand, if they do not match, the recognition result processing section 14 sends a light source switching signal to the light source switching control section 15, the light source switching control section 15 switches to a light source of another wavelength, irradiates the recording medium 3, and irradiates the recording medium 3. Perform the same processing as . [51 Effect] In the optical reading device of the present application that is equipped with a red LED and a tungsten lamp as a light source, first, in the case of a red LED, characters, barcodes, etc. written in a color in a wavelength range of 600 to 700 nm are detected. The reflection caused by the light is almost zero, and the parts marked in green or blue can be binarized and identified at exactly the same level as when marked in black. Next, when letters, barcodes, etc. are irradiated using a tungsten lamp, the wavelength of the reflected light from the letters, etc. written in blue or green is around 900 nm, and the reflectance is extremely high <"white" ( It can be binarized and identified at the same level as paper). [6] Example An example of the present invention will be described with reference to FIG. When the power is turned on, the light source (4a) is set in advance using a tungsten lamp, and the information written on the recording medium (3) is irradiated, and the information imaged on the image sensor (6) becomes white/white. The signal converted into a black binary signal is sent to the screen buffer αq. Based on this signal, it is determined whether it is a character or a barcode, and if it is a barcode, the signal accumulated in the screen buffer αQ is sent to the barcode recognition unit ■, and if it is a character, it is a character. Sends a signal to the recognition unit. For example, the character recognition results recognized by the character recognition unit are sequentially sent to the recognition result processing unit (141), and the recognition result processing unit α4 determines whether the format is in a predetermined format. , performs readability processing such as sounding a buzzer and lighting a readable lamp.However, if the recognition result processing unit 041 determines that reading is not possible, a light source switching signal is sent from the recognition result processing unit port 4 to the light source switching control unit (to). Based on the signal, the light source is set to red L.
Switch to ED (light source (4b)), perform the same process as above, and if reading is not possible with light source (4b), then switch to light source (4b).
Return to step 4a) and repeat the same process. As shown in FIG. 6, the light source switching control section is constituted by a NAND gate equivalent to 5N7438 manufactured by Texas Instruments. As a second embodiment, as shown in FIG. 7, in order to reduce power consumption, a photo sensor or the like is used to turn on the light source only when paper is detected.
If reading is not possible in b), the series of reading processes is stopped, and the operation can be resumed if there is a paper detection signal. still,
As an application of FIG. 7, it is also possible to repeat steps (4a) and (4b). As an example of the light source, as shown in FIG. 4(a), a plurality of tungsten lamps (light source 4a) and red LEDs (light source 4b) are arranged alternately on the upper wall of the scanner (6).
The light sources (4a) and (4b) shown in the configuration of FIG. 4(b) or FIG. The respective aggregates 4A and 4B arranged in
They may be placed above or below the scanner (U and B) as shown. At this time, instead of the tungsten light source (4a),
An LED having a wavelength of nm may also be used.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of the present invention. FIG. 2 is a diagram showing the wavelength dependence of reflected light when a tungsten light source is used. FIG. 3 is a diagram showing the light transmittance when a red LED is used as a light source and when a tungsten lamp is used. FIGS. 4A, 4B, and 4C are diagrams showing examples in which a plurality of light sources of a plurality of types according to the present invention are provided. FIG. 5 is a diagram showing an embodiment of the present invention. FIG. 6 is a diagram illustrating a NAND gate forming the light source switching control section. FIG. 7 shows a second embodiment of the invention. 1 Hand scanner 2 hands 8 Recording body 4a Light source (tungsten lamp) 4A Light source assembly (tungsten lamp) 4b Light source (red LED) 4B Light source assembly (red LED) 5 Lens 6 Image sensor 7 Amplifier board Recognition processing unit 9 Binarization unit 1O image buffer 11 Character/barcode determination circuit 12 Character recognition unit 13 Barcode recognition unit 14 Recognition result processing unit 15 Light source switching control unit agent Patent attorney Tetsu Udai MC-f (nm) Fig. 3 2nd figure 4b 4a 4b 4a 4b
4a 4bFigure 4Figure 5Figure 6

Claims (5)

[Claims] (1) In an optical reading device that optically reads characters and barcodes using a scanner equipped with a built-in image sensor in which multiple photoelectric conversion elements are arranged two-dimensionally, two types of light sources with different emission wavelength ranges are used. It determines whether the recognition result conforms to a predetermined format for each character and barcode, and if it conforms, it outputs the result, and if it does not, it outputs the result. An optical reading device characterized in that a light source switching signal is sent from a recognition result processing section to a light source switching control section, and the other light source is switched to illuminate and recognize the object to be read. (2) The optical reading device according to claim (1), wherein the two types of light sources having different emission wavelength ranges are a tungsten lamp and a red light emitting diode (red LED). (3) A claim characterized in that the two types of light sources with different emission wavelength ranges are a tungsten lamp and a red light emitting diode, and a plurality of these light sources are arranged alternately in a straight line to form a linear array light source. The optical reading device according to paragraph (2). (4) The optical reading device according to claim (1), wherein the light source switching control section that switches the light source based on the recognition result of the recognition result processing section is a NAND gate. (5) The target to be read is a green or blue barcode, or an OC
The optical reading device according to claims (1) and (2), characterized in that the information includes a dropout color record used for the R character.