JP2011197856A - Optical information reading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical information reading device, accurately reading by suppressing incorrect recognition produced by a situation particular to a color display device, even when an information code displayed on the color display device becomes a reading target.SOLUTION: An optical information reading device 1 includes an optical filter 28 for passing light, having a predetermined frequency band corresponding to illumination light, and for suppressing the passing of light other than the predetermined frequency band. By means of a light receiving sensor 26, the optical information reading device 1 receives reflected light taken in from the read target code through the optical filter 28. Further, based on a received light waveform in a predetermined direction (element disposition direction) in the light receiving sensor 26, the optical information reading device 1 generates a binary data identifying bright color regions and dark color regions in the predetermined direction, and generates a correction data, having a correction region of a predetermined width added to each bright color region in the generated binary data, corresponding to an pixel element on which a display light is suppressed by the optical filter 28.

Description

  The present invention relates to an optical information reader.

  In an optical information reader such as a barcode reader, a light receiving sensor (for example, a CCD sensor, a CMOS sensor, etc.) in which a plurality of light receiving elements are arranged is generally used, and an information code such as a barcode is used by the light receiving sensor. In addition to receiving reflected light from the light, a light reception signal (electric signal) corresponding to the image of the information code is output. The output received light signal is binarized by a binarization circuit, and the binary data is decoded by a decoding means.

JP 2005-293327 A Japanese Patent Laid-Open No. 10-320496

  In this type of optical information reader, there is a problem of how to remove noise contained in the light reception signal. For example, Patent Documents 1 and 2 disclose techniques for removing noise contained in a light reception signal. Patent Document 1 discloses a technique for removing high-frequency noise components from a light reception signal using a low-pass filter or the like. ing. Further, Patent Document 2 discloses a technique for solving a problem when a low-pass filter is used.

  On the other hand, as a noise removal method, an illumination light source that emits illumination light of a specific color is provided, and an optical filter that transmits light in a frequency band corresponding to the specific color and blocks light in other frequency bands is used in combination. It is also possible to consider a configuration that performs the above. According to this configuration, it is possible to satisfactorily remove disturbance light having a frequency that is significantly different from that of the illumination light, and to effectively suppress noise caused by the disturbance light in the received light signal.

  In addition, both the configuration using the low-pass filter and the configuration using the optical filter have specific advantages, and more effective noise removal can be expected if they are used in combination. However, there are various cases for the display mode of the information code to be read, and in some cases, noise removal may not be sufficiently performed even if the low-pass filter and the optical filter are used in combination. For example, in recent optical information readers, there is an increasing need to read information codes displayed on a color display device, and thus information codes displayed on a color display device are to be read. Even if the low-pass filter and the optical filter are used in combination, noise removal may not be performed properly due to circumstances peculiar to the color display device.

  For example, when an illumination light source that emits red illumination light is used and an optical filter that suppresses light other than a predetermined frequency band corresponding to red is used, a light / dark code (for example, a barcode) that is read on a paper medium or the like If so, it is possible to selectively transmit the red reflected light from the light color region, and to effectively remove disturbance light other than red, so the pattern of the light color region and the dark color region can be appropriately set. A reflected waveform can be obtained. However, when imaging a light and dark code (for example, a barcode) displayed on a color display device such as a liquid crystal display device, light other than the color to be transmitted through the optical filter (in this case, red) is generated from the light color region. There is a problem that light from a part of the bright color area is cut off.

  For example, as shown in FIG. 7, R pixel Ra, G pixel Ga, and B pixel Ba (sub pixel) are combined to form one display pixel Sa (pixel), and a plurality of such display pixels Sa are arranged. In the case of a liquid crystal display device, when white is displayed on a certain display pixel Sa, actually, the R pixel Ra, the G pixel Ga, and the B pixel Ba (sub-pixel) are each made to emit light and visually recognized as white. It generates bright light. When imaging a light / dark code displayed on such a liquid crystal display device, as shown in FIG. 8A, the red light generated from the R pixel Ra passes through the optical filter F for the R pixel Ra. It will be recognized as a bright color area. However, for the G pixel Ga and the B pixel Ba, since the green light and blue light from these pixels are suppressed by the optical filter F, the amount of light received by the light receiving sensor is suppressed as shown in the lower part of FIG. Thus, although it should be an area that should be recognized as a bright color area as shown in FIG. 8C, it is erroneously recognized as a dark color area as shown in FIG. 8B. If such a misrecognition is made, the size of each bright color area of the information code cannot be properly recognized, leading to a decoding failure of the entire information code.

  The present invention has been made to solve the above-described problems, and can read both an information code displayed on a color display device and an information code attached to an object, and is particularly displayed on a color display device. An object of the present invention is to provide an optical information reader capable of accurately reading an information code with a false recognition caused by circumstances peculiar to a color display device.

  According to the first aspect of the present invention, there is provided an optical system capable of reading, as a reading target code, an information code displayed on a color display device formed by arranging a plurality of display pixels obtained by combining pixel elements of a plurality of colors and an information code attached to an object. And an illumination unit that irradiates illumination light to the reading target code and light in a predetermined frequency band corresponding to the illumination light, and suppresses passage of light other than the predetermined frequency band. An optical filter, a light receiving sensor that receives reflected light from the reading target code through the optical filter, and outputs a light receiving signal corresponding to the reflected light, and a light receiving waveform in a predetermined direction in the light receiving sensor, Binarization means for generating binary data capable of specifying the light color area and the dark color area in the predetermined direction; and each light value in the binary data generated by the binarization means. Correction data generating means for generating correction data by adding a correction area having a predetermined width corresponding to the pixel element whose display light is suppressed by the optical filter to the area, and the correction data generating means generated by the correction data generating means And a decoding means capable of executing a decoding process based on the correction data.

  According to a second aspect of the present invention, in the optical information reading apparatus according to the first aspect, a correction mode in which the correction data generation unit generates the correction data, and a normal mode in which the correction data is not generated. Mode switching means is provided for switching to, and the decoding means performs decoding processing based on the binary data in the normal mode and performs decoding processing based on the correction data in the correction mode. None, wherein the mode switching means switches to the correction mode when a predetermined execution condition that is an execution reference of the correction mode is satisfied.

  According to a third aspect of the present invention, in the optical information reader according to the second aspect, the mode switching unit further includes the light color region or the dark color region in the binary data generated by the binarization unit. A region detecting unit that detects a region in which each length is a predetermined length, or a region in which the cycle of the light color region or the dark color region is a predetermined cycle, and the region detecting unit detects the predetermined length or the predetermined cycle. The correction mode is switched on condition that a region to be detected is detected.

  According to a fourth aspect of the present invention, there is provided the optical information reading device according to the third aspect, further comprising a reading port for deriving the illumination light from the illuminating means and taking in the reflected light from the code to be read. The reading target code is read while the color display device is in contact with the reading port.

  According to a fifth aspect of the present invention, in the optical information reading device according to the third or fourth aspect of the present invention, the mode switching unit further includes the adjacent bright data in the binary data generated by the binarizing unit. Provided with a predetermined ratio area detecting means for detecting an area where the ratio of the width of the color area and the dark color area is a predetermined ratio, on condition that the predetermined ratio area detecting means detects the area having the predetermined ratio; It is characterized by switching to the correction mode.

  According to a sixth aspect of the present invention, in the optical information reading device according to any one of the second to fourth aspects, the mode switching unit further includes binary data generated by the binarizing unit. A predetermined ratio area detecting means for detecting an area in which the ratio of the widths of the adjacent bright color area and the dark color area is a predetermined ratio, and the predetermined ratio area detected by the predetermined ratio area detecting means is predetermined. When the number of times continues, the correction mode is switched.

A seventh aspect of the present invention is the optical information reading device according to any one of the first to sixth aspects.
Further, the color display device has a configuration in which a plurality of the display pixels configured by arranging R pixels, G pixels, and B pixels in a predetermined column direction are arranged in at least the column direction.

  The invention according to claim 8 is the optical information reading apparatus according to claim 7, wherein the illumination means is configured to irradiate the red illumination light, and the optical filter includes G pixels and B pixels. The passage of the display light emitted is configured to be less than the passage of light emitted from the R pixel.

  A ninth aspect of the present invention is the optical information reading device according to any one of the first to eighth aspects, wherein the color display device is a display device provided in a portable terminal. It is said.

The invention according to claim 1 is provided with an optical filter that transmits light in a predetermined frequency band corresponding to the illumination light and suppresses passage of light other than the predetermined frequency band, and reflects the reflected light from the reading target code as an optical filter. The light receiving sensor is configured to receive light via By doing in this way, disturbance light other than the reflected light which illumination light reflected in the reading object code | cord | chord can be removed effectively.
On the other hand, with such a configuration, when the information code displayed on the color display device is the code to be read, a part of the pixel elements in the area where the bright color pattern is displayed (light that is suppressed by the optical filter is emitted). There is a concern that light from the pixel element) is suppressed by the optical filter, and a waveform component indicating a dark color is included in the waveform of the bright color pattern portion in the light reception signal as noise.
On the other hand, in the present invention, based on the light receiving waveform in the predetermined direction in the light receiving sensor, the binarizing means generates binary data that can specify the bright color area and the dark color area in the predetermined direction, and further the correction data generating means Thus, correction data having a predetermined width corresponding to the pixel element whose display light is suppressed by the optical filter is added to each bright color area in the generated binary data to generate correction data. Then, decoding processing is performed by the decoding means based on the generated correction data.
In this way, the width of pixel elements that are suppressed by the optical filter (pixel elements that should be detected as light color areas but are detected as dark color areas by suppressing light in the optical filter) is considered. Correction data to compensate for this can be generated. Since the decoding process is performed based on the correction data, it is possible to accurately read while suppressing erroneous recognition caused by the circumstances peculiar to the color display device.

  According to the second aspect of the present invention, there is provided mode switching means for switching between a correction mode in which correction data is generated by the correction data generation means and a normal mode in which no correction data is generated. The decoding means is configured to perform decoding processing based on the binary data in the normal mode, and to perform decoding processing based on the correction data in the correction mode. Is switched to the correction mode when the predetermined execution condition is satisfied. In this way, the correction data is not generated in the dark clouds but is generated when the predetermined execution condition that is the execution standard of the correction mode is satisfied. Correction processing can be omitted, and processing efficiency and processing time can be shortened.

  In the invention according to claim 3, in the binary data generated by the binarization means, the area where each length of the light color area or the dark color area is a predetermined length, or the period of the light color area or the dark color area is a predetermined period. An area detecting means for detecting the area is provided. And it switches to correction mode on condition that the area | region which becomes predetermined length or a predetermined period is detected by this area | region detection means. When the information code displayed on the color display device is imaged, each length of the light color region or the dark color region becomes a predetermined length due to the size of the pixel element of the color display device or the arrangement of the pixel elements. Since there is an increased possibility that an area, or an area in which the period of a light color area or a dark color area has a predetermined period is detected, if the detection mode is switched to the correction mode on the condition of such an area detection, the color display device captures an image. The correction processing can be performed by appropriately determining the possibility of being made.

  According to a fourth aspect of the present invention, there is provided a reading port for deriving illumination light from the illuminating means and taking in reflected light from the reading target code, and the reading target code is in a state where the color display device is in contact with the reading port. Is configured to read. In this way, since the distance between the reading port and the color display device can be kept at a certain short distance at the time of code imaging, each length of the light color region or dark color region or the cycle of the light color region or dark color region is It becomes easier to accurately determine whether the length corresponds to the pixel element or the cycle corresponds to the pixel element.

The invention according to claim 5 includes predetermined ratio area detecting means for detecting an area in which the ratio of the widths of adjacent bright color areas and dark color areas is a predetermined ratio in the binary data generated by the binarizing means. The correction mode is switched on condition that the area having the predetermined ratio is detected by the predetermined ratio area detecting means.
When the information code displayed on the color display device is imaged, the widths of the adjacent bright and dark color areas due to the regular arrangement of pixel elements and the suppression of light from some pixel elements If the ratio is switched to the correction mode on condition that such a predetermined ratio is detected, the possibility that the color display device has been imaged is determined more appropriately and the correction process is performed. It can be performed.

The invention according to claim 6 includes predetermined ratio area detecting means for detecting an area in which the ratio of the widths of the adjacent bright color area and dark color area is a predetermined ratio in the binary data generated by the binarizing means. When the predetermined ratio area detected by the predetermined ratio area detecting means continues a predetermined number of times, the mode is switched to the correction mode.
When the information code displayed on the color display device is imaged, the widths of the adjacent bright and dark color areas due to the regular arrangement of pixel elements and the suppression of light from some pixel elements If the ratio is switched to the correction mode on condition that such a predetermined ratio is detected, the possibility that the color display device has been imaged will be determined more appropriately and corrected. Processing can be performed. Further, when displaying a margin around a code in a color display device, for example, display pixels that display white are arranged to a certain extent, and therefore, in the margin display area, pixel elements that are suppressed by an optical filter are present. Many are included at regular intervals. Therefore, the color display device can be imaged by switching to the correction mode on condition that the predetermined ratio area (the ratio of the width of the light color area and the dark color area is the predetermined ratio, but the area) continues for a predetermined number of times. The correction process can be performed by more appropriately determining the characteristics.

  According to a seventh aspect of the present invention, the color display device has a configuration in which a plurality of display pixels configured by arranging R pixels, G pixels, and B pixels in a predetermined column direction are arranged in at least the column direction. According to the present invention, the information code displayed on the color display device can be read well with the RGB color display device widely used in various places as an object to be read. Can be increased.

  The invention according to claim 8 is configured such that the illumination means emits red illumination light, and the optical filter suppresses the passage of the display light emitted from the G pixel and the B pixel more than the passage of the light emitted from the R pixel. Is configured to do. In this case, when the information code attached to the object is read as the reading target code, the light reflected by the bright color region (red light) can be selectively transmitted by the optical filter, The disturbance light can be removed well. On the other hand, when reading the information code displayed on the color display device, the light component from the G pixel and B pixel is suppressed by the optical filter in the region where the bright color pattern is displayed, and the waveform component indicating the dark color in the waveform of the bright color pattern portion May be included as noise. However, in the present invention, it is possible to generate correction data in which noise due to suppression of light from such G and B pixels is corrected, and such noise (noise due to G and B pixels). It is possible to perform the decoding satisfactorily after properly removing.

  The invention of claim 9 is characterized in that the color display device is a display device provided in a portable terminal. In this way, it is possible to satisfactorily read an information code displayed on the mobile terminal using a mobile terminal widely used in various places as a reading target, and the convenience for the user can be further enhanced.

FIG. 1 is a block diagram illustrating an optical information reading apparatus according to the first embodiment of the invention. 2A is an explanatory diagram schematically illustrating the internal configuration of the optical information reading apparatus in FIG. 1, and FIG. 2B illustrates a state in which an object to be read is read while being in contact with the reading port. It is explanatory drawing to do. FIG. 3 is a flowchart illustrating the flow of reading processing performed by the optical information reading apparatus of FIG. FIG. 4 is an explanatory diagram for explaining reading of an information code printed on paper. FIG. 5 is an explanatory diagram for explaining a case where an information code displayed on the color display device is to be read. FIG. 6A illustrates the waveform (light reception waveform) of the light reception signal when the information code displayed on the color display device is imaged, and FIG. 6B is a binarization of the light reception waveform. It is explanatory drawing which shows binary data notionally. FIG. 6C is an explanatory diagram for explaining the correction of the binary data, and FIG. 6D conceptually shows correction data obtained by correcting the binary data of FIG. 6B. FIG. FIG. 7 is an explanatory diagram conceptually illustrating a pixel configuration of a color display device used conventionally. FIG. 8 is an explanatory diagram for explaining a problem in reading a barcode displayed on the color liquid crystal display device.

[First embodiment]
Hereinafter, an optical information reading apparatus according to a first embodiment of the present invention will be described with reference to the drawings.
(overall structure)
FIG. 1 is a block diagram illustrating the electrical configuration of the optical information reading apparatus according to the first embodiment. FIG. 2 is an explanatory diagram schematically illustrating the internal configuration of the optical information reading apparatus of FIG. It is. First, the overall configuration of the optical information reading apparatus 1 according to the present embodiment will be described with reference to FIGS. As shown in FIG. 1, the optical information reader 1 according to the present embodiment is configured as a code reader that reads an information code B such as a barcode, and an outer case is formed by a case (not shown). It has a configuration in which various electronic components are accommodated.

  The optical information reader 1 mainly includes an optical system such as an illumination light source 20, a light receiving sensor 26, an imaging lens 27, an optical filter 28, a reflecting mirror 29, a memory 35, a control circuit 40, an operation switch 42, a liquid crystal. It comprises a microcomputer (hereinafter referred to as “microcomputer”) system such as a display 46 and a power system such as a power switch 41. Note that these are mounted on the substrate 4 or housed in the case 2 (FIG. 2).

  The optical system includes an illumination light source 20, a light receiving sensor 26, an imaging lens 27, an optical filter 28, a reflecting mirror 29, and the like. The illumination light source 20 corresponds to an example of “illumination means”, and includes, for example, a red LED, a diffusion lens provided on the emission side of the LED, a condenser lens, and the like, and irradiates the red illumination light Lf. It is configured to do. In this embodiment, the illumination light source 20 is provided on both sides of the light receiving sensor 26, and the illumination light Lf can be irradiated toward the reading object R through the reading port 3 (FIG. 2) formed in the case. It is configured. Examples of the reading object R include various objects such as a resin material, a metal material, paper, or a color display device described later. In the optical information reading device 1 according to the present embodiment, In the reading object R, an information code (bar code in FIG. 1) indicated by processing such as printing, direct marking, or display by a display device is a “reading object code”. In the following description, a barcode is exemplified as the information code B, but it may be replaced with a two-dimensional code such as a QR code, a data matrix code, or a maxi code.

  The light receiving sensor 26 is configured to be able to receive the reflected light Lr irradiated and reflected on the reading object R or the information code B. For example, the light receiving sensor 26 is a primary element such as a C-MOS or CCD. A line sensor originally arranged or an area sensor arranged two-dimensionally corresponds to this. The light receiving sensor 26 is mounted on the substrate 4 so that incident light incident through the imaging lens 27 can be received by the light receiving surface 26a. The light receiving sensor 26 is configured to receive a pulse signal (driving signal) having a frequency set from the control circuit 40, and the signal of each light receiving element is synchronized with the input of each pulse from the control circuit 40. Are output in order.

  In the following description, a configuration in which the light receiving sensor 26 is a line sensor will be described as a representative example. In this representative example, each light receiving element of the light receiving sensor 26 outputs a light reception signal having a lower voltage as the amount of received light is larger. In this case, light reception amount signals at respective positions in the line sensor arrangement direction (predetermined direction) are sequentially output, and these signals are input to the low-pass filter circuit 31 as a light reception waveform.

  The optical filter 28 has a function of allowing light in a predetermined frequency band corresponding to the illumination light Lf to pass therethrough and suppressing light outside the predetermined frequency band. Specifically, the light of the predetermined red light wavelength band including the wavelength of the red light emitted from the illumination light source 20 is allowed to pass, and the light deviated from the predetermined red light wavelength band (for example, green light, blue light) ), And is provided between the reading port 3 (FIG. 2) formed in the case and the imaging lens 27, for example. Thereby, the light (reflected light Lr) reflected by the reading object R is selectively received by the illumination light Lf, and unnecessary light greatly deviating from the wavelength of the reflected light Lr is prevented from entering the light receiving sensor 26. is doing.

  The imaging lens 27 is constituted by, for example, a lens barrel and a plurality of condensing lenses accommodated in the lens barrel. In the present embodiment, the image forming lens 27 is incident on a reading port (not shown) formed in the case. The reflected light Lr is collected and a code image of the information code B is formed on the light receiving surface 26 a of the light receiving sensor 26.

  The microcomputer system is configured around a control circuit 40 and a memory 35 that can function as a microcomputer (information processing apparatus), and performs signal processing on the image signal of the information code B imaged by the optical system described above in hardware and software. It is possible.

  The control circuit 40 is a microcomputer capable of controlling the entire optical information reading apparatus 1 and includes a CPU, a system bus, an input / output interface, and the like, and has an information processing function. Various input / output devices (peripheral devices) are connected to the control circuit 40 via a built-in input / output interface. In this embodiment, a power switch 41, an operation switch 42, an LED 43, a buzzer 44, A liquid crystal display 46, a communication interface 48, and the like are connected. The communication interface 48 can be connected to a host computer HST corresponding to the host system of the optical information reader 1.

  The memory 35 is a semiconductor memory device, and corresponds to, for example, a RAM (DRAM, SRAM, etc.) or a ROM (EPROM, EEPROM, etc.). In addition to the above-described image data storage area, the RAM of the memory 35 is configured to be able to secure a work area and a reading condition table that are used by the control circuit 40 in each processing such as arithmetic operation and logical operation. . The ROM stores in advance a predetermined program that can execute a reading process and the like that will be described later, and a system program that can control each hardware such as the illumination light source 20 and the light receiving sensor 26.

  The low-pass filter circuit 31 is provided on the output side of the light receiving sensor 26 and has a function of removing a high frequency component of the light receiving signal using the light receiving signal output from the light receiving sensor 26 as an input signal. The low-pass filter circuit 31 is configured as a known low-pass filter, passes a signal having a frequency equal to or lower than a predetermined cutoff frequency without being attenuated, and inputs a signal in a high frequency region exceeding the cutoff frequency. The higher the signal frequency, the more the output signal that has passed through the filter is suppressed (attenuated).

  The low-pass filter circuit 31 may be a known low-pass filter (known low-pass filter using an operational amplifier) configured as an inverting amplifier circuit, or may be a known low-pass filter configured as a non-inverting amplifier circuit. . Alternatively, a known CR filter that does not use an operational amplifier may be used (in this case, it is desirable to provide a separate amplifier circuit between the light receiving sensor 26 and the low-pass filter circuit 31).

  The binarization circuit 33 corresponds to an example of “binarization means”, and a high-frequency component is generated from a signal output from the low-pass filter circuit 31 (a light receiving waveform in a predetermined direction (element arrangement direction) in the light receiving sensor 26). Based on the (removed signal), the light sensor 26 functions to generate binary data that can specify the light color area and the dark color area in a predetermined direction (element arrangement direction). This binarization circuit compares the output signal from the low-pass filter circuit 31 (light-receiving signal from which high-frequency noise has been removed) with a set threshold value, and outputs an L level signal if the threshold value is exceeded. If it is less than that, an H level signal is output. Note that the signal output from the binarization circuit 33 is stored in the memory 35 as pattern data of the information code B.

  The power supply system is composed of a power switch 41 and the like, and the conduction and interruption of the drive voltage supplied from the power supply are controlled by turning on and off the power switch 41 managed by the control circuit 40.

(Reading process)
Next, a reading process performed by the optical information reading apparatus 1 according to the present embodiment will be described with reference to FIG. FIG. 3 is a flowchart illustrating the flow of reading processing performed by the optical information reading apparatus 1 according to this embodiment. FIG. 4 is an explanatory diagram for explaining reading of an information code printed on paper. In FIG. 4, an explanatory diagram of an information code printed on paper is shown in the upper part, and a portion on the imaging line L1 in the information code is shown enlarged in the middle part. In the lower part, the received light waveform of the enlarged portion is shown. FIG. 5 is an explanatory diagram for explaining reading of the information code displayed on the color display device. In FIG. 5, an explanatory diagram of the information code displayed on the color display device is shown in the upper stage, and the display pixel configuration on the imaging line L1 in the color display apparatus is enlarged and shown in the middle stage. In the lower part, the received light waveform of the enlarged portion is shown. FIG. 6A illustrates the waveform of a light reception signal when an information code displayed on a color display device is imaged. FIG. 6B illustrates a binary value obtained by binarizing the light reception signal. It is explanatory drawing which shows data notionally. FIG. 6C is an explanatory diagram for explaining the correction of the binary data, and FIG. 6D conceptually shows correction data obtained by correcting the binary data of FIG. 6B. FIG.

  In the present embodiment, for example, the reading process shown in FIG. 3 is started with a predetermined operation by the user (for example, a predetermined operation on the operation switch 42) as a trigger, and first, a process of imaging an information code is performed (S1). In this processing, a light source drive signal is given to the illumination light source 20 from the control circuit 40 and the illumination light source 20 emits red illumination light Lf. In this illumination state, reflected light from the information code is received by the light receiving sensor 26. Received light.

  The light receiving sensor 26 receives the reflected light reflected by the reading target code and transmitted through the optical filter 28 by each light receiving element, and reflects from the reading target code based on the amount of light received by each light receiving element. A light reception signal corresponding to the light is output. Specifically, the signals are driven according to a pulse signal (drive signal) of a predetermined frequency given from the control circuit 40, and each signal of each light receiving element arranged in a line every time each pulse is inputted from the control circuit 40. Are output in order. For example, when the light receiving sensor 26 is configured as a line sensor in which N light receiving elements are arranged in a line, the signals of all the light receiving elements are output by inputting N pulses from the control circuit 40. It will be.

  For example, when the information code B (bar code or the like) printed on the paper P as shown in FIG. 4 is a reading target code, the light receiving sensor 26 configured as a line sensor converts the information code to be imaged into a line shape. An image is taken. In FIG. 4, the imaging position when the information code B (bar code or the like) recorded on the paper P is imaged by the light receiving sensor 26 is conceptually shown by a line (imaging line L1). The light is picked up by the sensor 26 in a line shape, and the light receiving signal from each light receiving element is sequentially output, whereby a light receiving waveform as shown in the lowermost stage of FIG. 4 is obtained. The light receiving waveform is a signal in which the position of the light receiving element is on the horizontal axis and the amount of received light is on the vertical axis, and the position of each light receiving element and the amount of received light are associated with each other. The light receiving signal (light receiving waveform) output from the light receiving sensor 26 in this way is converted into binary data by the binarization circuit 33 after the high frequency component is suppressed by the low pass filter circuit 31 described above, and the memory 35. Is remembered.

  After the imaging process of S1, a process of determining whether or not a predetermined period and a predetermined ratio exist in the light reception waveform generated by the imaging process of S1 is performed (S2). This determination process corresponds to a process of determining whether or not the information code captured in S1 is the information code displayed on the color display device.

  The optical information reading apparatus 1 according to the present embodiment can read an information code attached to an object (paper in FIG. 4) as shown in FIG. 4 as a reading target coat, and, for example, as shown in FIG. The information code displayed on the display device 100 can also be read as a reading target coat. The color display device 100 of FIG. 5 is configured as a liquid crystal display device, for example, and has a configuration in which a plurality of display pixels Sa in which pixel elements (R pixel Ra, G pixel Ga, and B pixel Ba) of a plurality of colors are combined are arranged. For example, it is provided in an information device such as a cellular phone, and an information code B is displayed under the control of a control circuit (not shown).

  As in FIG. 7, the color display device 100 is formed by arranging a plurality of display pixels Sa in which R pixels Ra, G pixels Ga, and B pixels Ba are arranged in a predetermined column direction in at least the column direction. In addition, as described above, during imaging by the light receiving sensor 26, the passage of light emitted from the G pixel Ga and the B pixel Ba in the optical filter 28 is suppressed more than the passage of light emitted from the R pixel. (See also FIG. 5). In the determination process of S2, whether or not the information code captured in S1 is the information code displayed on the color display device by detecting the presence of the predetermined period and the predetermined ratio generated in the light reception waveform due to such suppression. Judging.

  Specifically, first, an area where the ratio of the adjacent bright color area to the dark color area is 1: 2 is detected. As shown in FIG. 5, when imaging the color display device 100 in which display pixels Sa in which RGB pixel elements are arranged in a predetermined direction (horizontal direction in FIG. 5) are imaged, the direction in which the pixel elements are arranged (predetermined When the imaging line L1 (imaging position) of the light receiving sensor 26 is arranged along the direction), light from the G pixel Ga and the B pixel Ba is suppressed by the optical filter 28, so that these pixel elements The amount of light received by the light receiving element that images (G pixel Ga and B pixel Ba) is suppressed. As a result, as shown in the lowermost part of FIG. 5 and FIG. 6A, the light reception signal from the light color display pixel Sw displaying a light color (for example, white) is a signal indicating a light color region (a signal equal to or higher than the threshold value V1). And a signal indicating a dark color area (a signal less than the threshold value V1). When such a signal is binarized with reference to the threshold value V1, as shown in FIG. 6B, in the binary data after binarizing the light reception signal from the light color display pixel Sw, the light color region (light reception) The ratio of the width W1 of the region where the amount is specified to be equal to or greater than the threshold value V1 and the width B1 of the dark color region (region where the amount of received light is specified to be less than the threshold value V1) is 1: 2. That is, in the binary data of the light reception signal from the light color display pixel Sw, the width W1 of the light color region corresponds to one pixel element (the amount of R pixel Ra), and the width B1 of the dark color region has two pixel elements. Since this corresponds to the minute (the G pixel Ga and the B pixel Ba), W1: B1 is 1: 2. In S2, in the light color region and the dark color region specified by the light reception waveform (more specifically, the waveform after binarization), the portion where the width of the adjacent light color region and dark color region is 1: 2 is 1 Or a predetermined number is detected. It should be noted that the predetermined ratio serving as a determination criterion may be completely 1: 2, or may be a value having a width including some errors. For example, the predetermined ratio may be 1: n, and n may be a value such that 2-α ≦ n ≦ 2 + α (α is a predetermined error value).

  Further, in S2, a region in which the period of the bright color region (region where the amount of received light is specified to be equal to or greater than the threshold value V1) in the binary data (see FIG. 6B) is a predetermined length is detected. As shown in FIG. 2A, the optical information reading apparatus 1 according to the present embodiment is provided with a reading port 3 that derives illumination light from the illumination light source 20 and takes in reflected light from a reading target code. As shown in FIG. 2B, the reading target code can be read with the reading object R in contact with the reading port 3. Thus, when the positional relationship between the reading object R and the reading port 3 is determined to be constant, the magnification of the image of the reading object R formed on the light receiving sensor 26 is also fixed based on the apparatus configuration. Therefore, taking this magnification into account, the scale of the captured image can be specified, and the actual length of each part in the captured image can be detected. For example, when an image is captured while the color display device 100 (FIG. 5) is in contact with the reading port 3, it is possible to specify the magnification at which the color display device 100 forms an image on the light receiving sensor 26. The actual length of each part on the color display device 100 (for example, the actual length of the light color bar and dark color bar of the information code B displayed on the color display device 100, or each display pixel Sa (1 dot) Actual length etc.).

  Based on the premise that the scale of the captured image can be specified in this way, in S2, it is detected whether there is a part where the cycle of any light color region specified by the binary data has a predetermined length. is doing. Specifically, for example, in the portion where the width of the adjacent light color region and dark color region is 1: 2, as described above, the period T1 of the light color region (that is, the width of the adjacent light color region and dark color region). A predetermined first size (for example, 0.075 mm) in which the actual length of the light color area and the width of the dark color area in the portion where the ratio is 1: 2 is one dot in the VGA display. Or whether it corresponds to one of the predetermined second sizes (for example, 0.15 mm) for one dot in the QVGA display. For example, when the scale is taken into consideration, the portion of the captured image having the period T1 has the predetermined first size (for one dot in VGA display) or the predetermined second size (for one dot in QVGA display) on the color display device 100. In a corresponding case, it is highly likely that the light of the G pixel Ga and the B pixel Ba is suppressed after the bright (for example, white) display pixel Sa of the color display device 100 for VGA display or QVGA display is imaged. Therefore, in S2, in such a case, it is determined that “the light color area of the binary data has a predetermined period”. The “predetermined period” may be a completely single value or a value having a width including some errors.

  In the present embodiment, the control circuit that performs the determination process of S2 corresponds to an example of an “area detection unit”, and in the binary data generated by the binarization unit, a region in which the cycle of the light color region is a predetermined cycle In addition, in the binary data generated by the binarizing means, the ratio of the widths of adjacent bright color areas and dark color areas is a predetermined ratio (1). : 2) is detected. Furthermore, the control circuit that performs the determination process of S2 corresponds to an example of a “mode switching unit”, and switches between a correction mode in which correction data is generated by the correction data generation unit and a normal mode in which no correction data is generated. More specifically, when a predetermined execution condition that is a reference for executing the correction mode is satisfied (when a region having a light color region having a predetermined period is detected by the region detection unit, and a predetermined ratio region detection is performed) When the area where the adjacent bright color area and dark color area have a predetermined ratio (1: 2) is detected), the function is switched to the correction mode.

  When the predetermined period detection process and the predetermined ratio detection process as described above are performed in S2, it is determined that "the light color area of the binary data has a predetermined period" and "the adjacent light color area and dark color area" If it is determined that an area having a predetermined ratio (1: 2) has been detected ”, the result of S2 is Yes, and correction processing for correcting binary data as shown in FIG. 6B is performed (S3). ).

  In the correction process of S3, correction is performed by adding a light color region having a width L2 to one side of each light color region in the binary data obtained as shown in FIG. 6B. In other words, when the result in S2 is Yes, it can be said that the G pixel and B pixel which should be the light color region are originally suppressed and determined as the dark color region, and the width of the dark color region of the suppressed portion is determined. Is considered to be 2/3 of the above-mentioned predetermined period T1. Therefore, in the process of S3, as shown in FIG. 6C, a predetermined length L1 corresponding to the G pixel and the B pixel (described above) is applied to one side of each bright color area of the binary data obtained in S1. Correction data to which a light color area having a length 2/3 of the period T1) is added is generated. In this way, correction data as shown in FIG. 6D is obtained.

  The control circuit 10 that executes the process of S3 corresponds to an example of a “correction data generation unit”, and displays light for each light color area in the binary data generated by the binarization unit by the optical filter 28. Functions to generate correction data by adding a correction region having a predetermined width L2 corresponding to pixel elements (G pixel Ga and B pixel Ba) for which the suppression is suppressed.

  Note that if it is determined in S2 that either one of the above-mentioned predetermined cycle and predetermined ratio is not satisfied (that is, if the light color area of the binary data is not determined to be the predetermined cycle, or adjacent light colors) In the case where an area in which the area and the dark area have a predetermined ratio (1: 2) is not detected), the process proceeds to No in S2. In this case, since the possibility that the color display device 100 has been imaged is low, the correction process of S3 is not performed.

  After the process of S2 or S3, a process for determining whether or not a barcode exists is performed. This barcode detection is performed by a known method based on the binary data obtained in S1 or S3 (correction data in the case of S3). If a bar code is detected, the process proceeds to Yes in S4, and a decoding process for the detected bar code is performed (S5). In this decoding process, the size and position of each bright color area and each dark color area are specified based on the binary data stored in the memory 35, and decoding is performed by a known decoding method. After this decoding process, a process of outputting the decoding result to the liquid crystal display 46 or the like is performed (S7).

  In the present embodiment, the control circuit 40 corresponds to an example of “decoding means”, and performs decoding processing based on binary data in the normal mode, and performs decoding processing based on the correction data in the correction mode. Is functioning. In the present embodiment, the correction mode is when S2 is Yes, and the normal mode is No when S2.

(Main effects of the first embodiment)
The optical information reading apparatus 1 according to the present embodiment is provided with an optical filter 28 that allows light in a predetermined frequency band corresponding to the illumination light from the illumination light source 20 to pass and suppresses light other than the predetermined frequency band. The light receiving sensor 26 receives the reflected light from the reading target code via the optical filter 28. By doing in this way, disturbance light other than the reflected light which illumination light reflected in the reading object code | cord | chord can be removed effectively.
On the other hand, with such a configuration, when the information code B displayed on the color display device 100 is the code to be read, some pixel elements (light suppressed by the optical filter) in the area displaying the bright color pattern are used. There is a concern that light from a pixel element that emits light) is suppressed by the optical filter 28, and a waveform component indicating a dark color is included as noise in the waveform of the light color pattern portion in the received light signal.
On the other hand, in the present invention, based on the light reception waveform in the predetermined direction in the light receiving sensor 26, binary data capable of specifying the light color area and the dark color area in the predetermined direction is generated by the binarizing means, and further, correction data generation By means, a correction area having a predetermined width L2 corresponding to the pixel element (G pixel Ga, B pixel Ba) whose display light is suppressed by the optical filter 28 is added to each bright color area in the generated binary data. Thus, correction data is generated. Then, decoding processing is performed by the decoding means based on the generated correction data.
In this way, the width of the pixel element that is suppressed by the optical filter 28 (the pixel element that should be detected as a light color area but is detected as a dark color area by suppressing light in the optical filter) is taken into consideration. Thus, correction data that compensates for this can be generated. Since the decoding process is performed based on the correction data, it is possible to accurately read while suppressing erroneous recognition caused by the circumstances peculiar to the color display device.

  In the present embodiment, mode switching means for switching between a correction mode in which correction data is generated by the correction data generation means and a normal mode in which no correction data is generated is provided. The decoding means is configured to perform decoding processing based on the binary data in the normal mode, and to perform decoding processing based on the correction data in the correction mode. Is switched to the correction mode when the predetermined execution condition is satisfied. In this way, the correction data is not generated in the dark clouds but is generated when the predetermined execution condition that is the execution standard of the correction mode is satisfied. Correction processing can be omitted, and processing efficiency and processing time can be shortened.

  In the present embodiment, area detection means for detecting an area in which the period of the bright color area is a predetermined period in the binary data generated by the binarization means is provided. And it switches to correction mode on condition that the area | region which becomes a predetermined period is detected by this area | region detection means. When the information code displayed on the color display device is imaged, an area in which the period of the bright color area is a predetermined period is detected due to the size of the pixel elements of the color display apparatus or the arrangement of the pixel elements. Since the possibility increases, the correction process can be performed by appropriately determining the possibility that the color display device has been imaged by switching to the correction mode on condition that such a region is detected.

  Further, in the present embodiment, the reading port 3 that derives the illumination light from the illumination light source 20 and takes in the reflected light from the reading target code is provided, and the color display device 100 is in contact with the reading port 3. Is configured to read the code to be read. In this way, since the distance between the reading port 3 and the color display device 100 can be kept at a certain short distance when the code is imaged, it is more determined whether or not the cycle of the bright color region is a cycle corresponding to the pixel element. It becomes easy to judge accurately.

Further, in the present embodiment, the predetermined ratio area detection that detects an area in which the ratio of the widths of adjacent bright color areas and dark color areas is a predetermined ratio (1: 2) in the binary data generated by the binarization means. Means for switching to the correction mode on condition that the area having the predetermined ratio is detected by the predetermined ratio area detecting means.
When the information code B displayed on the color display device 100 is imaged as shown in FIG. 5, the adjacent bright light is caused by the regular arrangement of the pixel elements and the suppression of light from some of the pixel elements. Since there is a high possibility that the ratio between the width of the color area and the dark area becomes a predetermined ratio (1: 2), the color display device 100 captures an image when the mode is switched to the correction mode on condition that such a predetermined ratio is detected. The correction processing can be performed by more appropriately determining the possibility of being made.

  The color display device 100 to be imaged has a configuration in which a plurality of display pixels Sa configured by arranging R pixels Ra, G pixels Ga, and B pixels Ba in a predetermined column direction are arranged in at least the column direction. . According to the present invention, the information code B displayed on the color display device 100 can be satisfactorily read by using the RGB color display device 100 widely used in various places as a reading object. Convenience can be improved.

  Further, in the present embodiment, the illumination light source 20 is configured to irradiate red illumination light, and the optical filter 28 passes display light emitted from the G pixel and B pixel, and passes light emitted from the R pixel. It is comprised so that it may suppress more. In this way, when the information code B attached to the object is read as the reading target code as shown in FIG. 4, the light (red light) reflected by the illumination light in the bright color region is selectively selected by the optical filter. It can be transmitted, and disturbance light can be removed well. On the other hand, when the information code B displayed on the color display device 100 is read as shown in FIG. 5, light from the G pixel Ga and B pixel Ba is suppressed by the optical filter 28 in the region where the bright color pattern is displayed. There is a concern that a waveform component showing a dark color is included as noise in the waveform of the pattern portion. However, in the present invention, it is possible to generate correction data in which noise due to suppression of light from the G pixel Ga and B pixel Ba is corrected, and such noise (in the G pixel Ga and B pixel Ba). Decoding can be performed satisfactorily after properly removing (caused noise).

  In this embodiment, the color display device 100 provided in a mobile terminal (for example, a mobile phone) is a reading target. In this way, it is possible to satisfactorily read an information code displayed on the mobile terminal using a mobile terminal widely used in various places as a reading target, and the convenience for the user can be further enhanced.

[Other Embodiments]
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

In the above embodiment, both the predetermined ratio and the predetermined period are detected in the process of S2, but only one of them may be detected. For example, in the binary data generated by the above-described binarization circuit 33 by changing the processing of S2, the ratio of the widths of the adjacent bright color area and dark color area is a predetermined ratio (1: In addition to detecting the region 2), it is also possible to determine Yes in S2 (switch to the correction mode) when the detected predetermined ratio region continues a predetermined number of times.
When an information code such as a barcode is displayed on the color display device 100, a display pixel that displays a bright color (for example, white) is arranged with a certain size by a margin around the code, and the margin display area Then, a large number of pixel elements (G pixel Ga, B pixel Ba) suppressed by the optical filter 28 are included at regular intervals. Therefore, if the predetermined ratio area (the area where the ratio of the widths of the light color area and the dark color area is the predetermined ratio (1: 2)) continues for a predetermined number of times, the color display device is switched to the correction mode. In 100, it is possible to more appropriately determine the possibility that an information code such as a bar code has been imaged, and perform correction processing.

  In the above embodiment, the portion where the light color region has a predetermined cycle is detected in the binary data of the light reception waveform, but the portion where the dark color region has a predetermined cycle may be detected. Alternatively, a portion where the light color region has a predetermined length or a portion where the dark color region has a predetermined length may be detected.

DESCRIPTION OF SYMBOLS 1 ... Optical information reader 3 ... Reading port 20 ... Illumination light source (illumination means)
26 ... Light receiving sensor 28 ... Optical filter 33 ... Binarization circuit (binarization means)
40. Control circuit (correction data generating means, decoding means, mode switching means, area detecting means, predetermined ratio area detecting means)
100 ... Color display device B ... Bar code (information code)
Sa ... display pixel Ra ... R pixel (pixel element)
Ga ... G pixel (pixel element)
Ba ... B pixel (pixel element)

Claims (9)

An optical information reader capable of reading, as a reading target code, an information code displayed on a color display device formed by arranging a plurality of display pixels each having a combination of pixel elements of a plurality of colors and an information code attached to an object. ,
Illuminating means for illuminating the reading target code with illumination light;
An optical filter that transmits light in a predetermined frequency band corresponding to the illumination light and suppresses light other than the predetermined frequency band; and
A light receiving sensor that receives reflected light from the reading target code via the optical filter and outputs a light receiving signal corresponding to the reflected light;
Binarization means for generating binary data capable of specifying a light color region and a dark color region in the predetermined direction based on a light reception waveform in a predetermined direction in the light receiving sensor;
For each bright color area in the binary data generated by the binarization means, a correction area having a predetermined width corresponding to the pixel element whose display light is suppressed by the optical filter is added to generate correction data. Correction data generating means to perform,
Decoding means capable of executing decoding processing based on the correction data generated by the correction data generating means;
An optical information reading apparatus comprising: A mode switching means for switching between a correction mode in which the correction data is generated by the correction data generation means and a normal mode in which the correction data is not generated;
The decoding means is configured to perform decoding processing based on the binary data in the normal mode, and to perform decoding processing based on the correction data in the correction mode,
The optical information reading apparatus according to claim 1, wherein the mode switching unit switches to the correction mode when a predetermined execution condition that is an execution reference of the correction mode is satisfied. The mode switching means is
In the binary data generated by the binarization means, a region where each length of the light color region or the dark color region is a predetermined length, or a region where the cycle of the light color region or the dark color region is a predetermined cycle A region detecting means for detecting
3. The optical information reading apparatus according to claim 2, wherein the correction mode is switched on condition that the area having the predetermined length or the predetermined period is detected by the area detecting unit. A reading port for deriving the illumination light from the illumination means and taking in the reflected light from the reading object code;
The optical information reading device according to claim 3, wherein the reading target code is read in a state where the color display device is in contact with the reading port. The mode switching means is
In the binary data generated by the binarization means, a predetermined ratio area detection means for detecting an area in which the ratio of the width of the adjacent bright color area and the dark color area is a predetermined ratio,
5. The optical information reading apparatus according to claim 3, wherein the correction mode is switched on condition that an area having the predetermined ratio is detected by the predetermined ratio area detecting unit. The mode switching means is
In the binary data generated by the binarization means, a predetermined ratio area detection means for detecting an area in which the ratio of the width of the adjacent bright color area and the dark color area is a predetermined ratio,
The optical information reading according to any one of claims 2 to 4, wherein the correction mode is switched when the predetermined ratio area detected by the predetermined ratio area detecting unit continues a predetermined number of times. apparatus.   2. The color display device according to claim 1, wherein a plurality of the display pixels configured by arranging R pixels, G pixels, and B pixels in a predetermined column direction are arranged in at least the column direction. The optical information reading device according to claim 6. The illumination means is configured to irradiate the red illumination light,
8. The optical information reading device according to claim 7, wherein the optical filter suppresses the passage of the display light emitted from the G pixel and the B pixel as compared with the passage of the light emitted from the R pixel. apparatus.   The optical information reader according to claim 1, wherein the color display device is a display device provided in a mobile terminal.

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