JP5218316B2 - Optical information reader - Google Patents

Description

  The present invention relates to an optical information reader.

  2. Description of the Related Art Conventionally, an information code reading device shown in Patent Document 1 below is known as a technique related to an optical information reading device. This information code reader is configured to detect an inclination angle that is an angle formed by the optical axis of the illumination light with respect to the reference horizontal. If it is determined that proximity reading is performed because the apparatus is close to a horizontal posture based on the tilt angle, it is determined that the reading environment is relatively good, and the exposure time of the optical sensor is set to be short. In addition, the amplifier gain (amplification factor) of the waveform shaping unit is set small. Further, when it is determined that remote reading is performed because the apparatus is close to a vertical posture based on the tilt angle, it is determined that the reading environment is not relatively good, and the exposure time of the optical sensor is long. In addition to being set, the amplifier gain of the waveform shaping unit is set to be large.

  In the medium mark reading apparatus shown in Patent Document 2 below, on the premise that barcodes with different densities are read, the scanning speed is adjusted based on the frequency of the output waveform output according to the barcode. To reduce read errors.

JP 2006-309212 A JP-A-06-004701

  However, as in the invention described in Patent Document 1, when the exposure time is set to be long as remote reading because the apparatus is close to a vertical posture, a high-density information code that is easily affected by camera shake is to be read. However, there was a problem that reading failed due to camera shake. In particular, simply increasing the exposure time and increasing the amplification factor cannot properly suppress both the effects of camera shake and noise when considering the effects of noise. Accordingly, it is necessary to appropriately set the exposure time and the amplification factor.

  Moreover, in the said patent document 2, when barcode length is long, it is premised that it is low density, and when barcode length is short, it is high density, For example, like CODE128 employ | adopted as an object for public charges, There is also a problem in that it is not possible to reliably determine whether or not the barcode has a high density with a barcode having a long barcode length and a high density.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an optical information reading apparatus capable of improving reading accuracy regardless of the density of information codes.

In order to achieve the above object, the optical information reader of claim 1 according to claim 1 is an optical information reader capable of reading an information code in which a plurality of bright color patterns and dark color patterns are arranged. An imaging unit that images the information code, an exposure time control unit that can control an exposure time of the imaging unit, and an amplification factor control unit that can control an amplification factor that amplifies an image signal from the imaging unit; Binarizing means for dividing the amplified signal waveform of the image signal into a plurality of light color areas and dark color areas having width data by comparing with a predetermined threshold; and the plurality of parts divided by the binarizing means decoding means for decoding the sequence data bright areas and dark areas of are arranged, the arrangement density of the light-colored region and the dark region constituting the sequence data is prescribed A determination means for determining that the density is higher than the predetermined density, and determining that the density is not higher if the density is less than the predetermined density, wherein the determination by the decoding means has failed, wherein the determination When the arrangement density is determined to be high by the means, the exposure time is shortened by the exposure time control means and the amplification factor control means is compared with a case where the arrangement density is not high density. And when the determination means determines that the array density is not high, the exposure time control means causes the exposure time control means to compare with the exposure time control means. lower the amplification factor by the gain control means with a longer time, the determination means is widest among the bright region and the dark region constituting the sequence data is narrow When the number of pixels of the image signal corresponding to the region is equal to or less than a first threshold, the array density is determined to be a high density equal to or higher than the predetermined density, and the number of pixels exceeds the first threshold The arrangement density is determined not to be higher than the predetermined density .

The invention of claim 2 is an optical information reading apparatus capable of reading an information code in which a plurality of light color patterns and dark color patterns are arranged, and an image pickup means for picking up the information code, and an exposure of the image pickup means Comparing exposure time control means capable of controlling time, amplification rate control means capable of controlling an amplification factor for amplifying an image signal from the imaging means, and comparing the signal waveform of the amplified image signal with a predetermined threshold value And binarizing means for dividing the plurality of light color areas and dark color areas having width data, and decoding means for decoding array data in which the plurality of light color areas and dark color areas divided by the binarizing means are arranged If the arrangement density of the light color area and the dark color area constituting the arrangement data is equal to or higher than a predetermined density, it is determined that the density is high, and is less than the predetermined density. A determination unit that determines that the density is not high, and when the decoding by the decoding unit fails, and the determination unit determines that the arrangement density is high, the high density The exposure time control means shortens the exposure time and increases the amplification factor by the amplification factor control means, and the determination means does not make the arrangement density high compared to the case where it is determined that In the case where it is determined that the density is high, the exposure time control means lengthens the exposure time and the gain control means decreases the gain, and the determination When the total number of at least one of the light color area and the dark color area existing in a predetermined area in the array data is equal to or greater than a second threshold, It is determined that the column density is a high density that is equal to or higher than the predetermined density, and when the total number is less than the second threshold, it is determined that the arrangement density is not a high density that is equal to or higher than the predetermined density. Features.

According to a third aspect of the present invention, there is provided an optical information reading apparatus capable of reading an information code in which a plurality of light color patterns and dark color patterns are arranged, an image pickup means for picking up the information code, and exposure of the image pickup means Comparing exposure time control means capable of controlling time, amplification rate control means capable of controlling an amplification factor for amplifying an image signal from the imaging means, and comparing the signal waveform of the amplified image signal with a predetermined threshold value And binarizing means for dividing the plurality of light color areas and dark color areas having width data, and decoding means for decoding array data in which the plurality of light color areas and dark color areas divided by the binarizing means are arranged If the arrangement density of the light color area and the dark color area constituting the arrangement data is equal to or higher than a predetermined density, it is determined that the density is high, and is less than the predetermined density. A determination unit that determines that the density is not high, and when the decoding by the decoding unit fails, and the determination unit determines that the arrangement density is high, the high density The exposure time control means shortens the exposure time and increases the amplification factor by the amplification factor control means, and the determination means does not make the arrangement density high compared to the case where it is determined that In the case where it is determined that the density is high, the exposure time control means lengthens the exposure time and the gain control means decreases the gain, and the determination The means may predefine at least one of the light color area and the dark color area constituting the specific area included in the array data as the specific area. It is determined that the arrangement density is a high density that is equal to or higher than the predetermined density, and the arrangement density is equal to or higher than the predetermined density when the number of components exceeds the predetermined number. It is determined that the density is not high.

According to a fourth aspect of the present invention, in the optical information reading apparatus according to the third aspect , the determination means is the case where the number of components is equal to the specified number, and the light color region constituting the specific region and the When the arrangement configuration of the dark color region is different from the arrangement configuration preliminarily defined as the specific region, it is determined that the arrangement density is a high density equal to or higher than the predetermined density.

In the invention of claim 1, the two plurality of bright regions and dark regions that are divided by the value means based on the sequence data is arranged, the arrangement density of bright regions and dark regions constituting the sequence data, predetermined If the density is equal to or higher than the predetermined density, it is determined that the density is high, and if the density is less than the predetermined density, it is determined that the density is not high. When the decoding by the decoding unit fails and the determination unit determines that the arrangement density is high, the exposure time control unit is compared with the case where it is determined that the arrangement density is not high. Thus, the exposure time is set short and the gain is set high by the gain control means. Further, when the determination means determines that the arrangement density is not high, the exposure time control means sets the exposure time longer and the amplification factor is controlled as compared with the case where the arrangement density is determined to be high. The gain is set low by the means. The case where the decoding by the decoding means has failed includes not only the case where the decoding result is not obtained but also the case where a decoding result different from the expected result is obtained, for example.

As a result, when it is determined that the arrangement density is high, the exposure time is set short and the amplification factor is set high. Can be suppressed. Also, if it is determined that the arrangement density is not high, the exposure time is set long and the amplification factor is set low, so that it is relatively easy to generate noise when reading low density information codes that are not high density. The influence of can be suppressed.
Therefore, the reading accuracy of the information code can be improved regardless of the density of the information code.

In particular , the determination unit determines the arrangement density when the number of pixels of the image signal corresponding to the narrowest area among the light color area and the dark color area constituting the arrangement data is equal to or less than a first threshold that can be regarded as high density, for example. Is determined to be high density, and when the number of pixels exceeds the first threshold, it is determined that the arrangement density is not high density. Thereby, it is possible to reliably determine whether or not the array density is high by appropriately setting the first threshold value according to the use environment, for example, 10 pixels for a predetermined area. .

In the invention according to claim 2 , the determination means can regard the total number of at least one of the light color area and the dark color area existing in the predetermined area in the array data as a high density in relation to the predetermined area, for example. When it is equal to or higher than the second threshold, it is determined that the arrangement density is high, and when the total number is less than the second threshold, it is determined that the arrangement density is not high. Accordingly, it is possible to reliably determine whether or not the arrangement density is high by appropriately setting the second threshold value to, for example, five in relation to the predetermined region.

According to a third aspect of the present invention, the determination means is configured when the number of components of at least one of the light color area and the dark color area constituting the specific area included in the array data is less than a predetermined number that is defined in advance as the specific area. When the arrangement density is determined to be high and the number of components exceeds the specified number, it is determined that the arrangement density is not high.

  When one character of the barcode is a specific area, the number of dark color areas of the character is less than a predetermined number defined in advance as the character. For example, the dark color area is blurred due to the influence of camera shake. Since there is a high possibility that the number of areas recognized as areas is reduced, it is assumed that a high-density information code that is greatly affected by camera shake is targeted for reading. Therefore, when the number of components in a specific area is less than the specified number, it is determined that the arrangement density is high, and the exposure time is set short and the amplification factor is set high to read the high-density information code. It is possible to suppress the influence of camera shake that tends to occur.

  In addition, in the case where the number of components of the dark area in one character of the barcode exceeds a predetermined number previously defined as the character, for example, an area that is recognized as a dark area because the dark area is divided due to the influence of noise. Since there is a high possibility that the number has increased, it is assumed that a low-density information code that is greatly affected by noise is not a high-density information code. Therefore, when the number of components in a specific area exceeds the specified number, it is determined that the arrangement density is low, and the exposure time is set long and the amplification factor is set low to read a low density information code. The influence of noise that is likely to occur can be suppressed.

According to a fourth aspect of the present invention, the determination means is for the case where the number of components is equal to the specified number, and when the arrangement configuration of the light color region and the dark color region constituting the specific region is different from the pre-specified one as the specific region. It is determined that the arrangement density is high.

  When one character of the barcode is used as a specific area, even if the number of dark color areas of the character is equal to a predetermined number as the character, the arrangement is different from the predetermined arrangement For example, if a dark area is blurred due to the effects of camera shake, the area that is recognized as a dark area is likely to change, so that high-density information codes that are greatly affected by camera shake are to be read. Is assumed. Therefore, when the number of components in a specific area is equal to the specified number and the arrangement is different from the predetermined arrangement, the arrangement density is determined to be high, and the exposure time is shortened and the amplification factor is increased. By setting, it is possible to suppress the influence of camera shake that tends to occur when reading a high-density information code.

1 is a block diagram showing an electrical configuration of an optical information reading apparatus 10 according to a first embodiment. 3 is a flowchart illustrating a flow of a reading process in a control circuit 40 according to the first embodiment. Is an explanatory view showing the relationship between the bar code density and sequence data, 3 (A) shows a high density of states of the bar code B _1, FIG. 3 (B) a low density state of the bar code B ₂ of Indicates. It is a flowchart which illustrates the flow of the reading process in the control circuit 40 of 3rd Embodiment. FIG. 5A shows a part of array data affected by camera shake, and FIG. 5B shows a part of array data affected by noise. It is explanatory drawing for demonstrating the principal part of the reading process which concerns on 4th Embodiment, and shows the arrangement | sequence data of the timing pattern P in QR Code. FIG. 7A shows the arrangement data of the timing pattern P ₁ affected by camera shake, and FIG. 7B shows the arrangement data of the timing pattern P ₂ affected by noise.

[First Embodiment]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment in which an optical information reading device of the invention is embodied will be described with reference to the drawings.
As shown in FIG. 1, the optical information reader 10 is configured as a device that reads an information code such as a barcode or QR code displayed on an object. The optical information reading apparatus 10 includes a circuit unit 20 housed in a case (not shown). The circuit unit 20 mainly includes an illumination light source 21, a light receiving sensor 28, an imaging lens 27, and the like. And a microcomputer (hereinafter referred to as “microcomputer”) system such as a memory 35, a control circuit 40, and a trigger switch 42.

  The optical system is divided into a light projecting optical system and a light receiving optical system. The illumination light source 21 constituting the light projecting optical system functions as an illumination light source capable of emitting the illumination light Lf, and includes, for example, a red LED and a lens provided on the emission side of the LED. In addition, in FIG. 1, the example which irradiates the illumination light Lf toward the target object R with which the barcode B was displayed is shown notionally.

  The light receiving optical system includes a light receiving sensor 28, an imaging lens 27, a reflecting mirror (not shown), and the like. The light receiving sensor 28 is configured as a CCD area sensor, can receive the reflected light Lr irradiated and reflected on the barcode B or the object R, and the exposure time is instructed from the control circuit 40. It is configured to be controllable accordingly. The light receiving sensor 28 is mounted on a printed wiring board (not shown) so as to be able to receive incident light incident through the imaging lens 27. The light receiving sensor 28 may correspond to an example of an “imaging unit” recited in the claims.

  The imaging lens 27 functions as an imaging optical system capable of condensing incident light incident from the outside via a reading port (not shown) and forming an image on the light receiving surface 28a of the light receiving sensor 28. . In the first embodiment, after the illumination light Lf emitted from the illumination light source 21 is reflected by the barcode B, the reflected light Lr is condensed by the imaging lens 27 and is applied to the light receiving surface 28 a of the light receiving sensor 28. An image is formed.

  The microcomputer system includes an amplification circuit 31, an A / D conversion circuit 33, a memory 35, an address generation circuit 36, a synchronization signal generation circuit 38, a control circuit 40, a trigger switch 42, a light emitting unit 43, a buzzer 44, a vibrator 45, and a liquid crystal display. 46, a communication interface 48, and the like.

  The image signal (analog signal) output from the light receiving sensor 28 of the optical system is input to the amplifier circuit 31 and amplified with a predetermined amplification factor, and then input to the A / D conversion circuit 33. The signal is converted to a digital signal. When the digitized image signal, that is, image data (image information) is generated and input to the memory 35, it is stored in a predetermined code image information storage area. The synchronization signal generation circuit 38 is configured to generate a synchronization signal for the light receiving sensor 28 and the address generation circuit 36, and the address generation circuit 36 is based on the synchronization signal supplied from the synchronization signal generation circuit 38. Thus, the storage address of the image data stored in the memory 35 can be generated.

  The control circuit 40 is configured by a microcomputer that can control the entire optical information reader 10, has a CPU, a system bus, an input / output interface, and the like, has an information processing function, and has an information processing device together with the memory 35. Is configured. In the first embodiment, a trigger switch 42, a light emitting unit 43, a buzzer 44, a vibrator 45, a liquid crystal display 46, a communication interface 48, and the like are connected to the control circuit 40.

  Thereby, for example, the control circuit 40 can turn on / off the light emitting unit 43 that functions as an indicator for notifying information related to monitoring and management of the trigger switch 42 and reading of the barcode B, and a buzzer that can generate a beep sound and an alarm sound. Communication that enables ON / OFF of ringing 44, drive control of the vibrator 45 capable of generating vibration that can be transmitted to the user of the optical information reader 10, display control of the liquid crystal display 46, and serial communication with an external device Communication control of the interface 48 is enabled.

Next, a reading process performed by the control circuit 40 in the optical information reading apparatus 10 configured as described above will be described with reference to FIGS.
In the reading process according to the first embodiment, the exposure time of the light receiving sensor 28 and the output from the light receiving sensor 28 according to the information code to be read, specifically, the density of the light color pattern and the dark color pattern in the barcode B, are output. By controlling both the amplification factor of the generated signal, both the influence of camera shake and the influence of noise are suppressed.

  That is, since the relatively high density barcode B is composed of a light color pattern and a dark color pattern densely, if such a high density barcode B is to be read, it is easily affected by camera shake during reading. Decoding may fail. In addition, although the relatively low density barcode B is not easily affected by camera shake, if the amplification factor is increased, it may be susceptible to noise and decoding may fail.

Therefore, in the first embodiment, when the barcode B has a relatively high density, the exposure time is set short and the amplification factor is set high, and when the barcode B has a relatively low density, the exposure time is set. By setting the length long and the amplification factor low, decoding failure due to the effects of camera shake and noise is effectively suppressed.
A specific reading process will be described below.

  First, in step S101 of FIG. 2, an imaging process is performed, and the illumination light Lf is emitted from the illumination light source 21 toward the object R on which the barcode B is displayed in accordance with the operation of the trigger switch 42 by the operator. . As shown in FIG. 1, an image signal output from the light receiving sensor 28 when the reflected light Lr reflected by the object R is received by the light receiving sensor 28 with a preset initial exposure time To is obtained. Amplification circuit 31 amplifies the image with a preset initial amplification factor Go, and generates image data based on the amplified image signal.

  Next, in step S103, binarization processing is performed. In this process, the signal waveform of the image signal output and amplified by the light receiving sensor 28 is compared with a predetermined threshold, and the signal waveform is divided into a light color region and a dark color region based on the comparison. The predetermined threshold value may be a predetermined constant value or a value determined based on a signal waveform. The control circuit 40 that executes the process of step S103 corresponds to an example of “binarization means” recited in the claims.

  Subsequently, a decoding process is performed in step S105. In this process, array data in which a plurality of light color areas and dark color areas divided as described above are arranged is decoded based on a known decoding method. The control circuit 40 that executes the process of step S105 corresponds to an example of a “decoding unit” recited in the claims.

  If it is determined in step S107 that the decoding process has been successful (Yes in S107), the process at the time of successful decoding is performed, and the reading process ends.

  On the other hand, if the decoding process fails, it is determined No in step S107. Note that the case where decoding by the decoding process has failed includes not only a case where a decoding result is not obtained but also a case where a decoding result different from the expected result is obtained, for example.

  Next, in step S109, if the arrangement density of the light color pattern and the dark color pattern constituting the barcode B is equal to or higher than a predetermined density based on the arrangement data, it is determined that the density is high. If there is, it is determined that the density is not high. The control circuit 40 that executes the process of step S109 corresponds to an example of a “determination unit” recited in the claims.

Specifically, in the first embodiment, when the number of pixels of the image signal corresponding to the dark color area constituting the array data is equal to or less than the first threshold that can be regarded as high density, for example, as shown in FIG. as the bar code B _1, if the number of pixels of the most narrow dark region is 10 pixels or less, it is determined that the arrangement density is high density to a predetermined density or more, shown in FIG. 3 (B) as the bar code B _2, determines the number of pixels of the most narrow dark region when it exceeds the first threshold (10 pixels), the arrangement density is not high density to a predetermined density or more. 3A and 3B schematically show the state of light received by the light receiving sensor 28 in units of pixels in a predetermined region in one scanning direction.

  If it is determined that the arrangement density is high (Yes in S109), an exposure time reduction process is performed in step S111. In this process, the exposure time of the light receiving sensor 28 is set to be shorter than the case where it is determined that the exposure time is not high. Specifically, the exposure time is set to be shorter than a preset initial exposure time To.

  Subsequently, an amplification factor increase process is performed in step S113. In this process, the amplification factor for amplifying the image signal output from the light receiving sensor 28 is set higher than when it is determined that the image signal is not high density. Specifically, the amplification factor is set to increase with respect to a preset initial amplification factor Go. From the next time onward, the reading process corresponding to the exposure time and the amplification factor set as described above is performed.

  On the other hand, if it is determined that the arrangement density is not high (No in S109), an exposure time extension process is performed in step S115. In this process, the exposure time of the light receiving sensor 28 is set longer than in the case where it is determined that the density is high. Specifically, the exposure time is set to be longer than the initial exposure time To.

  Subsequently, an amplification factor lowering process is performed in step S117. In this process, the amplification factor for amplifying the image signal output from the light receiving sensor 28 is set lower than in the case where it is determined that the density is high. Specifically, the amplification factor is set to be lower than the initial amplification factor Go. From the next time onward, the reading process corresponding to the exposure time and the amplification factor set as described above is performed. The control circuit 40 that executes the processes of steps S111 and S115 corresponds to an example of “exposure time control means” recited in the claims, and the control circuit 40 that executes the processes of steps S113 and S117 is patented. This corresponds to an example of “amplification rate control means” recited in the claims.

  As described above, in the optical information reading apparatus 10 according to the first embodiment, the arrangement density of the light color pattern and the dark color pattern constituting the barcode B is based on the arrangement data divided by the binarization process. However, if the density is equal to or higher than the predetermined density, it is determined that the density is high, and if the density is less than the predetermined density, it is determined that the density is not high. When the decoding is unsuccessful and it is determined that the arrangement density is high, the exposure time is set shorter and the amplification factor is set compared to the case where it is determined that the arrangement density is not high. Is set high. When it is determined that the arrangement density is not high, the exposure time is set longer and the amplification factor is set lower than when the arrangement density is determined to be high.

Accordingly, when it is determined that the arrangement density is high, the exposure time is set short and the amplification factor is set high. Can be suppressed. If it is determined that the arrangement density is not high, the exposure time is set long and the amplification factor is set low, so that it is relatively likely to occur when reading a low density barcode B that is not high density. The influence of noise can be suppressed.
Accordingly, the reading accuracy of the barcode B can be improved regardless of the density of the barcode B.

  In particular, when the number of pixels in the dark color region with the narrowest width is equal to or less than a first threshold (10 pixels) that can be regarded as high density, it is determined that the arrangement density is high and the number of pixels exceeds the first threshold In addition, since it is determined that the arrangement density is not high, it is possible to reliably determine whether or not the arrangement density is high by appropriately setting the first threshold according to the use environment. .

[Second Embodiment]
Next, a second embodiment in which the optical information reading apparatus of the present invention is embodied will be described.
In the optical information reading apparatus 10 according to the second embodiment, in the above-described reading process, the determination process in step S109 of the flowchart in FIG. 2 is calculated based on the total number of dark color areas existing in a predetermined area. This is different from the optical information reading apparatus according to the first embodiment.

  Specifically, in the second embodiment, when the total number of dark color areas existing in a predetermined area in the array data is equal to or higher than a second threshold that can be regarded as a high density in relation to the predetermined area, for example, If the area shown in the lower part of FIG. 3A is the predetermined area, and the total number of dark areas existing in the predetermined area is 5 or more, it is determined that the arrangement density is high. As shown in FIG. 3B, when the total number of dark color areas existing in the predetermined area is less than the second threshold value (5), it is determined that the arrangement density is not high.

  Even in this case, whether or not the arrangement density of the light color pattern and the dark color pattern constituting the barcode B is high by appropriately setting the second threshold value in relation to the predetermined area. Can be reliably determined. In addition, it is not limited to determining whether or not the array density is high based on the total number of dark color areas existing in the predetermined area in the array data and the second threshold value. It may be determined whether or not the arrangement density is high based on the total number of color regions and a threshold value corresponding to the second threshold value.

[Third Embodiment]
Next, a third embodiment that embodies the optical information reading apparatus of the present invention will be described with reference to FIGS.
In the optical information reading apparatus 10 according to the third embodiment, the above-described reading processing is performed based on the flowchart shown in FIG. 4 instead of the flowchart in FIG. 2 according to the first embodiment. Different from the optical information reader.

  In the third embodiment, when the number of dark areas constituting the specific area included in the arrangement data is less than a predetermined number defined as the specific area, it is determined that the arrangement density is high, When the number of components exceeds the specified number, it is determined that the arrangement density is not high.

  Assuming that one character of the barcode B is a specific area, the number of constituents of the dark color area of the character is less than a predetermined number preliminarily defined as the character, for example, as shown in FIG. Since there is a high possibility that the number of areas recognized as dark color areas is reduced because the dark color areas are blurred due to the effects of camera shake, it is assumed that a high-density barcode B that is greatly affected by camera shake is the target of reading. . Therefore, in the third embodiment, when the number of components in the specific region is less than the specified number, it is determined that the arrangement density is high, and by setting the exposure time short and the amplification factor high, The influence of camera shake that is likely to occur when reading a high-density barcode B can be suppressed.

  Further, when the number of components of the dark color area in one character of the barcode B exceeds the prescribed number previously defined as the character, for example, as shown in FIG. 5B, the dark color area is divided due to the influence of noise. Therefore, since there is a high possibility that the number of areas recognized as dark color areas is increasing, it is assumed that a low-density barcode B, which is not a high-density which is greatly affected by noise, is to be read. Therefore, when the number of components in the specific region exceeds the specified number, it is determined that the arrangement density is low, and the low density barcode B is read by setting the exposure time long and the amplification factor low. It is possible to suppress the influence of noise that is likely to occur.

  In addition, even when the number of dark color regions in one character of the barcode B is equal to a predetermined number that is defined in advance as the character, if the arrangement is different from the predetermined arrangement, for example, camera shake may occur. Since the dark color region is blurred due to the influence of the above, it is highly possible that the region recognized as the dark color region has changed. Therefore, it is assumed that a high-density barcode B that is greatly affected by camera shake is used as a reading target. Therefore, when the number of components in a specific area is equal to the specified number and the arrangement is different from the predetermined arrangement, the arrangement density is determined to be high, and the exposure time is shortened and the amplification factor is increased. By setting, it is possible to suppress the influence of camera shake that is likely to occur when the high-density barcode B is read.

Hereinafter, the reading process in the third embodiment will be specifically described with reference to FIGS. 4 and 5.
First, in the same manner as in the first embodiment, if the decoding has failed after performing the processing of steps S101 to S105, and if it is determined No in step S107, it is included in the array data in step S201 of FIG. It is determined whether or not the number of constituents of the specific area, for example, the dark color area constituting the specific character is less than the specified number.

Here, as in the case of the character C ₁ of the barcode B ₁ shown in FIG. 5A, if the number of areas recognized as the dark color area is reduced because the dark color area is blurred due to the influence of camera shake, the character C ₁ Since the number of components of the dark color area is less than the specified number, it is determined Yes in step S201.

  In this case, as described above, since it is determined that the high-density barcode B that is easily affected by camera shake is to be read, in step S203, exposure time reduction processing is performed in the same manner as in step S111. In S205, amplification factor increase processing is performed in the same manner as in step S113.

On the other hand, after the determination of No in step S201, the dark color area is divided due to the influence of noise as in the character C ₂ of the barcode B ₂ shown in FIG. When are increasing the number of regions, the number of configuration of dark areas of the character C ₂ is determined Yes in step S207 because it exceeds the predetermined number.

  In this case, as described above, since it is determined that the low-density barcode B that is easily affected by noise is to be read, the exposure time extension process is performed in step S209 in the same manner as in step S115. In S211, the amplification factor lowering process is performed in the same manner as in step S117.

  Further, if the number of components of the dark color area of the character is equal to the prescribed number and the determination is No in step S207, the area recognized as the dark color area changes because the dark color area is blurred due to the effect of camera shake. Since the arrangement configuration is different from the arrangement arrangement defined in advance, Yes is determined in step S213.

  In this case, as described above, since it is determined that the high-density barcode B that is easily affected by camera shake is to be read, in step S203, exposure time reduction processing is performed in the same manner as in step S111. In S205, amplification factor increase processing is performed in the same manner as in step S113.

  As described above, in the third embodiment, when the number of dark color regions constituting the specific region (character or the like) included in the array data is less than the specified number, it is determined that the array density is high, When the number of components exceeds the specified number, it is determined that the arrangement density is not high. As a result, when the number of components in the specific area is less than the specified number, it is determined that the arrangement density is high, and the exposure time is set short and the amplification factor is set high so that the high-density barcode B It is possible to suppress the influence of camera shake that is likely to occur when reading. Further, when the number of components in a specific region exceeds the specified number, it is determined that the arrangement density is low, and the low density barcode B is read by setting the exposure time long and the amplification factor low. It is possible to suppress the influence of noise that is likely to occur.

  Also, when the number of dark areas constituting the specific area (characters, etc.) included in the array data is equal to the specified number, and the arrangement of the specific area is different from the arrangement defined in advance as the specific area Determines that the arrangement density is high. Thus, even when the region recognized as the dark color region changes due to the blur of the dark region due to the effect of camera shake, the high-density barcode B can be obtained by setting the exposure time short and the amplification factor high. It is possible to suppress the influence of camera shake that is likely to occur when reading.

  Note that in steps S201 and S207, the number of constituents of the dark color area in one character of the barcode B and the prescribed number are not compared, and the number of constituents of the bright color area in the one character and the prescribed number are determined. You may make it compare.

[Fourth Embodiment]
Next, a fourth embodiment that embodies the optical information reading apparatus of the present invention will be described with reference to FIGS.
The optical information reader 10 according to the fourth embodiment is different from the optical information reader according to the third embodiment in that the QR code Q is read instead of the barcode B.

  In the fourth embodiment, a QR code Q timing pattern TP is employed as the above-described specific area. That is, as shown in FIG. 6, the timing pattern TP is configured such that the light color region and the dark color region are alternately arranged 1: 1 between the finder patterns FP. When the number of dark color areas to be configured is less than a predetermined number specified in advance as a specific area, it is determined that the arrangement density is high, and when the number of elements exceeds the specified number, the arrangement density is not high. Is determined. Note that the prescribed number defined in advance is obtained from the distance between the finder patterns FP of the QR code Q.

Hereinafter, the reading process according to the fourth embodiment will be specifically described with reference to FIGS. 4 and 7.
First, as in the first embodiment, if the decoding of the QR code Q has failed after performing the processing of steps S101 to S105, if it is determined No in step S107, the timing pattern is determined in step S201 of FIG. It is determined whether or not the number of dark color regions constituting the TP is less than the specified number.

Here, as in the timing pattern TP ₁ of the QR code Q ₁ shown in FIG. 7A, when the number of areas recognized as the dark color area is reduced because the dark color area is blurred due to the influence of camera shake, this timing pattern Since the number of components of the dark color area of TP ₁ is less than the specified number, it is determined as Yes in step S201.

  In this case, as described above, since it is determined that the high-density QR code Q that is easily affected by camera shake is to be read, in step S203, exposure time reduction processing is performed in the same manner as in step S111. In S205, amplification factor increase processing is performed in the same manner as in step S113.

On the other hand, after the determination is No in the step S201, as shown in FIG. 5 QR code Q ₂ of the timing patterns TP ₂ shown (B), the recognized as dark areas to dark areas are separated by the influence of the noise When the number of regions is increasing that the configuration number of dark areas of the timing pattern TP ₂ is determined Yes in step S207 because it exceeds the predetermined number.

  In this case, as described above, since it is determined that the low-density QR code Q that is easily affected by noise is to be read, in step S209, exposure time extension processing is performed in the same manner as in step S115. In S211, the amplification factor lowering process is performed in the same manner as in step S117.

  In addition, after the determination that the number of components of the dark color area of the timing pattern TP is equal to the specified number and No in step S207, the area recognized as the dark color area changes because the dark color area is blurred due to the influence of camera shake. Since the arrangement configuration is different from the arrangement configuration defined in advance, Yes is determined in step S213.

  In this case, as described above, since it is determined that the high-density QR code Q that is easily affected by camera shake is to be read, in step S203, exposure time reduction processing is performed in the same manner as in step S111. In S205, amplification factor increase processing is performed in the same manner as in step S113.

  Thus, in the fourth embodiment, when the number of components in the timing pattern TP is less than the specified number, it is determined that the arrangement density is high, and the exposure time is set short and the amplification factor is set high. Thus, it is possible to suppress the influence of camera shake that is likely to occur when reading a high-density QR code Q. Furthermore, when the number of components in the timing pattern TP exceeds the specified number, it is determined that the arrangement density is low, and the exposure time is set long and the amplification factor is set low. It is possible to suppress the influence of noise that is likely to occur when reading.

Further, when the number of dark color regions constituting the timing pattern TP is equal to the specified number and the arrangement pattern of the timing pattern TP is different from the predetermined number, the arrangement density is high. judge. Accordingly, even when the area recognized as the dark color area changes due to the blur of the dark color area due to the influence of camera shake, the high-density QR code Q can be obtained by setting the exposure time short and the amplification factor high. It is possible to suppress the influence of camera shake that is likely to occur when reading.
Even in this case, like the barcode B, the reading accuracy of the QR code Q can be improved regardless of the density of the QR code Q. Note that the present invention is not limited to the QR code, and any two-dimensional code having a specific area such as the timing pattern TP can be adopted as a reading target of the fourth embodiment.

[Fifth Embodiment]
Next, a fifth embodiment that embodies the optical information reading apparatus of the present invention will be described.
The optical information reader 10 according to the fifth embodiment is different from the optical information reader according to the first embodiment in that the QR code Q is read instead of the barcode B.

  In the fifth embodiment, in the determination process in step S109 of FIG. 2, when the number of pixels of the image signal corresponding to the dark color area constituting the finder pattern FP of the QR code Q is equal to or less than a threshold that can be regarded as high density, It is determined that the arrangement density is a high density that is equal to or higher than a predetermined density, and when the number of pixels exceeds the threshold value, it is determined that the arrangement density is not a high density that is equal to or higher than the predetermined density.

  When it is determined that the arrangement density is high, the exposure time of the light receiving sensor 28 is set to be shorter than the case where it is determined that the exposure time is not high, and the amplification factor is not high. It is set higher than the case where it is determined. Thereby, it is possible to suppress the influence of camera shake that is relatively likely to occur when reading a high-density QR code Q.

  If it is determined that the arrangement density is not high, the exposure time of the light receiving sensor 28 is set to be longer than the case where it is determined that the light density is high, and the amplification factor is high. It is set lower than the case where it is determined. Thereby, it is possible to suppress the influence of noise that is relatively likely to occur when reading a low-density QR code Q that is not high-density.

  Even in this case, like the barcode B, the reading accuracy of the QR code Q can be improved regardless of the density of the QR code Q. Note that the above determination may be performed based on the number of pixels of the image signal corresponding to the dark color area constituting the timing pattern TP, for example, without being limited to the finder pattern FP. In addition to the QR code, other two-dimensional codes can be adopted as the reading target of the fifth embodiment.

DESCRIPTION OF SYMBOLS 10 ... Optical information reader 28 ... Light receiving sensor (imaging means)
40. Control circuit (exposure time control means, gain control means, binarization means, decoding means, determination means)
B ... Bar code (information code)
C ... Character (specific area)
FP ... Finder pattern Q ... QR code (information code)
TP ... Timing pattern (specific area)

Claims (4)

An optical information reader capable of reading an information code in which a plurality of light color patterns and dark color patterns are arranged,
Imaging means for imaging the information code;
Exposure time control means capable of controlling the exposure time of the imaging means;
An amplification factor control unit capable of controlling an amplification factor for amplifying an image signal from the imaging unit;
Binarizing means for dividing the amplified signal waveform of the image signal into a plurality of light color areas and dark color areas having width data by comparing with a predetermined threshold;
Decoding means for decoding array data in which the plurality of light color areas and dark color areas divided by the binarization means are arranged;
It determines that the arrangement density of the light-colored region and the dark region constituting the sequence data is determined to be a high density if the predetermined density or more, not a high density is less than the predetermined density Determination means,
When decoding by the decoding means fails,
When the determination means determines that the arrangement density is high, the exposure time is shortened by the exposure time control means and the amplification factor is compared with a case where the arrangement density is determined not to be high. Increase the amplification factor by the control means,
When the determination unit determines that the arrangement density is not high, the exposure time is increased by the exposure time control unit and the amplification factor is compared with a case where the arrangement density is determined to be high. The amplification factor is lowered by the control means ,
The determination means includes
The array density is not less than the predetermined density when the number of pixels of the image signal corresponding to the narrowest area among the light color area and the dark color area constituting the array data is not more than a first threshold value. Judged to be high density,
An optical information reading apparatus , wherein when the number of pixels exceeds the first threshold, the array density is determined not to be a high density that is equal to or higher than the predetermined density . An optical information reader capable of reading an information code in which a plurality of light color patterns and dark color patterns are arranged,
Imaging means for imaging the information code;
Exposure time control means capable of controlling the exposure time of the imaging means;
An amplification factor control unit capable of controlling an amplification factor for amplifying an image signal from the imaging unit;
Binarizing means for dividing the amplified signal waveform of the image signal into a plurality of light color areas and dark color areas having width data by comparing with a predetermined threshold;
Decoding means for decoding array data in which the plurality of light color areas and dark color areas divided by the binarization means are arranged;
Judgment that if the arrangement density of the light color area and the dark color area constituting the arrangement data is not less than a predetermined density, it is determined to be high density, and if it is less than the predetermined density, it is determined that the density is not high. Means, and
When decoding by the decoding means fails,
When the determination means determines that the arrangement density is high, the exposure time is shortened by the exposure time control means and the amplification factor is compared with a case where the arrangement density is determined not to be high. Increase the amplification factor by the control means,
When the determination unit determines that the arrangement density is not high, the exposure time is increased by the exposure time control unit and the amplification factor is compared with a case where the arrangement density is determined to be high. The amplification factor is lowered by the control means,
The determination means includes
When the total number of at least one of the light color area and the dark color area existing in a predetermined area in the array data is equal to or higher than a second threshold , the array density is a high density that is equal to or higher than the predetermined density. And
Wherein when the total number is less than the second threshold value, the reading light histological information shall be the determining means determines that the arrangement density is not high density the the predetermined density or more devices. An optical information reader capable of reading an information code in which a plurality of light color patterns and dark color patterns are arranged,
Imaging means for imaging the information code;
Exposure time control means capable of controlling the exposure time of the imaging means;
An amplification factor control unit capable of controlling an amplification factor for amplifying an image signal from the imaging unit;
Binarizing means for dividing the amplified signal waveform of the image signal into a plurality of light color areas and dark color areas having width data by comparing with a predetermined threshold;
Decoding means for decoding array data in which the plurality of light color areas and dark color areas divided by the binarization means are arranged;
Judgment that if the arrangement density of the light color area and the dark color area constituting the arrangement data is not less than a predetermined density, it is determined to be high density, and if it is less than the predetermined density, it is determined that the density is not high. Means, and
When decoding by the decoding means fails,
When the determination means determines that the arrangement density is high, the exposure time is shortened by the exposure time control means and the amplification factor is compared with a case where the arrangement density is determined not to be high. Increase the amplification factor by the control means,
When the determination unit determines that the arrangement density is not high, the exposure time is increased by the exposure time control unit and the amplification factor is compared with a case where the arrangement density is determined to be high. The amplification factor is lowered by the control means,
The determination means includes
When the number of components of at least one of the light color area and the dark color area constituting the specific area included in the array data is less than a predetermined number preliminarily defined as the specific area , the arrangement density is the predetermined density It is determined that the density is higher than the density of
Wherein when the configuration number exceeds the predetermined number, reading light histological information shall be the determining means determines that the arrangement density is not high density the the predetermined density or more devices. The determination means includes
When arrangements of the light-colored region and the dark region and the number of constituent constitutes the specific area A is equal to the predetermined number is different from the predefined be arranged configured as the specific area, the array density There optical information reading apparatus according to claim 3, wherein the stamp Teisu Rukoto to be dense wherein the predetermined density or more.

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