JP5915296B2 - Code image reading apparatus, operation method of code image reading apparatus, and code image reading program - Google Patents

Description

  The present invention relates to a code image reading apparatus, an operation method of the code image reading apparatus, and a code image reading program.

  The code image reading apparatus has a camera for photographing a code. When the code resolution of the photographed code image is low, the code may not be recognized correctly. The optical resolution decreases as the defocus increases. Therefore, the user shoots the code at the shooting distance corresponding to the in-focus distance set at the time of designing the camera. When the shooting distance is not appropriate, the code image reading apparatus cannot correctly recognize the code.

  The resolution corresponds to, for example, the number of pixels per figure of the minimum structural unit of the code. In the one-dimensional code and the two-dimensional code, there are no regulations regarding the physical size at the time of printing the code, and therefore codes of various sizes and resolutions exist. For this reason, the camera of the code image reading apparatus is designed according to a standard resolution and size code (hereinafter also referred to as an assumed code) assumed in advance. For this reason, a code having a size or resolution different from the assumed code may not be recognized.

  In recent years, there has been proposed a code image reading apparatus that determines the cause of out-of-focus or insufficient resolution and instructs the user to move the terminal (code image reading apparatus) when code recognition fails (for example, a patent) Reference 1). Also, a code image reading device that determines the size of a code in a captured image and controls the focal position has been proposed (for example, see Patent Document 2).

JP 2006-344066 A JP 2010-204792 A

  In a camera having an autofocus (hereinafter also referred to as AF) function, for example, by performing AF by a user's button operation, the optical resolution can be increased to a predetermined level or more. In other words, the user needs to perform troublesome button operations and the like in order to perform AF. Further, the user does not know in what shooting situation the AF should be performed. For this reason, the code image reading operation cannot be performed efficiently. Further, in the method of adjusting the focal position based on the size of the code in the photographed image, it is difficult to correspond to codes of various print sizes.

  An object of the present invention is to improve the efficiency of a code image reading operation.

  In one embodiment of the present invention, a code image reading device detects an image capturing unit that captures an image and whether or not a code is included in an arbitrary inspection region of the captured image, and the code in the inspection region is blurred. A code detection unit that determines whether or not the image is a moving image, a movement state detection unit that detects the movement state of the code image reading device, and detection of the start timing of autofocus adjustment when the code is blurred When the detection is based on the result and the code is not a blurred image, the control unit determines whether or not the zoom adjustment is necessary based on the resolution of the code in the inspection area, and the autofocus in response to the detection of the start timing When the control unit determines that an autofocus unit that performs adjustment and zoom adjustment is necessary, the zoom adjustment unit that performs zoom adjustment and the cause of unrecognizable code A notification unit for notifying the user user notification Flip, and a code processing unit to retrieve the data stored in the code.

  The efficiency of the code image reading operation can be improved.

1 illustrates an example of a code image reading device according to an embodiment. An example of the relationship between code size and resolution is shown. An example of the code recognition conditions of the code image reading apparatus shown in FIG. 1 is shown. 2 illustrates an example when the code image reading apparatus illustrated in FIG. 1 performs AF adjustment. An example when the code image reading apparatus shown in FIG. 1 performs zoom adjustment is shown. An example of the user notification of the code image reading apparatus shown in FIG. 1 is shown. 2 shows an example of the operation of the code image reading apparatus shown in FIG. An example of the operation of the code detector shown in FIG. 1 is shown. An example of AF timing detection is shown. An example of processing related to resolution conditions is shown.

  Hereinafter, embodiments will be described with reference to the drawings.

  FIG. 1 shows an example of a code image reading apparatus 10 according to an embodiment. The code image reading device 10 captures a one-dimensional code such as a JAN code or a two-dimensional code such as a QR code (registered trademark) and takes out data stored in the code. For example, the code image reading apparatus 10 is equipped with a digital camera having an autofocus function and a zoom function. The code image reading device 10 includes, for example, an imaging unit 20, a code detection unit 30, a moving state detection unit 40, a control unit 50, an autofocus unit 60 (hereinafter also referred to as an AF unit), a zoom adjustment unit 70, a notification unit 80, A code processing unit 90 and a display unit 100 are provided. Hereinafter, autofocus is also referred to as AF.

  The imaging unit 20 shoots a subject such as a code to be read, for example, and generates image data IMGD. Then, the imaging unit 20 outputs the image data IMGD to the code detection unit 30, the control unit 50, and the code processing unit 90. The control unit 50 and the code processing unit 90 may receive the image data IMGD via the code detection unit 30.

  The code detection unit 30 arbitrarily selects an inspection area from the captured image corresponding to the image data IMG. For example, the code detection unit 30 may select the central portion of the captured image as the inspection region, or may sequentially select the inspection region from any position of the captured image. Further, the code detection unit 30 detects whether or not a code is included in an arbitrary inspection region. Then, the code detection unit 30 determines whether the code is a blurred image when the code is included in the inspection area.

  For example, the movement state detection unit 40 detects the movement state of the code image reading device 10 using the output of the acceleration sensor. For example, the movement state detection unit 40 detects the movement state of the code image reading device 10 by the user as the movement direction and the movement speed. The movement state detection unit 40 may detect the movement state of the code image reading device 10 using the output of an angular velocity sensor, a geomagnetic sensor, or the like. For example, the code image reading apparatus 10 is equipped with sensors (sensors such as an acceleration sensor, an angular velocity sensor, and a geomagnetic sensor) that can be used to detect a moving state. Sensors such as an acceleration sensor, an angular velocity sensor, and a geomagnetic sensor may be provided in the movement state detection unit 40 or may be provided outside the movement state detection unit 40.

  The control unit 50 receives the determination result IINF of the code detection unit 30, the detection result MINF of the movement state detection unit 40, and the image data IMGD. Then, the control unit 50 determines a processing method that enables code recognition based on the determination result IINF of the code detection unit 30 and the detection result MINF of the movement state detection unit 40.

  For example, when receiving the determination result IINF indicating that the code is a blurred image from the code detection unit 30, the control unit 50 detects the start timing of the autofocus adjustment based on the detection result MINF. That is, the control unit 50 detects the start timing of the autofocus adjustment based on the detection result MINF of the moving state detection unit 40 when the code in the captured image (more specifically, the inspection region) is blurred. Then, the control unit 50 outputs a signal ACNT indicating the start timing of the autofocus adjustment to the AF unit 60.

  When the control unit 50 receives the determination result IINF indicating that the code is not a blurred image from the code detection unit 30, the control unit 50 performs zooming based on the resolution of the code in the photographed image (more specifically, the inspection region). It is determined whether adjustment is necessary. The resolution corresponds to the number of pixels per figure of the minimum constituent unit of the code. For example, the resolution is the number of pixels per side of the graphic of the minimum structural unit of the code. Hereinafter, the graphic of the minimum constituent unit of the code is also referred to as a unit graphic.

  For example, the control unit 50 determines that zoom adjustment is necessary when the number of pixels per side of the unit graphic is smaller than a preset minimum value. Thus, when the code is not a blurred image, the control unit 50 determines whether or not zoom adjustment is necessary based on the resolution of the code in the inspection area. Then, the control unit 50 outputs a signal ZCNT indicating whether or not zoom adjustment is necessary to the zoom adjustment unit 70.

  Further, the control unit 50 outputs a signal ICNT related to user notification such as an operation method of the code image reading device 10 to the notification unit 80. For example, the control unit 50 outputs a signal CCNT indicating that a recognizable code has been detected to the code processing unit 90.

  The AF unit 60 performs autofocus adjustment when the control unit 50 determines that autofocus adjustment of the digital camera is necessary. For example, the AF unit 60 performs autofocus adjustment in response to the signal ACNT received from the control unit 50.

  The zoom adjustment unit 70 performs zoom adjustment when the control unit 50 determines that zoom adjustment of the digital camera is necessary. For example, the zoom adjustment unit 70 performs zoom adjustment when receiving a signal ZCNT indicating that zoom adjustment is necessary from the control unit 50.

  The notification unit 80 determines whether to notify the user of the processing status and operation method based on the signal ICNT from the control unit 50. And the notification part 80 determines the content of notification, when notifying a user. For example, the notification unit 80 notifies the user of the moving direction and the like of the code image reading device 10 using the display unit 100.

  For example, the notification unit 80 is configured to keep the code image reading device 10 away from the code when the signal ICNT indicating that the code after the autofocus adjustment is performed is a blurred image from the control unit 50. The user notification DINF is output to the display unit 100. Thereby, an instruction (user notification DINF) to move the code image reading device 10 away from the code is displayed on the display unit 100. That is, the notification unit 80 provides information (user notification DINF) for keeping the code image reading device 10 away from the code via the display unit 100 when the code after the autofocus adjustment is blurred. To notify the user.

  Alternatively, when the notification unit 80 receives from the control unit 50 a signal ICNT indicating that zoom adjustment by the zoom adjustment unit 70 is not possible, a user notification DINF for causing the code image reading device 10 to approach the code. Is output to the display unit 100. For example, when the zoom value (imaging magnification) calculated based on the resolution of the code is a zoom value outside the adjustment range in the zoom adjustment unit 70, zoom adjustment in the zoom adjustment unit 70 is impossible.

  In other words, when the zoom value calculated based on the resolution of the code is a zoom value outside the adjustment range in the zoom adjustment unit 70, the notification unit 80 is configured to provide information for causing the code image reading device 10 to approach the code ( User notification DINF) is notified to the user via the display unit 100. As described above, when the code cannot be recognized, the notification unit 80 notifies the user of the user notification DINF (for example, the moving direction of the code image reading device) corresponding to the cause of the unrecognized code.

  The code processing unit 90 takes out data stored in the code. For example, when receiving a signal CCNT indicating that a recognizable code has been detected from the control unit 50, the code processing unit 90 extracts data stored in the code in the captured image corresponding to the image data IMGD. That is, when the control unit 50 determines that the code can be recognized, the code processing unit 90 uses the image data IMGD to extract the data stored in the code to be read.

  Then, the code processing unit 90 outputs the extracted data DOUT to the display unit 100. Thereby, the data DOUT stored in the code is displayed on the display unit 100. The display unit 100 is, for example, a liquid crystal display, and displays the processing result DOUT of the code processing unit 90, the user notification DINF determined by the notification unit 80, and the like.

  The configuration of the code image reading device 10 is not limited to this example. For example, the zoom adjustment unit 70 may be omitted. At this time, the controller 50 does not need to determine whether or not zoom adjustment is necessary. Therefore, the operation of the control unit 50 can be simplified.

  FIG. 2 shows an example of the relationship between the size and resolution of the code COD. FIG. 2 shows an example of the relationship between QR code size and resolution. In the QR code, the number of cells is determined for each of 40 types of versions. A cell is the smallest unit of code. For example, the number of cells per side of the QR code is set for each version from 21 to 177. The resolution (for example, the number of pixels per side of the cell) depends on the physical size when the QR code is printed. In the one-dimensional code and the two-dimensional code, there are no regulations regarding the physical size at the time of printing the code, and therefore codes of various sizes and resolutions exist.

  The codes CODAa, CODb, and CODc have the same size (the length of one side of the entire code) and have different resolutions. For example, the number of pixels per side of the code CODb cell is larger than the number of pixels per side of the code CODb cell. The number of pixels per side of the code CODc cell is smaller than the number of pixels per side of the code CODb cell.

  The codes CODd, CODb, and CODe have different sizes and the same resolution. For example, the length of one side of the code CODd is shorter than the length of one side of the code CODb. The length of one side of the code CODe is longer than the length of one side of the code CODb.

  FIG. 3 shows an example of code recognition conditions of the code image reading apparatus 10 shown in FIG. FIG. 3 shows the optical resolution and resolution of the code image when the shooting distance (distance between the code and the code image reading device 10) changes. The broken line of the optical resolution shows an example of the optical resolution when AF is not used. The solid line of resolution indicates an example of resolution when zoom is not used (when the zoom value is minimized), and the broken line of resolution indicates an example of resolution when the zoom value is maximized. That is, the shaded area in the figure indicates a range in which zoom adjustment is possible.

  A high optical resolution indicates a small focus shift. That is, as the optical resolution becomes lower, a blurred image is taken. A high resolution indicates that the number of pixels per side of a unit graphic (for example, a QR code cell) is large. The resolution decreases as the shooting distance increases. The code image reading apparatus 10 cannot correctly recognize the code when the optical resolution and resolution of the photographed code image are low.

  For example, the code image reading apparatus 10 can recognize a code when the optical resolution is higher than a predetermined lower limit level TH10 and the resolution is higher than a predetermined lower limit level TH20. That is, the code image reading device 10 cannot recognize the code when the shooting distance is closer than the distance D10 because the optical resolution cannot be higher than the lower limit level TH10. Also, the code image reading device 10 cannot recognize the code when the shooting distance is longer than the distance D20 because the resolution cannot be higher than the lower limit level TH20.

  For example, the code image reading apparatus 10 can recognize the code without performing zoom adjustment when the shooting distance is in the range from the distance D10 to the distance D16. Further, the code image reading apparatus 10 can recognize the code after performing zoom adjustment when the shooting distance is in the range from the distance D16 to the distance D20. Therefore, the code image reading apparatus 10 can recognize the code when the shooting distance is in the range from the distance D10 to the distance D20.

  When AF is not used, the shooting distance at which the optical resolution is higher than the lower limit level TH10 is a narrow range from the distance D12 to the distance D14. That is, when AF is not used, the shooting distance that satisfies the optical resolution condition for recognizing the code is a narrow range from the distance D12 to the distance D14. By using AF, the range of the photographing distance where the optical resolution is higher than the lower limit level TH10 can be widened. For example, when using the AF, the code image reading apparatus 10 can make the optical resolution higher than the lower limit level TH10 by setting the shooting distance to the distance D10 or more. That is, by performing the AF adjustment, the shooting distance that satisfies the optical resolution condition for recognizing the code is expanded to the distance D10 or more.

  When the zoom is not used, the shooting distance at which the resolution is higher than the lower limit level TH20 is the distance D16 or less. By using the zoom, the range of the photographing distance where the resolution is higher than the lower limit level TH20 can be widened. For example, when the code image reading apparatus 10 captures a code at an imaging distance in the range of the distance D16 to the distance D20, the resolution can be made higher than the lower limit level TH20 by using the zoom. That is, by performing the zoom adjustment, the photographing distance that satisfies the resolution condition for recognizing the code is expanded to the distance D20.

  The resolution level TH22 in the figure indicates the upper limit of the resolution. For example, the level TH22 corresponds to the upper limit of the resolution when the code is prevented from protruding from the screen (for example, the screen of the display unit 100). At this time, the code image reading apparatus 10 can determine whether or not the code protrudes from the screen based on the resolution of the code in the photographed image (more specifically, the inspection region). Note that the determination of whether or not the code protrudes from the screen may be performed without using the resolution. In other words, the upper limit level TH22 of resolution may not be set.

  FIG. 4 shows an example when the code image reading apparatus 10 shown in FIG. 1 performs AF adjustment. FIG. 4 shows an example of AF adjustment and zoom adjustment when the code CODb is photographed at a position (distance D18) far from the optimum photographing distance D13 assumed at the time of designing the camera. The broken line in the figure indicates the optical resolution and resolution of the code image when AF adjustment and zoom adjustment are not performed. The code CODb 'in the figure corresponds to a code image when the code CODb is photographed at the photographing distance D18.

  First, the code image reading apparatus 10 checks the condition of the optical resolution for recognizing the code CODb '(whether the optical resolution is higher than the lower limit level TH10). The optical resolution of the code CODb ′ captured without using AF does not satisfy the optical resolution condition (optical resolution higher than the lower limit level TH10). In this state, the code CODb 'cannot be recognized. Therefore, the code image reading apparatus 10 performs AF adjustment and focuses on the code CODb ′. That is, the code image reading apparatus 10 performs shooting using AF, and generates a shot image having an optical resolution higher than the lower limit level TH10.

  Next, the code image reading apparatus 10 checks a resolution condition (whether or not the resolution is higher than the lower limit level TH20) for recognizing the code CODb '. In the example in the figure, since the shooting distance is long, the resolution of the code CODb 'shot without using the zoom is out of the resolution range where the code can be recognized. In this state, the code CODb 'cannot be recognized. For this reason, the code image reading apparatus 10 calculates a zoom value for making the resolution higher than the lower limit level TH20, and performs zoom adjustment.

  Then, the code image reading apparatus 10 captures the code CODb ′ with the zoom value set by the zoom adjustment. The focal length of this shooting is set based on, for example, the focal length of the shooting performed before zoom adjustment (focal length set by AF adjustment). Thus, a captured image (code CODb) that satisfies both the optical resolution and the resolution is generated.

  As described above, the code image reading apparatus 10 can set the optical resolution and resolution of the code CODb ′ photographed at the distance D18 farther than the photographing distance D13 higher than the lower limit levels TH10 and TH20, respectively. Thereby, the code image reading apparatus 10 can recognize the code CODb ′. That is, even when the user places the code image reading device 10 at a position (distance D18) farther than the optimum shooting distance D13 assumed at the time of designing the camera, the code image reading device 10 also stores the data stored in the code CODb ′. Can be taken out.

  FIG. 5 shows an example when the code image reading apparatus 10 shown in FIG. 1 performs zoom adjustment. FIG. 5 shows an example of zoom adjustment when a code CODc having a resolution different from that of a standard resolution and size code assumed at the time of camera design (hereinafter also referred to as an assumed code) is photographed. The assumed code is, for example, the code CODb. The thick broken line in the figure indicates the resolution of the code CODc when imaged without zoom adjustment, and the thin broken line in the figure indicates the resolution of the assumed code CODb when imaged without zoom adjustment. . For example, the photographing distance of the codes CODb and CODc is the optimum distance D13 assumed at the time of designing the camera.

  The code CODc cell is smaller than the code CODb cell. Therefore, even when the user captures the code CODc at the optimum distance D13, the resolution of the captured code CODc is lower than the resolution of the assumed code CODb (broken line in the figure). For this reason, the resolution of the code CODc photographed without using the zoom is out of the resolution range in which the code can be recognized. In this state, the code CODc cannot be recognized. For this reason, the code image reading apparatus 10 calculates a zoom value for making the resolution higher than the lower limit level TH20, and performs zoom adjustment.

  Then, the code image reading apparatus 10 captures the code CODc with the zoom value set by the zoom adjustment. The resolution of the code CODc photographed by performing the zoom adjustment becomes higher than the lower limit level TH20 (solid line in the figure). That is, a captured image (code CODc) that satisfies the resolution condition is generated. In the example of FIG. 5, since the code CODc is photographed at the optimum distance D13, the optical resolution is higher than the lower limit level TH10 without performing AF adjustment.

  Thus, the code image reading apparatus 10 can make the optical resolution and resolution of the photographed code CODc higher than the lower limit levels TH10 and TH20, respectively, even when the resolution of the code CODc to be read is different from the resolution of the assumed code CODb. Therefore, the code image reading apparatus 10 can recognize the code CODc having a resolution different from the resolution of the assumed code CODb, and can extract the data stored in the code CODc.

  Note that the code image reading apparatus 10 can recognize a code having a size different from the size of the assumed code CODb (for example, the code CODe shown in FIG. 2) by performing AF adjustment and zoom adjustment. That is, the code image reading apparatus 10 can extract data stored in a code having a resolution or size different from that of the assumed code CODb.

  FIG. 6 shows an example of a user notification of the code image reading apparatus 10 shown in FIG. The code COD (10) is a code COD photographed at a position closer than the distance D10. The code COD (20) is a code COD photographed at a photographing distance (for example, a range from the distance D10 to the distance D20) that satisfies both the optical resolution and the resolution. The code COD (30) is a code COD photographed at a position farther than the distance D20. Also, the meanings of the solid line, broken line, and hatching in the resolution of FIG. 6 are the same as in FIG.

  When the shooting distance is shorter than the distance D10, even if AF adjustment is performed, the focus is not achieved. That is, the code image reading device 10 cannot increase the optical resolution of the photographed image above the lower limit level TH10 when the photographing distance is shorter than the distance D10. For this reason, the code image reading device 10 outputs a user notification DINF for keeping the code image reading device 10 away from the code COD to the display unit 100. For example, the code image reading apparatus 10 displays “Please move away” on the display unit 100.

  Further, when the shooting distance is longer than the distance D20, the resolution of the code COD (30) to be shot does not become higher than the lower limit level TH20 even if zoom adjustment is performed. That is, the code image reading apparatus 10 cannot increase the resolution of the code COD above the lower limit level TH20 when the shooting distance is longer than the distance D20. Therefore, the code image reading device 10 outputs a user notification DINF for causing the code image reading device 10 to approach the code COD to the display unit 100. For example, the code image reading apparatus 10 displays “Please move closer” to the display unit 100.

  As described above, the code image reading apparatus 10 responds according to the cause of the inability to recognize the code COD (for example, a response method when the optical resolution condition is not satisfied, and a response method when the resolution condition is not satisfied). To the user. Thereby, in this embodiment, the convenience of the code image reading apparatus 10 can be improved.

  For example, in a code image reading apparatus in which a user is not notified of a countermeasure according to the cause of the inability to recognize the code COD, it is difficult for the user to understand the reason why the code cannot be recognized. For this reason, an inappropriate operation such as moving the code image reading device 10 in the wrong direction may be performed. On the other hand, in this embodiment, since the user is notified of a handling method according to the cause of the unrecognizable code COD, the user can appropriately operate the code image reading device 10 even when the code is not recognized. .

  In the range where the shooting distance is from the distance D10 to the distance D20, the code image reading apparatus 10 can recognize the code COD (20), and therefore the user's handling method is not instructed. For example, when the code image reading apparatus 10 recognizes the code COD, the code image reading apparatus 10 may display processing contents such as data reading on the display unit 100.

  Further, the content of the user notification is not limited to this example. For example, the code image reading apparatus 10 may notify the user of the reason for the recognition failure instead of the handling method. Alternatively, the code image reading apparatus 10 may notify both of the reason for non-recognition and the handling method.

  FIG. 7 shows an example of the operation of the code image reading apparatus 10 shown in FIG. The operation of FIG. 7 may be realized only by hardware, or may be realized by controlling the hardware by software. For example, the software (program) causes an electronic device (for example, a mobile phone) having a camera function to execute the operation of FIG.

  In the process S100, the photographing unit 20 photographs a subject such as a code to be read without using AF. In process S110, the code detection unit 30 performs the code detection process shown in FIG. 8 and detects whether or not the code is photographed. A method for detecting a code in a captured image is disclosed in, for example, Japanese Patent No. 4180497. Further, when the code is photographed, the code detection unit 30 determines whether or not the photographed code is a blurred image. Whether or not the image is blurred is determined based on the dispersion of pixel values, for example, as shown in FIG. Note that the determination based on the variance of the pixel values includes determination based on the standard deviation of the pixel values. Accordingly, whether or not the image is blurred may be determined based on the standard deviation of the pixel values.

  In the process S120, the control unit 50 determines whether or not a code is detected based on the result of the process S110 (determination result of the code detection unit 30). When the code is not detected (No in process S120), the code image reading apparatus 10 performs the recognition impossibility process in process S260 and ends the series of processes. On the other hand, when the code is detected (Yes in process S120), the operation of the control unit 50 proceeds to process S130.

  In process S130, the control unit 50 determines whether the code is a blurred image based on the result of process S110 (the determination result of the code detection unit 30). That is, in process S130, the control unit 50 determines whether or not the photographed code satisfies an optical resolution condition for recognizing the code. When the code is a blurred image (Yes in process S130), the operation of the control unit 50 proceeds to process S190. On the other hand, when the code is not a blurred image (No in process S130), the operation of the control unit 50 proceeds to process S140.

  In step S140, the control unit 50 determines whether or not the code resolution satisfies the resolution condition. The resolution condition is a resolution condition for recognizing a code. For example, the resolution condition is expressed by Expression (1) using the number N of pixels per side of a unit graphic (for example, a QR code cell), the estimation error α, and the minimum value Tmin.

Tmin <N−α (1)
For example, as shown in FIG. 10, the number of pixels N and the estimation error α are calculated based on a histogram of the length (number of pixels) of the white / black pattern of the code. For example, the estimation error α corresponds to the half width at half maximum of the peak. The minimum value Tmin is, for example, the minimum number of pixels (for example, 3 pixels) per side of a unit graphic necessary for code recognition, and is set in advance. That is, the minimum value Tmin corresponds to the lower limit level TH20 shown in FIG. For example, when the number N of pixels satisfies the formula (1), the control unit 50 determines that the resolution of the code satisfies the resolution condition.

  When the resolution of the code satisfies the resolution condition (Yes in process S140), the code image reading apparatus 10 performs the process S170 (code reading) and ends the series of processes. On the other hand, when the code resolution does not satisfy the resolution condition (No in step S140), the operation of the control unit 50 proceeds to step S150. As described above, in step S140, the control unit 50 determines whether or not zoom adjustment is necessary based on the resolution of the code.

  In step S150, the control unit 50 determines whether zoom adjustment is possible. For example, the control unit 50 determines whether or not the target zoom value Zm that satisfies Expression (2) is within a range that can be adjusted by the zoom adjustment unit 70.

Tmin / (N−α) <Zm (2)
The control unit 50 determines that zoom adjustment is possible when the target zoom value Zm satisfying the expression (2) is within a range adjustable by the zoom adjustment unit 70. In other words, the control unit 50 determines that zoom adjustment is not possible when the target zoom value Zm satisfying the expression (2) is not within the range adjustable by the zoom adjustment unit 70.

  When zoom adjustment is not possible (No in process S150), the code image reading apparatus 10 performs a user notification (an instruction to approach) in process S180, and ends a series of processes. On the other hand, when zoom adjustment is possible (Yes in process S150), the operation of the code image reading apparatus 10 proceeds to process S160.

  In process S160, the code image reading apparatus 10 performs zoom shooting. For example, the control unit 50 calculates, as an appropriate zoom value, the minimum zoom value that can be adjusted by the zoom adjustment unit 70 among the target zoom values Zm that satisfy Expression (2). Then, the zoom adjustment unit 70 performs zoom adjustment based on the appropriate zoom value calculated by the control unit 50. The photographing unit 20 photographs a subject such as a code to be read with the appropriate zoom value adjusted by the zoom adjusting unit 70.

  Thus, in this embodiment, when the resolution of the captured code does not satisfy the resolution condition, the user does not need to determine the zoom adjustment magnification (zoom value). For this reason, in this embodiment, the usability of the code image reading apparatus 10 can be improved. When the code resolution satisfies the resolution condition, zoom adjustment is not performed. That is, in this embodiment, unnecessary zoom adjustment is not performed, so that the time until the code is recognized can be shortened.

  Note that the focal length of zoom shooting in step S160 is set based on the focal length of AF shooting in step S200, for example, when AF shooting in step S200 is performed. Further, when the AF shooting in the process S200 is not performed, the focal length of the zoom shooting in the processing S160 is, for example, the focal length set when the camera is designed (the focal length of the shooting in the processing S100). That is, the focal length of the zoom shooting in step S160 is set based on the focal length of the shooting performed immediately before the shooting in step S160.

  In process S170, the code processing unit 90 retrieves data stored in the code. For example, the code image reading apparatus 10 displays information indicated by the extracted data on the display unit 100. This completes the code reading process.

  In process S180, the code image reading apparatus 10 displays an instruction for causing the code image reading apparatus 10 to approach the code on the display unit 100. For example, the notification unit 80 outputs a user notification DINF for causing the code image reading device 10 to approach the code to the display unit 100. As a result, an instruction for causing the code image reading device 10 to approach the code (an instruction such as “Please approach”) is displayed on the display unit 100.

  As described above, the code image reading apparatus 10 provides the user with an appropriate response method (instructions such as “keep close”) when the resolution of the photographed code does not satisfy the resolution condition even after performing zoom adjustment. Notice. Thereby, in this embodiment, the convenience of the code image reading apparatus 10 can be improved.

  In step S190, the control unit 50 detects whether or not the AF adjustment start timing is reached. For example, as illustrated in FIG. 9, the control unit 50 detects the AF adjustment start timing based on the detection result of the moving state detection unit 40. For example, when it is determined that the code image reading device 10 is not moved, the control unit 50 determines the AF adjustment start timing. Note that the control unit 50 may determine the AF adjustment start timing when it is determined that the code image reading device 10 is continuously moving in the optical axis direction of the camera for a predetermined time. Alternatively, when it is determined that the moving direction has changed in the opposite direction during the period in which the code image reading device 10 is moving in the optical axis direction, the control unit 50 may determine that the AF adjustment start timing has been reached.

  When the AF adjustment start timing is not detected (No in process S190), the code image reading apparatus 10 performs the recognition impossibility process in process S260 and ends the series of processes. On the other hand, when the AF adjustment start timing is detected (Yes in process S190), the operation of the code image reading apparatus 10 proceeds to process S200.

  In process S200, the code image reading apparatus 10 performs AF shooting. For example, the AF unit 60 performs AF adjustment in response to detection of the AF adjustment start timing by the control unit 50. Then, the photographing unit 20 photographs a subject such as a code to be read at a focal length set by AF adjustment.

  Thus, in this embodiment, when the photographed code does not satisfy the optical resolution condition, the user does not need to finely adjust the photographing distance in accordance with the optical characteristics of the camera. Further, in this embodiment, it is not necessary for the user to determine the timing for performing the AF adjustment. For this reason, in this embodiment, the usability of the code image reading apparatus 10 can be improved. Further, when the photographed code satisfies the optical resolution condition, AF adjustment is not performed. That is, in this embodiment, unnecessary AF adjustment is not performed, so that the time until the code is recognized can be shortened.

  Processes S210 and S220 are the same as processes S110 and S120. Note that in steps S210 to S240, a captured image generated by AF shooting in step S200 is used. The process S230 is the same as the process S130 except for the branch destination when the code is a blurred image (Yes in the process S230). For example, when the code after AF shooting is a blurred image (Yes in process S230), the operation of the control unit 50 proceeds to process S240.

  The process S240 is the same as the process S140 except for the branch destination of the determination result. For example, when the resolution of the code after AF shooting satisfies the resolution condition (Yes in process S240), the code image reading apparatus 10 performs a user notification (instruction to move away) in process S250 and ends the series of processes. To do. On the other hand, when the resolution of the code after AF shooting does not satisfy the resolution condition (No in process S240), the recognition impossibility process in process S260 is performed, and the series of processes ends.

  Here, as shown in FIG. 3, the resolution becomes lower as the shooting distance becomes longer. For this reason, when the resolution condition is not satisfied in step S240, if the code image reading device 10 is moved away from the code, there is a high possibility that the resolution condition will not be satisfied even if zoom adjustment is performed. Therefore, in the example of FIG. 7, when the resolution of the code after AF shooting does not satisfy the resolution condition (No in processing S240), the recognition impossibility processing in processing S260 is performed, and the series of processing ends.

  Note that the resolution condition of the process S240 may be different from the expression (1) described in the process S140. For example, the resolution condition may be a condition that considers the maximum zoom value Zmax that can be adjusted by the zoom adjustment unit 70 as shown in Expression (3).

Tmin <Zmax · (N−α) (3)
Alternatively, the process S240 may be omitted. That is, when the code after AF shooting is a blurred image (Yes in process S230), the code image reading apparatus 10 may perform a user notification (instruction to move away) in process S250 and end the series of processes. .

  In the process S250, the code image reading device 10 displays an instruction for keeping the code image reading device 10 away from the code on the display unit 100. For example, the notification unit 80 outputs a user notification DINF for keeping the code image reading device 10 away from the code to the display unit 100. As a result, an instruction (an instruction such as “Please keep away”) for moving the code image reading device 10 away from the code is displayed on the display unit 100.

  As described above, the code image reading apparatus 10 can appropriately respond to the code after AF shooting (when the code after AF shooting is a blurred image) (“Please keep away”). Etc.) is notified to the user. Thereby, in this embodiment, the convenience of the code image reading apparatus 10 can be improved.

  That is, in this embodiment, when it is determined that the code cannot be recognized even if AF adjustment or zoom adjustment is performed, the user can be notified of a handling method that enables the code to be recognized (steps S180 and S250). Thereby, in this embodiment, the efficiency of the code image reading operation can be improved.

  In the process S260, the code image reading device 10 notifies the user that the code cannot be read, for example. As described above, in this embodiment, when it is determined that there is no corresponding method for recognizing the code, the series of processing ends without instructing the moving direction of the code image reading device 10.

  In the series of operations illustrated in FIG. 7, the maximum number of times of photographing performed before reading the code is three (processing S100, S200, and S160). The code reading process takes the longest time to shoot an image. Therefore, by reducing the number of image shootings, the processing time of the entire code reading process is effectively shortened. That is, in this embodiment, the processing time of the entire code reading process can be shortened.

  For example, in the method of changing the zoom value step by step, image capturing and resolution condition determination are repeated until the appropriate zoom value is reached. For this reason, the number of times of image shooting increases. Furthermore, if it takes time to reach the appropriate zoom value, the user's hand may move and the shooting distance may shift. At this time, AF adjustment needs to be performed again, and the number of times of image shooting further increases. For this reason, in the method of changing the zoom value step by step, the processing time of the entire code reading process becomes longer. In other words, in this embodiment, the processing time of the entire code reading process can be shortened as compared with the method of changing the zoom value step by step.

  The operation of the code image reading device 10 is not limited to this example. For example, the processes S150 and S160 may be omitted. In this operation, when the resolution of the code does not satisfy the resolution condition (No in process S140), the code image reading apparatus 10 performs a user notification (an instruction to approach) in process S180, and ends the series of processes. For example, the code image reading apparatus 10 equipped with a digital camera that does not have a zoom function performs an operation in which steps S150 and S160 are omitted from the operation in FIG.

  Further, the maximum value (for example, the maximum value Tmax shown in FIG. 10) corresponding to the upper limit level TH22 shown in FIG. 3 may be included in the resolution condition of the process S140. At this time, the code image reading apparatus 10 can determine whether or not the code protrudes from the screen of the display unit 100 based on the resolution of the code. For example, when the code image reading apparatus 10 determines that the code protrudes from the screen of the display unit 100, the code image reading apparatus 10 performs the user notification (instruction to move away) in step S250 and ends the series of processes.

  FIG. 8 shows an example of the operation of the code detection unit 30 shown in FIG. Note that the operation in FIG. 8 corresponds to, for example, the processes S110 and S210 illustrated in FIG. The operation of FIG. 8 may be realized only by hardware, or may be realized by controlling the hardware by software.

  In process S300, the code detection unit 30 arbitrarily selects an inspection region from the captured image. For example, the code detection unit 30 selects the center portion of the captured image as the inspection region. Note that the code detection unit 30 may sequentially select inspection regions from arbitrary positions in the captured image. When the inspection areas are sequentially selected, for example, the series of operations shown in FIG. 8 is repeated until a code (including a blurred code) is detected.

  In process S310, the code detection unit 30 calculates the numbers of black and white edges Heg and Veg in the horizontal and vertical directions of the inspection area. The number of black and white edges is calculated, for example, by detecting the number of points corresponding to the number of black and white boundaries where the gradation of the pixel changes suddenly. For example, in the two-dimensional code, many edges are detected both in the horizontal direction and in the vertical direction of the inspection area. In the one-dimensional code, for example, the number of edges in one of the horizontal direction and the vertical direction of the inspection area increases.

  In process S320, the code detection unit 30 determines whether both the horizontal edge number Heg and the vertical edge number Veg are larger than a preset reference value REF1. When both the edge numbers Heg and Veg are larger than the reference value REF1 (Yes in process S320), the operation of the code detection unit 30 proceeds to process S330. On the other hand, when at least one of the edge numbers Heg and Veg is equal to or less than the reference value REF1 (No in process S320), the operation of the code detection unit 30 proceeds to process S400.

  In process S330, the code detection unit 30 calculates the black pixel rate BRatio of the inspection area. For example, a two-dimensional code is generated so that the ratio of black and white is not biased to one. In process S340, the code detection unit 30 determines whether or not the black pixel rate BRatio is between a predetermined minimum value Bmin and a predetermined maximum value Bmax.

  When the black pixel ratio BRatio is between the minimum value Bmin and the maximum value Bmax (Yes in process S340), the operation of the code detection unit 30 proceeds to process S350. On the other hand, when the black pixel ratio BRatio does not fall between the minimum value Bmin and the maximum value Bmax (No in process S340), the code detection unit 30 determines in step S390 that the inspection area is other than the code, and the series Terminate the process. That is, the code detection unit 30 determines that the code is not included in the inspection area when the ratio of black and white in the inspection area is biased to one (No in processing S340).

  In process S350, the code detection unit 30 calculates a variance SV of pixel values in the inspection area. In process S360, the code detection unit 30 determines whether or not the variance SV of pixel values is larger than a preset reference value REF3. For example, in a blurred monochrome image, the variance SV of pixel values is small.

  When the variance SV of pixel values is larger than the reference value REF3 (Yes in processing S360), the code detection unit 30 determines in step S370 that the inspection region is a two-dimensional code (a non-blurred two-dimensional code), and a series of The process ends. That is, when the pixel value variance SV is larger than the reference value REF3 (Yes in step S360), the code detection unit 30 determines that a recognizable two-dimensional code is included in the captured image.

  On the other hand, when the variance SV of pixel values is equal to or less than the reference value REF3 (No in process S360), the code detection unit 30 determines that the inspection area is a blurred two-dimensional code in process S380, and ends a series of processes. . That is, the code detection unit 30 determines that a blurred two-dimensional code is included in the captured image when the pixel value variance SV is equal to or less than the reference value REF3 (No in step S360).

  In process S400, the code detection unit 30 determines whether one of the horizontal edge number Heg and the vertical edge number Veg is larger than a preset reference value REF2. The reference value REF2 may be the same value as the reference value REF1, or may be a value different from the reference value REF1.

  When one of the edge numbers Heg and Veg is larger than the reference value REF2 (Yes in process S400), the operation of the code detection unit 30 proceeds to process S410. On the other hand, when both the edge numbers Heg and Veg are less than or equal to the reference value REF2 (No in process S400), the code detection unit 30 determines in step S390 that the inspection area is other than a code, and ends the series of processes. That is, the code detection unit 30 determines that the code is not included in the inspection area when the number of black and white boundaries in the inspection area is small (No in processing S400).

  In process S410, the code detection unit 30 calculates the correlation Hc between the horizontal lines and the correlation Vc between the vertical lines in the inspection area. Hereinafter, the correlation Hc between horizontal lines and the correlation Vc between vertical lines are also referred to as a horizontal line correlation Hc and a vertical line correlation Vc, respectively. In the one-dimensional code, for example, one of the horizontal line correlation Hc and the vertical line correlation Vc increases.

  In process S420, the code detection unit 30 determines whether one of the horizontal line correlation Hc and the vertical line correlation Vc is greater than a preset reference value REF4. When one of the horizontal line correlation Hc and the vertical line correlation Vc is larger than the reference value REF4 (Yes in step S420), the operation of the code detection unit 30 proceeds to step S430.

  On the other hand, when both the horizontal line correlation Hc and the vertical line correlation Vc are less than or equal to the reference value REF4 (No in process S420), the code detection unit 30 determines that the inspection area is a blurred one-dimensional code in process S460. Then, a series of processing ends. That is, when both the horizontal line correlation Hc and the vertical line correlation Vc are equal to or smaller than the reference value REF4 (No in step S420), the code detection unit 30 determines that a blurred one-dimensional code is included in the captured image. To do.

  In process S430, the code detection unit 30 calculates a variance SV of pixel values in the inspection area. In process S440, the code detection unit 30 determines whether or not the variance SV of pixel values is greater than the reference value REF3. When the pixel value variance SV is larger than the reference value REF3 (Yes in step S440), the code detection unit 30 determines in step S450 that the inspection region is a one-dimensional code (a one-dimensional code that is not blurred). The process ends. That is, when the variance SV of pixel values is larger than the reference value REF3 (Yes in process S440), the code detection unit 30 determines that a recognizable one-dimensional code is included in the captured image.

  On the other hand, when the variance SV of the pixel values is equal to or less than the reference value REF3 (No in process S440), the code detection unit 30 determines that the inspection area is a blurred one-dimensional code in process S460 and ends the series of processes. . That is, when the variance SV of pixel values is equal to or less than the reference value REF3 (No in processing S440), the code detection unit 30 determines that a blurred one-dimensional code is included in the captured image.

  That is, the conditions for determining a captured image as a recognizable two-dimensional code are the conditions of the number of edges Heg and Veg in the process S320, the condition of the black pixel ratio BRatio in the process S340, and the condition of the variance SV of the pixel values in the process S360. It is time to meet. Further, the condition for determining that the captured image is a blurred two-dimensional code satisfies the conditions of the number of edges Heg and Veg in the process S320 and the condition of the black pixel ratio BRatio in the process S340, and the condition of the variance SV of pixel values in the process S360. Is not satisfied.

  The conditions for determining a captured image as a recognizable one-dimensional code are the number of edges Heg and Veg in step S400, the inter-line correlation Hc and Vc in step S420, and the pixel value variance SV in step S440. When the condition is met. The conditions for determining that the captured image is a blurred one-dimensional code satisfy the conditions of the number of edges Heg and Veg in the process S400, the interline correlations Hc and Vc in the process S420, and the variance SV of the pixel values in the process S440. This is when the condition is not satisfied.

  In the processes S370 to S390, S450, and S460, the code detection unit 30 outputs the determination result IINF to the control unit 50. Thereby, the control part 50 can implement process S120, S130, S220, S230, etc. which were shown in FIG.

  As described above, the code detection unit 30 determines whether the image is blurred based on the variance SV of pixel values without performing complicated processing such as detection of the difference between the shooting distance and the focal length. Thereby, in this embodiment, it can suppress that the time of the process which determines whether it is a blurred image becomes long.

  The operation of the code detection unit 30 is not limited to this example. For example, the processes S350, S360, S430, and S440 may be performed before the process S310. At this time, the determination result of whether or not the variance SV of pixel values is larger than the reference value REF3 is stored in a flag or the like. For example, when the variance SV of pixel values is equal to or less than the reference value REF3, a flag indicating that the image is blurred is set.

  FIG. 9 shows an example of AF timing detection. The code image reading device 10 detects the movement of the code image reading device 10 in the Z-axis direction, the X-axis direction, and the Y-axis direction (FIG. 9A). The Z-axis direction is a direction (optical axis direction) along the optical axis of the camera (more specifically, the photographing lens) of the code image reading device 10. In the code image reading device 10 in FIG. 9A, the photographing lens of the camera is disposed on the side facing the code COD in FIG. 9A. The X-axis direction and the Y-axis direction are directions orthogonal to the Z-axis direction. Moreover, the X-axis direction and the Y-axis direction are orthogonal to each other, for example.

  For example, the movement state detection unit 40 calculates the respective movement speeds of the code image reading device 10 in the Z-axis direction, the X-axis direction, and the Y-axis direction using outputs of sensors such as an acceleration sensor, an angular velocity sensor, and a geomagnetic sensor. (FIG. 9B). The thick line waveform in the figure shows an example of changes in the moving speed of the code image reading apparatus 10 in the Z-axis direction, the X-axis direction, and the Y-axis direction. The waveform above the speed “0” indicates that the waveform moves to the opposite side of the movement direction of the waveform below the speed “0”. The ranges DVX, DVY, DVZ are, for example, predetermined ranges centered on the speed “0”.

  The movement in the X-axis direction and the Y-axis direction occurs, for example, when the user is performing alignment for putting the code COD in the screen of the display unit 100. When the code COD fits within the screen of the display unit 100, the moving speeds in the X-axis direction and the Y-axis direction are substantially “0”. For example, the control unit 50 determines that there is no movement in the X-axis direction of the code image reading device 10 when the moving speed in the X-axis direction is changing within a predetermined range DVX set in advance. Similarly, the control unit 50 determines that there is no movement of the code image reading apparatus 10 in the Y-axis direction when the movement speed in the Y-axis direction is changing within a predetermined range DVY set in advance.

  The movement in the Z-axis direction occurs, for example, when the user is adjusting the shooting distance to the code COD. When the adjustment of the shooting distance is completed (when the user determines that the code COD can be recognized), the moving speed in the Z-axis direction is substantially “0”. For example, the control unit 50 determines that there is no movement of the code image reading device 10 in the Z-axis direction when the movement speed in the Z-axis direction changes within a predetermined range DVZ set in advance.

  In the period from time t10 to time t20, the change in the moving speed in the X-axis direction and the Y-axis direction is not within the predetermined ranges DVX and DVY. Therefore, the control unit 50 determines that the code image reading apparatus 10 is in the middle of alignment in the X-axis direction and the Y-axis direction.

  After time t20, the movement speeds in the X-axis direction and the Y-axis direction change within the predetermined ranges DVX and DVY. Therefore, the control unit 50 determines that the alignment of the code image reading device 10 in the X-axis direction and the Y-axis direction has been completed. That is, the control unit 50 determines that the code COD is contained in the screen of the display unit 100. When the code COD is within the screen of the display unit 100, the code COD is present in the captured image.

  Here, one of the recognition conditions of the code COD is that the code COD exists in the captured image. Therefore, when the moving speeds in the X-axis direction and the Y-axis direction change within the predetermined ranges DVX and DVY (after time t20), one of the recognition conditions for the code COD is satisfied.

  In the period from time t20 to time t30, the change in the movement speed in the Z-axis direction is not within the predetermined range DVZ. Therefore, the control unit 50 determines that the shooting distance is being adjusted.

  After time t30, the movement speeds in the X-axis direction, the Y-axis direction, and the Z-axis direction change within the predetermined ranges DVX, DVY, DVZ. Therefore, the control unit 50 determines that the code image reading device 10 is stopped. When the code image reading apparatus 10 is stopped, it is highly likely that the user has determined that the code COD can be recognized, so the control unit 50 determines that it is the AF adjustment start timing. That is, when it is determined that the code image reading apparatus 10 has not moved (the circle “No movement” in FIG. 9), the control unit 50 determines the AF adjustment start timing.

  Note that when the adjustment period of the shooting distance (the period from time t20 to time t30) is long, the control unit 50 is likely to be at a loss as the user cannot determine an appropriate shooting distance. May be detected during the shooting distance adjustment period. For example, when the control unit 50 determines that the code image reading device 10 continues to move in the Z-axis direction for a predetermined time from the end of alignment (time t20), the circle of “elapsed predetermined time” in FIG. Or the AF adjustment start timing. Alternatively, the control unit 50 determines that the movement of the code image reading apparatus 10 in the Z-axis direction has changed in the opposite direction after the end of alignment (after time t20) (in the “movement direction change” in FIG. 9). Or a start timing of AF adjustment.

  That is, the control part 50 should just be formed so that at least one of the three states mentioned above can be detected. Then, the control unit 50 detects the AF adjustment start timing by detecting at least one of the three states based on the detection result of the movement state detection unit 40. Thereby, in this embodiment, AF adjustment can be performed at an appropriate timing according to the moving state of the terminal (code image reading device 10) by the user. The three states are organized and shown below as a first state, a second state, and a third state.

  The first state is a state where the code image reading device 10 is stopped. The second state is a state in which the code image reading device 10 is not moved in the X-axis direction and the Y-axis direction, and the code image reading device 10 is continuously moving in the optical axis direction of the camera for a predetermined time. It is. The third state is a state in which the code image reading device 10 is not moved in the X-axis direction and the Y-axis direction, and the movement of the code image reading device 10 in the Z-axis direction is changed in the opposite direction.

  FIG. 10 shows an example of processing related to the resolution condition.

  First, the control unit 50 detects the length (number of pixels) of the white / black pattern for each line of the inspection area AR (AR10, AR12) (FIG. 10A). In the one-dimensional code COD20, the control unit 50 performs, for example, white / black pattern length detection only on a horizontal line. In the two-dimensional code COD22, the control unit 50 detects the length of the white / black pattern for both the vertical and horizontal lines, for example.

  Then, the control unit 50 creates a histogram of the detected length (number of pixels) (FIG. 10B). For example, in the one-dimensional code COD20 and the two-dimensional code COD22, the length of the white / black pattern is an integral multiple of the width of the unit graphic (the smallest bar for the barcode and the cell for the QR code). Therefore, in the histogram of the length (number of pixels) of the white / black pattern, peaks occur at equal intervals (N, 2 × N, 3 × N, 4 × N).

  For this reason, the control unit 50 selects a section N having the smallest number of pixels among the sections (number of pixels) N, 2 × N, 3 × N, 4 × N where the peak is generated, as a unit graphic (for example, QR code). (Cell) is calculated as the number of pixels per side (estimated number of pixels). The estimated pixel number N corresponds to the pixel number N in Expression (1) described with reference to FIG. Further, the control unit 50 calculates an estimation error ± α of the estimated number of pixels N. For example, the control unit 50 calculates the half width at half maximum of the peak in the section N as the estimation error α.

  Note that the control unit 50 may use the weighted average of the intervals between the second and subsequent peaks as the estimated number of pixels N using the fact that peaks occur at regular intervals. At this time, the accuracy of the estimated number of pixels N is improved. Alternatively, the control unit 50 may calculate the estimated pixel number N by another method. Further, the control unit 50 may use the frequency distribution when the inspection area AR is FFT instead of the white / black pattern length histogram.

  Next, the control unit 50 detects whether or not the resolution of the code COD satisfies the resolution condition based on the estimated number of pixels N and the estimated error α (FIG. 10C). When the estimated number of pixels N is smaller than the minimum value Tmin, for example, the code COD is not recognized due to software processing limitations. Therefore, the control unit 50 determines that zoom adjustment is necessary when the estimated number of pixels N is smaller than the minimum value Tmin. Further, when the estimated number of pixels N is larger than the maximum value Tmax, for example, there is a high possibility that the code COD protrudes from the screen of the display unit 100, and there is a high possibility that the code COD is not recognized.

  Even when the estimated number of pixels N is larger than the maximum value Tmax, the code COD may not protrude from the screen of the display unit 100, so the maximum value Tmax may not be included in the resolution condition. The resolution condition at this time is expressed by Expression (1) described with reference to FIG. Note that the resolution condition including the maximum value Tmax is expressed by, for example, Expression (4).

Tmin + α <N <Tmax−α (4)
When the estimated number of pixels N does not satisfy the resolution condition (Equation (1) or Equation (4)), the code image reading device 10 adjusts the resolution of the code COD by performing zoom adjustment with an appropriate zoom value. For example, in order to prevent the code COD after zoom shooting from protruding from the screen of the display unit 100, the control unit 50 zooms such that the estimated pixel number N of the code COD after zoom shooting is slightly larger than the minimum value Tmin. Is calculated as an appropriate zoom value.

  That is, the control unit 50 calculates, for example, the minimum value (= Tmin / (N−α)) among the target zoom values Zm of the equation (2) described in FIG. 7 as an appropriate zoom value. When the settable zoom value is a discrete value, the control unit 50 sets the minimum zoom value (settable value) among the settable zoom values larger than the minimum value (= Tmin / (N−α)). Is calculated as an appropriate zoom value. In addition, when there is no settable zoom value larger than the minimum value (= Tmin / (N−α)), the control unit 50 determines that the resolution condition is not satisfied even when zoom adjustment is performed.

  As described above, in this embodiment, the code image reading apparatus 10 includes the control unit 50 that performs control according to the cause of the unrecognizable code COD based on the optical resolution and resolution of the code COD. For example, when the code COD is a blurred image (insufficient optical resolution), the control unit 50 detects the AF adjustment start timing based on the movement state of the code image reading device 10. Thereby, in this embodiment, AF adjustment can be automatically performed at an appropriate timing.

  Further, when the code COD is not a blurred image, the control unit 50 determines whether or not zoom adjustment is necessary based on the resolution of the code COD. Thereby, in this embodiment, zoom photographing set to an appropriate zoom value can be automatically performed at an appropriate timing. Furthermore, when it is determined that the code COD cannot be recognized even after the AF adjustment or the zoom adjustment is performed, the control unit 50 notifies the user of a handling method that enables the code COD to be recognized. Thereby, in this embodiment, the convenience of the code image reading apparatus 10 can be improved. That is, in this embodiment, the efficiency of the code image reading operation can be improved.

The invention described in the above embodiments is organized and disclosed as an appendix.
(Appendix 1)
A code image reading device equipped with a digital camera,
A shooting section for shooting images;
A code detection unit that detects whether a code is included in an arbitrary inspection area of the photographed image, and determines whether the code in the inspection area is a blurred image;
A moving state detecting unit for detecting a moving state of the code image reading device;
When the code is the blurred image, the auto focus adjustment start timing is detected based on the detection result of the moving state detection unit, and when the code is not the blurred image, it is determined whether zoom adjustment is necessary or not. A control unit for determining based on the resolution of the code in the inspection area;
An autofocus unit that performs the autofocus adjustment in response to detection of the start timing;
A zoom adjustment unit that performs the zoom adjustment when the control unit determines that the zoom adjustment is necessary;
A notification unit for notifying the user of a user notification according to the cause of the unrecognized code;
A code image reading apparatus, comprising: a code processing unit that extracts data stored in the code.
(Appendix 2)
The control unit detects the start by detecting at least one of a first state, a second state, and a third state based on the detection result of the moving state detection unit when the code is the blurred image. Detect the timing,
The first state is a state where the code image reading device is stopped,
In the second state, the code image reading device is not moved in a direction orthogonal to the optical axis direction of the digital camera, and the code image reading device is continuously moved in the optical axis direction for a predetermined time. Is in a state
The third state is a state in which the code image reading device is not moved in a direction orthogonal to the optical axis direction, and the movement of the code image reading device in the optical axis direction is changed in the opposite direction. The code image reading apparatus according to appendix 1, wherein the code image reading apparatus is provided.
(Appendix 3)
The code image reading unit according to appendix 1 or appendix 2, wherein the code detection unit determines that the code is the blurred image when a variance of pixel values in the inspection area is equal to or less than a preset reference value. apparatus.
(Appendix 4)
The notification unit notifies the user of the user notification for moving the code image reading device away from the code when the code after the autofocus adjustment is the blurred image. The code image reading device according to any one of appendix 1 to appendix 3.
(Appendix 5)
When the code is not the blurred image, the control unit determines whether or not the number of pixels per side of the graphic of the minimum structural unit of the code is smaller than a preset minimum value, and 1 of the graphic The code image reading device according to any one of appendix 1 to appendix 4, wherein when the number of pixels per side is smaller than the minimum value, it is determined that the zoom adjustment is necessary.
(Appendix 6)
The control unit detects an estimation error α based on a distribution when calculating the number N of pixels per side of the graphic in the inspection region, and the number N of pixels uses the estimation error α and the minimum value Tmin. Whether or not the code can be recognized based on whether or not the target zoom value Zm satisfying the formula (2) is within the range adjustable by the zoom adjustment unit when the formula (1) is not satisfied. Judging Tmin <N−α (1)
Tmin / (N−α) <Zm (2)
The code image reading device according to appendix 5, wherein:
(Appendix 7)
The notification unit notifies the user of the user notification for causing the code image reading device to approach the code when the target zoom value does not exist within a range adjustable by the zoom adjustment unit. The code image reading device according to appendix 6.
(Appendix 8)
An operation method of a code image reading apparatus equipped with a digital camera,
Take a picture,
Detecting whether or not a code is included in an arbitrary inspection area of the photographed image, and determining whether or not the code in the inspection area is a blurred image;
Detecting the movement state of the code image reading device,
When the code is the blurred image, the auto focus adjustment start timing is detected based on the detection result of the moving state, and when the code is not the blurred image, it is determined whether zoom adjustment is necessary or not. Based on the resolution of the code in the
In response to the detection of the start timing, the autofocus adjustment is performed,
When it is determined that the zoom adjustment is necessary, the zoom adjustment is performed,
When the code is unrecognizable, notify the user of a user notification according to the cause of the unrecognizable code,
When the recognizable code is detected, the data stored in the code is taken out.
(Appendix 9)
When the code is the blurred image, the start timing is detected by detecting at least one of a first state, a second state, and a third state based on the detection result of the moving state,
The first state is a state where the code image reading device is stopped,
In the second state, the code image reading device is not moved in a direction orthogonal to the optical axis direction of the digital camera, and the code image reading device is continuously moved in the optical axis direction for a predetermined time. Is in a state
The third state is a state in which the code image reading device is not moved in a direction orthogonal to the optical axis direction, and the movement of the code image reading device in the optical axis direction is changed in the opposite direction. The operation method of the code image reading device according to appendix 8, characterized in that it exists.
(Appendix 10)
The code image reading apparatus operating method according to appendix 8 or appendix 9, wherein when the variance of pixel values in the inspection area is equal to or less than a preset reference value, the code is determined as the blurred image.
(Appendix 11)
Supplementary notes 8 to 8, wherein, when the code after the autofocus adjustment is performed is the blurred image, the user notification for moving the code image reading device away from the code is notified to the user. The operation method of the code image reading device according to any one of appendix 10.
(Appendix 12)
When the code is not the blurred image, it is determined whether or not the number of pixels per side of the graphic of the minimum structural unit of the code is smaller than a preset minimum value, and the number of pixels per side of the graphic The operation method of the code image reading device according to any one of appendix 8 to appendix 11, wherein the zoom adjustment is determined to be necessary when is smaller than the minimum value.
(Appendix 13)
Equation (1) in which an estimation error α is detected based on a distribution when calculating the number N of pixels per side of the graphic in the inspection region, and the number N of pixels uses the estimation error α and the minimum value Tmin. If the target zoom value Zm satisfying the expression (2) is within a range that can be adjusted by the zoom adjustment unit, it is determined whether or not the code can be recognized. N-α (1)
Tmin / (N−α) <Zm (2)
An operation method of the code image reading device according to appendix 12.
(Appendix 14)
The user notification for causing the code image reading device to approach the code is notified to the user when the target zoom value is not within a range adjustable by the zoom adjustment unit. Method of the code image reading apparatus of the present invention.
(Appendix 15)
A code image reading program to be executed by an electronic device equipped with a digital camera,
A code image reading program for causing the electronic device to operate as the code image reading device according to any one of appendix 1 to appendix 7.
(Appendix 16)
A code image reading program to be executed by an electronic device equipped with a digital camera,
Shooting process to take images,
A code detection process for detecting whether or not a code is included in an arbitrary inspection area of the photographed image and determining whether or not the code in the inspection area is a blurred image;
A movement state detection process for detecting a movement state of the electronic device;
When the code is the blurred image, the auto focus adjustment start timing is detected based on the detection result of the moving state, and when the code is not the blurred image, it is determined whether zoom adjustment is necessary or not. Control processing to be determined based on the resolution of the code in
In response to detection of the start timing, autofocus processing for performing the autofocus adjustment;
A zoom adjustment process for performing the zoom adjustment when it is determined that the zoom adjustment is necessary;
When the code is unrecognizable, a notification process for notifying the user of a user notification according to the cause of the unrecognized code;
When the recognizable code is detected, a code image reading program for causing the electronic device to execute code processing for extracting data stored in the code.
(Appendix 17)
When the code is the blurred image, the start timing is detected by detecting at least one of a first state, a second state, and a third state based on the detection result of the moving state,
The first state is a state in which the electronic device is stopped,
The second state is a state in which the electronic device is not moved in a direction orthogonal to the optical axis direction of the digital camera, and the electronic device is continuously moved in the optical axis direction for a predetermined time. And
The third state is a state in which the electronic device is not moved in a direction orthogonal to the optical axis direction, and the movement of the electronic device in the optical axis direction is changed in the opposite direction. The code image reading program according to appendix 16.
(Appendix 18)
The code image reading program according to appendix 16 or appendix 17, wherein when the variance of pixel values in the inspection area is equal to or less than a preset reference value, the code is determined to be the blurred image.
(Appendix 19)
Supplementary note 16 to supplementary note 18, wherein when the code after performing the autofocus adjustment is the blurred image, the user notification for keeping the electronic device away from the code is notified to the user. The code image reading program according to any one of the above.
(Appendix 20)
When the code is not the blurred image, it is determined whether or not the number of pixels per side of the graphic of the minimum structural unit of the code is smaller than a preset minimum value, and the number of pixels per side of the graphic The code image reading program according to any one of Supplementary Note 16 to Supplementary Note 19, wherein when the value is smaller than the minimum value, it is determined that the zoom adjustment is necessary.
(Appendix 21)
Equation (1) in which an estimation error α is detected based on a distribution when calculating the number N of pixels per side of the graphic in the inspection region, and the number N of pixels uses the estimation error α and the minimum value Tmin. If the target zoom value Zm satisfying the expression (2) is within a range that can be adjusted by the zoom adjustment unit, it is determined whether or not the code can be recognized. N-α (1)
Tmin / (N−α) <Zm (2)
The code image reading program according to appendix 20, characterized by:
(Appendix 22)
The code according to claim 21, wherein when the target zoom value does not exist within a range adjustable by the zoom adjustment unit, the user notification for causing the electronic device to approach the code is notified to the user. Image reading program.

  From the above detailed description, features and advantages of the embodiments will become apparent. This is intended to cover the features and advantages of the embodiments described above without departing from the spirit and scope of the claims. Further, any person having ordinary knowledge in the technical field should be able to easily come up with any improvements and modifications, and there is no intention to limit the scope of the embodiments having the invention to those described above. It is also possible to rely on suitable improvements and equivalents within the scope disclosed in.

  DESCRIPTION OF SYMBOLS 10 ... Code image reading apparatus; 20 ... Photographing part; 30 ... Code detection part; 40 ... Movement state detection part; 50 ... Control part; 60 ... Auto-focus part; Processing unit: 100, display unit, AR10, AR12, inspection area; COD, COD20, COD22, CODa, CODb, CODb ', CODc, CODd, CODe, code

Claims (8)

A code image reading device equipped with a digital camera,
A shooting section for shooting images;
A code detection unit that detects whether a code is included in an arbitrary inspection area of the photographed image, and determines whether the code in the inspection area is a blurred image;
A moving state detecting unit for detecting a moving state of the code image reading device;
When the code is the blurred image, the auto focus adjustment start timing is detected based on the detection result of the moving state detection unit, and when the code is not the blurred image, it is determined whether zoom adjustment is necessary or not. A control unit for determining based on the resolution of the code in the inspection area;
An autofocus unit that performs the autofocus adjustment in response to detection of the start timing;
A zoom adjustment unit that performs the zoom adjustment when the control unit determines that the zoom adjustment is necessary;
A notification unit for notifying the user of a user notification according to the cause of the unrecognized code;
A code processing unit for retrieving data stored in the code ,
The control unit detects the start by detecting at least one of a first state, a second state, and a third state based on the detection result of the moving state detection unit when the code is the blurred image. Detect the timing,
The first state is a state where the code image reading device is stopped,
In the second state, the code image reading device is not moved in a direction orthogonal to the optical axis direction of the digital camera, and the code image reading device is continuously moved in the optical axis direction for a predetermined time. Is in a state
The third state is a state in which the code image reading device is not moved in a direction orthogonal to the optical axis direction, and the movement of the code image reading device in the optical axis direction is changed in the opposite direction. There is
Code image reading apparatus according to claim. The code image reading apparatus according to claim 1 , wherein the code detection unit determines that the code is the blurred image when a variance of pixel values in the inspection area is equal to or less than a preset reference value . The notification unit notifies the user of the user notification for moving the code image reading device away from the code when the code after the autofocus adjustment is the blurred image. The code image reading device according to claim 1 or 2. When the code is not the blurred image, the control unit determines whether or not the number of pixels per side of the graphic of the minimum structural unit of the code is smaller than a preset minimum value, and 1 of the graphic 4. The code image reading apparatus according to claim 1 , wherein when the number of pixels per side is smaller than the minimum value, it is determined that the zoom adjustment is necessary . 5. The control unit detects an estimation error α based on a distribution when calculating the number N of pixels per side of the graphic in the inspection region, and the number N of pixels uses the estimation error α and the minimum value Tmin. Whether or not the code can be recognized based on whether or not the target zoom value Zm satisfying the formula (2) is within the range adjustable by the zoom adjustment unit when the formula (1) is not satisfied. To judge
Tmin <N−α (1)
Tmin / (N−α) <Zm (2)
The code image reading device according to claim 4 . The notifying unit notifies the user of the user notification for causing the code image reading device to approach the code when the target zoom value is not within a range adjustable by the zoom adjusting unit. The code image reading device according to claim 5. An operation method of a code image reading apparatus equipped with a digital camera,
Take a picture,
Detecting whether or not a code is included in an arbitrary inspection area of the photographed image, and determining whether or not the code in the inspection area is a blurred image;
Detecting the movement state of the code image reading device,
When the code is the blurred image, by detecting at least one of the first state, the second state, and the third state based on the detection result of the moving state, the start timing of the autofocus adjustment is detected, When the code is not the blurred image, determine whether zoom adjustment is necessary based on the resolution of the code in the inspection area;
In response to the detection of the start timing, the autofocus adjustment is performed,
When it is determined that the zoom adjustment is necessary, the zoom adjustment is performed,
When the code is unrecognizable, notify the user of a user notification according to the cause of the unrecognizable code,
When the recognizable code is detected, the data stored in the code is extracted,
The first state is a state where the code image reading device is stopped,
In the second state, the code image reading device is not moved in a direction orthogonal to the optical axis direction of the digital camera, and the code image reading device is continuously moved in the optical axis direction for a predetermined time. Is in a state
The third state is a state in which the code image reading device is not moved in a direction orthogonal to the optical axis direction, and the movement of the code image reading device in the optical axis direction is changed in the opposite direction. There is
A method for operating a code image reading apparatus. A code image reading program to be executed by an electronic device equipped with a digital camera,
A code image reading program for causing the electronic device to operate as the code image reading apparatus according to claim 1.

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