JP2020046980A - Bar code reading device, bar code reading method and program - Google Patents

Abstract

To improve reading performance of a bar code in a configuration including a 2D imager-type bar code reader and a camera.SOLUTION: A 2D imager-type bar code reader, when reading a bar code, allows first imaging means 8 for imaging a subject and second imaging means 9 for imaging the subject in the same imaging direction as that of the first imaging means 8 and at a different depth of field R2 from that of the first imaging means 8 to simultaneously perform an imaging operation. The reader determines a distance to the subject upon the imaging operation, uses as a decoding target an image captured at a depth of field R1 or a depth of field R2 corresponding to the determination result of the distance to the subject of two images individually captured by the first imaging means 8 and the second imaging means 9 in association with the imaging operation, and decodes the bar code in the subject. Accordingly, a wide reading depth R3 including the reading depth R1 of the first imaging means 8 and the reading depth R2 of the second imaging means 9 can be secured in reading the bar code.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a barcode reading device, a barcode reading method, and a program.

  2. Description of the Related Art Conventionally, a bar code reader used for reading a bar code is provided with a camera together with, for example, a bar code reader based on a laser method, and can record a photographed image of a slip and a photographed image of a stained state of a product. A configuration is known (for example, see Patent Document 1 below). In recent years, with the spread of two-dimensional barcodes, there are many barcode readers that employ a 2D imager system instead of a laser system as a barcode reader. Here, the 2D imager method is a method of reading a barcode based on an image captured by a two-dimensional image sensor.

JP-A-2004-345826

  By the way, a barcode reader is required to have a certain level of reading performance such as reading speed, reading depth, minimum resolution, and reading angle. Here, the reading depth is a distance range in which a barcode can be read (for example, 60 mm to 150 mm), and the reading speed is the number of barcode reading attempts per second (for example, 100 times / second). The reading depth becomes smaller as the size of the barcode becomes smaller. For example, if the barcode is a one-dimensional barcode, the reading depth becomes smaller as the minimum bar width becomes smaller.

  However, in a 2D imager-type barcode reader, an autofocus function may be added without securing the optical system of the two-dimensional image sensor as a fixed focus in order to secure a wider reading depth, but this increases the cost. . In addition, there is a problem that the reading speed is sacrificed in the autofocus function because it takes time to adjust the focus.

  The present invention has been made in view of such a conventional problem, and has as its object to improve barcode reading performance in a configuration including a 2D imager-type barcode reader and a camera.

  In order to solve the above-mentioned problems, in a barcode reading apparatus according to the present invention, a first imaging unit for imaging a subject, an imaging direction of the first imaging unit is the same as that of the first imaging unit, and the first imaging unit A second imaging unit for imaging the subject at a different depth of field, and an imaging control unit for causing the first imaging unit and the second imaging unit to simultaneously perform an imaging operation when reading a barcode. Determining means for determining a distance to the subject at the time of the image capturing operation; and determining the distance between two images individually captured by the first image capturing means and the second image capturing means following the image capturing operation. Decoding means for decoding a barcode of the subject, with the image on the side taken at the depth of field corresponding to the determination result of the means as a decoding target.

  Further, in the barcode reading method of the present invention, when reading the barcode, the first imaging means for imaging the subject, and the imaging direction is the same as the first imaging means, and the first imaging means Means for causing the second imaging means for imaging the subject at a depth of field different from the means to simultaneously perform an imaging operation; determining the distance to the subject at the time of the imaging operation; and Of the two images individually captured by the first imaging unit and the second imaging unit, the image on the side captured at the depth of field corresponding to the determination result of the distance to the subject is to be decoded. Decoding a barcode in the subject.

  Further, according to the program of the present invention, when reading a barcode, a computer has a first image pickup means for picking up an image of an object, and the first image pickup means has the same image pickup direction as the first image pickup means, and Means for causing the second imaging means for imaging the subject at a different depth of field to perform an imaging operation at the same time; processing for determining a distance to the subject at the time of the imaging operation; Of the two images individually captured by the first imaging unit and the second imaging unit, the image on the side captured at the depth of field corresponding to the determination result of the distance to the subject is to be decoded. And decoding a barcode in the subject.

  According to the present invention, barcode reading performance can be improved in a configuration including a 2D imager type barcode reader and a camera.

It is a figure which shows the external appearance of the barcode reader which concerns on this invention, (a) is a front view, (b) is a back view. (A) is a perspective view showing a part of the tip side of the barcode reader, and (b) and (c) are partial cross-sectional views on the tip side of the barcode reader, showing a module structure of a camera. FIG. 3 is a block diagram illustrating an electrical configuration of the barcode reader. FIG. 3 is a block diagram illustrating an electrical configuration of a barcode reader unit and a camera unit. It is a flowchart which shows the reading process of a barcode. It is a conceptual diagram showing the outline of the barcode reading method.

  Hereinafter, an embodiment of the present invention will be described. FIG. 1 is a diagram showing the appearance of a barcode reading device 1 according to the present embodiment, wherein FIG. 1 (a) is a front view and FIG. 1 (b) is a back view. The barcode reading device 1 is a handy terminal that is mainly used for reading barcodes, and is also used for photographing images of slips and, if necessary, for soiling of products. It has a mounted configuration.

  As shown in FIG. 1A, the barcode reading device 1 has a substantially rectangular vertically long casing 2, and a display 3, a first indicator 4, and a 2, an indicator 5, an operation key group 6, and a speaker 7 are provided. The display 3 displays various information on a screen. The first indicator 4 and the second indicator 5 are LEDs (Light Emitting Diodes) capable of emitting light of a plurality of colors, and at the tip of the housing 2, the state of the power supply of the barcode reader 1 and various other Lights or flashes in a color corresponding to the state of

  The operation key group 6 includes a plurality of keys including a power key 6a and a center trigger key 6b. The center trigger key 6b is used by a user to read a barcode or to photograph a voucher or a product having the barcode. Each of the keys constituting the operation key group 6 (the symbols are omitted in the figure) includes function keys, numeric keys, and the like, and is used for various operations of the barcode reader 1.

  Here, the barcode reading device 1 has two types of operation modes, a scan mode and a photographing mode. The scan mode is an operation mode for reading a barcode, and the photographing mode is an operation mode for photographing a slip or a product. The barcodes that can be read by the barcode reader 1 in the scan mode are one-dimensional barcodes and two-dimensional barcodes. Further, the user can set a desired operation mode by operating a predetermined key of the operation key group 6.

  On the other hand, as shown in FIG. 1B, on the back side of the barcode reader 1, side trigger keys 11 are provided on both sides of the housing 2, respectively. The side trigger key 11 is used for an instruction to read a barcode and an instruction for photographing, similarly to the center trigger key 6b. In addition, as shown in FIG. 2A, a reading unit 2 a that has a substantially triangular cross section and protrudes is formed at the center of the front end of the rear surface of the housing 2.

  A bar code reader 8 of a 2D imager type and a camera 9 are arranged on both sides in the width direction of the housing 2 on a slope portion of the reading unit 2a on the front end side of the housing 2. Between the barcode reader 8 and the camera 9, a flash LED 10 that emits light when necessary by the camera 9 and irradiates the subject with auxiliary shooting light is disposed. As shown in FIG. 2A, the reading direction B of the barcode in the barcode reader 8 is a predetermined angle (hereinafter, a vent angle) with respect to the extension direction A of the tip end along the length direction of the housing 2. And in this embodiment, the vent angle is 25 degrees.

  The barcode reader 8 and the camera 9 are each modularized and housed in the housing 2. FIG. 2B and FIG. 2C are partial cross-sectional views of the distal end side of the barcode reading device 1 schematically showing the module structure of the camera 9 and the arrangement structure of the camera 9 in the housing 2. The camera 9 includes a substrate 91, a cylindrical housing 92 fixed to the substrate 91, a CMOS (Complementary Metal Oxide Semiconductor) sensor 53 mounted on the substrate 91, a lens holder 93 housed in the housing 92, and a lens. 52. An IR cut filter (not shown) is provided between the CMOS sensor 53 and the lens holder 93.

  Although not shown, a coil is wound around the outer periphery of the lens holder 93, and a magnet covering the coil is provided on the inner peripheral surface of the housing 92. Then, the lens holder 93 moves in the axial direction in the housing 92 by the action of the magnetic force generated by the coil and the magnet, and the distance between the lens 52 and the CMOS sensor 53 changes, thereby enabling focus adjustment. . Further, the substrate 91 is attached to the housing 2 so as to be rotatable around the fulcrum O shown in the figure, and is moved from the reference state shown in FIG. 2B to the state shown in FIG. The state can be changed to the rotation state shown.

  Here, the optical axis of the lens 52 is parallel to the optical axis of the optical system (the lens 42 shown in FIG. 4A) of the barcode reader 8 described later, and the photographing direction of the camera 9 overlapping the optical axis of the lens 52. C is inclined with respect to the extension direction A of the front end of the housing 2 like the bar code reading direction B. That is, the inclination angle of the photographing direction C in the reference state is 25 degrees like the vent angle of the barcode reader 8 as shown in FIG. That is, when the camera 9 is in the reference state, the shooting direction C of the camera 9 is the same as the bar code reading direction B. The tilt angle of the shooting direction C in the rotating state is 60 degrees, and this angle is determined in consideration of workability when shooting a product or the like.

  FIG. 3 is a block diagram schematically illustrating an electrical configuration of the barcode reading device 1. The barcode reading device 1 is mainly configured by a CPU (Central Processing Unit), and is connected to a control unit 21 including a first image processing unit 22 and a second image processing unit 23, and to the control unit 21. And each part. That is, the control unit 21 includes a RAM (Random Access Memory) 24, a main storage unit 25, a recording unit 26, a display unit 27, a key input unit 28, an indicator unit 29, a sound emitting unit 30, a communication unit 31, a bar code reader. The unit 41 and the camera unit 51 are connected.

  The main storage unit 25 is an internal storage such as a flash memory built in the barcode reading device 1. The main storage unit 25 stores a control program for causing the control unit 21 to control the operation of the barcode reading device 1 and various setting information such as information on an operation mode set by a user. The control unit 21 controls the operation of the barcode reading device 1 according to the operation mode according to the control program.

  The RAM 24 is a working memory of the control unit 21. The RAM 24 stores a control program read from the main storage unit 25 and stores various data temporarily used by the control unit 21. The recording unit 26 includes, for example, various memory cards that are detachable from the barcode reading device 1 and a card interface that enables input and output of data to and from the memory card. The recording unit 14 stores identification information of a barcode read from a slip or the like, various data associated with the barcode, such as a read date and time, and data of a shot image of a slip or a product.

  The display unit 27 includes the display 3 and a driving circuit thereof. The display 3 is, for example, an LCD (Liquid Crystal Display) or an ELD (Electro Luminescent Display). The key input unit 28 includes a plurality of keys such as a center trigger key 6b, and supplies operation information indicating key operation contents by the user to the control unit 21. The indicator unit 29 includes an LED (light emitting diode) constituting the first indicator 4 and the second indicator 5, a white LED constituting the flash LED 10, and a drive circuit for driving them.

  The bar code reader unit 41 is a part of the bar code reader 8 described above, and as shown in FIG. 4A, a lens 42, a CMOS sensor 43, a sensor drive circuit 44, an image correction circuit 45, an illumination LED 46, and the like. , And a laser aimer 47.

  The CMOS sensor 43 is a monochrome image sensor that does not have a color filter with about 1 million effective pixels and captures an image of a subject such as a slip or a product when reading a barcode in the scan mode. That is, the CMOS sensor 43 captures the subject by photoelectrically converting the optical image of the subject formed by the lens 42. Although the specific module structure of the barcode reader 8 is not shown, the distance between the lens 42 and the CMOS sensor 43 is fixed. That is, the focus of the barcode reader 8 is fixed.

  The sensor drive circuit 44 drives the CMOS sensor 43 at a predetermined frame rate (for example, 60 fps) while reading the barcode, and inputs the photoelectrically converted electric signal to the image correction circuit 45. The image correction circuit 45 converts the input electric signal into image data for each frame, performs image correction such as dot defect correction so as to obtain an optimal image, and then outputs the corrected image data to the control unit 21. (First image processing unit 22).

  The illumination LED 46 is a red LED, and irradiates a slip or the like with a red auxiliary light for constantly securing the brightness required for reading a barcode on a subject. The laser aimer 47 is constituted by a light source such as an LD (LASER Diode), and irradiates a laser beam toward a slip or the like to form a light image indicating a barcode reading position, for example, light representing only a rectangular corner. Display the image on a slip or the like. The illumination LED 46 and the laser aimer 47 are modularized together with the CMOS sensor 43, and their operations are controlled in synchronization with the imaging operation of the CMOS sensor 43. Specifically, the illumination LED 46 is turned on only during the imaging period (specifically, the exposure period) of the CMOS sensor 43, and the laser aimer 47 is turned on only during the non-imaging period of the CMOS sensor 43.

  The camera section 51 is a part that constitutes the camera 9, and as shown in FIG. 4B, a lens 52 and a CMOS sensor 53, a sensor drive circuit 54, an image correction circuit 55, an AF (Auto Focus) drive circuit. And an actuator drive circuit 57.

  The CMOS sensor 53 is a color image sensor on which a color filter having an effective number of pixels of about 8 million pixels is mounted. The CMOS sensor 53 detects an object at the time of photographing a slip or a product in a photographing mode and at the time of reading a barcode in a scan mode. Take an image. That is, the CMOS sensor 53 captures an image of a subject by photoelectrically converting an optical image of the subject such as a slip formed by the lens 52. Note that the CMOS sensor 53 may be a CCD (Charge Coupled Device) sensor. In this regard, the same applies to the CMOS sensor 43 included in the barcode reader 8.

  The sensor driving circuit 54 drives the CMOS sensor 53 and inputs the photoelectrically converted electric signal to the image correction circuit 55. The sensor driving circuit 54 drives the CMOS sensor 53 at a predetermined frame rate (for example, 60 fps) in both the photographing mode and the scan mode. The image correction circuit 55 converts the input electric signal into image data, and performs automatic white balance adjustment (AWB), automatic exposure adjustment (AE), peripheral dimming correction, dot defect correction, etc. so as to obtain an optimal image. After the image correction is performed, the corrected image data is transferred to the control unit 21 (the second image processing unit 23).

  As described above, the AF (Auto Focus) drive circuit 56 adjusts the focus to an optimal position as needed by changing the distance between the lens 52 and the CMOS sensor 53. Here, the closest focus position that can be adjusted in the present embodiment is closer than the fixed focus position of the barcode reader 8. The actuator drive circuit 57 changes the state of the substrate 91 and the housing 92 of the camera 9 in the housing 2 between the reference state and the rotation state by driving the above-described actuator as needed.

  The sound emitting unit 30 includes a sound generating circuit, an amplifier, and a speaker 7, and emits various notification sounds as needed. The communication unit 31 performs communication according to a predetermined protocol with an external data management server or the like by wire or wireless as needed, and transmits data stored (saved) in the recording unit 26.

  Next, the operation of the barcode reader 1 having the above configuration will be described. First, the operation when the shooting mode is set as the operation mode will be described. In the barcode reading device 1, when the photographing mode is set as the operation mode by the user, the control unit 21 controls the actuator driving circuit 57 of the camera unit 51 and moves the camera 9 in the housing 2 as shown in FIG. The rotation state is controlled as shown in c). That is, the camera 9 is controlled so that the photographing direction C of the camera 9 is inclined by 60 degrees with respect to the extension direction A of the front end of the housing 2.

  After that, the control unit 21 starts the imaging operation of the subject in the camera unit 51, and displays the captured image on the display 3 in live view. Then, when there is a photographing instruction from the user, the control unit 21 stores the image data in the recording unit 26 with the image photographed at that time as a photographed image.

  Accordingly, the photographing direction C of the camera 9 is inclined more than the vent angle with respect to the extension direction A of the front end of the housing 2, so that the user can confirm the position and size of the slip or the product on the display 3. Can perform shooting work.

  In the present embodiment, only the shooting direction C of the camera 9 is variable, but the reading direction B of the barcode in the barcode reader 8, that is, the vent angle can be changed together with the shooting direction C of the camera 9. Is also good. In the present embodiment, the photographing direction C of the camera 9 can be changed by rotating the entire module of the camera 9 in the housing 2. The mirror 9 may be provided so as to be rotatable and positioned, and the shooting direction C of the camera 9 may be changeable by controlling the rotation angle of the mirror. That is, a configuration in which a subject such as a slip or a product is imaged through a mirror can be adopted. The same applies to the barcode reader 8 in this regard.

  Further, when it is possible to change one or both of the photographing direction C of the camera 9 and the barcode reading direction B of the barcode reader 8, a movable portion is provided in the housing 2, and the barcode reader is provided in the movable portion. One or both of the camera 8 and the camera may be arranged, and the reading direction B and the photographing direction C may be changed by rotating the movable part by the user.

  Next, the operation when the scan mode is set as the operation mode will be described. Here, the camera 9 has returned to the reference state in accordance with, for example, a key operation of the user or a setting of the scan mode by the user. In the scan mode, as shown in FIG. It is assumed that C is the same as the bar code reading direction B in the bar code reader 8.

  FIG. 5 is a flowchart illustrating a reading process executed by the control unit 21 in response to a user's instruction to read a barcode in the scan mode. When the control unit 21 starts processing in response to the barcode reading instruction, the control unit 21 first controls the camera unit 51 to set the focus position of the camera 9 to the closest position, that is, a position closer to the focus position of the barcode reader 8. (Step S1). Thereby, the depth of field of the camera 9 is set to be shorter than the depth of field of the barcode reader 8. Note that both of the depths of field may partially overlap.

  Next, the control unit 21 performs an image acquisition setting in the barcode reader unit 41 and the camera unit 51, that is, an initialization process for imaging (step S <b> 2). In both cases, the imaging operation at the predetermined frame rate is started simultaneously (step S3).

  Thereafter, the control unit 21 obtains each image data transferred from the barcode reader unit 41 and the camera unit 51 by the first image processing unit 22 and the second image processing unit 23 individually, and obtains each of the obtained image data. The data is temporarily stored in the RAM 24 (step S4). Further, the control unit 21 reduces the image data obtained from the camera unit 51 by the second image processing unit 23 to a size corresponding to the number of display pixels of the display 3 and displays the reduced size on the display unit 27 (step S5). . In the following description, an image acquired by the barcode reader unit 41 is called a reader-side image, and an image acquired by the camera unit 51 is called a camera-side image.

  Further, the control unit 21 checks whether or not the brightness of the reader-side image is equal to or higher than a specified value (Step S6). In such processing, the control unit 21 obtains, for example, an integrated value of the luminance value of the pixel as the brightness information for the monochrome image data temporarily stored in the RAM 24 by the first image processing unit 22, and the obtained value is determined in advance by a predetermined rule. Check if it is greater than or equal to the value.

  At this time, since the brightness of the image on the reader side is the brightness in a state where the auxiliary light from the illumination LED 46 is irradiated, the distance to a subject such as a slip or a product (hereinafter, referred to as a barcode reading distance) is short. The lightness becomes closer to (closer) and darker to longer (far) (see FIG. 6). In addition, the predetermined brightness is set in advance to a brightness at which the reading distance of the barcode is shorter than the reading depth of the barcode reader 8, that is, less than the shortest reading depth.

  When the brightness of the reader-side image is less than the specified value (step S6: NO), the control unit 21 determines that the barcode reading distance is longer than at least the shortest reading depth of the barcode reader 8. Judgment is made, and barcode decoding processing is performed on the reader-side image (step S7). The reason why the image on the reader side is to be decoded is as follows.

  That is, the depth of field of the camera 9 is set to be closer to the depth of field of the barcode reader 8 when capturing the reader-side image and the camera-side image. Therefore, when the reading distance of the barcode is longer than the shortest distance of the reading depth of the barcode reader 8, the image on the reader side is less blurred than the image on the camera side, that is, suitable for decoding the barcode. This is because it is an image.

  Conversely, when the brightness of the reader-side image is equal to or greater than the specified value (step S6: YES), the control unit 21 determines that the barcode reading distance is shorter than the shortest reading depth of the barcode reader 8. It is determined to be short, and a barcode decoding process is performed on the camera-side image (step S8).

  The reason why the image on the camera side is to be decoded is that the depth of field of the camera 9 is set closer to the depth of field of the barcode reader 8 and the reading distance of the barcode is When the distance is shorter than the shortest distance, the image on the camera side is an image less blurred than the image on the reader side, that is, an image suitable for decoding a barcode.

  Note that the decoding processing in step S7 and step S8 is the same as the decoding processing generally performed in a conventional 2D imager type barcode reader, and a description thereof will be omitted.

  FIG. 6 is a conceptual diagram illustrating an outline of a barcode reading method according to the present embodiment. This diagram conceptually shows the difference in the reading depth between the barcode reader 8 and the camera 9 and the difference between the reader-side images G1 to G3 according to the barcode reading distance. When reading a barcode, the depth of field of the camera 9 is set closer to the depth of field of the barcode reader 8, so that the reading depth R2 of the camera 9 is larger than the reading depth R1 of the barcode reader 8. near.

  Further, the reader-side image G1 shown in the figure is an example of an image when the barcode reading distance is shorter than the reading depth R1 of the barcode reader 8, and the reader-side image G2 has the barcode reading distance. This is an example of an image in the case of entering the depth R1, and the reader-side image G3 is an example of an image in the case where the barcode reading distance is longer than the reading depth R1. The brightness of each of the reader-side images G1 to G3 becomes brighter as the barcode reading distance is shorter. Further, the size of the barcode in each of the reader-side images G1 to G3 decreases as the barcode reading distance increases.

  When the reading distance of the barcode is longer than the shortest distance of the reading depth R1 of the barcode reader 8, the reader-side image captured at that time, for example, the reader-side image G2 or the reader-side image G3 is used as a decoding target. . When the reading distance of the barcode is shorter than the shortest distance of the reading depth R1 of the barcode reader 8, for example, when the reading distance is within the area shown by the broken line frame in FIG. For example, a camera-side image (not shown) is used as a decoding target instead of the reader-side image G1.

  If the decoding has failed in the decoding process in step S7 or the decoding process in step S8 (step S9: NO), the control unit 21 returns to the process in step S4 and repeats the subsequent processes. If the decoding is successful in the decoding process of step S7 or the decoding process of step S8 (step S9: YES) while repeating the process, the control unit 21 records the decoding result, that is, the identification information read from the barcode. It is stored in the unit 26 (step S10).

  Further, the control unit 21 notifies the user that the reading of the barcode has been completed, for example, by causing the sound emitting unit 30 to output a notification sound for notifying the reading completion from the speaker 7 (step S12). The barcode reading process ends.

  Although not shown in the figure, when the user inputs a barcode reading instruction a plurality of times in succession in the scan mode, the control unit 21 performs steps S1 and Step S2 is skipped.

  As described above, in the barcode reader 1, when reading a barcode, both the barcode reader 8 and the camera 9 take an image of an object (a slip or a product, for example). The depth of field is set closer to the depth of field of the barcode reader 8. If it can be determined that the barcode reading distance (the distance to the subject) is longer than the shortest reading depth of the barcode reader 8, the image on the reader side is to be decoded. If it can be determined that the barcode reading distance is shorter than the shortest reading depth of the barcode reader 8, the camera-side image is to be decoded. That is, the barcode is decoded with the image on the side imaged at the depth of field corresponding to the reading distance of the barcode as a decoding target.

  Accordingly, the bar code reader 1 has a wider reading depth than when the bar code reader 8 is used alone, that is, the reading depth R1 of the bar code reader 8 and the reading depth of the camera 9 as shown in FIG. A wide reading depth R3 including R2 can be secured.

  Moreover, there is no need to add the autofocus function to the barcode reader 8, and the reading speed is not sacrificed unlike the case where the autofocus function is added to the barcode reader 8. In addition, the reader-side image captured at the same time as the camera-side image is used for determining the barcode reading distance. Therefore, for example, there is no useless operation time (imaging time) as in the case where the reader-side image is acquired only for determining the reading distance of the barcode, and the reading speed is not sacrificed by this.

  The reading speed required for a barcode reader is usually about 100 msec. On the other hand, the reading speed that can be realized in the present embodiment is as follows. That is, the time from when the barcode reading instruction is issued to the start of the imaging operation is about 30 msec, and the single imaging time in the barcode reader unit 41 and the camera unit 51 is as long as the frame rate is 60 fps. It is about 17 msec, and the time required for the decoding process on the reader-side image and the camera-side image is about 20 msec. Therefore, the shortest speed from when the user instructs to read the barcode to when the first reading is completed is about 67 msec, and the shortest speed after the second reading is about 37 msec.

  As described above, in the present embodiment, the barcode reading performance can be improved in the configuration including the 2D imager type barcode reader and the camera. Moreover, by effectively utilizing the camera used for shooting, it can be realized at low cost.

  Also, in the barcode reading device 1, the barcode reading performance can be improved at low cost by determining the barcode reading distance based on the brightness of the reader-side image. That is, for example, an optional distance sensor may be separately provided in the barcode reader 1, and the barcode reading distance may be determined based on the detection result of the distance sensor. Even in that case, the barcode reading performance can be improved. On the other hand, in the barcode reader 1, such a distance sensor is not required and the cost is low.

  In addition, the barcode reading device 1 includes the illumination LED 46 that illuminates a slip or the like with red auxiliary light when reading a barcode, so that the barcode reading distance can be determined more accurately. In addition, the CMOS sensor 43 that captures an image on the reader side is a monochrome image sensor that does not have a color filter, and receives light more than a color image sensor that has a color filter mounted thereon, such as the CMOS sensor 52 that captures an image on the camera side. High sensitivity. This also allows the barcode reading distance to be more accurately determined.

  The determination of the barcode reading distance may be performed using the camera-side image instead of the reader-side image, or may be performed using both the reader-side image and the camera-side image. Further, as described above, since the optical axis of the lens 42 of the barcode reader 8 and the optical axis of the lens 52 of the camera 9 are parallel, the distance to the subject is calculated based on the parallax existing between the two images. (Such techniques are known). Therefore, when both the reader-side image and the camera-side image are used, the barcode reading distance may be determined not only based on the brightness of both images but also based on the parallax existing between both images. it can.

  Further, in the barcode reading device 1, when reading a barcode, the focus position of the camera 9 is controlled to be the closest position and closer to the focus position of the barcode reader 8, and the depth of field of the camera 9 is reduced. It is set closer to the depth of field of the barcode reader 8. For this reason, it is possible to read a barcode having a smaller size than when reading a barcode using only the barcode reader 8, and it is possible to correspond to a barcode having various sizes.

  Regarding this point, for example, the reading depth of the barcode reader 8 is set in advance to the distance range indicated by R2 in FIG. 6, while the reading position of the camera 9 is changed to the focusing position of the barcode reading device 8 when reading the barcode. It can also be realized by controlling to a farther position and setting the reading depth of the camera 9 to a distance range indicated by R1 in FIG. However, in this case, the camera-side image must have the same resolution as the reader-side image, and the camera 9 needs to use a color image sensor whose effective pixel number is about three times that of the CMOS sensor 52. is there. Therefore, the cost of the camera 9 is increased, and the advantage of using the camera 9 for reading a barcode is reduced by half.

  On the other hand, in a configuration in which the depth of field of the camera 9 is set closer to the depth of field of the barcode reader 8 as in the case of the barcode reader 1, the camera 9 captures a slip or product. It is sufficient to secure the minimum number of effective pixels necessary for the operation. Therefore, the barcode reader 1 can handle not only barcodes of various sizes but also low cost.

As described above, one embodiment of the present invention and its modifications have been described. However, these can be appropriately changed as long as the operation and effect of the present invention can be obtained. And inventions equivalent thereto. Hereinafter, the invention described in the claims of the present application is appended.
(Appendix 1)
First imaging means for imaging a subject;
A second imaging unit that has the same imaging direction as the first imaging unit and captures the subject at a different depth of field than the first imaging unit;
When reading a barcode, an imaging control unit that causes the first imaging unit and the second imaging unit to simultaneously perform an imaging operation;
Determining means for determining a distance to the subject during the imaging operation;
Of the two images individually captured by the first imaging unit and the second imaging unit in accordance with the imaging operation, the image of the side captured at the depth of field corresponding to the determination result of the determination unit Decoding means for decoding a barcode in the subject,
A bar code reader comprising:
(Appendix 2)
2. The barcode reader according to claim 1, wherein the determination unit determines a distance to the barcode based on at least one of the two images.
(Appendix 3)
3. The barcode reader according to claim 2, wherein the determination unit determines a distance to the barcode based on brightness information of one of the two images.
(Appendix 4)
4. The bar code reader according to claim 3, further comprising an illumination unit that irradiates the subject with auxiliary light when reading the bar code.
(Appendix 5)
One of the first imaging means or the second imaging means images the subject with a monochrome imaging device having no color filter,
The determining means determines a distance to the subject based on brightness information of an image of the two images captured by the monochrome image sensor,
The bar code reader according to claim 3 or 4, wherein
(Appendix 6)
The second imaging means has a focus adjustment function,
By controlling the focus position in the second image pickup means at the time of the image pickup operation to a position closer to the focus position in the first image pickup means, the depth of field in the second image pickup means is set to the first position. Further comprising a focus control means for controlling the depth of field different from the depth of field of the imaging means,
5. The barcode reader according to any one of supplementary notes 1 to 4, wherein:
(Appendix 7)
A first imaging unit that captures an image of a subject when reading a barcode; and an image of the subject that has the same imaging direction as the first imaging unit and has a different depth of field than the first imaging unit. Causing the second imaging means to perform an imaging operation simultaneously;
Determining a distance to the subject during the imaging operation;
Of the two images individually captured by the first imaging unit and the second imaging unit in association with the imaging operation, the side imaged at the depth of field corresponding to the determination result of the distance to the subject Decoding the barcode in the subject, with the image of
A bar code reading method comprising:
(Appendix 8)
On the computer,
A first imaging unit that captures an image of a subject when reading a barcode; and an image of the subject that has the same imaging direction as the first imaging unit and has a different depth of field than the first imaging unit. Processing for causing the second imaging means to simultaneously perform an imaging operation;
A process of determining a distance to the subject during the imaging operation;
Of the two images individually captured by the first imaging unit and the second imaging unit in association with the imaging operation, the side imaged at the depth of field corresponding to the determination result of the distance to the subject A process of decoding a barcode in the subject, with the image of
A program for executing

REFERENCE SIGNS LIST 1 barcode reader 2 housing 3 display 8 barcode reader 9 camera 11 side trigger key 14 recording unit 21 control unit 25 main storage unit 27 display unit 28 key input unit 29 indicator unit 41 barcode reader unit 42 lens 43 CMOS sensor 46 Illumination LED
47 laser aimer 51 camera unit 52 lens 53 CMOS sensor 56 AF drive circuit 57 actuator drive circuit B reading direction C shooting direction O fulcrum

Claims (8)

First imaging means for imaging a subject;
A second imaging unit that has the same imaging direction as the first imaging unit and captures the subject at a different depth of field than the first imaging unit;
When reading a barcode, an imaging control unit that causes the first imaging unit and the second imaging unit to simultaneously perform an imaging operation;
Determining means for determining a distance to the subject during the imaging operation;
Of the two images individually captured by the first imaging unit and the second imaging unit in accordance with the imaging operation, the image of the side captured at the depth of field corresponding to the determination result of the determination unit Decoding means for decoding a barcode in the subject,
A bar code reader comprising:   2. The barcode reading device according to claim 1, wherein the determination unit determines a distance to the barcode based on at least one of the two images.   3. The bar code reading device according to claim 2, wherein the determining unit determines a distance to the bar code based on brightness information of one of the two images.   The bar code reader according to claim 3, further comprising an illumination unit that irradiates the subject with auxiliary light when reading the bar code. One of the first imaging means or the second imaging means images the subject with a monochrome imaging device having no color filter,
The determining means determines a distance to the subject based on brightness information of an image of the two images captured by the monochrome image sensor,
The bar code reader according to claim 3 or 4, wherein: The second imaging means has a focus adjustment function,
By controlling the focus position in the second image pickup means at the time of the image pickup operation to a position closer to the focus position in the first image pickup means, the depth of field in the second image pickup means is set to the first position. Further comprising a focus control means for controlling the depth of field different from the depth of field of the imaging means,
The barcode reader according to any one of claims 1 to 4, wherein: A first imaging unit that captures an image of a subject when reading a barcode; and an image of the subject that has the same imaging direction as the first imaging unit and has a different depth of field than the first imaging unit. Causing the second imaging means to perform an imaging operation simultaneously;
Determining a distance to the subject during the imaging operation;
Of the two images individually captured by the first imaging unit and the second imaging unit in association with the imaging operation, the side imaged at the depth of field corresponding to the determination result of the distance to the subject Decoding the barcode in the subject, with the image of
A bar code reading method comprising: On the computer,
A first imaging unit that captures an image of a subject when reading a barcode; and an image of the subject that has the same imaging direction as the first imaging unit and has a different depth of field than the first imaging unit. Processing for causing the second imaging means to simultaneously perform an imaging operation;
A process of determining a distance to the subject during the imaging operation;
Of the two images individually captured by the first imaging unit and the second imaging unit in association with the imaging operation, the side imaged at the depth of field corresponding to the determination result of the distance to the subject A process of decoding a barcode in the subject, with the image of
A program for executing

Images