JP2008262342A - Optical information reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical information reader having enhanced operability. <P>SOLUTION: A bar code image region which is the closest to the center of a pickup image is extracted, and a tilt angle α of a first mirror 31 and a tilt angle β of a second mirror 34 are calculated based on the central position of the bar code image region, and the first mirror 31 and the second mirror 34 are rotated by driving the first motor 33 and the second motor 36. A cross marker light M1 emitted from a first marker light source 40 is reflected on the first mirror 31 and the second mirror 34, and moved to the center of the target bar code image region. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is an optical information reading apparatus that reads optical information represented by a two-dimensional code such as a one-dimensional code such as a bar code or a QR code (“QR code” is a registered trademark of Denso Wave Inc.). An optical device having an image pickup means for picking up optical information, a read means for reading optical information based on a picked-up image picked up by the image pickup means, and a read start instruction means for instructing the read means to start reading. The present invention relates to a static information reader.

  Conventionally, as this type of optical information reading device, an area sensor (imaging means) composed of a CCD imaging device, an LED that emits marker light (also referred to as guide light) for instructing optical information to be read, and A handy type equipped with a trigger switch (reading start instruction means) is known. The marker light includes area marker light indicating the range of the visual field and cross marker light indicating the center of the visual field. The operator of the optical information reading apparatus moves the apparatus itself so that the cross marker light overlaps the optical information to be read, and turns on the trigger switch.

By the way, in recent years, the density of optical information has been increased, and a large amount of optical information tends to be recorded in a small area. For this reason, in order to cope with such a tendency, a high-resolution optical information reader using an area sensor having a large number of pixels has been used.
However, with the downsizing of barcodes, QR codes, etc. (hereinafter simply referred to as codes), multiple codes have fallen within the imaging field of view of the area sensor, and codes other than the codes that the operator wanted to read can be used. The problem of reading also occurred.

In order to solve the above problems, for example, optical information reading devices described in Patent Documents 1 and 2 have been proposed. Patent Document 1 discloses a laser beam generator, a scanning mirror device for scanning a barcode by reflecting a laser beam generated from the laser beam generator, and detecting reflected light from the barcode. A light receiving element, a microcomputer that reads a bar code based on an output signal of the light receiving element, and a device that controls the range of reciprocal angular displacement of the reflecting mirror provided in the scanning mirror device.
Then, by detecting stop bits or start bits at both ends of the bar code and limiting the scanning range of the laser beam to the range up to the clearance formed next to them, another bar code existing in the vicinity is erroneously detected. To avoid reading.

Patent Document 2 describes an illumination LED that illuminates a two-dimensional code, a marker light laser diode that irradiates a marker light to the two-dimensional code, an area sensor that images the two-dimensional code, and a reading instruction. And a trigger switch. The marker light indicates a two-dimensional area narrower than the imaging field of view of the area sensor as a reading range.
When the trigger switch is pressed halfway, the marker light is irradiated from the marker light laser diode to the two-dimensional code, and the first image of the two-dimensional code is picked up by the area sensor, and the image of the first image is displayed. From the data, the irradiation position of the marker light in the imaging field is obtained.

Next, when the irradiation of the marker light is stopped and the trigger switch is turned on, the illumination LED is turned on to illuminate the two-dimensional code, and a second image of the two-dimensional code is captured by the area sensor. Subsequently, an estimation process of the existence area of the two-dimensional code in the second image is performed, and the image of the second image corresponding to the two-dimensional code including all of the plurality of two-dimensional codes within the reading range. A two-dimensional code reading process is performed based on the data.
JP 10-40328 (paragraphs 25-38, FIGS. 1-3, 5) Japanese Patent Laying-Open No. 2005-84890 (paragraphs 25 to 27, FIGS. 1 and 2)

However, each of the optical information reading devices described above has a problem that the operability is poor because the operator moves the device itself by moving the marker light onto the optical information.
In particular, when the optical information is small, it is difficult to align the marker light with the optical information. Further, when there are a plurality of optical information, it is difficult to align the marker light with the optical information to be read.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to realize an optical information reading apparatus with good operability.

  In order to achieve the above object, according to the first aspect of the present invention, in the first aspect of the present invention, an image pickup means (50) for picking up optical information (C1, C2) and a picked-up image (F) picked up by the image pickup means. In the optical information reading device (10) having reading means (70, S11) for reading the optical information based on the above and reading start instructing means (13, 13a) for instructing the reading means to start reading, Marker light irradiating means for irradiating marker light (M1) that indicates optical information to be read, and detecting means for detecting image areas (D1, D2) corresponding to the optical information based on the captured image S6), a selection means (S7, S8) for selecting an image area closest to the center (G) of the captured image among the image areas detected by the detection means, and a selection means selected by the selection means Direction changing means (30, S9, S10) for changing the irradiation direction of the marker light irradiated from the marker light irradiation means so that the marker light is irradiated to the optical information corresponding to the image area. The reading means uses technical means for reading optical information located in a direction in which the marker light is irradiated when reading start is instructed by the reading start instructing means.

  In the invention according to claim 2, in the optical information reader (10) according to claim 1, when a plurality of the image regions (D1, D2) are detected by the detecting means (S6), The selecting means (S7, S8) uses technical means for selecting the image area closest to the center of the captured image and then sequentially selecting the next closest image area.

  According to a third aspect of the present invention, in the optical information reading device (10) according to the second aspect, the selection means (70, S7, S8) selects the image area (D1, D2) to be selected every predetermined time. The technical means of changing to is used.

  According to a fourth aspect of the present invention, in the optical information reading device (10) according to any one of the first to third aspects, the selection means (S7, S8) includes the image area (D1, D2). And calculating a distance (R1, R2) between the center (G1, G2) of the image and the center (G) of the captured image (F), and selecting an image area with the shortest distance as the closest image area. Use.

  According to a fifth aspect of the present invention, in the optical information reading device (10) according to any one of the first to third aspects, the selection means (S7, S8) includes the image area (D1, D2). Technical means for calculating the distance (R1, R2) between the center (G1, G2) of the image and the end (F1) of the captured image (F) and selecting the image area with the shortest distance as the closest image area Is used.

  According to a sixth aspect of the present invention, in the optical information reading device (10) according to any one of the first to fifth aspects, the selection means (S7, S8) is a center of the captured image (F) ( When G) and the image area (D1, D2) overlap, a technical means of selecting the overlapping image area is used.

  According to a seventh aspect of the present invention, in the optical information reading device (10) according to any one of the first to sixth aspects, the direction changing means (30, S9, S10) includes the marker light (M1). ), A light path changing means (31, 34) for changing the optical path of the marker light emitted from the light source, and a marker emitted from the light path changing means by displacing the light path changing means. And an actuator (33, 36) that changes the light irradiation direction, and uses technical means for changing the irradiation direction of the marker light by controlling the operation of the actuator.

  According to an eighth aspect of the present invention, in the optical information reader (10) according to any one of the first to sixth aspects, the direction changing means (30, S9, S10) includes the marker light (M1). ), A first optical path changing means (31) for changing the optical path of the marker light emitted from the light source, and an optical path of the marker light emitted from the first optical path changing means. Second optical path changing means (34), a first actuator (33) for displacing the first optical path changing means, a second actuator (36) for displacing the second optical path changing means, And a technical means for changing the irradiation direction of the marker light into a two-dimensional direction by controlling the operations of the first and second actuators.

  According to a ninth aspect of the present invention, in the optical information reading device (10) according to the seventh or eighth aspect, the direction changing means (30, S9, S10) is a center of the captured image (F). By controlling the operation amount of the actuator (33, 36) corresponding to the distance (R1, R2) from (G) to the image area (D1, D2), the optical path changing means (31, 34) A technical means of controlling the amount of displacement is used.

  According to a tenth aspect of the present invention, in the optical information reading device (10) according to any of the seventh to ninth aspects, the actuator (33, 36) includes the optical path changing means (31, 34). The optical path changing means reflects the marker light emitted from the light source (40), and rotates by the actuator to change the reflection angle of the marker light (M1). Use technical means to do.

  According to an eleventh aspect of the present invention, in the optical information reader (10) according to any one of the seventh to tenth aspects, the actuator slides the optical path changing means (31, 34). And the optical path changing means reflects the marker light emitted from the light source (40), and changes the reflection angle of the marker light emitted from the light source by sliding with the actuator. Use technical means that there is.

  According to a twelfth aspect of the present invention, in the optical information reading device (10) according to any of the seventh to eleventh aspects, the restricting means (80) for restricting the displacement of the optical path changing means (31, 34). , 81) is used.

  In addition, the code | symbol in the said parenthesis respond | corresponds with the code | symbol described in embodiment of the invention mentioned later.

(Effect of the invention according to claim 1)
According to the first aspect of the present invention, it is possible to select the image area closest to the center of the captured image and irradiate the optical information corresponding to the selected image area with the marker light.
In other words, an image region corresponding to the optical information to be read only needs to be included in the captured image, and even when the marker light does not exist on the optical information, the marker light is automatically optically detected. It can be moved over information.
Further, even if the optical information is small, the marker light can be automatically moved onto the optical information.
Therefore, the operator does not need to move the apparatus itself so that the marker light comes on the optical information to be read, so that the operability of the apparatus can be improved.

(Effect of the invention according to claim 2)
According to the second aspect of the present invention, after selecting the image area closest to the center of the captured image, the next closest image area can be sequentially selected.
That is, after moving the marker light onto the optical information corresponding to the image area closest to the center of the captured image, the marker light can be sequentially moved onto the next optical information.
Further, even if each optical information is small, the marker light can be automatically moved sequentially onto a plurality of optical information.
Therefore, it is not necessary for the operator to move the marker light on the plurality of pieces of optical information by moving the device itself, so that the operability of the device can be improved.

(Effect of the invention according to claim 3)
According to the third aspect of the present invention, the image area to be selected can be changed every predetermined time.
That is, after the marker light is moved onto the optical information corresponding to the image region closest to the center of the captured image, the marker light can be automatically and sequentially moved onto the next closest optical information every predetermined time.
Further, even if each optical information is small, the marker light can be automatically moved sequentially onto a plurality of optical information.
Therefore, since the operator only needs to give an instruction to start reading by the reading start instruction means when the marker light moves on the optical information to be read, the operability of the apparatus can be improved.

(Effect of the invention according to claim 4)
Since the distance between the location other than the center of the image area and the center of the captured image varies greatly depending on the degree of inclination of the image area with respect to the captured image, the image area closest to the center of the captured image cannot be selected accurately.
However, in the invention according to claim 4, since the distance between the center of the image area and the center of the captured image is calculated, the image area with the shortest distance can be accurately selected as the image area closest to the center of the captured image. .
Therefore, the marker light can be reliably moved onto the optical information to be read.

(Effect of the invention according to claim 5)
According to the fifth aspect of the present invention, the distance between the center of the image area and the edge of the captured image can be calculated, and the image area with the shortest distance can be selected as the image area closest to the center of the captured image.
In other words, since the distance between the center of the image area and the edge of the captured image has a small variation as described above, the image area closest to the center of the captured image can be accurately selected. The marker light can be moved reliably.

(Effect of the invention according to claim 6)
According to the sixth aspect of the present invention, when the center of the captured image and the image region overlap, the overlapping image region can be selected.
That is, when the operator moves the apparatus over the optical information to be read, the image area corresponding to the optical information has a high probability of being located at the center of the captured image. Is overlapped, the marker light can be reliably moved onto the optical information to be read by selecting the overlapping image area.

(Effect of the invention according to claim 7)
According to the seventh aspect of the present invention, the optical path changing means for changing the optical path of the marker light emitted from the light source that emits the marker light is displaced, and the irradiation direction of the marker light emitted from the optical path changing means is changed. By controlling the operation of the actuator to be operated, the irradiation direction of the marker light can be changed.

(Effect of the invention according to claim 8)
According to the invention described in claim 8, the operation of the first actuator for displacing the first optical path changing means for changing the optical path of the marker light emitted from the light source that emits the marker light, and the first optical path change. The irradiation direction of the marker light can be changed to a two-dimensional direction by controlling the operation of the second actuator for displacing the second optical path changing means for changing the optical path of the marker light emitted from the means.

(Effect of the invention according to claim 9)
By controlling the operation amount of the actuator in accordance with the distance from the center of the captured image to the image region, the displacement amount of the optical path changing unit can be controlled.

(Effect of the invention according to claim 10)
The optical path changing means reflects the marker light emitted from the light source and can change the reflection angle of the marker light by rotating by the operation of the actuator.

(Effect of the invention according to claim 11)
The optical path changing means reflects the marker light emitted from the light source, and can change the reflection angle of the marker light by sliding by the operation of the actuator.

(Effect of the invention according to claim 12)
Since the restricting means for restricting the displacement of the optical path changing means is provided, the optical path changing means is excessively displaced, and there is no possibility that the irradiable range of the marker light exceeds the appropriate range (field of view).

<First Embodiment>
Embodiments according to the present invention will be described with reference to the drawings.
In the following embodiments, a barcode reader that reads a barcode as optical information will be described as a representative example of the optical information reader according to the present invention. The bar code means a one-dimensional code such as EAN / UPC, interleaved 2 of 5, coder bar, code 39/128, standard 2 of 5, RSS.

(Main composition)
The main configuration of the barcode reader according to this embodiment will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing a partial internal structure of the barcode reader according to this embodiment.
The barcode reader 10 is a gun type and includes a housing 11 and a grip 12 attached to the lower portion of the housing 11. The grip 12 is formed in a size and shape that can be held by a person with one hand, and a trigger switch 13 is provided on the entire surface of the grip 12 for instructing the start of barcode reading. The trigger switch 13 is disposed at a position where an operation of pulling with the index finger mainly of the hand holding the grip 12 can be performed. When the trigger switch 13 is pulled, the reading start switch 13a (FIG. 3) disposed inside the grip 12 is turned on, and reading of the barcode is started.

  A reading port 11 a is formed in the front surface of the housing 11. Illumination light for illuminating the barcode and marker light for indicating the barcode are emitted from the reading port 11a, and reflected light reflected by the barcode is further incident. A camera module 15 and a circuit board 14 are provided inside the housing 11. The camera module 15 includes a first marker light source 40 for irradiating the cross marker light M1 (FIG. 2) and a second marker light source 41 (FIG. 2) for irradiating the area marker light M2 (FIG. 2). These are mounted with the irradiation direction directed toward the reading port 11a. Although only the first marker light source 40 is shown in FIG. 1, the second marker light source 41 is actually disposed on the other side of the first marker light source 40.

  In addition, a mirror module 30 for changing the irradiation direction of the cross marker light M1 emitted from the first marker light source 40 is mounted in front of the first marker light source 40 in the camera module 15. Further, the camera module 15 is equipped with an optical sensor 52 and an imaging device 51 arranged in front of the optical sensor 52. The imaging device 51 includes an imaging lens for imaging the reflected light reflected by the barcode on the light receiving portion of the optical sensor 52. The optical sensor 52 electrically detects an image formed on the light receiving unit as a two-dimensional captured image. The optical sensor 52 is, for example, a CCD image sensor in which CCDs (Charge Coupled Devices) are arranged in two dimensions (vertical and horizontal), or a C-MOS (Complementary Metal Oxide Semiconductor) in two dimensions (vertical and horizontal). And a two-dimensional image sensor such as a C-MOS image sensor.

  Although not shown in FIG. 1, the camera module 15 includes an illumination unit 60 (FIG. 3) that illuminates a barcode. The illumination unit 60 includes a group of a plurality of LEDs serving as an illumination light source and an illumination lens that is disposed in front of the LEDs and collects and diffuses the light around the imaging device 51. A plurality of sets are arranged toward the reading port 11a. Illumination light from the illumination unit 60 is applied to the barcode through the reading port 11a, and reflected light from the barcode enters through the reading port 11a, and forms an image on the optical sensor 52 through the imaging device 51 described above. Is done. That is, the barcode is imaged. Note that the illumination light from the illumination unit 60 is, for example, white light.

  Further, although not shown in FIG. 1, the camera module 15 is equipped with a light amount sensor 62 for detecting the amount of reflected light from the barcode. That is, when the amount of reflected light from the barcode is insufficient, the detection time (exposure time) by the optical sensor 52 is lengthened so that a reading error due to insufficient reflected light from the barcode does not occur. .

(Configuration of mirror module)
Here, the configuration of the mirror module 30 will be described with reference to FIG.
The mirror module 30 includes a first mirror 31 for reflecting the laser light L1 emitted from the first marker light source 40, a first motor 33 for rotating the first mirror 31, and a first mirror 31. A second mirror 34 for reflecting the reflected laser beam L2 in the direction of the barcode and a second motor 36 for rotating the second mirror 34 are provided.

  As shown in FIG. 2, the field of view F of the optical sensor 52 is a rectangular region. The area marker light M2 that defines the range of the field of view F includes an L-shaped portion that defines the four corners of the field of view F, two linear portions that respectively define the central portions of the upper and lower ends of the field of view F, It is comprised from two T-shaped parts which each define the center part.

  The first marker light source 40 includes a marker light source (not shown) and a marker optical element (not shown) arranged in front thereof. The marker light source is composed of, for example, a laser diode that emits red laser light with good visibility, and emits a thin beam of laser light as marker light toward the front. The marker optical element is composed of a lens for changing the incident thin beam-like laser light into a cross shape and emitting it as a cross marker light M1.

  The second marker light source 41 includes a marker light source (not shown) and a marker optical element (not shown) arranged in front of the marker light source. The marker light source is composed of, for example, a laser diode that emits red laser light with good visibility, and emits a thin beam of laser light as marker light toward the front. The marker optical element is composed of a lens for changing the incident thin beam-like laser light into the above-mentioned L shape or the like and emitting it as the area marker light M2.

  The first mirror 31 is attached to the tip of the rotary shaft 32 of the first motor 33, and rotates by driving the first motor 33. The first mirror 31 has a first reflecting surface 31 a that reflects the cross marker light M <b> 1 emitted from the first marker light source 40 to the second mirror 34. The first mirror 31 determines the position of the cross marker light M1 in the horizontal direction (X-axis direction) based on the rotation angle thereof. The range of the rotation angle of the first mirror 31 is set to α.

  The second mirror 34 is attached to the tip of the rotation shaft 35 of the second motor 36 and rotates by driving the second motor 36. The second mirror 34 has a second reflecting surface 34 a that reflects the cross marker light M <b> 1 reflected by the first mirror 31 toward the visual field F. The second mirror 34 determines the position of the cross marker light M1 in the vertical direction (Y-axis direction) based on the rotation angle thereof. The range of the rotation angle of the second mirror 34 is set to β.

  The first mirror 31 and the second mirror 34 are so-called micro mirrors. The reflecting surfaces of the first mirror 31 and the second mirror 34 are finished to mirror surfaces with high reflectivity. For example, as the first mirror 31 and the second mirror 34, a silicon substrate having a mirror-finished substrate surface can be used. Further, it is also possible to use a mirror in which a layer of aluminum, silver, or the like is formed on one substrate surface of a substrate formed of glass or synthetic resin, and the one substrate surface is a reflective surface.

  As the first motor 33 and the second motor 36, for example, a synchronous motor that operates in synchronization with pulsed power such as a stepping motor (also referred to as a pulse motor) is used. A stepping motor has characteristics such that the momentum is proportional to the number of drive pulses, the rotation angle of one step is proportional to the duty ratio of the pulses, good compatibility with the digital control circuit, and no feedback circuit is required. Accurate positioning control can be realized with a simple circuit configuration.

  An actuator created by MEMS (Micro Electro Mechanical Systems) technology can also be used as an actuator for rotating the first mirror 31 and the second mirror 34. For example, an actuator using an electrostatic force such as an electrostatic micromotor, a parallel plate electrostatic actuator, a comb-shaped electrostatic actuator, a micro ultrasonic motor, or the like can be used. These actuators using the MEMS technology are ultra-compact, and can be accommodated in a small barcode reader when combined with a micromirror.

(Function of mirror module)
The cross marker light M1 emitted from the first marker light source 40 is reflected by the first reflection surface 31a of the first mirror 31 through the optical path L1. The cross marker light M1 reflected by the first reflecting surface 31a passes through the optical path L2, is reflected by the second reflecting surface 34a of the second mirror 34, and is applied to the visual field F.

  When the first motor 33 rotates in the + α direction and the first mirror 31 rotates in the + α direction, the cross marker light M1 moves in the field F to the left. Further, when the first motor 33 rotates in the -α direction and the first mirror 31 rotates in the -α direction, the cross marker light M1 moves in the visual field F to the right. When the second motor 36 rotates in the + β direction and the second mirror 34 rotates in the + β direction, the cross marker light M1 moves downward in the field of view F. Further, when the second motor 36 rotates in the -β direction and the second mirror 34 rotates in the -β direction, the cross marker light M1 moves upward in the visual field F.

(Electrical configuration)
Next, the main electrical configuration of the barcode reader 10 will be described with reference to FIG.
The camera module 15 includes a semiconductor laser provided in each of the first marker light source 40 and the second marker light source 41, a marker for driving the first motor 33 and the second motor 36 of the mirror module 30. A drive circuit 37 is mounted. The camera module 15 is driven by a sensor driving circuit 53 for supplying a clock for outputting a pixel signal from the light receiving element of the optical sensor 52 to the optical sensor 52 and each LED of the illumination unit 60. An illumination drive circuit 61 is mounted.

  On the circuit board 14 (FIG. 1), a waveform shaping unit 44, a microcomputer decoding processing unit 70, a memory 71, a data output unit 72, and a buzzer 73 are mounted. The waveform shaping unit 44 is a low-pass filter that removes noise of an analog signal that is photoelectrically converted by the optical sensor 52 and corresponds to the luminance, and an amplification circuit that amplifies the signal output from the low-pass filter with a predetermined amplification factor (gain). And a differential circuit that converts the signal output from the amplifier circuit into a pulse signal, and an absolute value circuit that converts the pulse signal output from the differential circuit into a pulse train that takes an absolute value.

Although not shown, the microcomputer decoding processing unit 70 temporarily stores a CPU that executes decoding processing and control of each circuit, a ROM that stores various control programs executed by the CPU, processing results of the CPU, and the like. A RAM to be stored, a clock signal generation circuit, and an input / output circuit for inputting / outputting data to / from each circuit are provided.
The microcomputer decoding processing unit 70 determines light and dark by comparing each pulse of the pulse train output from the absolute value circuit of the waveform shaping unit 44 with a predetermined reference value, and outputs binary data corresponding to the determination result. The binary data is generated and stored in the memory 71. Then, a light / dark pattern is extracted based on the binary data stored in the memory 71, and the optical information encoded in the barcode to be read is decoded.

  The data output unit 72 outputs the decoded data and the like to an external device (not shown). The buzzer 73 generates a sound such as “beep” when the optical information is successfully decoded. Further, the barcode reader 10 is provided with a power supply circuit 64 for supplying operating power to the microcomputer decode processing unit 70 and each circuit, and a battery 65 for supplying power to the power supply circuit 64. The battery 65 can be charged by an external power source such as an AC power source. Further, the microcomputer decode processing unit 70 is electrically connected to a reading start switch 13 a that is linked to the trigger switch 13.

(Bar code reading process)
Next, a barcode reading process executed by the CPU of the microcomputer decoding processing unit 70 will be described with reference to the drawings. This barcode reading process is a feature of the present invention.
FIG. 4 is an explanatory diagram of a barcode that enters the field of view of the optical sensor. FIG. 5 is an explanatory diagram showing coordinates of an image region (hereinafter referred to as a barcode image region) corresponding to a barcode. FIG. 6 is an explanatory diagram showing the distance between the center of the captured image and the center of the barcode image area. FIG. 7 is an explanatory diagram of the center coordinates of the barcode image area. FIG. 8 is a flowchart showing the flow of the barcode reading process executed by the CPU.
Here, as shown in FIG. 4, it is assumed that there are two barcodes C <b> 1 and C <b> 2 in the visual field F of the optical sensor 52.

  As shown in FIG. 5, an X axis and a Y axis with the lower left corner of the captured image E as the origin (0, 0) are set in the captured image E of the optical sensor 52. The captured image E has a plurality of (J × K) pixel unit blocks in which J pixels are arranged in the X-axis direction and K pixels are arranged in the Y-axis direction, and each block has XY coordinates. Is set. Then, the XY coordinates of a predetermined portion of an image region (hereinafter referred to as a barcode image region) corresponding to the barcode included in the captured image E can be obtained as the XY coordinates of a block in which the predetermined portion exists. ing.

  In FIG. 5, barcode images P1 and P2 corresponding to the barcodes C1 and C2 are displayed in the captured image E, and barcode image areas D1 and D2 corresponding to the barcode images P1 and P2 are displayed. Yes. Note that the blocks shown in FIG. 5 are merely examples, and the blocks can be further subdivided to obtain more accurate coordinates.

  When the power of the barcode reader 10 is turned on, the CPU of the microcomputer decode processing unit 70 performs initial setting (step (hereinafter abbreviated as S) 1 in FIG. 8). In this initial setting, the XY coordinates (xm, yn) of the center G of the captured image E are read from the ROM and temporarily stored in the RAM. Subsequently, the illumination drive circuit 61 is operated to turn on the illumination unit 60 (S2). Subsequently, the marker driving circuit 37 is operated to irradiate the cross marker light M1 and the area marker light M2 (S3). Subsequently, the sensor drive circuit 53 is operated to capture a captured image captured by the optical sensor 52 (S4).

  The captured image data corresponding to the captured captured image is stored in the memory 71 in units of blocks shown in FIG. 5, and XY coordinates are associated with the stored captured image data. Subsequently, when the operator operates the trigger switch 13 (FIG. 1), it is determined whether or not the reading start switch 13a (FIG. 3) is turned on (S5). (S5: No), all barcode image areas included in the captured image E are extracted (S6).

  The determination as to whether or not it is a barcode image area can be performed using, for example, the technique described in Japanese Patent Laid-Open No. 2001-307014. That is, in a region to be determined, whether or not a specific light / dark pattern is formed by repetition of a bar (dark) and a space (bright) constituting a barcode.

  Here, the captured image data stored in block units in the memory 71 in the previous S4 is scanned in the X-axis direction, and the light / dark pattern indicated by the captured image data is stored in advance in a ROM or the like for barcode determination. If the condition of the light / dark pattern is satisfied, it is determined that the image is a barcode image area. If the condition of the specific light / dark pattern is not satisfied, it is determined that the image is not a barcode image area.

  When the scanning of the captured image data in the X-axis direction and the above determination are all completed, a set portion of blocks that are continuously determined to be the barcode image region is set in the barcode image region. In this embodiment, as shown in FIG. 5, an area composed of a light and dark pattern in the barcode image P1 of the barcode C1 is set as the barcode image region D1, and the barcode image P2 of the barcode C2 is set. Of these, the area composed of the light and dark patterns is set as the barcode image area D2. In consideration of the quiet zones formed at both ends of the barcode, an area obtained by extending the both ends of the barcode image area by several blocks can be set as the barcode image area.

  Subsequently, four vertices Q1 to Q4 (FIG. 5) of the barcode image area determined to be the barcode image area are obtained. That is, among all the blocks constituting the barcode image area, the XY coordinate of the block having the minimum X coordinate value and the maximum Y coordinate value is the vertex Q1, and both of the blocks having the maximum X coordinate value and the Y coordinate value are used. The XY coordinate is the vertex Q2, the XY coordinate of the block having the minimum X coordinate value and the Y coordinate value is the vertex Q3, and the XY coordinate of the block having the maximum X coordinate value and the minimum Y coordinate value is the vertex Q4. . In this embodiment, the vertices Q1 to Q4 of the barcode image areas D1 and D2 corresponding to the barcodes C1 and C2 are obtained.

  Next, the CPU obtains the center positions of the barcode image areas D1, D2, that is, the center coordinates G1 (x1, y1), G2 (x2, y2), respectively (S7). The X coordinate of the center coordinate is a value obtained by dividing the value obtained by subtracting the X coordinate value of the vertex Q1 (Q3) from the X coordinate value of the vertex Q2 (Q4) by 2, and the Y coordinate is Y of the vertex Q1 (Q2). The value obtained by subtracting the Y coordinate value of the vertex Q3 (Q4) from the coordinate value is divided by 2.

  Subsequently, a bar code image area having a center position closer to the center G of the captured image E is selected from the center positions obtained in S7 (S8). Here, as shown in FIG. 6, the distance between the center G1 of the barcode image area D1 and the center G of the captured image E is R1, and the center G2 of the barcode image area D2 and the center G of the captured image E are If the distance is R2 and R1 <R2, the barcode image area D1 having the center G1 is selected as the barcode image area corresponding to the barcode to be read.

Subsequently, the movement direction and movement amount of the cross marker light M1 are calculated using the center of the barcode image area selected in S8 as a target position (S9).
The moving direction and the moving amount of the cross marker light M1 are determined by the tilt angle α of the first mirror 31 and the tilt angle β of the second mirror 34. Here, the maximum angles of the inclination angles α and β are 30 degrees, and the first mirror 31 is swung by 30 degrees, whereby the cross marker light M1 can be moved between the left and right ends of the field of view F. It is assumed that the cross marker light M1 can be moved between the upper and lower ends of the field of view F by swinging 34 by 30 degrees.

  The cross marker light M1 is located at the left end of the field of view F when the tilt angle α of the first mirror 31 is 0 degree, which is the initial value, and at the right end of the field of view F, when the tilt angle α is 30 degrees, the maximum angle. Shall be located. The cross marker light M1 is positioned at the lower end of the field of view F when the tilt angle β of the second mirror 34 is 0 degree, which is the initial value, and at the upper end of the field of view F, when the tilt angle β is 30 degrees, which is the maximum angle. Shall be located.

  The distance from the right end of the captured image E of the field of view F to the center of the barcode image area is x, the distance from the lower end of the captured image E to the center of the barcode image area is y, the width of the field of view F is W, and the length of the field of view F is vertical. When the width is H, the inclination angles α and β are obtained by the following equations (1) and (2).

α = 30 degrees * (x / W) (1)
β = 30 degrees * (y / H) (2)

  For example, the horizontal width W of the visual field F is 18 cm and the vertical width H is 12 cm. As shown in FIG. 7, x1 of the central coordinates G1 (x1, y1) of the barcode image area D1 is 15 cm, and the distance y is 5 cm. Assuming that the inclination angle α = 30 degrees * (15 cm / 18 cm) = 25 degrees, the inclination angle β = 30 degrees * (4 cm / 12 cm) = 10 degrees.

The relationship between the center coordinates of the barcode image area and the inclination angles α and β is calculated in advance by the above formula and stored in the ROM of the microcomputer decoding processing unit 70 in a table format. Then, the inclination angles α and β corresponding to the center coordinates of the barcode image area are read from the ROM.
Note that the inclination angles α and β can be calculated using the above formulas every time the calculation is made.

  Subsequently, the CPU outputs a drive command signal corresponding to the calculation result in S9 to the marker drive circuit 37 (FIG. 3), and moves the cross marker light M1 to the center of the barcode image area selected in S8 (S10). ). That is, the marker drive circuit 37 drives the first motor 33 based on the input drive command signal, rotates the first mirror 31 by the inclination angle α from the initial value, and drives the second motor 36 to drive the second mirror. 34 is rotated from the initial value by an inclination angle β, and the cross marker light M1 is moved to the center of the barcode image area selected in S8.

  The correspondence between the rotation angle of the first motor 33 and the tilt angle α of the first mirror 31 and the correspondence between the rotation angle of the second motor 36 and the tilt angle β of the second mirror 34 are, for example, in a table format. Prestored in the ROM or the like of the microcomputer decoding processing unit 70, the calculated rotation angles corresponding to α and β are read from the above table, and the drive signal (drive pulse signal) corresponding to the read rotation angle is a marker. Each mirror is rotated by outputting it from the drive circuit 37 to each motor.

  Subsequently, the decoding process is executed based on the barcode image area that overlaps the position set as the movement target position of the cross marker light M1, that is, the captured image data corresponding to the barcode image area selected in the previous S8 (S11). ). That is, the barcode image area indicated by the moved cross marker light M1 is estimated to be an image area corresponding to the barcode that the operator wants to read.

  Subsequently, it is determined whether or not the decoding is successful (S12). If it is determined that the decoding is successful (S12: Yes), the decoding result is output to the data output unit 72 (S13). ”Or the like is generated to notify that the decoding is successful (S14).

(Effect of 1st Embodiment)
(1) As described above, when the barcode reader 10 of the first embodiment is used, the center of the captured image E is obtained when a plurality of barcode image regions exist in the captured image E by the optical sensor 52. The cross marker light M1 can be moved to the barcode image area where the distance between G and the center of the barcode image area is the shortest.
That is, the barcode image area corresponding to the barcode to be read only needs to be included in the captured image E, and the cross marker light M1 is generated even when the cross marker light M1 does not exist on the barcode. It can be automatically moved onto the barcode.
Even if the barcode is small, the cross marker light M1 can be automatically moved onto the barcode.
Therefore, the operator does not have to move the barcode reader 10 itself so that the cross marker light M1 is placed on the barcode to be read, so that the operability of the barcode reader 10 can be improved.

(2) Since the distance between the location other than the center of the barcode image area and the center G of the captured image varies greatly depending on the degree of inclination of the barcode image area with respect to the captured image E, the bar closest to the center G of the captured image E The code image area cannot be selected accurately.
However, the barcode reader 10 of the above embodiment calculates the distance between the center of the barcode image area and the center G of the captured image E.
Therefore, since the barcode image area closest to the center G of the captured image E can be accurately selected, the cross marker light M1 can be reliably moved onto the barcode to be read.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to FIG.
In the barcode reader of this embodiment, when a plurality of barcode image areas exist in the captured image, the marker light is emitted at predetermined intervals in the order of the distance between the center of the captured image and the center of the barcode image area. It can be automatically moved to each barcode image area. FIG. 9 is a flowchart in which a part of the reading process executed by the CPU of the microcomputer decode processing unit 70 is omitted. The hardware configuration of the barcode reader is the same as that of the barcode reader 10 of the first embodiment, except that a part of the reading process executed by the CPU is different. The same reference numerals are used for the same components.

  When the CPU of the microcomputer decoding processor 70 calculates the center position of each barcode image area (S7), it determines the moving order of the cross marker light M1 in the order in which the calculated center position is closer to the center of the captured image (S7a). . Subsequently, the movement direction and movement amount of the cross marker light M1 to the center position of each barcode image area are calculated by the same method as in the first embodiment (S7b). Subsequently, based on the calculation result, the cross marker light M1 is moved to the first barcode image region, that is, the barcode image region closest to the center G of the captured image E (S7c).

  Subsequently, it is determined whether or not a timer start flag indicating that a timer for measuring a time interval for automatically moving the cross marker light M1 to the next barcode image area is started is ON (S7d). At this stage, since it is not turned on yet, a negative determination is made (S7d: No), and the timer start flag is turned on (S7e). Subsequently, the timer t for measuring the time interval t1 is started (S7f). Said time interval t1 is 1-2 seconds, for example, and can be set to arbitrary time.

  Subsequently, it is determined whether or not the measurement time of the timer t has reached t1 (S7g), and when it is determined that t1 has not been reached (S7g: No), it is determined whether or not the reading start switch 13a is turned on. Determine (S7j). If it is determined that the reading start switch 13a is turned on (S7j: Yes), the process skips to S11 and executes the barcode decoding process corresponding to the barcode image area indicated by the cross marker light M1 (FIG. 8).

  If it is determined that the reading start switch 13a is not turned on (S7j: No), the processing from S4 to S7c is executed to move the cross marker light M1. Since the timer start flag is still ON, an affirmative determination is made (S7d: Yes), the process skips to S7g, and it is determined whether or not the timer t has timed up. If it is determined that the timer t has expired (S7g: Yes), the cross marker light M1 is moved to the center position of the next barcode image area (S7h), and the timer start flag is turned OFF (S7i). ). Subsequently, when it is determined that the reading start switch 13a is not turned on (S7j: No), S4 to S7j are executed again.

That is, until the reading start switch 13a is turned on, the cross marker light M1 can be automatically moved at the time interval t1 in the order that the center position of the barcode image area is closer to the center G of the captured image E.
Then, the operator can read the barcode to be read by operating the trigger switch 13 when the cross marker light M1 moves on the barcode image area corresponding to the barcode to be read. In addition, the barcode reader of the second embodiment can achieve the same effects (1) and (2) as the first embodiment.

(Example of change)
In the second embodiment described above, the cross marker light M1 is automatically moved to each barcode image area. However, the cross marker light M1 can be moved manually. For example, a movement switch for moving the cross marker light M1 is provided in the barcode reader so that the cross marker light M1 moves in each barcode image area each time the operator turns on the movement switch.

FIG. 10 is a flowchart in which a part of the reading process executed by the CPU of the microcomputer decoding processing unit 70 is omitted.
The CPU of the microcomputer decoding processor 70 moves the cross marker light M1 to the first barcode image region, that is, the barcode image region closest to the center G of the captured image E based on the calculation result in S7b (S7c). Subsequently, it is determined whether or not the movement switch is turned on (S7d). If it is determined that the movement switch is turned on (S7d: Yes), the cross marker light M1 is moved to the center position of the next barcode image area (S7h). ). Subsequently, it is determined whether or not the reading start switch 13a is turned on (S7j). If it is determined that the reading start switch 13a is not turned on (S7j: No), S4 to S7c are executed to move the marker light. At this time, if the movement order determined in S7a this time is the same as the movement order determined in S7a in the previous routine, the movement of the cross marker light M1 by the process in S7c is not performed.

That is, each time the movement switch is turned on, the cross marker light M1 can be moved in the order in which the center position of the barcode image area is closer to the center G of the captured image E.
Then, the operator can read the barcode to be read by operating the trigger switch 13 when the cross marker light M1 moves on the barcode image area corresponding to the barcode to be read.

<Third Embodiment>
In each of the embodiments described above, the cross marker light M1 is moved to the barcode image area where the distance between the center G of the captured image E and the center of the barcode image area is the shortest. It is also possible to move the cross marker light M1 to the barcode image area having the shortest distance from the center of the image area. For example, the cross marker light M1 may be moved to the center of the right end or the left end of the captured image E, or to the barcode image area where the distance between the center of the upper or lower end of the captured image E and the center of the barcode image area is the shortest. it can.
Even when this control is used, the operability of the barcode reader can be improved. A bar code reader that executes this control corresponds to the optical information reader according to claim 5 of the present invention.

<Fourth embodiment>
In each of the above-described embodiments, the cross marker light M1 is moved to the barcode image region having the shortest distance from the center G of the captured image E. However, there is a barcode image region that overlaps the center G of the captured image E. In this case, the cross marker light M1 can be moved to the overlapping barcode image area.
Even when this control is used, the operability of the barcode reader can be improved. A bar code reader that executes this control corresponds to the optical information reader according to claim 6 of the present invention.

<Fifth Embodiment>
Next, a fifth embodiment of the invention will be described with reference to FIG.
The bar code reader of this embodiment is characterized in that the cross marker light M1 can be moved by sliding the first mirror 31. FIG. 11 is an explanatory diagram showing the relationship between the slide of the first mirror 31 and the movement of the cross marker light M1, FIG. 11A is an explanatory diagram of a state where the first mirror 31 is in the neutral position, and FIG. FIG. 4C is an explanatory diagram of a state where the first mirror 31 is slid forward, and FIG. 8C is an explanatory diagram of a state where the first mirror 31 is slid rearward.

  The first mirror 31 is attached to a member that slides back and forth, and the member slides back and forth by an actuator. For example, a rack and pinion mechanism is used. A first mirror 31 is attached to the rack, and a mechanism in which a rotating shaft of a motor (for example, a stepping motor) is inserted and fixed to a pinion that meshes with the teeth of the rack is used.

  As shown in FIG. 11B, when the first mirror 31 moves forward, the cross marker light M1 moves to the left. As shown in FIG. 11C, when the first mirror 31 moves backward, The cross marker light M1 moves to the right. The correspondence between the rotation amount of the motor and the movement amount of the cross marker light M1 is stored, for example, in a table format in advance in the ROM or the like of the microcomputer decoding processing unit 70, and the calculated movement amount of the cross marker light M1. By rotating the motor by the corresponding rotation amount, the cross marker light M1 can be moved to the target position.

  The bar code reader of the third embodiment can also achieve the same effects (1) and (2) as the first embodiment. As a mechanism for moving the first mirror 31, a ball screw feed mechanism or the like can be used.

<Other embodiments>
(1) At least one of the first mirror 31 and the second mirror 34 may be provided with a restricting means for restricting the rotation of the mirror. FIG. 12 is an explanatory diagram of a regulating member that regulates the rotation of the first mirror 31. The restricting members 80 and 81 are arranged so that the first mirror 31 does not rotate beyond the maximum and minimum angles. The restricting members 80 and 81 are each formed in a bar shape, and are disposed on the back surface side of the reflecting surface of the first mirror 31. Although not shown, a similar regulating member is also arranged on the back surface side of the reflecting surface of the second mirror 34.

The restricting member 80 restricts excessive rotation of the first mirror 31 in the + direction, and the restricting member 81 restricts excessive rotation of the first mirror 31 in the − direction. For example, the restricting members 80 and 81 restrict the first mirror 31 from rotating beyond the range of 30 degrees.
Thus, by arranging the regulating members 80 and 81, there is no possibility that the rotation of the first mirror 31 becomes excessive and the irradiable range of the cross marker light M1 exceeds the visual field.

(2) Only the first mirror 31 can be rotated so that the cross marker light M1 can be moved only in the X-axis direction.
(3) Instead of the first mirror 31 and the second mirror 34, prisms may be used.
(4) In each of the above-described embodiments, the case where the inclination angles α and β are 30 degrees has been described, but an angle other than 30 degrees can be set according to the aspect ratio of the field of view F.

(5) The present invention can also be applied to an optical information reading apparatus that does not include the illumination unit 60 and uses natural light such as sunlight or extraneous light such as room illumination.
(6) The present invention can be applied to reading various optical information in addition to a barcode reader, a two-dimensional code such as QR code, PDF417, data matrix, maxi code, RSS composite.

It is explanatory drawing which shows the partial internal structure of the barcode reader which concerns on 1st Embodiment. 3 is an explanatory diagram showing a configuration of a mirror module 30. FIG. 2 is an explanatory diagram showing the main electrical configuration of the barcode reader 10 in blocks. FIG. It is explanatory drawing of the barcode which entered into the visual field of the optical sensor. It is explanatory drawing which shows the coordinate of a barcode image area | region. It is explanatory drawing which shows the distance of the center of a captured image, and the center of a barcode image area | region. It is explanatory drawing of the center coordinate of a barcode image area. It is a flowchart which shows the flow of the barcode reading process which CPU performs. It is a flowchart which abbreviate | omits and shows a part of reading process which CPU of the microcomputer decoding process part 70 in 2nd Embodiment performs. It is a flowchart which abbreviate | omits and shows a part of reading process which CPU of the microcomputer decoding process part 70 performs in the example of a change of 2nd Embodiment. It is explanatory drawing which shows the relationship between the slide of the 1st mirror 31, and the movement of the cross marker light M1, (a) is explanatory drawing of the state in which the 1st mirror 31 exists in a neutral position, (b) is the 1st mirror 31. (C) is explanatory drawing of the state which the 1st mirror 31 slid back. It is explanatory drawing of the control member which controls rotation of the 1st mirror.

Explanation of symbols

10. Bar code reader, 13. Trigger switch, 30. Mirror module,
31..First mirror, 33..First motor, 34..Second mirror,
36..Second motor, 40..First marker device, 41..Second marker device,
51..Image forming device, 52..Optical sensor, C1..First code,
C2 .. Second code, F .. Field of view, M1... Cross marker light, M2.

Claims (12)

An imaging means for imaging optical information;
Reading means for reading the optical information based on a captured image captured by the imaging means;
Reading start instruction means for instructing the reading means to start reading;
In an optical information reader having
Marker light irradiating means for irradiating marker light indicating optical information to be read; and
Detecting means for detecting an image region corresponding to the optical information based on the captured image;
A selection means for selecting an image area closest to the center of the captured image among the image areas detected by the detection means;
Direction changing means for changing the irradiation direction of the marker light emitted from the marker light irradiating means so that the optical information corresponding to the image region selected by the selecting means is irradiated with the marker light;
With
The optical information reading apparatus, wherein the reading unit reads optical information located in a direction in which the marker light is irradiated when reading start is instructed by the reading start instructing unit.   When a plurality of the image areas are detected by the detection unit, the selection unit selects an image area closest to the center of the captured image, and then sequentially selects the next closest image area. The optical information reader according to claim 1.   The optical information reading apparatus according to claim 2, wherein the selection unit changes an image area to be selected every predetermined time.   The said selection means calculates the distance of the center of the said image area | region, and the center of the said captured image, and selects the image area of the shortest distance as the said nearest image area | region. The optical information reader according to any one of the above.   The said selection means calculates the distance of the center of the said image area | region, and the edge part of the said captured image, and selects the image area of the shortest distance as the said nearest image area | region. The optical information reader according to any one of the above.   The said selection means, when the center of the said captured image and the said image area have overlapped, select the image area which has overlapped, The Claim 1 thru | or 5 characterized by the above-mentioned. Optical information reader. The direction changing means includes
A light source that emits the marker light;
An optical path changing means for changing the optical path of the marker light emitted from the light source;
An actuator for displacing the optical path changing means to change the irradiation direction of the marker light emitted from the optical path changing means,
The optical information reading apparatus according to claim 1, wherein an irradiation direction of the marker light is changed by controlling an operation of the actuator. The direction changing means includes
A light source that emits the marker light;
First optical path changing means for changing the optical path of the marker light emitted from the light source;
Second optical path changing means for changing the optical path of the marker light emitted from the first optical path changing means;
A first actuator for displacing the first optical path changing means;
A second actuator for displacing the second optical path changing means,
The optical direction according to any one of claims 1 to 6, wherein an irradiation direction of the marker light is changed to a two-dimensional direction by controlling operations of the first and second actuators. Information reader. The direction changing means includes
9. The displacement amount of the optical path changing unit is controlled by controlling an operation amount of the actuator corresponding to a distance from a center of the captured image to the image region. The optical information reading device described. The actuator rotates the optical path changing means,
8. The optical path changing unit reflects marker light emitted from the light source, and rotates by the actuator to change a reflection angle of the marker light. The optical information reading apparatus according to claim 9. The actuator slides the optical path changing means;
The optical path changing means reflects the marker light emitted from the light source, and changes the reflection angle of the marker light emitted from the light source by sliding with the actuator. The optical information reading device according to claim 7.   12. The optical information reading apparatus according to claim 7, further comprising a restricting unit that restricts displacement of the optical path changing unit.

Images