JP2012038083A - Optical information reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical information reader capable of minimizing reading of an unintended information code and increasing a reading speed.SOLUTION: With marker light M being projected on a reading surface R, a signal is obtained from pixels included in a primary obtaining range H1 set at a center portion of effective pixels (S2). A center position of a secondary obtaining range is corrected from an initial position by a shift amount from a position of center marker light MC to the center of the obtained pixels (S5). In the following secondary obtaining process, a signal is obtained from the secondary obtaining range H2 whose size is substantially the same as a size indicated by range marker light ME and whose center position is a position corrected in S5 (S7). The signal obtained in the secondary obtaining process is used for decode processing.

Description

  The present invention relates to an optical information reader that optically reads a barcode (one-dimensional code) or a two-dimensional code such as a QR code (registered trademark).

  2. Description of the Related Art An optical reader is known that includes a marker light projection unit that emits marker light indicating a reading position (for example, Patent Document 1). Since the reading position is known by the marker light, the position of the optical reader can be easily adjusted to an appropriate position where the information code can be read.

  In addition, since the reading optical axis and the marker optical axis are slightly shifted due to dimensional errors or assembly errors of parts, Patent Document 1 includes a correcting unit. Specifically, the amount of deviation between the center of the visual field of the reading unit and the reading center indicated by the marker light projected from the marker light projecting unit is measured.

  Although the amount of deviation differs depending on the reading distance, in Patent Document 1, for example, the measurement of the amount of deviation is performed only once after the assembly is completed, and an arithmetic expression indicating the correspondence between the reading distance and the amount of deviation at the time of measuring the amount of deviation. In addition, an arithmetic expression indicating the relationship between the marker light interval and the reading distance is also obtained. When reading the code, the reading distance is obtained from the marker light interval, and further, the deviation amount is obtained from the reading distance. And the correction which sets the reading center in use to the position displaced by the deviation | shift amount is performed.

JP 2005-85214 A

  The technique of Patent Document 1 obtains the amount of deviation from the marker light interval. On the other hand, when capturing an image for code reading, the marker light becomes an obstacle, so it is necessary to capture the image with the marker light turned off. Therefore, the technique of Patent Document 1 needs to capture an image twice when reading a code. Also, since the distance between the two marker lights is relatively wide, it is necessary to capture all pixels in order to measure the amount of deviation, and it is also necessary to capture all pixels to acquire an image for reading the code. There is. Accordingly, since it is necessary to capture all pixels twice, there is a problem that the code reading speed cannot be sufficiently increased.

  The technique of Patent Document 1 virtually shifts the center of the image by the amount of shift at the time of decoding after taking in all the pixels. Since all the pixels are captured, the pixels are captured regardless of the inside or outside of the marker light range. Therefore, an unintended information code outside the marker light range may be read.

  Further, although the amount of deviation is obtained from the marker light interval when reading the code, there is a problem that an expensive distance sensor is required to obtain the marker light interval.

  The present invention has been made based on this situation, and an object of the present invention is to provide an optical information reader capable of increasing the reading speed while suppressing unintentional reading of an information code. Is to provide.

  According to the invention described in claim 1 for achieving the object, first, the marker light is projected onto the reading surface by the marker light projecting means by the primary capturing means and set at the center of the effective pixel. A signal is captured from a pixel included in the primary capture range. Then, the center position of the secondary capture range is determined based on the amount of deviation between the position of the marker light in the pixel from which the signal is captured by the primary capture means and the center of the visual field included in the captured pixel.

  In this way, after determining the center position of the secondary capture range based on the amount of deviation between the position of the marker light and the center of the visual field included in the captured pixel, the secondary capture is performed for secondary capture for reading the code. Execute capture means. For this reason, it is suppressed that an image of a portion deviating from the marker light is captured, and as a result, an inconvenience that an unintended information code is read is suppressed.

  Further, since the primary capture range captured by the primary capture means is set at the center of the effective pixels and is not all of the effective pixels, it is compared with that of Patent Document 1 that captures all the pixels in order to obtain the shift amount. Reading speed.

  According to the second aspect of the present invention, the marker light projecting means projects the range marker light indicating the reading range on the reading surface in addition to the center marker light indicating the reading center, and captures it by the secondary capturing means. The next capture range has a size that substantially matches the size indicated by the range marker light. Therefore, the inconvenience of reading an unintended information code outside the range indicated by the range marker light is suppressed. Note that the sizes here match not only the areas but also the shapes.

  According to the third aspect of the present invention, the vertical and horizontal pixel counts of the secondary capture range are respectively determined in the vertical or horizontal direction determined by the size of the primary capture range from the vertical or horizontal pixel count of the effective pixels. The number of pixels is set by subtracting the maximum value of the number of shifted pixels. Therefore, regardless of the actual amount of deviation, the secondary acquisition range, that is, the reading range of the information code, is maximized while matching the center and range of the secondary acquisition range with the center marker light and range marker light. can do.

  Note that the maximum value of the number of shifted pixels in the vertical or horizontal direction determined by the size of the primary capture range is, for example, the vertical or horizontal direction of the primary capture range when the center of the primary capture range is set as the center of the visual field. Of the number of pixels.

  According to the fourth aspect of the present invention, the size of the secondary capture range is determined based on the size of the range marker light actually projected on the reading surface. Therefore, the size of the secondary capture range can be matched with the size indicated by the range marker light with high accuracy.

  The range indicated by the marker light projected on the reading surface by the marker light projection means can be set to various ranges as long as it is a range detected by an effective pixel. For example, as in claim 5, it can be larger than the primary capture range and less than or equal to ½ of the effective pixels of the area sensor. As described above, since the secondary capture range is a size that approximately matches the size indicated by the range marker light, the secondary capture range is also one of the effective pixels of the area sensor. A small range of / 2 or less. Therefore, high-speed reading is possible. In addition, since the range indicated by the range marker light on the reading surface is small, in the case of a technique for virtually shifting the center of the image after capturing all the pixels as in Patent Document 1, many unintended information codes are captured. Will end up. Therefore, there is a high possibility that an unintended information code is read. However, in the present invention, since the secondary capture range is a size that substantially matches the size indicated by the range marker light, it is possible to suppress unintended information code reading.

  When reading a one-dimensional code, as in claim 6, the secondary capture range is rectangular, the number of pixels in the horizontal direction is the same as the number of effective pixels in the horizontal direction of the area sensor, and the pixels in the vertical direction The number is made smaller than the number of effective pixels in the vertical direction of the area sensor.

  Furthermore, when reading a one-dimensional code, only the amount of shift in the vertical direction needs to be corrected. Therefore, as in claim 7, the marker light projecting unit projects linear marker light indicating the vertical center of the reading range onto the reading surface, and the shift amount correcting unit captures the signal by the primary capturing unit. The central row of the secondary capture range may be determined based on the amount of vertical displacement between the position of the marker light in the pixel and the center of the visual field included in the captured pixel. This simplifies the processing in the deviation amount correcting means.

  According to another aspect of the present invention, the shift amount correcting means may determine a pixel having a luminance value equal to or greater than a predetermined threshold as the marker light position. Since the portion where the marker light is projected is bright, the pixels of the portion where the marker light is projected have high luminance among the pixels that have received the signal. Therefore, a pixel having a luminance value equal to or greater than a predetermined threshold can be determined as the marker light position. In addition, since only the luminance value and the threshold value are compared, the position of the marker light can be easily determined.

  Further, as in claim 9, the secondary capture range can be set by designating a start address and an end address, and in this case, based on the deviation amount determined by the deviation amount correction means, Determine the end address.

  Further, when reading a one-dimensional code, as described in claim 10, a secondary capture range is set by designating a start line and the number of read lines, and a deviation amount determined by a deviation amount correction means. The starting line may be determined based on the above.

It is a fragmentary longitudinal cross-section which shows the structure outline | summary of the housing etc. of the optical information reader 10 which concerns on embodiment of this invention. It is a block diagram which shows the structure outline | summary of the circuit part of the optical information reader which concerns on embodiment. It is explanatory drawing which shows the structure of the marker projector. It is a figure which shows an example of the pattern of the marker light M projected on the reading surface R by the marker projector. (A) is a diagram showing the optical axis C1 of the marker light projector 60, the visual field center axis C2 and the angle of view θ of the imaging lens 27, and (B) is the central marker light MC at distances d1, d2, and d3. FIG. 6 is a diagram showing a relationship with a field center axis C2 of the imaging lens 27. It is a figure which illustrates all the effective pixels and secondary taking-in range H2. It is a figure which illustrates all the effective pixels and the primary capture range H1. 3 is a flowchart showing processing contents of a control circuit 40. It is a figure explaining the deviation | shift amount ((DELTA) x, (DELTA) y) calculated by step S4 of FIG. It is the figure which illustrated the whole position of the secondary taking-in range H after correcting a center position by Step S5 of Drawing 8. It is a figure which shows an example of the secondary acquisition range of a high-speed reading mode. It is a figure which shows an example of the secondary taking-in range H2 in barcode reading mode. It is a figure which shows the linear marker light in barcode reading mode.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, a schematic configuration of the optical information reading apparatus 10 according to the present embodiment will be described with reference to FIGS. 1 and 2.

  As shown in FIG. 1, an optical information reader 10 is formed integrally with a housing main body 11 having a rounded and thin, substantially rectangular box shape, and a lower surface of the housing main body 11 near the center rear end. A gun-type housing comprising a grip portion 12 is provided. The grip portion 12 is set to have an outer diameter that allows an operator to hold the grip portion 12 with one hand. Illumination light Lf and marker light M, which will be described later, are brought into contact with the operator's index finger holding the grip portion 12. A trigger switch 14 is provided for instructing the emission of light.

  A circuit unit 20 to be described later is accommodated inside the housing body 11, and a light emitting diode 21 that emits illumination light Lf is disposed at the front end of the housing body 11 so that the reflected light Lr can enter. A reading port 11a is formed. In FIG. 1, printed wiring boards 15 and 16 constituting the circuit unit 20, an area sensor 23 mounted on the printed wiring board 16, an imaging lens 27, and a marker light projector 60 that projects marker light M are shown. Etc. are also illustrated.

  As shown in FIG. 2, the circuit unit 20 mainly includes an optical system such as a marker light projector 60, a light emitting diode 21, an area sensor 23, and an imaging lens 27, a memory 35, a control circuit 40, an operation switch 42, A microcomputer (hereinafter referred to as “microcomputer”) system such as a liquid crystal display 46 and a power supply system such as a power switch 41 and a battery 49 are mounted on the printed wiring boards 15 and 16 or the housing body 11. It is decorated inside.

  The optical system includes a marker light projector 60, a light emitting diode 21, an area sensor 23, an imaging lens 27, and the like. The light emitting diode 21 is configured to be able to irradiate the illumination light Lf toward the reading surface R through the reading port 11 a of the housing body 11. On the reading surface R, an information code such as a one-dimensional code or a two-dimensional code is recorded. The recording form includes printing, engraving, and the like.

  The area sensor 23 is configured to be able to receive the reflected light Lr irradiated and reflected on the reading surface R. For example, the area sensor 23 includes a light receiving element that is a solid-state image pickup element such as a C-MOS or a CCD. It is arranged in two dimensions of m rows and n columns in the order of 10,000. The light receiving element converts the received light into an electrical signal and outputs it, and may be referred to as a pixel below.

  The light receiving surface 23a of the area sensor 23 is positioned so as to be visible from the outside of the housing body 11 through the reading port 11a. The area sensor 23 receives incident light incident through the imaging lens 27 as the light receiving surface 23a. It is mounted on the printed wiring board 16 so that it can receive light.

  The imaging lens 27 functions as an imaging optical system capable of condensing incident light incident from the outside through the reading port 11a and forming an image on the light receiving surface 23a of the area sensor 23. It is comprised by the cylinder and the some condensing lens accommodated in this barrel. In the present embodiment, the illumination light Lf emitted from the light emitting diode 21 is reflected by the information code, and the reflected light Lr incident on the reading port 11a is collected, thereby forming a code image on the light receiving surface 23a of the area sensor 23. The image is made possible.

  FIG. 3 is an explanatory diagram showing the configuration of the marker light projector 60. The marker light projector 60 projects the marker light M indicating the reading range of the information code onto the reading surface R. As shown in FIG. 3, a laser diode 62 and a collimating lens provided on the emission side of the laser diode 62 are provided. 64, a diffraction grating plate 66 capable of forming a pattern of the marker light M, a field stop 68 provided with a slit having a predetermined shape, and the like.

  The field stop 68 is configured to be switchable to various slit shapes, and the pattern of the marker light M can be switched to various patterns by switching the slit shape. Note that switching of the pattern of the marker light M by switching the slit shape is described in detail in Japanese Patent Application Laid-Open No. 2008-191999, and thus the description thereof is omitted here.

  FIG. 4 is a diagram illustrating an example of the pattern of the marker light M projected onto the reading surface R by the marker light projector 60. The marker light M shown in FIG. 4 indicates four L-shaped range marker lights ME indicating the four corners of the information code reading range E, and the center of at least one of the upper and lower sides or the left and right sides of the reading range E. The center marker light MC has a cross shape. When the marker light M is thus displayed on the reading surface R, the information code can be surely positioned within the capturing range by positioning the information code within the range indicated by the marker light M.

  Since the marker light M spreads away from the marker light projector 60, the marker light M increases as the distance to the reading surface R increases. The spread of the marker light M is adjusted by the diffraction grating plate 66, and the angle of view of the imaging lens 27 (the angle that the optical center of the lens forms as two diagonal points of the screen, the range that can be clearly imaged by the lens). The angle). Therefore, even if the reading distance changes, the relationship between the size of the range indicated by the range marker light ME and the size of the secondary capture range described later does not change.

  Next, returning to FIG. 2, the outline of the configuration of the microcomputer system will be described. The microcomputer system includes an amplification circuit 31, an A / D conversion circuit 33, a memory 35, an address generation circuit 36, a synchronization signal generation circuit 38, a control circuit 40, an operation switch 42, an LED 43, a buzzer 44, a liquid crystal display 46, and a communication interface 48. Etc. As its name suggests, this microcomputer system is composed mainly of a control circuit 40 and a memory 35 that can function as a microcomputer (information processing device), and the image signal of the code image captured by the optical system described above is hardware. It can perform signal processing in terms of hardware and software. The control circuit 40 also performs control related to the entire system of the optical information reading apparatus 10.

  The image signal (analog signal) output from the area sensor 23 of the optical system is amplified by a predetermined gain by being input to the amplifier circuit 31, and then input from the analog signal when input to the A / D conversion circuit 33. Converted into a digital signal. The digitized image signal, that is, image data (image information) is input to the memory 35 and stored. The synchronization signal generation circuit 38 is configured to generate a synchronization signal for the area sensor 23 and the address generation circuit 36. The address generation circuit 36 is based on the synchronization signal supplied from the synchronization signal generation circuit 38. Thus, the storage address of the image data stored in the memory 35 can be generated.

  The memory 35 is a semiconductor memory device, and corresponds to, for example, a RAM (DRAM, SRAM, etc.) or a ROM (EPROM, EEPROM, etc.). In addition to the image processing program, the ROM stores in advance a system program that can control each hardware such as the marker light projector 60, the light emitting diode 21, and the area sensor 23.

  The control circuit 40 is a microcomputer that can control the entire optical information reader 10 and includes a CPU, a system bus, an input / output interface, and the like. The control circuit 40 can constitute an information processing apparatus together with the memory 35 and has an information processing function. . The control circuit 40 is configured to be connectable to various input / output devices (peripheral devices) via a built-in input / output interface, and includes a power switch 41, an operation switch 42, an LED 43, a buzzer 44, and a liquid crystal display 46. The communication interface 48, the marker light projector 60, and the like are connected.

  Thereby, for example, monitoring and management of the power switch 41 and the operation switch 42, turning on / off the LED 43 functioning as an indicator, turning on / off the buzzer 44 capable of generating a beep sound and an alarm sound, and further reading the information code Enables the screen control of the liquid crystal display 46 capable of displaying the code content by the communication, the communication control of the communication interface 48 enabling serial communication with an external device, the projection control of the marker light M from the marker light projector 60, and the like. ing. The operation switch 42 includes the trigger switch 14 described above.

  The power supply system includes a power switch 41, a battery 49, and the like. When the power switch 41 managed by the control circuit 40 is turned on and off, the conduction of the drive voltage supplied from the battery 49 to each device and each circuit described above is established. Or shut off is controlled. The battery 49 is a secondary battery that can generate a predetermined DC voltage, and corresponds to, for example, a lithium ion battery.

  FIG. 5A is a diagram showing the optical axis C1 of the marker light projector 60, the visual field center axis C2 and the angle of view θ of the imaging lens 27, and FIG. 5B shows the distances d1, d2, and d3. The relationship between the center marker light MC (showing the center of the three center marker lights MC, ie, the center of the top and bottom and the left and right, and the following center marker light MC is also the same) and the field center axis C2 of the imaging lens 27. FIG.

  As shown in FIG. 5A, the optical axis C1 of the marker light projector 60 and the visual field center axis C2 of the imaging lens 27 are not parallel. Since the optical axis C1 and the visual field center axis C2 coincide with each other at the distance d2, as shown in FIG. 5B, at the distance d2, the optical axis C1 and the visual field center axis C2 are on the optical axis C1 of the marker light projector 60. It coincides with the central marker light MC located. However, the center marker light MC is positioned above the visual field center axis C2 of the imaging lens 27, for example, at a distance d3 that is farther than the distance d2, for example, at a distance d1 before the distance d2 (on the imaging lens side). The central marker light MC is positioned below the visual field center axis C2 of the imaging lens 27. Although the spread of the marker light M projected from the marker light projector 60 is not shown in FIG. 5A, this spread matches the angle of view θ of the imaging lens 27 as described above. It is like that.

  As shown in FIG. 5, there is a deviation between the center marker light MC and the visual field center axis C2 of the imaging lens 27 except for the distance d2. Therefore, when the capture range is set to all effective pixels and the size of the range marker light is set so as to indicate the capture range, the capture cannot actually be performed even though the range is indicated by the range marker light. There is always a range, and there is always a range that is captured even though it is outside the range indicated by the range marker light. Therefore, an unintended information code outside the range indicated by the range marker light may be read.

  Therefore, in the present embodiment, in consideration of the shift amount between the center marker light MC and the visual field center axis C2 of the imaging lens 27, a range (secondary capture range H2) that is captured to decode the information code is A range smaller than all effective pixels is set. Further, primary capture is performed before secondary capture, and a shift amount is calculated using an image captured by primary capture.

  FIG. 6 is a diagram illustrating all effective pixels and the secondary capture range H2, and FIG. 7 is a diagram illustrating all effective pixels and the primary capture range H1. The examples in FIGS. 6 and 7 are for VGA (640 pixels × 480 pixels).

  As shown in FIG. 6, the secondary capture range H2 is slightly smaller than all effective pixels, specifically, 590 pixels × 430 pixels. On the other hand, as shown in FIG. 7, the primary capture range H1 is 100 pixels × 100 pixels. Further, the position of the primary capture range H1 is also fixed in advance. Specifically, the center of the primary capture range H1 is set to the center of all effective pixels (that is, the center of the visual field). The size of the primary capture range is determined in consideration of the amount of shift, and is set to a size that allows the central marker light MC to fall within the primary capture range H1 even if the shift is large. On the other hand, in the secondary capture range H2 of this embodiment, in order to ensure the maximum capture size, the number of vertical and horizontal pixels is calculated from the number of vertical and horizontal pixels of all effective pixels, respectively. The number of pixels is obtained by subtracting the number of pixels in the vertical and horizontal directions.

  Next, the operation of the optical information reading apparatus 10 configured as described above will be described. FIG. 8 is a flowchart showing the processing contents of the control circuit 40. The process shown in FIG. 8 is started, for example, when the power switch 41 is turned on and a predetermined self-diagnosis process or the like is normally completed, and the operator presses the trigger switch 14 to turn it on.

  In step S1, exposure is performed while irradiating illumination light and projecting the marker light M toward the reading surface R. Specifically, the control circuit 40 outputs a light emission signal to the light emitting diode 21 and the marker light projector 60 based on the synchronization signal. Thereby, the light emitting diode 21 that has received the light emission signal emits the illumination light Lf, and the marker light projector 60 projects the marker light M. Thereby, the illumination light Lf and the marker light M are reflected by the reading surface R, and the reflected light Lr enters the imaging lens 27 through the reading port 11a, and the light receiving surface 23a of the area sensor 23 is exposed. . The illumination light irradiation, marker light projection, and exposure are performed for a preset time, and the next step S2 is performed after the illumination light irradiation and exposure are completed. The projection time of the marker light M may be the same as the illumination light irradiation time, or may be longer than the illumination light irradiation time until the next illumination light irradiation.

  In the subsequent step S2, a primary capture process, which is a process corresponding to the primary capture means in the claims, is performed. This primary capturing process is a process of capturing a pixel from which an electrical signal is captured by limiting to the above-described primary capturing range set at the center of the visual field.

  In the subsequent step S3, the position of the central marker light MC in the pixel that has received the signal in step S2 is detected. In the detection method, for example, a luminance value is determined for each pixel, and the center of the pixels having the luminance value equal to or greater than a predetermined threshold is detected as the position of the central marker light MC. Since the central marker light MC is much brighter than the illuminance of the illumination, the position can be detected by a simple process of examining pixels whose luminance value is equal to or greater than the threshold value.

  Subsequently, steps S4 and S5, which are processes corresponding to the deviation amount correcting means, are executed. In step S4, the shift amount (Δx, Δy) between the position of the center marker light MC detected in step S3 and the center of the visual field included in the captured pixel (that is, the center of the captured pixel in the present embodiment) is calculated. calculate. FIG. 9 is a diagram for explaining the deviation amounts (Δx, Δy) calculated in step S4. As shown in FIG. 9, the lateral shift amount Δx is the difference between the visual field center C2 (precisely, it is a pixel on the visual field center axis C2, but is described in this way for convenience) and the center of the central marker light MC. This is a difference in horizontal position, and the vertical shift amount Δy is a vertical position difference between the visual field center C2 and the center of the center marker light MC. In the example of FIG. 9, Δx is negative and Δy is positive.

  In the subsequent step S5, the center position of the secondary capture range H2 is corrected. Specifically, the center position of the secondary capture range H2 is set to the above-mentioned visual field center as an initial value, and in this step S5, the center position of the secondary capture range H2 is set to a step with respect to the initial value. The position is set to the position shifted by the shift amount (Δx, Δy) calculated in S4. FIG. 10 is a diagram illustrating the overall position of the secondary capture range H2 after correcting the center position in step S5. In the figure, “◯” C2 ′ is the center position of the corrected secondary capture range H2. is there.

  In subsequent step S6, exposure is again performed by irradiating illumination light. However, unlike step S1 described above, the marker light M is not projected in step S6. In the subsequent step S7, secondary capture is performed. This secondary capture is a process of capturing a signal from a pixel in the secondary capture range H2 whose center position has been corrected in step S5, and captures the signal by designating a start address and an end address. Here, if the initial values of the start address and end address are (x1, y1) and (x2, y2), respectively, the start address and end address specified in step S7 are (x1 + Δx, y1 + Δy), (x2 + Δx). , Y2 + Δy). This step S7 corresponds to the secondary capturing means in the claims.

  The subsequent step S8 is a process corresponding to the reading means in the claims, and the decoding process is performed using the signal fetched in step S7. Then, in the subsequent step S9, it is determined whether the decoding has succeeded (decoding is OK). If this determination is negative, the processes after step S1 are executed again, and if this determination is affirmative, the process ends.

  As described above, according to the present embodiment described above, step S2 of FIG. 8 is executed, and the marker light M is projected onto the reading surface R, and is included in the primary capture range H1 set at the center of the effective pixel. The signal is taken in from the pixel to be recorded. Then, the center position of the secondary capturing range is corrected from the initial position by the amount of deviation (Δx, Δy) between the position of the center marker light MC in the pixel that has captured the signal and the center of the captured pixel (that is, the center of the visual field). Yes. Subsequent secondary capture has a size substantially equal to the size indicated by the range marker light ME, and captures a signal from the secondary capture range H2 centered on the position corrected in step S5 (step S7). For this reason, it is possible to suppress capturing of an image of a portion deviating from the range marker light ME, and as a result, it is possible to suppress inconvenience that an unintended information code is read.

  Further, the center position of the secondary capture range is determined based on the amount of deviation between the position of the marker light M and the center of the captured pixel, and a distance sensor is not required for this determination, so the apparatus can be constructed at low cost. it can.

  Furthermore, since the primary capture range H1 is set at the center of the effective pixels and is not all of the effective pixels, the reading speed is higher than that of Patent Document 1 in which all pixels are captured in order to obtain the shift amount. Can be speeded up.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment, The following embodiment is also contained in the technical scope of this invention, and also the summary other than the following is also included. Various modifications can be made without departing from the scope.
(Modification 1)
The optical reader may have a high-speed reading mode. The high-speed reading mode is a mode in which the number of pixels in the secondary capture range H2 is considerably reduced with respect to all effective pixels. For example, the number of pixels in the secondary capture range H2 is set to 1/2 or less of the total number of effective pixels. Mode.

  FIG. 11 is a diagram illustrating an example of the secondary capture range H2 in the high-speed reading mode. In the example of FIG. 11, the total number of effective pixels is 1280 pixels × 960 pixels, and the secondary capture range H2 is 640 pixels × 480 pixels. Therefore, since the ratio of the number of pixels is 1/4, the capture time is 1/4 compared to the case where all effective pixels are captured in the secondary capture. Even in such a high-speed reading mode, the center position of the secondary capture range H2 is determined by executing the processing of steps S1 to S5 in FIG. That is, even in the high-speed reading mode, since the primary capture range is only 100 × 100 pixels, the capture time is 1/130 compared to the case where all effective pixels are captured in the primary capture.

Note that the range marker light ME projected in the high-speed reading mode has a size that substantially matches the size of the secondary capture range in the high-speed reading mode. Accordingly, the size is different from the range marker light ME in the above-described embodiment. Therefore, it is necessary to make it possible to project a plurality of types of marker light M in the same apparatus. As this method, there is a method of switching the slit shape of the field stop 68 as described above.
(Modification 2)
Further, the optical information reader may have a barcode reading mode. In the barcode reading mode, the secondary capture range H2 has a strip shape. More specifically, the secondary capture range H2 in the barcode reading mode has a horizontally long rectangular shape, the number of pixels in the horizontal direction is the same as the effective pixel in the horizontal direction of the area sensor 23, and the number of pixels in the vertical direction is the same. In this mode, the area sensor 23 is smaller than the number of effective pixels in the vertical direction. Then, the barcode is read as the information code.

  In the barcode reading mode, the secondary capture range H2 may be designated by designating the reading start line and the number of reading lines. FIG. 12 is a diagram illustrating an example of the secondary capture range H2 in the barcode reading mode. In the example of FIG. 12, the size of the secondary capture range H2, that is, the number of read lines is set to 200 lines in the barcode reading mode.

  In this case, the correction amount may be only vertical information, that is, the number of rows. Therefore, as shown in FIG. 13, the marker light M may be a linear marker light M. The marker light M shown in FIG. 13 indicates the center in the vertical direction of the reading range. Therefore, in the secondary capture, the upper and lower 200 lines are read with the position shifted by Δy with respect to the center of the visual field as the reading center line.

Further, a bar code reader having only the bar code reading mode may be manufactured with the same mechanical configuration.
(Other variations)
In the above-described embodiment, the size of the secondary capture range H2 is fixed. However, the size of the secondary capture range H2 may be determined based on the size of the range marker light ME. In this case, in order to determine the size of the secondary capture range H2, first, exposure is performed in a state where the range marker light ME is projected onto the reading surface R, and signals are acquired from all effective pixels of the area sensor 23. Then, by analyzing the luminance value for each pixel from the acquired signal, the positions of the range marker light ME at the four corners are detected. And the size divided by the range marker light ME is detected from the positions of the range marker light ME at the four corners. Then, this size is determined as the size of the secondary capture range.

  In the above-described embodiment, the center of the pixels having a luminance value equal to or higher than the threshold value is detected as the position of the central marker light MC. Instead, the shape of the central marker light MC is detected. The position of the center marker light MC may be detected based on the detected shape.

DESCRIPTION OF SYMBOLS 10: Optical information reader, 11: Housing main body, 11a: Reading port, 12: Grip part, 14: Trigger switch, 15: Printed wiring board, 16: Printed wiring board, 20: Circuit part, 21: Light emitting diode, 23: Area sensor, 23a: Light receiving surface, 27: Imaging lens, 31: Amplification circuit, 33: A / D conversion circuit, 35: Memory, 36: Address generation circuit, 38: Synchronization signal generation circuit, 40: Control circuit , 41: power switch, 42: operation switch, 43: LED, 44: buzzer, 46: liquid crystal display, 48: communication interface, 49: battery, 60: marker light projector (marker light projection means), 62: laser Diode, 64: Collimate Torrens, 66: Grating plate, 68: Field stop, D: Information code, E: Reading range, H1: Primary capturing range, H2: Secondary capturing range, Lf: Illumination light, Lr: Reflected light, M: Marker light ME: Range marker light, MC: Center marker light, R: Reading surface, S2: Primary capturing means, S4, S5: Deviation correction means, S7: Secondary capturing means, S8: Reading means

Claims (10)

An area sensor that converts a two-dimensional optical image of the reading surface into an electrical signal by a plurality of pixels and outputs the electrical signal;
Reading means for reading the information code recorded on the reading surface based on the electric signal output from the area sensor,
An optical information reading device comprising marker light projection means for projecting at least a marker light indicating a reading center onto a reading surface,
Primary capture means for capturing a signal from a pixel included in a primary capture range set at the center of an effective pixel in a state where the marker light is projected onto a reading surface by the marker light projection means;
Shift amount correcting means for determining the center position of the secondary capture range based on the shift amount between the position of the marker light in the pixel that has captured the signal by the primary capture means and the field of view center included in the captured pixel; ,
A second capturing unit that captures an electrical signal from a pixel in a secondary capturing range determined from a center position determined by the deviation amount correcting unit and a preset size in a state where the marker light is extinguished. Is an optical information reader that reads an information code based on a pixel that has received a signal by a secondary capturing means. In claim 1,
The marker light projecting means projects center marker light indicating a reading center and range marker light indicating a reading range on a reading surface,
The shift amount correcting means is based on the shift amount between the position of the central marker light in the pixel from which the signal is captured by the primary capture means and the visual field center included in the captured pixel, and the center position of the secondary capture range. Decide
The secondary capturing means has a center position determined by the shift amount correcting means in a state in which the marker light is extinguished, and a secondary capturing range having a size substantially the same as the size indicated by the range marker light. An optical information reading device that takes in an electric signal from the pixel. In claim 2,
The primary uptake range and the secondary uptake range are both rectangular shapes,
The number of vertical pixels of the secondary capture range is set to the number of pixels obtained by subtracting the maximum value of the number of shifted pixels in the vertical direction determined by the size of the primary capture range from the number of vertical pixels of the effective pixels.
The number of horizontal pixels of the secondary capture range is set to the number of pixels obtained by subtracting the maximum value of the number of laterally shifted pixels determined by the size of the primary capture range from the number of horizontal pixels of the effective pixels. An optical information reader characterized by the above. In claim 2,
In a state where the range marker light is projected on the reading surface, an electric signal is obtained from all effective pixels of the area sensor, thereby detecting a size defined by the range marker light. A secondary capture size determining means for determining the size of the next capture range;
The size of the secondary capture range in the secondary capture means is the size determined by the secondary capture size determination means. In any one of Claims 2-4,
The range of the marker light projected by the marker light projecting means is larger than the primary capture range and less than half of the effective pixels of the area sensor. Information reader. In claim 1,
The secondary capture range is rectangular and the number of pixels in the horizontal direction is the same as the number of effective pixels in the horizontal direction of the area sensor, while the number of pixels in the vertical direction is the effective number of pixels in the vertical direction of the area sensor. It is smaller than the number of pixels,
The optical information reader is characterized in that the reading means reads a one-dimensional code as the information code. In claim 6,
The marker light projecting unit projects linear marker light indicating the vertical center of the reading range onto the reading surface,
The shift amount correcting unit is configured to determine a secondary capture range based on a vertical shift amount between a position of the marker light and a center of the visual field included in the captured pixel in the pixel from which the signal is captured by the primary capture unit. An optical information reader characterized by determining a central row. In any one of Claims 1-7,
The optical information reading apparatus according to claim 1, wherein the shift amount correcting unit determines a pixel having a luminance value equal to or greater than a predetermined threshold among the pixels having received a signal by the primary capturing unit as the position of the marker light. In any one of Claims 1-8,
The secondary capture means sets a secondary capture range by designating a start address and an end address, and the start address and end address based on the deviation amount determined by the deviation amount correction means An optical information reading apparatus characterized in that In claim 6 or 7,
The secondary capture means sets a secondary capture range by designating a start row and the number of read rows, and determines the start row based on the deviation amount determined by the deviation amount correction means. An optical information reading apparatus.

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