JP2020160486A - Code reading apparatus and program - Google Patents

Abstract

To efficiently read even in a dark place.SOLUTION: A code reading apparatus 1 is to read an optical readable code. The code reading apparatus 1 comprises: an image pick-up device 211 that photographs an image of the code; adjusting an exposure time E when photographing the image of the code after next time by the image pick-up device 211 and an output image size R of the image of the code after the next time based on the image of the code photographed by the pick-up device 211; and performing control to output the image of the code with the adjusted output image size R while the image-pickup device 211 photographs with the adjusted exposure time E, when the image of the code is photographed from the next time onward.SELECTED DRAWING: Figure 4

Description

The present invention relates to a code reader and a program.

Conventionally, when an image within a specified scanning range in a prescan image read by prescan is analyzed and the maximum value of the output value of the prescan image is smaller than the threshold value, the maximum value of the output value of the prescan image is the scanner device. An image reading control method for adjusting the exposure time so as to have the maximum value of the dynamic range of the above and performing the image reading of this scan is disclosed (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2000-287040

However, the image scanning control method disclosed in Patent Document 1 has a problem that when a dark document is scanned, the scanning frame rate is lowered by adjusting the exposure time, so that the scanning takes a long time.

The present invention has been made in view of such a problem, and an object of the present invention is to efficiently read even in a dark place.

In order to solve the above problems, the code reader according to the present invention is
A code reader that reads an optically readable code.
An imaging means for capturing an image of the code and
Based on the image of the code taken by the imaging means, the adjusting means for adjusting the exposure time at the time of shooting the image of the code after the next time by the imaging means and the output image size of the image of the code after the next time. ,
When the image of the code is taken from the next time onward, the image pickup means takes a picture with the exposure time adjusted by the adjusting means, and the control means for controlling to output the image of the code of the output image size.
It is characterized by having.

According to the present invention, reading can be performed efficiently even in a dark place.

It is a front view which shows the whole structure of the code reading apparatus of embodiment of this invention. It is a block diagram which shows the internal structure of a code reader. It is a top view of the imager module and the imager controller. It is a flowchart which shows the control procedure of the code reading process by a code reading device. It is a flowchart which shows the control procedure of the exposure time / image size adjustment processing by a code reader. (A) is a diagram showing the size of the entire image captured by the image sensor, (b) is a diagram showing half the size of the entire image captured by the image sensor, and (c) is a diagram showing the size of the entire image captured by the image sensor. It is a figure which showed the time allocation schematically.

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

FIG. 1 is a front view showing the overall structure of the code reader according to the embodiment of the present invention.
The code reading device (computer) 1 of the present embodiment is a portable device having a code reading function such as a one-dimensional bar code and a two-dimensional code.

The code reading device 1 includes a case 2 as a housing. The code reading device 1 includes a trigger key 12A, various keys 12B, and a display unit 14 on the front surface of the case 2. The code reading device 1 includes a trigger key 12C on the side surface of the case 2. Further, the code reading device 1 includes an imager module (scanner device) 21 at the tip of the case 2.

The trigger keys 12A and 12C are trigger keys that accept the input of the start command of the code reading operation by the imager module 21. The various keys 12B include input keys for numbers and characters, function keys, and the like, and accept input operations for various information. The display unit 14 displays information such as menus and statuses related to the input operation, and information such as the status and decoding results at the time of executing the code reading operation using the imager module 21.

FIG. 2 is a block diagram showing an internal configuration of the code reading device 1.

The code reading device 1 includes a CPU (Central Processing Unit) 11 as an adjusting means, a controlling means, a decoding means, and a determining means, an operation unit 12, a RAM (Random Access Memory) 13, a display unit 14, and a storage unit 15. A communication unit 16, an imager controller 19, an imager module 21, a power supply unit 22, and a laser drive power supply 23 are provided.

Each part of the code reader 1 except the imager module 21 and the power supply part 22 is connected to each other via the bus 24. The imager module 21 includes an image pickup element (imaging means) 211, a variable focus lens 212, a focus mechanism 213 that drives the variable focus lens 212 to adjust the focus, an aimer (light emitting means) 214, and an illumination (illumination means). It has 215 and.

The CPU 11 controls each part of the code reading device 1. The CPU 11 reads various programs from the storage unit 15 and develops them in the RAM 13, and executes various processes in cooperation with the programs expanded in the RAM 13.

The operation unit 12 has key groups such as various keys 12B, trigger keys 12A, and 12C, receives an operation of pressing each key of the key group, converts the operation information into an input signal, and outputs the operation information to the CPU 11.

The RAM 13 is a volatile semiconductor memory and provides a working memory space for the CPU 11. Further, the RAM 13 is used for temporary storage of various data and development when executing various programs.

The display unit 14 is composed of an LCD (Liquid Crystal Display), an EL (Electro Luminescent) display, or the like, and displays various information according to the display information input from the CPU 11.

The storage unit 15 is a readable and writable non-volatile memory, for example, a flash memory. Various programs and setting data are stored in advance in the storage unit 15. Alternatively, the storage unit 15 may be an EEPROM (Electrically Erasable and Programmable Read Only Memory) or a hard disk. Alternatively, a ROM (Read Only Memory) may be used in the dedicated code reading device. The program stored in the storage unit 15 includes a program 15a that scans the code using the imager module 21 and decodes the image data of the acquired code.

The communication unit 16 includes a communication antenna, a signal processing unit, a modulation unit, a demodulation unit, and the like, and wirelessly communicates with the access point. An access point is a device that relays communication. That is, the code reading device 1 communicates with an external device such as a server device connected to the access point via the access point by the communication unit 16. The communication unit 16 processes the signal of the transmission information in the signal processing unit, modulates it in the modulation unit, and wirelessly transmits the transmission information from the communication antenna to the access point as radio waves. Further, the communication unit 16 receives the radio wave transmitted from the access point by the communication antenna, demodulates it in the demodulation unit, processes the signal in the signal processing unit, and acquires the received information.

Further, the communication unit 16 may be a wireless communication unit that wirelessly communicates with the server device via the base station by the mobile phone communication method. Further, the communication unit 16 may be a wired communication unit that performs wired communication with the server device via a cradle on which the code reading device 1 is placed or a communication cable.

The imager controller 19 controls the operation of each part of the imager module 21 and controls the transmission and reception of data between the imager module 21 and other parts of the code reading device 1. The imager controller 19 is composed of a semiconductor circuit such as an ASIC (Application Specific Integrated Circuit).

The imager controller 19 synchronizes the captured image data with the frame synchronization signal synchronized with the output timing of one frame of the captured image data, the line synchronization signal synchronized with the output timing of one line of the image data, and the image data. The clock signal for this is input. The imager controller 19 monitors the transfer timing of image data to the RAM 13 based on the frame synchronization signal, the line synchronization signal, and the clock signal. The imager controller 19 has a DMA (Direct Memory Access) transfer function that directly transfers the image data input from the image sensor 211 to the imager controller 19 to the RAM 13 without going through the CPU 11.

The imager module 21 is a module that adjusts the focal position of the varifocal lens 212 to capture the code of the subject. The image sensor 211 is a CMOS (Complementary Metal Oxide Semiconductor) image sensor, although it is not particularly limited. The image pickup element 211 captures (acquires) image data by photoelectrically converting a subject image incident through an optical system including a varifocal lens 212 and converting it into an electric signal.

The image sensor 211 outputs the image data of the lines designated by the image area designation signal input from the imager controller 19 to the imager controller 19 as line data line by line. Further, the image sensor 211 outputs a frame synchronization signal, a line synchronization signal, and a clock signal to the imager controller 19. The varifocal lens 212 is, for example, a liquid lens and is an optical element that forms a part of the optical system of the imager module 21. This liquid lens has a configuration in which the focal position can be changed at high speed according to the voltage applied to the focus mechanism 213.

The focus mechanism 213 is a drive unit that adjusts the focal position of the variable focus lens 212. When the varifocal lens 212 is a liquid lens, the focus mechanism 213 is an electric circuit including an electrode for applying a voltage to a predetermined position of the liquid lens. When a solid lens such as glass or plastic is used as the varifocal lens 212, for example, a voice coil motor is used for the focus mechanism 213.

The aimer 214 uses a measurement index of the distance between the imager module 21 and the code that is the subject, and a laser beam as a spot light (target light) that serves as a reference for matching the imaging direction and the subject direction of the imager module 21. It is a laser diode (LD) that emits light. The illumination 215 is composed of, for example, a light source such as an LED (Light Emitting Diode), and emits irradiation light for brightly illuminating the subject and a region around the subject.

The power supply unit 22 is composed of a secondary battery or the like, and supplies electric power to each unit of the code reading device 1. The laser drive power supply 23 supplies electric power for driving the Aimer 214 to emit spot light. The laser drive power supply 23 is arranged on the main board together with the imager controller 19.

Next, the arrangement of each part of the imager module 21 will be described in detail with reference to FIG.
FIG. 3 is a plan view of the imager module 21.

In the imager module 21, the optical system 212A including the variable focus lens 212 is arranged so that the outside of the imager module 21 can be imaged. Further, the image sensor 211 is arranged perpendicular to the optical axis of the optical system 212A. The Aimer 214 and the Illumination 215 are arranged in parallel with the optical system 212A and the focus mechanism 213. The Amer 214 is arranged so that the emitted beam-shaped laser beam is included in the angle of view that can be imaged by the imager module 21 (optical system 212A and image sensor 211) within a focal length that can be changed with respect to the optical system 212A. .. In the present embodiment, the beam of the laser beam is emitted in a direction parallel to the optical axis of the optical system 212A. Further, the illumination 215 is arranged so that the light emitted in a fan shape is included in the angle of view that can be photographed by the imager module 21 (optical system 212A and image sensor 211) within a focal length that can be changed for the optical system 212A. There is.

Next, the operation of the code reading device 1 will be described with reference to FIG. FIG. 4 is a flowchart showing a control procedure of the code reading process by the code reading device 1.

The code reading process is a process of scanning the code using the imager module 21 and decoding the image data of the acquired code. In the code reading device 1, the CPU 11 executes the code reading process in cooperation with the program 15a read from the ROM 15 and appropriately expanded in the RAM 13 with the trigger keys 12A and 12C pressed and input by the user as a trigger. To do.

As shown in FIG. 4, first, the CPU 11 of the code reading device 1 sends a command to the imager controller 19 to activate the imager module 21 (step S1).

Next, the CPU 11 makes initial settings (step S2). Specifically, the CPU 11 sends a command to the imager controller 19, and sets the exposure time E when the image sensor 211 shoots the code as the subject to a predetermined initial value (exposure value of standard brightness) E0. The output image size R when transferring (outputting) the image data of the code captured by the image sensor 211 to the RAM 13 is set to the overall size Rfull of the image data. Further, the CPU 11 sets the loop number L of the code reading process to the initial value (L = 0).

Next, the CPU 11 increments the value of the number of loops L of the code reading process by 1 (step S3).

Next, the CPU 11 sends a command to the imager controller 19 to cause the image sensor 211 to take a picture of the code, and to directly transfer the image data of the code sent from the image sensor 211 to the imager controller 19 to the RAM 13 by DMA (step S4). .. Further, in step S4, the CPU 11 sends a command to the imager controller 19 and irradiates the illumination 215 when the code is photographed by the image sensor 211 so that a bright image can be photographed. Further, when the image data of the code is transferred, the Aimer 214 is irradiated so that the user can indicate the shooting position.

Next, the CPU 11 decodes the code based on the image data transferred to the RAM 13 (step S5).

Next, the CPU 11 determines whether or not the code decoding is successful (step S6).

If it is determined in step S6 that the code decoding is successful (step S6; YES), the CPU 11 displays (outputs) the decoded data on the display unit 14 (step S7), and ends the code reading process.
On the other hand, in step S6, when it is determined that the code decoding has not succeeded, that is, it has failed (step S6; NO), the CPU 11 determines whether or not the value of the loop count L is larger than 3 (step S6; NO). Step S8).

If it is determined in step S8 that the value of the loop count L is greater than 3 (step S8; YES), the CPU 11 displays decoding failure data (for example, character data such as "code cannot be read"). It is displayed (output) on the unit 14 (step S9), and the code reading process is completed.
On the other hand, in step S8, when it is determined that the value of the number of loops L is not greater than 3, that is, 3 or less (step S8; NO), the CPU 11 performs the exposure time / image size (output image size) adjustment process. (Described later) is performed (step S10). Then, the CPU 11 returns the process to step S3, and repeats the subsequent processes.

FIG. 5 is a flowchart showing a control procedure of the exposure time / image size (output image size) adjustment process by the code reading device 1. The exposure time / image size adjustment process is a process of determining the exposure time and the output image size at the time of the next and subsequent shootings by the image sensor 211.

As shown in FIG. 5, first, the CPU 11 determines the exposure time candidate E1 (step S21). Specifically, the CPU 11 derives the brightness value of the image data of the code decoded in step S5 of the code reading process described above. Then, the CPU 11 performs an exposure control process on the derived luminance value to determine an appropriate exposure time candidate E1. Since the exposure control process is a known technique, the description thereof will be omitted.

Next, the CPU 11 determines whether or not the length of the exposure time candidate E1 is shorter than the length of the minimum exposure time Emin that can be set in the imager module 21 (step S22).

When it is determined in step S22 that the length of the exposure time candidate E1 is shorter than the length of the minimum exposure time Emin (step S22; YES), the CPU 11 sends a command to the imager controller 19 to set the output image size R. As shown in FIG. 6A, the size Rfull of the entire image captured by the image sensor 211 is adjusted (step S23), the exposure time E is adjusted to the minimum exposure time Emin (step S24), and the exposure time is adjusted. -End the image size adjustment process.

Further, in step S22, when it is determined that the length of the exposure time candidate E1 is not shorter than the length of the minimum exposure time Emin, that is, equal to or greater than the length of the minimum exposure time Emin (step S22; NO), the CPU 11 It is determined whether or not the length of the exposure time candidate E1 is shorter than the length of the first maximum exposure time Emax1 that can be set in the imager module 21 (step S25). Here, the first maximum exposure time Emax1 means the maximum exposure time that can be set in the imager module 21 when the output image size R is set to Rfull.

When it is determined in step S25 that the length of the exposure time candidate E1 is shorter than the length of the first maximum exposure time Emax1 (step S25; YES), the CPU 11 sends a command to the imager controller 19 to output the image size. R is adjusted to the size Rfull of the entire image captured by the image sensor 211 (step S26), the exposure time E is adjusted to the exposure time candidate E1 (step S27), and the exposure time / image size adjustment process is completed. ..

Further, in step S25, when it is determined that the length of the exposure time candidate E1 is not shorter than the length of the first maximum exposure time Emax1, that is, is equal to or longer than the length of the first maximum exposure time Emax1 (step S25). (NO), the CPU 11 determines whether or not the length of the exposure time candidate E1 is shorter than the length of the second maximum exposure time Emax2 that can be set in the imager module 21 (step S28). Here, the second maximum exposure time Emax2 is the maximum exposure time that can be set in the imager module 21 when the output image size R is set to half the size Rhalf of Rfull (see FIG. 6B). means.

When it is determined in step S28 that the length of the exposure time candidate E1 is shorter than the length of the second maximum exposure time Emax2 (step S28; YES), the CPU 11 sends a command to the imager controller 19 to output the image size. As shown in FIG. 6B, R is adjusted to Rhalf, which is half the size of Rfull (step S29), and the exposure time E is adjusted to the exposure time candidate E1 (step S27), and the exposure time and image size are adjusted. The adjustment process ends.

Further, in step S28, when it is determined that the length of the exposure time candidate E1 is not shorter than the length of the second maximum exposure time Emax2, that is, is equal to or longer than the length of the second maximum exposure time Emax2 (step S28). (NO), the CPU 11 sends a command to the imager controller 19 to adjust the output image size R to half the size Rhalf of Rfull (step S30), and to adjust the exposure time E to the second maximum exposure time Emax2. (Step S31), the exposure time / image size adjustment process is completed.

Next, one aspect of the code reading process executed in the dark place will be described with reference to FIG. 6 (c). FIG. 6C is a diagram schematically showing the time allocation of the code reading process.

As shown in FIG. 6C, first, in the code reading device 1, the imager module (scanner device) 21 is activated by the trigger key 12A and 12C being pressed and input by the user, and the exposure time E is initially set. The value E0 is set and the output image size R is set to Rfull. Then, the first code reading process (loop count L = 1) is performed.

In the first code reading process, the image sensor 211 takes a picture of the code at the exposure time E0, and the image data of the taken code is transferred to the RAM 13 with the output image size Rfull. Then, in the first code reading process, the decoding fails because the brightness value of the image data transferred to the RAM 13 is low, and the above-mentioned exposure time / image size adjustment process is performed. Here, it is assumed that the exposure time E0 is adjusted to the exposure time candidate E1 and the output image size R is adjusted to Rfull in the same manner as in the first code reading process. Then, the second code reading process (loop count L = 2) is performed.

In the second code reading process, the image sensor 211 takes a picture of the code with the exposure time candidate E1, and the image data of the taken code is transferred to the RAM 13 with the output image size Rfull. Then, even in the second code reading process, the decoding fails because the brightness value of the image data transferred to the RAM 13 is low, and the above-mentioned exposure time / image size adjustment process is performed. Here, it is assumed that the exposure time candidate E1 is adjusted to the second maximum exposure time Emax2, and the output image size R is adjusted to Rhalf. Then, the third code reading process (loop count L = 3) is performed.

In the third code reading process, the image sensor 211 takes a picture of the code with the second maximum exposure time Emax2, and the image data of the taken code is transferred to the RAM 13 with the output image size Rhalf. That is, in the third code reading process, the exposure time is longer, but the time spent for image transfer is shorter, which is almost the same time as the time spent for the first and second code reading processes. The reading process is being performed. Then, in the third code reading process, the image data transferred to the RAM 13 has a higher luminance value and is decoded because the image was taken with the second maximum exposure time Emax2, which has a longer exposure time than the exposure time candidate E1. Succeed in.

As described above, the code reading device 1 of the present embodiment is a code reading device 1 that reads an optically readable code, and is photographed by an image sensor 211 that captures an image of the code and an image sensor 211. Based on the code image, the exposure time E at the time of taking the image of the code after the next time by the image sensor 211 and the output image size R of the image of the code after the next time are adjusted, and the image of the code after the next time is taken. At times, the image sensor 211 takes a picture with the adjusted exposure time E, and controls to output an image of the code of the adjusted output image size R.
According to such a configuration, for example, even when the code reading operation is performed in a dark place and the exposure time E at the time of shooting the code image from the next time onward is adjusted to be long, the output image is output. By reducing the size R, it is possible to adjust so that the transfer time of the image data is shortened.
Therefore, since the code can be read in a dark place in the same time as in a normal time, the code can be read efficiently even in a dark place.

Further, when the decoding fails, the code reading device 1 adjusts the exposure time E and the output image size R based on the image of the code to be decoded, so that the decoding failure is repeated. It can be suppressed.

Further, the code reading device 1 determines and determines an exposure time (exposure time candidate E1) as a candidate at the time of shooting the image of the code from the next time onward based on the brightness value of the image of the code to be decoded. When the length of the candidate exposure time is shorter than the length of the predetermined minimum exposure time Emin, the exposure time E is adjusted to the minimum exposure time Emin and the output image size R is Rfull (predetermined size). Adjust to.
According to such a configuration, the reading accuracy of the code can be improved and the code can be read efficiently.

Further, in the code reading device 1, the length of the candidate exposure time (exposure time candidate E1) is equal to or greater than the length of the minimum exposure time Emin, and is longer than the length of the predetermined maximum exposure time Emax1. If it is short, the exposure time E is adjusted to the candidate exposure time, and the output image size R is adjusted to Rfull (predetermined size).
According to such a configuration, the reading accuracy of the code can be improved and the code can be read efficiently.

Further, in the code reading device 1, the length of the candidate exposure time (exposure time candidate E1) is equal to or longer than the length of the first maximum exposure time Emax1 and the second maximum exposure time Emax2 is predetermined. If it is shorter than the length, the exposure time E is adjusted to the candidate exposure time, and the output image size R is adjusted to Rfull (predetermined size).
According to such a configuration, the reading accuracy of the code can be improved and the code can be read efficiently.

Further, when the length of the candidate exposure time (exposure time candidate E1) is equal to or longer than the length of the second maximum exposure time Emax2, the code reading device 1 sets the exposure time E to the second maximum exposure time Emax2. At the same time, the output image size R is adjusted to Rhalf (half the size of the predetermined size).
According to such a configuration, the reading accuracy of the code can be improved and the code can be read efficiently.

Further, the code reading device 1 includes an illumination 215 and an aimer 214, turns on the illumination 215 when the image sensor 211 captures an image of the code, and transfers the image of the code captured by the image sensor 211 ( Since the aimer 214 is turned on when the output) is performed, the code reading accuracy can be improved even in a dark place.

The present invention is not limited to the above embodiment, and various modifications can be made.
For example, in the above embodiment, the CPU 11 decodes the code based on the image data DMA-transferred to the RAM 13, but the imager controller 19 mounts the decoding function on the ASIC board in terms of hardware. It may be possible to calculate.

Further, as the varifocal lens in the above embodiment, a liquid lens, a solid lens using glass or the like is given as an example, but the present invention is not limited thereto. For example, a varifocal lens using KTN (potassium niobate tantalate, KTa _1-x Nb _x O ₃ ), which is a kind of "electro-optical crystal" whose refractive index changes depending on the applied voltage, can also be used.

Further, in the above-described embodiment, an example in which the storage unit 15 (for example, flash memory, EEPROM, hard disk, ROM) is used as a computer-readable medium for the program according to the present invention has been disclosed, but the present invention is not limited to this example. As another computer-readable medium, a portable recording medium such as a CD-ROM can be applied. A carrier wave is also applied to the present invention as a medium for providing data of a program according to the present invention via a communication line.

Further, in the above embodiment, the code reading process is terminated when the code decoding is successful, but the set values of the exposure time E and the output image size R when the decoding is successful are inherited and a plurality of codes are continuously connected. You may read it.
In addition, specific details such as the numerical values and the order of control shown in the above-described embodiment can be appropriately changed without departing from the spirit of the present invention.

Although the embodiments of the present invention have been described, the scope of the present invention is not limited to the above-described embodiments, but includes the scope of the invention described in the claims and the equivalent scope thereof.
The inventions described in the claims originally attached to the application of this application are added below. The item number of the claim described in the appendix is the scope of the claims originally attached to the application of this application.

[Additional Notes]
<Claim 1>
A code reader that reads an optically readable code.
An imaging means for capturing an image of the code and
Based on the image of the code taken by the imaging means, the adjusting means for adjusting the exposure time at the time of shooting the image of the code after the next time by the imaging means and the output image size of the image of the code after the next time. ,
When the image of the code is taken from the next time onward, the image pickup means takes a picture with the exposure time adjusted by the adjusting means, and the control means for controlling to output the image of the code of the output image size.
A code reader comprising.
<Claim 2>
A decoding means for decoding the code based on the image of the code taken by the imaging means is provided.
The first aspect of the present invention is characterized in that, when decoding by the decoding means fails, the adjusting means adjusts the exposure time and the output image size based on the image of the code to be decoded. The code reader described.
<Claim 3>
A determination means for determining a candidate exposure time at the time of shooting the image of the code from the next time onward based on the brightness value of the image of the code to be decoded is provided.
When the length of the candidate exposure time determined by the determination means is shorter than the length of the predetermined minimum exposure time, the adjusting means adjusts the exposure time to the minimum exposure time and outputs the output. The code reading device according to claim 2, wherein the image size is adjusted to a predetermined size.
<Claim 4>
When the length of the exposure time as the candidate is equal to or greater than the length of the minimum exposure time and shorter than the length of the first maximum exposure time determined in advance, the adjusting means sets the exposure time as the candidate. The code reading device according to claim 3, wherein the output image size is adjusted to the predetermined size while adjusting the exposure time.
<Claim 5>
When the length of the candidate exposure time is equal to or longer than the length of the first maximum exposure time and shorter than the length of the predetermined second maximum exposure time, the adjusting means said the exposure time. The code reading device according to claim 4, wherein the output image size is adjusted to half the size of the predetermined size while adjusting the exposure time to be the candidate exposure time.
<Claim 6>
When the length of the candidate exposure time is equal to or longer than the length of the second maximum exposure time, the adjusting means adjusts the exposure time to the second maximum exposure time and the output image size. The code reading device according to claim 5, wherein the size is adjusted to half the size of the predetermined size.
<Claim 7>
Lighting means to illuminate the shooting position and
Light emitting means for guiding the shooting position,
With
The control means is characterized in that the lighting means is turned on when the imaging means is made to take an image of the code, and the light emitting means is turned on when the image of the code taken by the taking image is output. The code reading device according to any one of claims 1 to 6.
<Claim 8>
A computer of a code reader equipped with an imaging means for capturing an image of an optically readable code,
An adjusting means for adjusting the exposure time at the time of shooting the image of the code after the next time by the imaging means and the output image size of the image of the code after the next time based on the image of the code taken by the imaging means.
A control means for controlling the imaging means to take an image at the exposure time adjusted by the adjusting means and output an image of the code of the output image size when the image of the code of the next time or later is taken.
A program characterized by functioning as.

1 Code reader 11 CPU (adjustment means, control means, decoding means, determination means)
211 Image sensor (imaging means)
214 Aimer (light emitting means)
215 Illuminations (lighting means)

Claims (8)

A code reader that reads an optically readable code.
An imaging means for capturing an image of the code and
Based on the image of the code taken by the imaging means, the adjusting means for adjusting the exposure time at the time of shooting the image of the code after the next time by the imaging means and the output image size of the image of the code after the next time. ,
When the image of the code is taken from the next time onward, the image pickup means takes a picture with the exposure time adjusted by the adjusting means, and the control means for controlling to output the image of the code of the output image size.
A code reader comprising. A decoding means for decoding the code based on the image of the code taken by the imaging means is provided.
The first aspect of the present invention is characterized in that, when decoding by the decoding means fails, the adjusting means adjusts the exposure time and the output image size based on the image of the code to be decoded. The code reader described. A determination means for determining a candidate exposure time at the time of shooting the image of the code from the next time onward based on the brightness value of the image of the code to be decoded is provided.
When the length of the candidate exposure time determined by the determination means is shorter than the length of the predetermined minimum exposure time, the adjusting means adjusts the exposure time to the minimum exposure time and outputs the output. The code reading device according to claim 2, wherein the image size is adjusted to a predetermined size. When the length of the exposure time as the candidate is equal to or greater than the length of the minimum exposure time and shorter than the length of the first maximum exposure time determined in advance, the adjusting means sets the exposure time as the candidate. The code reading device according to claim 3, wherein the output image size is adjusted to the predetermined size while adjusting the exposure time. When the length of the candidate exposure time is equal to or longer than the length of the first maximum exposure time and shorter than the length of the predetermined second maximum exposure time, the adjusting means said the exposure time. The code reading device according to claim 4, wherein the output image size is adjusted to half the size of the predetermined size while adjusting the exposure time to be the candidate exposure time. When the length of the candidate exposure time is equal to or longer than the length of the second maximum exposure time, the adjusting means adjusts the exposure time to the second maximum exposure time and the output image size. The code reading device according to claim 5, wherein the size is adjusted to half the size of the predetermined size. Lighting means to illuminate the shooting position and
Light emitting means for guiding the shooting position,
With
The control means is characterized in that the lighting means is turned on when the imaging means is made to take an image of the code, and the light emitting means is turned on when the image of the code taken by the taking image is output. The code reading device according to any one of claims 1 to 6. A computer of a code reader equipped with an imaging means that captures an image of an optically readable code.
An adjusting means for adjusting the exposure time at the time of shooting the image of the code after the next time by the imaging means and the output image size of the image of the code after the next time based on the image of the code taken by the imaging means.
A control means for controlling the imaging means to take an image at the exposure time adjusted by the adjusting means and output an image of the code of the output image size when the image of the code of the next time or later is taken.
A program characterized by functioning as.

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