JPH05165992A - Portable optical information reader - Google Patents

Abstract

PURPOSE:To display the image pickup state of optical information obtained by an image sensor without using any expensive display device such as a monitor finder. CONSTITUTION:The analog video signal from the image sensor 12 is amplified by an amplifying circuit 24 and then coded by a binary coding circuit 26 into a binary signal, a counter part 28 measures widths, and then a decoding part 30 restores a combination of the widths to information on a bar code. This portable bar code reader is provided with an image generating circuit 44 which generates image information showing the image pickup state (position) of the bar code by the image sensor 12 by compressing the digital signal from the binary coding circuit 26, and the generated image information is displayed on a liquid crystal display device 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable optical information reading device for reading optical information such as a bar code by using an image sensor such as a CCD.

[0002]

2. Description of the Related Art Conventionally, as an optical information reading device for reading optical information, as shown in FIG. 9, for example, an image sensor 82 composed of a CCD or the like, and a bar code label having a bar code printed on the image sensor 82. An optical system 86 including various lenses for forming the image of 84, an amplifier circuit 88 for amplifying a weak analog video signal output from the image sensor 82, and a binary analog video signal amplified by the amplifier circuit 88. A binarization circuit 90 for converting the digital signal into a digital signal, a counter unit 92 for determining a narrow bar and a wide bar of the barcode by counting the width of the digital signal output from the binarization circuit 90, and a counter unit 92. The barcode is restored (decoded) based on the output signal from and the decoding result is output to the outside through the external terminal 94a. Constructed bar code reader is known by a decoding unit 94 that. In general, the counter unit 92 and the decoding unit 94 include a CPU, ROM, and R.
It is realized as one process of an electronic control unit (ECU) including a microcomputer such as an AM.

In such an optical information reading device, in order to accurately restore the optical information, it is necessary for the image sensor to accurately image the optical information. However, the user manually determines the imaging direction. The portable optical information reading device has a problem that it is difficult to match the imaging direction with the optical information.

Therefore, in recent years, a display device is provided in the optical information reading device, and an image picked up by an image sensor is displayed so that the image pickup direction can be positioned in the direction of the optical information to be read (eg, SA
AB company's EVS120 type barcode reader) has been put to practical use.

[0005]

However, in such a conventional device, since the analog image signal from the image sensor is directly input to the display device to display the image picked up by the image sensor, a video camera is used as the display device. However, there is a problem in that an expensive display device such as a monitor finder (or view finder) that can display the intermediate colors used for the above must be used. In addition, since a display device such as a monitor finder is used in a so-called peep mode, there is a problem that the portable optical information reading device for reading a bar code is not easy to use. Further, since the monitor finder displays an image like a general television, there is a problem that an expensive two-dimensional image sensor corresponding to this must be used as the image sensor.

Conventionally, as an optical information reading device, an object to which optical information to be read is attached is scanned and irradiated with laser light, and the reflected light is guided to an image sensor, whereby the optical information is read. There is also known a laser system for reading the. In this type of device, the irradiation state of laser light can be visually confirmed when the distance to the symbol is short. However, the light amount of the laser beam is kept low for safety, and it is difficult to visually confirm it if the distance is a little, and the same problem as described above occurs. Further, in such a laser type apparatus, since the laser beam is scanned, the horizontal scanning distance increases as the distance between the optical information to be read and the apparatus increases, and in some cases, a plurality of optical information may be read. is there.

The present invention has been made in view of the above problems, and is a portable optical information reading device capable of displaying the imaging state of optical information by an image sensor without using an expensive display device such as a monitor finder. The purpose is to provide a device.

[0008]

That is, the invention according to claim 1 made in order to achieve the above object is an image sensor for capturing an external image, and an external image is formed on the image sensor. Optical means, binarizing means for binarizing an analog video signal output from the image sensor, and an external image captured by the image sensor from the binarized data obtained by the binarizing means. In the portable optical information reading device in which the decoding means for restoring the optical information to be stored is integrally housed in the main body case having the holding portion for hand-holding, the binarized data obtained by the binarizing means. Based on the image information, image information generating means for generating image information representing the imaging position of the optical information in the image sensor, and a display hand for displaying the image information generated by the image information generating means. Are summarized as portable optical information reading apparatus is characterized by providing the, the.

According to a second aspect of the present invention, an image sensor for picking up an external image, an optical means for forming the external image on the image sensor, and an analog video signal output from the image sensor are binary. A holding unit for hand-holding is a binarizing unit for digitizing, and a decoding unit for restoring optical information included in an external image captured by the image sensor from the binarized data obtained by the binarizing unit. In a portable optical information reading device housed integrally in a main body case having the above, the optical information is identified based on a frequency characteristic of an analog video signal output from the image sensor, and the image based on the identification result. An image information generating unit that generates image information that represents the imaged position of the optical information in the sensor, and the image information that is generated by the image information generating unit. It is summarized as portable optical information reading apparatus is characterized in that display means, the provided for.

[0010]

In the portable optical information reader according to the first aspect of the present invention constructed as described above, the optical means first forms an external image on the image sensor,
The image sensor outputs an analog video signal corresponding to the formed external image, the binarizing means binarizes the analog video signal, and the decoding means images the image sensor from the binarized data. The optical information included in the external image is restored. In addition, 2 obtained by the binarization means
The binarized data is also input to the image information generation unit, and the image information generation unit generates image information representing the imaging position of the optical information in the image sensor based on the binarized data. Then, the generated image information is displayed on the display means.

That is, in the invention described in claim 1,
Based on the image signal binarized by the binarizing means, image information representing the imaging position of the optical information in the image sensor is generated and displayed on the display means. For this reason, the image information has no intermediate color unlike the analog video signal from the image sensor, and therefore, it is not necessary to use an expensive display device such as a monitor finder capable of displaying the intermediate color as the display means, and the binary value is used. It is possible to use an inexpensive display device (for example, a liquid crystal display) that can display the encoded data. In addition, a one-dimensional image sensor is used as an image sensor in a device that reads optical information that can be restored by one scan such as a barcode in order to display the imaging position of the optical information on the image sensor on the display device. It is also possible.

Next, in the portable optical information reader according to the second aspect, the optical means first forms an external image on the image sensor, as in the apparatus according to the first aspect.
The image sensor outputs an analog video signal corresponding to the formed external image, the binarizing means binarizes the analog video signal, and the decoding means images the image sensor from the binarized data. The optical information included in the external image is restored. On the other hand, in this apparatus, the analog video signal output from the image sensor is input to the image information generating means, and the image information generating means identifies the optical information to be read based on the frequency characteristic of the analog video signal, and the image sensor Image information representing the imaging position of the optical information in is generated. Then, the generated image information is displayed on the display means.

That is, in the invention described in claim 2,
By identifying the optical information from the frequency characteristic of the analog video signal output from the image sensor, image information representing the imaging position of the optical information in the image sensor is generated and displayed on the display means. Therefore, also in the present invention, similarly to the invention described in claim 1, it is not necessary to use an expensive display device such as a monitor finder capable of displaying intermediate colors in the display means, and the binarized data can be displayed. An inexpensive display device (for example, a liquid crystal display) can be used, and a one-dimensional image sensor can be used as the image sensor.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 2 is a sectional view showing the structure of the portable bar code reader of the embodiment. As shown in FIG. 2, the bar code reading apparatus of the present embodiment is a portable bar code reading apparatus in which various parts are integrally incorporated in a main body case 2 having a grip portion 2a for a user to manually support. Is. The grip portion 2a is provided with an operation lever 6 for turning on the trigger switch 4 by a user's operation with a finger and inputting a barcode reading command to the apparatus. Further, the main body case 2 is formed with an opening 2b for taking in an image of an object such as a bar code label having a bar code printed therein, and a light emission for irradiating the object around the opening 2b. The element 8 is provided.

Next, inside the main body case 2, there is provided a one-dimensional image sensor 12 for taking an external image, the light receiving surface of which is arranged toward the opening 2b, and the opening 2b.
On the optical path from the image sensor 12 to the image sensor 12, there is provided an optical system 14 as the optical means, which is composed of various lenses for forming an external image on the image sensor 12. still,
The image sensor 12 has a large number of CCDs arranged in a line.
And each C by the clock signal input from the outside.
A well-known CCD that sequentially outputs light-receiving signals from a CD to the outside
It is a sensor.

On the other hand, a liquid crystal display device 16 as the display means capable of displaying various kinds of information by a dot matrix is provided at the end of the main body case 2 on the side opposite to the opening 2b, which is inclined obliquely upward. There is. Then, between the liquid crystal display device 16 and the image sensor 12, an analog video signal from the image sensor 12 is processed so that the image pickup state of the bar code by the image sensor 12 is displayed on the liquid crystal display device 1.
6, the bar code captured by the image sensor 12 is restored when the trigger signal from the trigger switch 4 is received, and the restored information is displayed on the liquid crystal display device 16 and is output to an external device. A circuit board 18 on which a circuit is formed is stored. In addition, body case 2
A power source 20 for supplying power to each of the above parts is housed inside the grip portion 2a formed below the.

Next, FIG. 1 is a block diagram showing the configuration of a signal processing circuit formed on the circuit board 18. As shown in FIG. 1, on the circuit board 18, similarly to the conventional device shown in FIG. 9, an amplifier circuit 24 for amplifying an analog video signal output from the image sensor 12, and an analog video signal amplified by the amplifier circuit 24. Binarizing circuit 26 as the binarizing means for binarizing and converting the digital signal into a digital signal, and the bar code imaged by the image sensor 12 by counting the width of the digital signal output from the binarizing circuit 26. Counter section 2 for determining whether the narrow bar or wide bar
8 and a decoding unit 30 as a decoding unit that restores the barcode based on the output signal from the counter unit 28 and outputs the result to an external device via the external terminal 30a.

Further, the circuit board 18 is provided with a display information generating section 32 for generating display information for displaying the decoding result of the decoding section 30 on the liquid crystal display device 16. The display information generating unit 32 is for displaying the information of the barcode restored by the decoding unit 30 on the liquid crystal display device 16, and the restored data (generally, a binary signal,
Alternatively, display information for displaying a character corresponding to the ASCII code or the like) is generated. Then, the generated display information is stored in a specific address of the image memory 36 via the switching circuit 34.

The above-mentioned decoding unit 30 and display information generating unit 3
2, and the switching circuit 34 is driven by a control unit 38 which operates by receiving a trigger signal from the trigger switch 4, and the switching circuit 34 restores a barcode in the decoding unit 30 in accordance with a command from the control unit 38. When the display information is generated, the display information generating unit 32 is switched to the display information generating unit 32, and the display information indicating the decoding result generated by the display information generating unit 32 is stored in the image memory 36.

The switching circuit 34 is normally switched to the side of an image generating circuit 44, which will be described later, and the image memory 36 stores image information generated by the image generating circuit 44 and representing the image pickup state of the bar code in the image sensor 12.
To store. The display information or the image information stored in the image memory 36 is directly used as it is in the liquid crystal display device 16.
Displayed in. Further, the counter unit 28, the decoding unit 30,
The functions of the control unit 38 and the control unit 38 can be realized as one process of an electronic control unit (ECU) including a microcomputer.

Next, the circuit board 18 receives a clock signal from the timing generation circuit 40, which outputs a clock signal for capturing an external image to the image sensor 12, and a clock signal from the timing generation circuit 40. Alternatively, an address generation circuit 42 for generating an address when writing the image information in the image memory 36 is provided,
The switching circuit 34 sequentially writes the display information or the image information in the storage area in the image memory 36 corresponding to the address generated by the address generation circuit 42.

Further, the circuit board 18 is provided with an image generating circuit 44 as the image information generating means for receiving the digital signal output from the binarizing circuit 26 and generating the image information. This image generation circuit 44
The digital signal from the binarization circuit 26 to the image memory 3
It is for converting into a data size corresponding to the storage capacity of 6.

That is, first, the liquid crystal display device 16 of the present embodiment.
Is for the purpose of displaying a barcode image pickup state (image pickup position) by the image sensor 12 and decoded data, not for displaying a video image.
An inexpensive liquid crystal display device with a very small number of around 00 × 30 dots is used.

Therefore, in the image generation circuit 44, when the image sensor 12 scans each CCD by the clock signal and outputs an analog video signal, the existence probability of the bar portion of the bar code is obtained at regular intervals. , If the existence probability is equal to or higher than a predetermined value (for example, 50%), 1 is output as the representative data in a certain time, and if the existence probability is less than the predetermined value, 0 is output as the representative data in the certain time, thereby a binary The digital signal output from the digitization circuit 26 is thinned out, and the data size is adapted so that the liquid crystal display device 16 can display the image pickup state of the barcode by the image sensor 12.

That is, the image generation circuit 44 of the present embodiment.
Is a frequency dividing circuit 52 and an AND gate 5 as shown in FIG.
4, 56, a counter 58, and a comparison circuit 60, and converts the digital signal output from the image sensor 12 into digital data of 0 or 1 at regular intervals by the following procedure. The data of 12 N pixels is compressed into the data of 1 pixel of the liquid crystal display device 16.

That is, as shown in FIG. 4, in the image generating circuit 44, the frequency dividing circuit 52 first outputs the clock signal from the timing generating circuit 40 to 1 / N (N = N in this embodiment).
10) and the divided signal is input to the AND gate 54. Further, by inputting the digital signal from the binarization circuit 26 obtained by binarizing the analog video signal obtained by the image sensor 12 to the AND gate 56 together with the clock signal from the timing generation circuit 40, the AND gate 56 outputs the digital signal. The clock signal is passed through in part 1 of the above. Then, by inputting the output from the AND gate 56 to the AND gate 54, it is shown from the AND gate 54 what proportion the 1-level portion of the digital signal exists for N clocks of the clock signal. Output the existence probability signal. Then, the output from the AND gate 54 is counted by the counter 58 to be converted into a binary signal representing the existence probability of the one level portion, and this value and the existence probability 50 set in advance are compared by the comparison circuit 60. By comparing with the data DATA that represents%, data is generated that is 1 when the existence probability of the bar in the N count is 50% or more, and 0 when it is less than 50%. Then, this data becomes image information representing the imaging state of the barcode, and is sequentially stored in the image memory 36.

In the bar code reading apparatus of this embodiment constructed as described above, when the user directs the opening 2b toward an object such as a bar code label, the light emitting element 8 irradiates the object and the optical signal is emitted. The system 14 images the image of the barcode printed on the object onto the image sensor 12. The image sensor 12 outputs an electric signal according to the intensity of the light of the formed image, and the amplification circuit 24 amplifies the signal to a required signal level. Then, this amplified signal is binarized by the binarization circuit 26 and becomes a digital signal. In this state, when the operation lever 6 is operated and the trigger signal is generated from the trigger switch 4, the digital signal is output from the counter unit 28.
The width is measured at, and the decoding unit 30 restores the barcode information by the combination of the widths. At this time, the opening 2b
The bar code can be restored without any problem if is accurately oriented in the direction of the object, but if the opening 2b is not oriented in the direction of the object, the image formed on the image sensor 12 is not the intended barcode. In addition, the barcode cannot be restored.

However, in this embodiment, the image generation circuit 4
4 generates image information representing the imaging state of the barcode by the image sensor 12 from the digital signal from the binarization circuit 26, and displays the image information on the liquid crystal display device 16 until the operation lever 6 is operated. To do. Since this image information is formed by the existence probability of the bar code for every N clocks of the clock signal as described above, the display image represents the imaged image of the bar code itself as shown in FIG. However, it is possible to confirm the deviation from the center (CENTER) of the image pickup position of the barcode. Therefore, the user can accurately adjust the image pickup position of the barcode by confirming the display image of the liquid crystal display device 16 before operating the operation lever 6, and can surely restore the barcode. Is possible.

Further, in the present embodiment, not only the image information indicating the image pickup state of the bar code but also the operation lever 6
The restored data of the barcode after the operation is also displayed on the liquid crystal display device 16. Therefore, from the displayed image,
After the operation lever 6 is operated, it is possible to confirm whether or not the barcode can be restored, so that the reading failure of the barcode can be more surely prevented.

Furthermore, in this embodiment, the image sensor 1
Since the image pickup state of each scan of 2 is sequentially written in the image memory 36, if the data is written in the image memory 36 from the smallest address, the liquid crystal display device 16 is shown in FIG. As described above, an image capable of intuitively capturing a change in the image pickup position of the barcode due to camera shake or the like is displayed, and the image pickup direction of the barcode can be easily corrected.

Here, in the above embodiment, the image generation circuit 44 is configured to generate the image information representing the image pickup state of the bar code by compressing the digital data output from the binarization circuit 26. The image generation circuit 44 may generate image information indicating the image pickup state of the barcode based on the frequency characteristic of the analog video signal.

That is, in the bar code, the bar and the space are always arranged alternately, and the combination is continuous for about 10 pairs (or more). Therefore, the analog image signal obtained by capturing the bar code is the bar code. It is considered to have a unique signal frequency component. Therefore, if this unique signal frequency component is detected, the image pickup state of the barcode by the image sensor 12 can be detected and image information can be generated.

In this case, the image generation circuit 44
6, the output signal from the amplifier circuit 24 (that is, the analog video signal) is passed through the filter circuit 62 to extract only the signal of the specific frequency component of the analog video signal, and the comparison circuit 64 By comparing the extracted signal level with the reference value, it is determined that there is a bar code when the signal level is equal to or higher than the reference value, and there is no bar code when the signal level is lower than the reference value. It may be stored in the memory 36.

In this case, the reference value may be a preset fixed value, or may be set based on the average intensity of the signal in the band removed by the filter circuit 62. Further, in the above-mentioned embodiment, a liquid crystal display device capable of full-screen dot display is used as the display device. However, for example, a liquid crystal display device dedicated to character display of 5 × 7 dots or a previously designed symbol is turned on. It is also possible to use a display device such as a liquid crystal or a light emitting diode for displaying OFF.

When a display device dedicated to character display is used, the contents of the image memory 36 are once returned to the display information generating section 32 composed of a microcomputer, and converted by the display information generating section 32 so as to be suitable for character display. Then, the data may be output to the display device.

That is, since the character display portion is usually a 5 × 7 matrix, as shown in FIG.
The external character pattern may be facilitated in advance, and the pattern may be switched and displayed according to the detection position of the barcode. Further, when using a display device for displaying a symbol designed in advance, a display device such as a liquid crystal or a light emitting diode as shown in FIG. 8B is used, and a display mark that lights according to the detected bar code position is used. Should be switched.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of a portable barcode reader according to an embodiment.

FIG. 2 is a cross-sectional view showing a structure of a portable bar code reader according to an embodiment.

FIG. 3 is an electric circuit diagram showing a circuit configuration of an image generation circuit 44.

FIG. 4 is a time chart explaining the operation of the image generation circuit 44.

5 is an explanatory diagram showing a display state of image information on the liquid crystal display device 16. FIG.

FIG. 6 is an electric circuit diagram showing another configuration example of the image generation circuit 44.

FIG. 7 is a time chart explaining the operation of the image generation circuit shown in FIG.

FIG. 8 is an explanatory diagram illustrating another configuration example of a display device and a display state of image information on the display device.

FIG. 9 is a schematic configuration diagram showing a configuration of a conventional optical information reading device.

[Explanation of symbols]

2 ... Main body case 12 ... Image sensor 14 ... Optical system 16 ... Liquid crystal display device 18 ... Circuit board 20 ... Power supply 24 ... Amplifying circuit 26 ... Binarization circuit 28 ... Counter unit 30 ... Decoding unit 32 ... Display information generating unit 34 ... Switching circuit 36 ... Image memory 38 ... Control unit 40 ... Timing generation circuit 42 ...
Address generation circuit 44 ... Image generation circuit 52 ... Frequency division circuit 54,
56 ... AND gate 58 ... Counter 60 ... Comparison circuit

Claims (2)

[Claims] 1. An image sensor for capturing an external image, an optical means for forming an external image on the image sensor, a binarizing means for binarizing an analog video signal output from the image sensor, Decoding means for restoring optical information contained in an external image captured by the image sensor from the binarized data obtained by the binarizing means is integrated in a main body case having a holding portion for hand-holding. In the portable optical information reading device housed in, image information generation for generating image information representing the imaging position of the optical information in the image sensor based on the binarized data obtained by the binarizing means. A portable optical information reading device comprising: a means and a display means for displaying the image information generated by the image information generating means. 2. An image sensor for capturing an external image, an optical means for forming an external image on the image sensor, a binarizing means for binarizing an analog video signal output from the image sensor, Decoding means for restoring optical information contained in an external image captured by the image sensor from the binarized data obtained by the binarizing means is integrated in a main body case having a holding portion for hand-holding. In the portable optical information reading device housed in, the optical information is identified based on the frequency characteristic of the analog video signal output from the image sensor, and the optical information is captured by the image sensor based on the identification result. Image information generating means for generating image information representing the position, and display means for displaying the image information generated by the image information generating means are provided. A portable optical information reader characterized by the above.