JPH0696246A - Bar code reader - Google Patents

Abstract

PURPOSE:To provide the bar code reader which is simply constituted at a low cost, and can be arranged within a range where a bar code is readable surely and sufficiently for practical use even from a position considerably separated from the optical axis of a bar code reading means such as a television camera without hiding the target of the readable range for the bar code with an object supporting the bar code and without considering the thickness of the object. CONSTITUTION:A data processing circuit 26 reads bar code information from a bar code 22 photographed by a television camera 20 through a video circuit 23 and a frame memory 24. The center of the photograph enable range of the television camera 20 is irradiated with spot light from a spot light device 30 so as to support the arrangement of the bar code 22 into the photograph enable range and after this arrangement is completed, the spot light device 30 is turned off so as to prevent the reflected light of spot light from being made incident to the television camera 20.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to bar code readers.

[0002]

2. Description of the Related Art In order to read a bar code with a bar code reader, the bar code must be placed within the bar code reading range of the bar code reading means of the bar code reader.

In a bar code reading apparatus which reads a bar code with a TV camera and reads the displayed contents of the bar code from the taken bar code image, the bar code is arranged within the angle of view which is the bar code reading range of the TV camera. Must-have.

In a conventional bar code reading apparatus using a TV camera, a bar code is arranged within a bar code reading range by a monitor TV connected to the TV camera as described in Japanese Patent Application No. 3-255556. Have confirmed.

Alternatively, as shown in FIG. 5 (A), a half mirror 12 is arranged on the optical axis 10a of the television camera 10 and a half of the reading range display frame projection device 14 arranged on the side of the optical axis 10a. An image 16a of the reading range display frame 16 in the reading range display frame projection device 14 is projected on a bar code mounting table (not shown) via the mirror 12.

Further, in the prior art, as shown in FIG. 5B, the base 1 where the optical axis 10a of the television camera 10 supported by the support column 20 raised from the base 18 intersects.
The reading range display frame 22 is directly printed or stamped on the upper surface of 8, or a sticker on which the reading range display frame 22 is printed is attached. Further, in the related art, as shown in FIG. 5C, the reading range display frame 24 is supported at a position separated by a predetermined distance above the upper surface of the base 18.

[0007]

Among the conventional bar code readers having various configurations as described above, the one using the monitor television is expensive.

The half mirror 12 shown in FIG.
When the reading range display frame projection device 14 and the reading range display frame projection device 14 are used, the reading range display frame projection device 14 having a complicated structure requiring the light source 14a, the condenser lens 14b, the reading range display frame 16, the projection lens 14c, etc. While increasing the price of the code reading device, the amount of light incident on the television camera 10 by the half mirror 12 is reduced, and the need for a stronger illumination light source also increases the price of the bar code reading device.

The reading range display frame 22 shown in FIG. 5B, which is directly printed or engraved on the upper surface of the base 18, or printed on a sticker attached to the upper surface, is inexpensive. However, if the bar code is directly printed or the object to which the sticker with the bar code is attached has a plane area larger than the reading range display frame 22, it is hidden by the object. , The reading range display frame 22 cannot be confirmed.

Further, in the case of having the reading range display frame 24 supported at a position separated by a predetermined distance above the upper surface of the base 18 shown in FIG. Bar codes printed directly on objects with greater thickness or printed on stickers attached to the top surface are unreadable. Even if the thickness of the object is smaller than the predetermined distance, the base 1
The work of passing the object between the upper surface of 8 and the reading range display frame 22 is complicated, and the efficiency of reading the bar code from a large number of objects is not high. Furthermore, when the light from the illumination means (not shown) illuminates the reading range display frame 22 from diagonally above, the shadow of the reading range display frame 22 overlaps with the bar code and causes a reading error. Furthermore, when the object is thin and the distance from the bar code of the object on the upper surface of the base 18 to the reading range display frame 22 is relatively large, it is oblique to the optical axis 10a of the television camera 10. When visually inspected, even if the bar code of the object appears in the area surrounded by the reading range display frame 22, the bar code actually protrudes from the area and a bar code reading error occurs. .

The present invention has been made under the above circumstances, and an object of the present invention is to prevent the readable range of a bar code from being obscured by an object supporting the bar code, and the thickness of the object. It is irrelevant to the above, has a simple structure, is inexpensive, and ensures that the bar code can be placed within the readable range with sufficient efficiency for practical use even from a position that is considerably distant from the optical axis of the bar code reading means such as a TV camera. The object of the present invention is to provide a bar code reader capable of performing the above.

[0012]

In order to achieve the above-mentioned object, a bar code reading device according to the present invention comprises a bar code reading means and a bar code reading range by the bar code reading means at a bar code arrangement position. Spotlight means for irradiating the center with a spotlight, and for preventing the incident of the reflected light of the spotlight on the barcode reading means when reading the barcode at the barcode arrangement position by the barcode reading means And means are provided.

[0013]

In the bar code reading apparatus according to the present invention having the above-described structure, the spot light means places the spot light at the center of the bar code reading range of the bar code reading means at the bar code arrangement position. Irradiate. After arranging the bar code at the above-mentioned arrangement position guided by the spotlight, when reading the bar code at the bar code arranging position by the bar code reading means, the spotlight incident prevention means prevents the spotlight from being applied to the bar code reading means. The incidence of reflected light is prevented, and the occurrence of bar code reading errors is prevented.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Various embodiments of the present invention will now be described in detail with reference to the accompanying FIGS. FIG. 1 schematically shows the configuration of a bar code reader according to the first embodiment of the present invention.

The television camera 20 is supported above the upper surface of the base at a position separated by a predetermined distance from the upper surface by a pillar (not shown) raised from a base (not shown). The television camera 20 can take an image within a predetermined range (shootable range) centered on a predetermined position on the upper surface of the base where the optical axis 20a of the optical system intersects,
The predetermined position is the center position 21 of the image capturing range.

The image is a bar code 22 printed directly on an object (not shown) placed on the upper surface of the base or printed on a label attached to the upper surface of the base. It is arranged within the above predetermined range.

A video circuit 23 for converting an optical image of the bar code 22 photographed by the TV camera 20 into an electric video signal is connected to the television camera 20, and the video circuit 23 receives a bar code from the video signal. A frame memory 24 that electrically reproduces the image of the code 22 is connected. Further, the frame memory 24 is connected to the frame memory 24 from the image of the barcode 22 that is electrically reproduced on the frame code 2.
A data processing circuit 26 for reading the display content (bar code information) 2 is connected.

On the column (not shown), illumination means 28 for illuminating the predetermined range on the upper surface of the base with a predetermined illuminance around the center position 21 of the image-capturing range, and the above-mentioned shooting on the upper surface of the base. A spotlight device 30 that irradiates the possible range center position 21 with light is supported.

The illumination means 28 is not necessary if the illuminance in the predetermined range on the upper surface of the base is secured to an extent sufficient for photographing by the television camera 20 by the ambient light of the bar code reader or natural light. Is. The spotlight device 30 is connected to the control unit 32 together with the video circuit 23 of the television camera 20.

In FIG. 2A, the center 21 of the photographable range at the center of the predetermined range 32 on the upper surface of the base,
A spotlight 30a illuminated by the spotlight device 30 is shown therein.

The spotlight device 30 is shown in FIG.
As shown in FIG. 2, it can be basically constructed only by a combination of an inexpensive light source 30b such as a light emitting diode or a tungsten light bulb and a simple condenser lens 30c. Further, as shown in FIG. It can also be configured by the light source 30d in which the lens is integrated, which is more inexpensive than the configuration shown in FIG.

In this embodiment, the predetermined area 32 on the upper surface of the base is not explicitly shown on the upper surface of the base, but a bar code of a type having a size that falls within the predetermined area 32. If it is agreed in advance that only the bar code 22 will be handled by the bar code reader of this embodiment, the center of the bar code 22 of this kind will be visually inspected by the spotlight 30a.
The bar code 22 of this kind inevitably falls within the predetermined range 32 by matching the center (the center 21 of the photographable range of the center of the predetermined range 32 on the upper surface of the base). .

It is known that the center alignment by visual measurement as described above is highly accurate in practical use, and the alignment error is generally several percent. Therefore, if the size of the bar code to be used is determined to be slightly smaller than the predetermined range 32 in consideration of this alignment error, the occurrence of a read error due to the bar code placement error can be avoided.

While the bar code 22 whose center alignment with respect to the center of the spotlight 30a is completed is being illuminated by the spotlight 30a, the bar code image from the television camera 20 is converted into a video signal by the video circuit 23 and the frame is converted. When the bar code information is read out by the data processing circuit 26 via the memory 24, the illuminance of the central portion of the bar code 22 illuminated by the spotlight 30a is the illuminance of the peripheral portion not illuminated by the spotlight 30a. The data processing circuit 26 cannot read the barcode information of the barcode 22 significantly higher than the above.

Therefore, in this embodiment, the spotlight 3
After the center alignment of the bar code 22 with respect to the center of 0a is completed, the spotlight device 30 is temporarily turned off, and the bar code image photographed by the television camera 20 is stored in the frame memory 24 via the video circuit 23 during this time. accumulate.

The time required for accumulating the bar code image photographed by the television camera 20 in the frame memory 24 through the video circuit 23 is about 1/30 second, and the time required for the spotlight device 30 is about this time. Temporarily turning off the light cannot be perceived by the user of the bar code reading device and causes no trouble.

Turning on and off the spotlight device 30, and corresponding video circuit 23 and frame memory 2
The operation of 4 is stopped and started by the control unit 33 connected to both the spotlight device 30 and the video circuit 23, and the operation of the control unit 33 can be performed manually or automatically in a predetermined cycle. . FIG. 3 schematically shows the structure of a bar code reader according to the second embodiment of the present invention.

In this embodiment, the light source of the illuminating means 28 and the light source of the spotlight device 30 emit light of different wavelengths, and the light source of the illuminating means 28 is, for example, a high-intensity red LED. Is used as the light source of the spotlight device 30, for example, a high-intensity green LED is used.

An optical filter 40 is arranged on the optical axis 20a of the television camera 20. In this embodiment, the optical filter 40 is a red transmission filter (for example, HOYA R-62).
As shown in FIG. 4, the optical filter 40 does not transmit the green light G from the high-intensity green LED, which is the light source of the spotlight device 30 having a wavelength shorter than about 600 nm, and has a wavelength of about 600 nm. Since the red light R from the high-intensity red LED having a wavelength longer than 600 nm is transmitted,
The reflected light of the spotlight 30 a of the spotlight device 30 is prevented from entering the television camera 20.

Therefore, the control unit 33 of the first embodiment for turning on and off the spotlight device 30 and for stopping and starting the operations of the video circuit 23 and the frame memory 24 corresponding thereto is used. Instead, the spotlight device 30 is always lit while the power of the bar code reading device is turned on, and the bar code information can be read.

[0031]

As described above in detail, in the bar code reading apparatus according to the present invention, the spotlight emitted from the spotlight device is always illuminated on the bar code and the bar code is supported by the object supporting the bar code. The readable range for the code is not hidden, and it is irrelevant to the thickness of the above-mentioned object, and can be reliably used practically even from a position far away from the optical axis of the bar code reading means such as a TV camera. The bar code can be arranged sufficiently efficiently within the readable range, and the spot light incidence preventing means for preventing the reflected light of the spot light from entering the spot light device or the bar code reading means can be easily constructed. It is cheap.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a configuration of a bar code reading device according to a first embodiment of the present invention.

FIG. 2A is the barcode reading device of FIG.
The figure which shows the spotlight radiated from the spotlight device to the center position of the photographing range of the television camera in conformity with the optical axis of the television camera. It is a figure which shows roughly the combination of a light source and a condensing lens, (C) is a figure which shows the light source with a condensing lens for the bar code reader of FIG. 1 schematically.

FIG. 3 is a diagram schematically showing a configuration of a bar code reading device according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating a wavelength of light emitted from a light source of an illumination unit and a wavelength of light emitted from a light source of a spotlight device in the bar code reading apparatus of the second embodiment shown in FIG. The figure which shows the function of the optical filter which transmits the light from the light source of the means, but does not transmit the light from the light source of the spotlight device.

5 (A), (B), and (C) are diagrams schematically showing various image-capturable range display means in a conventional bar code reading apparatus using a television camera.

[Explanation of symbols]

20 ... Television camera, 20a ... Optical axis, 21 ... Center position of imageable range, 22 ... Bar code, 23 ... Video circuit, 2
4 ... Frame memory, 26 ... Data processing circuit, 28 ... Illuminating means, 30 ... Spotlight device, 30a ... Spotlight, 32 ... Predetermined range (imageable range), 33 ... Control section, 40 ... Optical filter.

Claims (1)

[Claims] 1. A bar code reading means, a spot light means for irradiating a spot light to the center of a bar code reading range by the bar code reading means at a bar code arranging position, and a bar code arranging position by the bar code reading means. A bar code reading device, comprising: spot light incidence preventing means for preventing reflected light of the spot light from entering the bar code reading means when reading the bar code.