JP3510695B2 - Data symbol reading device - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a data symbol reader for reading coded information such as two-dimensional data symbols.

[0002]

2. Description of the Related Art Today, a method and apparatus for converting product information into a bar code and reading the bar code with a bar code reader are widely used for application to, for example, a POS system. However, the bar code is read one-dimensionally by scanning in the bar arrangement direction, and there is a limit to the amount of information.

Therefore, in recent years, as a device capable of carrying more information, for example, a two-dimensional data symbol in which a black and white mosaic pattern is two-dimensionally arranged and a data symbol reading device for reading the two-dimensional data symbol have been developed. This data symbol reading device is roughly classified into one having a configuration in which an image sensor, for example, an area sensor such as a CCD is used to read a data symbol pattern two-dimensionally at the same time, and a line sensor is used for each line. There is a configuration in which the reading unit and the data symbol are relatively moved in a direction orthogonal to the main scanning direction to perform sub-scanning and two-dimensional reading while scanning.

Among them, the one using the image pickup device (area sensor) is excellent in that it is not necessary to move the reading section and the data symbol relative to each other because of the sub-scanning and the reading can be performed in a short time. It is attracting attention.

FIG. 10 shows a conventional data symbol reader having a structure using this image pickup device (area sensor).
FIG. 11 shows a symbol reading area and a data symbol in the data symbol reading device, respectively.
As shown in FIG. 10, the data symbol reading device 10
In the case of 0, the reading unit 102 is built in the casing 101, and the symbol reading area 36
The surroundings of the area up to are covered with a housing 103, and a rectangular opening 104 including the symbol reading area 36 is formed at the tip of the housing 103.
Then, at the time of reading, the data symbol 38 and the data symbol reading device 100 are moved relative to each other so that the data symbol 38 is aligned so as to enter the tip opening 104 of the housing 103.

In this case, it is necessary to perform alignment so that a part of the data symbol 38 does not protrude from the tip end opening 104 of the housing 103. For example, as shown in FIG. 11, even when a part of the data symbol 38 overlaps with the leading edge portion 105 of the housing 103, a read error occurs.

However, since the casing 103 is made of an opaque member, it is difficult to confirm the positional relationship between the data symbol 38 and the tip opening 104, and the data symbol 38 protrudes from the tip outer edge 106 of the casing 103. Even if it is visually confirmed that there is not, a reading error may occur due to the state as shown in FIG.

Therefore, the work of surely positioning the data symbol in the opening of the tip of the housing must be performed carefully.
It takes time and labor, and the advantages of the data symbol reading device using the area sensor described above are not fully utilized.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a data symbol reading device which can read data symbols easily, quickly and accurately.

[0010]

The above objects are achieved by the present invention described in (1) to (6) below.

(1) A data symbol reading device for reading a two-dimensional data symbol, comprising: an image sensor;
A reading unit having an optical system for forming an image of the data symbol on the symbol reading region on the light receiving surface of the image sensor, a casing for housing the reading unit, and an extension from the casing to the symbol reading region side. A guide member that defines a distance for forming an image of the data symbol on the symbol reading area on the light receiving surface of the image sensor by the optical system,
The guide member has an opening on at least one side of the guide member, and the symbol reading area extends beyond the opening surface of the opening to the outside of the guide member. Symbol reader.

(2) The guide member is composed of a casing whose cross section parallel to the symbol reading area is a quadrangle, and has openings on a pair of opposite side surfaces of the casing. The data symbol reading device according to (1) above, wherein the reading region exists beyond the opening surface of each of the openings to the outside of the housing.

(3) The guide member is formed of a casing whose cross section parallel to the symbol reading region has a quadrangular shape, and has openings on each of four side surfaces of the casing. Is the data symbol reading device according to the above (1), which is present beyond the opening surface of each opening to the outside of the housing.

(4) On the light receiving surface of the image pickup device,
The data symbol reading device according to (3) above, in which a portion other than a portion corresponding to the symbol reading area is shielded from light.

(5) The data symbol reading device according to any one of (1) to (4), wherein the reading unit further has a light source that illuminates the symbol reading area.

(6) The data symbol reading device according to any one of (1) to (5), which has a signal processing circuit for processing a signal from the image pickup device and a light source driving circuit for driving the light source. .

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The data symbol reading apparatus of the present invention will be described below in detail with reference to the preferred embodiments shown in the accompanying drawings.

FIG. 1 is a perspective view showing a first embodiment of a data symbol reading device of the present invention, and FIG. 2 is a block diagram showing a circuit configuration of the data symbol reading device shown in FIG. As shown in these drawings, a data symbol reading device 1A of the present invention has a casing 2 made of, for example, various hard resins or metals. This casing 2
Is composed of a grip portion 21 to be gripped by hand and a head portion 22 formed at one end thereof. Inside the grip portion 21, a signal processing circuit 5, a light source drive circuit 42 and a communication driver 16 described later are provided. The reading unit 4 that receives the light from the symbol reading region 36 is housed in the head unit 22.

The reading section 4 includes a symbol reading area 3
6, a pair of light sources (illumination devices) 41 for illuminating 6, a CCD (charge coupled device) 43 as an image pickup element, and light from the symbol reading area 36 (reflected light in this embodiment) is formed on the CCD 43. And an optical system 44 that leads to

The CCD 43 and the optical system 44 are both light sources 4.
It is installed between 1. In the CCD 43, a large number of photodiode pixels are arranged in a matrix, and each pixel is configured to accumulate charges according to the amount of light received and transfer the charges sequentially at a predetermined time. The transferred charges form the image signal of the read image.

In this embodiment, the CCD 43
Is only required to be able to detect the brightness (luminance) of each part of the data symbol 38, but a CCD 43 for a color image can also be used depending on the configuration of the data symbol to be read.

Further, the optical system 44 is constructed by arbitrarily combining optical components such as various lenses, prisms, filters, mirrors, etc., and in the case of the present embodiment, it is a reduction optical system.

As the light source 41, for example, a light emitting element such as an LED, a halogen lamp, a semiconductor laser or the like can be used. A diffuser plate (not shown) having a rough surface may be installed on the light emitting side of the light source 41 in order to make the brightness on the symbol reading area 36 more uniform.
A light source drive circuit 42 for lighting the light source 41 is connected to the light source 41.

The symbol reading area 36 is located on the reference plane (the plane on which the data symbol 38 is located) and the light source 41.
Of the CCD 43 and the reflected light is reflected by the CCD 43.
This is an area where light can be received and the data can be read. The symbol reading area 36 has auxiliary reading areas 37a and 37b described later.

In this embodiment, as shown in FIG. 4, the data symbol (symbol code) 38 has x rows × y columns (x,
Each y is composed of a black or white (or transparent) mosaic arranged in an integer of 2 or more. The black or white color of this mosaic is, for example, 0 in binary.
Or, it represents 1, and the desired information is specified by this combination. Needless to say, the data symbol 38 is not limited to the one having the illustrated configuration.

In the reading section 4 configured as described above, the light source drive circuit 42 turns on the light sources 41, and the light emitted from each of the light sources 41 is converted into the symbol reading area 3.
6 and the reflected light is transmitted through the optical system 44 to the CCD.
An image is formed on the light receiving surface of 43, and an image signal (analog signal) corresponding to the received light amount is output.

The head portion 22 of the casing 2 keeps the reading portion 4 at a predetermined distance from the symbol reading area 36, that is, an image of the data symbol 38 placed on the symbol reading area 36 by the optical system 44. As a guide member for defining the image forming distance on the light receiving surface of the CCD 43, the housing 3 extending from the reading unit 4 to the symbol reading area 36 side is provided. The housing 3 is configured to substantially surround the optical path of the illumination light from the light source 41 and the optical path of the reflected light from the symbol reading area 36, and the cross section (transverse cross section) parallel to the symbol reading area 36 is It has a rectangular shape.

Further, the housing 3 is formed in such a length that the light from the symbol reading area 36 is imaged on the light receiving surface of the CCD 43 by the optical system 44 when the tip of the housing 3 comes into contact with the reference surface. There is.

As shown in FIG. 1, the housing 3 has four side surfaces, of which a pair of opposing side surfaces (side surfaces corresponding to the left and right side surfaces of the grip portion 21) have rectangular openings. 32 is formed. As a result, at the time of reading, the alignment for positioning the data symbol 38 in the symbol reading area 36 can be performed while visually confirming through the opening 32, and the data symbol 38 protrudes from the symbol reading area 36, etc. Is prevented and accurate reading can be performed. The opening 32 is
It may be formed on the front and rear side surfaces of the housing 3.

As shown in FIG. 4, when the tip of the housing 3 comes into contact with the reference surface, the symbol reading area (shown by the one-dot chain line in FIG. 4) 36 is formed at the tip of the housing 3. A portion including the entire area of the opening (shown by a chain double-dashed line in FIG. 4) 31 and beyond the tip opening 31, that is, the housing 3
Beyond the opening surface of each opening 32 formed on the side surface of the housing 3
It has auxiliary reading areas 37a and 37b that extend to the outside.

As a result, when the data symbol 38 is read, not only when the data symbol 38 is inside the tip opening 31, but also when the data symbol 38 extends out of the tip opening 31 as shown in FIG. As long as it is within the auxiliary reading areas 37a and 37b, accurate reading can be performed.

More specifically, in the CCD 43 and the optical system 44, the magnification of the optical system 44 and the size of the CCD 43 are appropriately set so that the symbol reading area 36 is larger than the area surrounded by the tip of the housing 3. ing.

The tip end opening 31 of the housing 3 is a tip end surface of the housing 3 with the optical axis of the optical system 44 as a normal line, both inner side surfaces of the housing 3 facing each other, and both opening surfaces of the opening 32 facing each other. Constitutes an area (inner area S1) surrounded by a total of four intersecting lines. The value obtained by dividing the actual dimension of the light receiving surface of the CCD 43 in the long side direction by the image magnification of the optical system 44 is the inner area S.
1 so that it is larger than the actual dimension in the long side direction of CCD4
3, the image magnification of the optical system 44, the inner area S1 and the like are set.

For example, the size of the inner area S1 is 4 cm in length × 4 in width.
cm, the light receiving surface of the CCD 43 is 1 cm in length × 1.5 cm in width, and the image magnification of the optical system (reduction optical system) 44 is 0.25, the light receiving area in the vertical direction by the CCD 43 (the vertical direction of the symbol reading area 36). The dimension is 1 / 0.25 = 4 cm, which is the same as the vertical dimension of the inner area S1, but the CCD 43 can receive the light in the horizontal direction (the symbol reading area 36).
Is 1.5 / 0.25 = 6 cm, so that a readable portion is produced by exceeding 1 cm in both lateral directions of the inner region S1. This portion is the auxiliary reading areas 37a and 37b. This auxiliary reading area 37
The shapes and sizes of a and 37b are set as desired by appropriately adjusting the arrangement, configuration, dimensions, etc. of the light source 41, the optical system 44, and the CCD 43.

In the casing 2, a signal processing circuit 5 for processing the image signal from the reading section 4 is provided on, for example, a printed circuit board. As shown in FIG. 2, the signal processing circuit 5 mainly includes a CCD drive circuit 6, an amplifier circuit 8,
Binarization circuit 10, memory 12, control means (CPU) 1
5 and these connecting lines.

Further, the control means 15 includes the light source drive circuit 4
2. Communication driver 16 and switch circuit 1 having main switch (power switch), trigger switch, etc.
3 is connected, and further, a display device (not shown) such as an LCD (liquid crystal display element) or a CRT is connected if necessary.

In the data symbol reader 1A, reading is started by turning on the trigger switch, and the signal processing circuit 5 performs predetermined signal processing as described later. The signal processed by the signal processing circuit 5 is decoded into necessary data, and then input by a communication driver 16 to a computer 17 such as a personal computer or a workstation installed outside. In such a computer 17, the input data is stored and tabulated.

The light source drive circuit 42 is a circuit for supplying electric power to the light source 41 to turn it on, and its operation is controlled by the control means 15.
Controlled by. By turning on the main switch,
The control means 15 activates the light source drive circuit 42, and the light source 41 is thereby turned on. Here, the lighting time of the light source 41 is set as desired by the light source drive circuit 42 or the control means 15.

When the main switch is turned on, the control means 15 operates the CCD drive circuit 6. CCD
A CCD horizontal drive pulse and a CCD vertical drive pulse are output from the drive circuit 6 to the CCD 43, and charge accumulation and transfer in the CCD 43 are controlled.

Further, the CCD drive circuit 6 generates a clock signal and sends a signal (composite clock signal) obtained by combining this signal with a horizontal synchronizing signal and a vertical synchronizing signal to the control means 15.

The image signal (analog signal) sequentially output from the CCD 43 of the reading section 4 is amplified by the amplifier circuit 8, converted into a digital image signal by an A / D converter (not shown), and input to the binarization circuit 10. To be done.

In the binarization circuit 10, the digital image signal is compared with the threshold data and binarized. The binarized data output from the binarization circuit 10 is stored in a predetermined address of the memory 12 by an address counter built in the control means 15. The address counter is driven by the composite clock signal input from the CCD drive circuit 6.

Data is sequentially read from the memory 12 in accordance with the address designated by the address counter, and for one screen of data, the arithmetic unit of the control means 15 detects, for example, contours (information about the data symbol 38). Image extraction), dropout correction, rotation, and other image processing, and the decoder built in the control means 15 decodes the data into data according to the system of the data symbols 38. This decoded data is output to the host computer 17 via the communication driver 16.

FIG. 3 is a perspective view showing a second embodiment of the data symbol reading apparatus of the present invention. The data symbol reading device 1B shown in the figure is the same as the data symbol reading device 1A except that the configurations of the guide member 30 and the CCD 43 are different. Hereinafter, differences from the data symbol reading device 1A will be described.

The guide member 30 in the data symbol reading device 1B has the same function as that of the housing 3, has four side surfaces, and a rectangular opening 33 is formed in all of them. In other words, the guide member 30
Is composed of four pillars 34 standing upright near the four corners of the symbol reading area 36. With such a configuration, at the time of reading, the alignment for positioning the data symbol 38 in the symbol reading area 36 can be performed while visually confirming from the opening 33 from any direction. Protrusion from the symbol reading area 36 is prevented, and more accurate reading can be performed.

As shown in FIG. 6, when the tip of each pillar 34 comes into contact with the reference surface, the symbol reading area (see FIG.
The middle one-dot chain line) 36 includes the entire region of the tip region 35 (shown by the two-dot chain line in FIG. 6) surrounded by the tips of the four pillars 34, and a portion beyond the tip region 35, that is, It has auxiliary reading areas 37c, 37d, 37e, 37f that extend beyond the opening surface of each opening 33 formed on the side surface of the guide member 30 and extend to the outside of the guide member 30.

As a result, when the data symbol 38 is read, not only when the data symbol 38 is in the front end region 35, but also when the data symbol 38 is out of the front end region 35 as shown in FIG. As long as the auxiliary reading areas 37c, 37d, 37e, and 37f are present, accurate reading can be performed.

More specifically, the CCD 43 and the optical system 44 in this embodiment are also the same as in the first embodiment.
The magnification of the optical system 44 and the dimensions of the CCD 43 are appropriately set so that the symbol reading area 36 is larger than the area surrounded by the tip of the guide member 30.

As shown in FIG. 8, the front end region 35 surrounded by the front ends of the four pillars 34 is located at the front end surface of the guide member 30 whose normal line is the optical axis of the optical system 44.
An area (inner area S2, indicated by double diagonal lines in FIG. 8) excluding each columnar portion 34 from the area surrounded by the outer contour of the column is formed. Then, each value obtained by dividing the actual dimension of the light receiving surface of the CCD 43 in the long side direction and the short side direction by the image magnification of the optical system 44 is
The dimensions of the CCD 43 and the optical system 44 are set to be larger than the actual dimensions of the inner area S2 in the horizontal direction (corresponding to the long side direction of the CCD light receiving surface) and the vertical direction (corresponding to the short side direction of the CCD light receiving surface), respectively. The image magnification, the inner area S2, and the like are set.

As indicated by the diagonal lines in FIG. 8, the symbol reading area 36 is an auxiliary reading area 37c, 37d extended from the inner area S2 in the vertical and horizontal directions in FIG. 4 by a predetermined length equal to the width of the opening 33. , 37e, 37f, and have a cross shape as a whole.

Further, in this embodiment, as shown in FIG. 9, the light receiving surface of the CCD 43 is covered with masks 45 for shielding the four corners thereof. This mask 45
This is to improve the reading accuracy by eliminating or distinguishing unnecessary data outside the symbol reading area 36.
The portion not covered with light by the mask 45 (image sensor exposed portion 46) corresponds to the symbol reading area 36.

Pixels (unnecessary pixels) in the portion of the CCD 43 that are shielded by the mask 45 are A / D converted in the signal processing circuit 5 as in the effective pixels of the image pickup element exposed portion 46.
The data is stored in the memory 12 after being digitized, but the address on the memory 12 where the data regarding the unnecessary pixel is stored is known. Then, the arithmetic unit of the control means 15 performs image processing by invalidating the data read when the address corresponding to the unnecessary pixel is designated. Therefore, inconvenience such as erroneous detection of the data symbol 38 due to the installation of the mask 45 does not occur.

In this embodiment, the mask 45 may be omitted, but it is preferable to provide the mask 45 in order to improve the reading accuracy of the data symbol 38.
Furthermore, as described above, in the signal processing circuit 5,
It is more preferable that the data regarding the unnecessary pixels in the portion shielded by the mask 45 is treated as invalid. Further, even when the mask 45 is not provided, for the same reason, it is preferable that the signal processing circuit 5 handles the data regarding the unnecessary pixels outside the symbol reading area 36 as invalid.

The data symbol reading apparatus of the present invention has been described above based on the illustrated embodiments, but the present invention is not limited to these. For example, the data symbol reading device of the present invention may be any device in which an opening is formed on any one of the three side surfaces of the housing 3 on one side surface.

The cross-sectional shape of the housing 3 is not limited to a quadrangle, but may be any shape such as a polygon such as a triangle, a hexagon, an octagon, a circle, an ellipse, etc., and is formed on the side surface. The formation position of the opening and the like are also arbitrary as in the above. Further, the shape of the opening formed on the side surface of the housing 3 is also
The shape is not limited to the rectangle as shown.

Further, the reading section 4 may be configured not to have the light source 41 and to illuminate the symbol reading area 36 by taking in external light (natural light).

[0057]

As described above, according to the data symbol reading apparatus of the present invention, since the side portion of the guide member is open, the alignment of the data symbol at the time of reading can be visually confirmed through the opening. It can be done with confirmation.

Further, since the symbol reading area exists beyond the opening surface of the opening formed in the guide member to the outside of the guide member, it is easy to position the data symbol in the symbol reading area.

As described above, the alignment of the data symbols is extremely easy, and the reading error due to the protrusion of the data symbols from the symbol reading area is surely prevented, and the accurate reading can be performed.

Further, when the light receiving surface of the image pickup device is shielded by a mask or the like in a predetermined pattern, the reading accuracy can be improved even when the symbol reading region and the light receiving region of the image pickup device have different shapes. .

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a data symbol reading device of the present invention.

FIG. 2 is a block diagram showing a circuit configuration of the data symbol reading device shown in FIG.

FIG. 3 is a perspective view showing a second embodiment of the data symbol reading device of the present invention.

4 is a plan view showing a symbol reading area and a data symbol in the data symbol reading device shown in FIG.

5 is a plan view showing a symbol reading area and data symbols in the data symbol reading device shown in FIG. 1. FIG.

FIG. 6 is a plan view showing a symbol reading area and data symbols in the data symbol reading device shown in FIG.

FIG. 7 is a plan view showing a symbol reading area and data symbols in the data symbol reading device shown in FIG.

8 is a plan view showing a relationship between a leading end region and a symbol reading region in the data symbol reading device shown in FIG.

9 is a bottom view showing a configuration of a light receiving surface of a CCD in the data symbol reading device shown in FIG.

FIG. 10 is a perspective view showing a configuration of a conventional data symbol reading device.

11 is a plan view showing a symbol reading area and a data symbol in the conventional data symbol reading device shown in FIG.

[Explanation of symbols]

1A, 1B data symbol reader 2 casing 21 grip 22 Head 3 housing 30 Guide member 31 Tip opening 32, 33 openings 34 Pillar 35 Tip area 36 symbol reading area 37a to 37f auxiliary reading area 38 data symbols 4 Reader 41 light source 42 Light source drive circuit 43 CCD 44 Optical system 45 mask 46 Image sensor exposed part 5 Signal processing circuit 6 CCD drive circuit 8 amplifier circuit 10 Binarization circuit (comparator) 12 memories 13 switch circuit 15 Control means (CPU) 16 Communication driver 17 Host computer 100 data symbol reader 101 casing 102 reading unit 103 housing 104 opening 105 Tip edge 106 tip outer edge Internal area of S1 and S2

Claims (6)

(57) [Claims] 1. A data symbol reading device for reading a two-dimensional data symbol, comprising: an image sensor; and an optical system for forming an image of the data symbol on a symbol reading area on a light receiving surface of the image sensor. A reading unit, a casing accommodating the reading unit, and an extension of the casing toward the symbol reading region side, and an image of the data symbol on the symbol reading region is formed by the optical system on the light receiving surface of the image sensor. And a guide member that defines a distance for forming an image on the guide member, the guide member having an opening that opens in at least one direction on a side portion thereof, and the symbol reading area exceeds an opening surface of the opening. And a data symbol reading device which is present outside the guide member. 2. The guide member is formed of a casing having a quadrangular cross section parallel to the symbol reading area, and has openings on a pair of opposite side surfaces of the casing. The region exists beyond the opening surface of each of the openings to the outside of the housing.
The data symbol reader described in 1. 3. The guide member is formed of a casing whose cross section parallel to the symbol reading region has a quadrangular shape, and has openings on four side surfaces of the casing. , Exists beyond the opening surface of each of the openings to the outside of the housing.
The data symbol reader described in 1. 4. The data symbol reading device according to claim 3, wherein a portion of the light receiving surface of the image pickup element other than a portion corresponding to the symbol reading area is shielded from light. 5. The data symbol reading device according to claim 1, wherein the reading unit further includes a light source that illuminates the symbol reading area. 6. The data symbol reading device according to claim 1, further comprising a signal processing circuit that processes a signal from the image sensor and a light source driving circuit that drives the light source.