JP2754915B2 - Optical reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical reader for reading a symbol such as a character or a code on the surface of an object. Among them, an optical reader that reads characters displayed on the surface of an object is called an OCR (optical character reader), and an optical reader that reads a bar code is called a BCR (bar code scanner).

Further, the above-mentioned optical reading device is a hand-held type which can irradiate light toward an object by holding the housing by hand, receive reflected light thereof, and read symbols, and the housing is fixed. There is a fixed type in which several laser beams are scanned in multiple directions, and a symbol can be read simply by holding an object over the laser beam. Laser scanners that scan laser beams optically and irradiate distant objects,
There is a touch scanner that receives a reflected light from an object by bringing a reading window of the optical reading device into contact with the object.

[0003]

2. Description of the Related Art Bar codes and characters (hereinafter, may be referred to as "bar codes") which are read by an optical reading device are
There are various things, large and small. Therefore, in order to deal with a wide range of objects, the optical reading device generally has a scanning range adapted to a wide bar code.

For this reason, in a situation where large and small products with bar codes are mixed and mixed, such as a POS cash register business and a transportation business, a plurality of bar codes often enter the scanning range. Occur. In particular, in the case of a laser scanner, such a state is more likely to occur because a bar code having a deep reading depth and a different distance from the scanner can be read (see FIG. 8).

The optical reading device recognizes the contents of a bar code by processing an image of the bar code included in the scanning range. When a plurality of bar codes are simultaneously included in the scanning range, any one of the bar codes is to be recognized. Conventionally, it is not possible to judge whether a barcode has been processed earlier in time (referred to as the former), or if more than one barcode is entered with caution, the reading is suspended (referred to as the latter). I was doing it.

[0006]

When the former is adopted,
A user may read a bar code of a product that the user does not intend, and an irreversible error may remain afterward. In the latter case, a fatal error will not occur, but in a cluttered working situation, it is imperative that the operator must not put extra barcodes in the scanning range. This places an excessive burden on the worker and causes a reduction in work efficiency.

[0007] The above is a problem in the OCR as well. Since the scanning range is two-dimensional in the OCR, a plurality of character strings may be arranged in the scanning range more than the BCR. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is intended to be read by a user even when a plurality of symbols, such as barcodes, simultaneously enter the scanning range.
An object of the present invention is to provide an optical reading device capable of recognizing a missing object. The present invention also relates to a plurality of barcodes.
When symbols such as the code
Only recognize what the user intended to read.
It is an object of the present invention to provide an optical reading device that can perform the following.

[0008]

Generally, regardless of the type of the touch scanner or the laser scanner, a user consciously or unconsciously brings a symbol to be read to the center of the scanner. Never attempt to read a symbol at the end of the read scan range. As described above, even when a plurality of symbols enter the scanning range at the same time, the target symbol is located at a position near the center of the scanning range, and another symbol is located around the scanning range.

In order to achieve the above object, an optical reading apparatus according to the present invention comprises a symbol position detecting means for detecting a position where an image of a symbol obtained by scanning exists within a scanning range, and a center of the scanning range. in a range of parts, if at least some symbols image detected by the symbol position detecting means are present to identify the symbol image, the symbol image detected by the symbol position detecting means of the central portion of the scanning range a constant A symbol image specifying means that does not specify the symbol image if not included in the range;
And has a recognizing symbol recognition means the contents of the specified symbol by the symbol image specifying means (claim 1). specific
If there is more than one symbol image to be
Of these symbol images at the center of the scanning area or
Identifying one symbol image closest to the center of the scanning range
Preferred (claim 2).

[0010]

[Action] If the optical reader according to claim 1, wherein, in a range of the central portion of the scanning range, if there is at least some symbols image, to identify the symbol, a range of the center portion of the scanning range If no symbol image is included in the symbol, no symbol can be specified. Therefore, even when a plurality of symbols enter the scanning range at the same time , a symbol located far from the center of the scanning range.
Can be excluded from reading. Claim 2
In the case of the optical reading device described, a plurality of specified symbol images
In some cases, the symbolic image at the center of the scan range
One symbol image closest to the center of the scanning area
Can be specified, so only the specified symbol
It can be read.

The "fixed area at the center of the scanning area"
Is too small, the operability is impaired. Therefore, it is preferable to set the value in consideration of the size of the image when the symbol to be read appears in the scanning range.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 2 is a diagram for reading a symbol such as a barcode.
FIG. 1 shows a laser beam output type handheld optical reading device, and FIG.
Shows a functional block diagram of an electric circuit including a microcomputer. In this optical reading device, a semiconductor laser oscillation device 2, an aberration-free lens 3 for converging output light of the semiconductor laser oscillation device 2 and a rotation for scanning the output light over a predetermined angular width are provided in a pistol-shaped casing 1. Type polygon mirror 4, motor 1 for rotating and driving polygon mirror 4
1. A light receiving element 7, such as a CCD, which receives light reflected from a plurality of barcodes 6a, 6b placed at a distance D and radiated from an opening 13 at the tip of the housing 1, and reflected from a polygon mirror surface. A scanning target light receiving element 12 which is installed at an end of an effective scanning angle range of reflected light to be directly received and receives the reflected light, and a waveform shaping and binarization of an output signal of the light receiving element 7 to obtain a bar to be read. An image signal S2 including a signal (bar code signal) corresponding to the shape of the code is obtained, a processing unit 9a for identifying the contents of the bar code based on the image signal S2 according to the control procedure of the present invention, and a light detecting element 12 for scanning detection. The substrate 9 on which a processing unit 9b for generating a synchronizing signal S1 for defining a scanning range by waveform shaping and binarizing the output signal of the above is stored. A code 10 protruding from the housing 1 is a signal code for providing an output signal of the processing unit 9a to the outside, and the lever 8 is a reading switch of an optical reading device.

FIG. 3 is a diagram showing the position coordinates of each part of the scanning range of the light receiving element 7. The both ends of the scanning range are 0 and 2N, the center of the scanning range is N, and the reading zone of the central portion of the scanning range is N. Both ends are indicated by NM and N + M. FIG. 4 is a waveform diagram of the synchronizing signal S1 and the image signal S2. Both ends of the scanning range of the light receiving element 7 are temporally defined by the synchronizing signal S1. In the scanning range, an image signal S2 including two bar code signals is drawn.
Both ends of the two bar code signals are b1, e1, b
2, e2.

FIG. 1 is a block diagram showing a main part of the processing units 9a and 9b. An image signal S2 representing a read barcode image is input to a symbol position detection unit 91.
The symbol position detecting section 91 outputs a position coordinate signal S3 that defines the position coordinates <bi, ei> (i = 1,2,...) At both ends of the bar code included in the image signal S2. Where the subscript i is
At the same time, it is a number corresponding to each bar code included in the scanning range. Based on the position coordinate signal S3, the symbol image specifying unit 92 reads the read zone <NM, N + M at the center of the scanning range.
>, If at least a part of the symbol image detected by the symbol position detection unit 91 is present, the symbol image closest to the center N is specified among those symbol images, and the symbol image is detected by the symbol position detection unit 91 in the reading zone. If the detected symbol image is not included, a process of not specifying the symbol image is performed. The signal S4 representing the position coordinates <b, e> at both ends of the symbol image specified as a result of this processing enters the symbol recognition section 93, and the symbol recognition section 93 generates a barcode signal S2 based on the position coordinate signal S4. And recognize the contents of the target barcode.

FIG. 5 is a flowchart showing a processing procedure of the symbol image specifying unit 92. In step (1), position coordinates <bi, ei> (i = 1,2,..., N) at both ends of the barcode
In step (2), the first barcode (the order of the barcodes is arbitrary) i = 1 is set, and a numerical value Dmi indicating the shortest distance between the barcode and the center is set.
Let n be M. In step (3), it is determined whether i = n,
If i = n, ei <NM or b in step (4)
Determine i> N + M. This condition is shown in FIG.
Alternatively, as shown in FIG. 6B, the bar code does not cover the reading zone <NM, N + M>. In this case, the process jumps to step (13) and starts the process of the next bar code i + 1.

When the bar code is in the reading zone <NM, N +
If M>, it is determined in step (5) whether bi≤N. If the answer is no, it indicates that the barcode is to the right of the center line (see FIG. 6 (c)). At this time, Di = bi-N is set as in step (6).

If bi.ltoreq.N in step (5), the process proceeds to step (10) to determine whether ei.gtoreq.N. If YES, it means that the bar code is over the center line (see FIG. 6 (d)), and this bar code <bi, ei> is determined to be read (step (12)).

If ei <N, the bar code is to the left of the center line (see FIG. 6 (e)), and step (1)
In step 1), Di = N-ei. In step (7), Di and M obtained as described above are compared. If Di <M, Di and Dmin are compared in step (8). (In the first case, since Dimin = M, Di <Dmin), Di <Dm
If in, set Dmin = Di. In this way, the bar code having the smallest distance Di between the bar code and the center is found.

Then, in step (13), i is incremented and the process returns to step (3). In step (3), the above determination is made for all the barcodes. If i = n, the process proceeds to step (15) to check whether Dmin <M. If Dmin = M, FIG.
There is no barcode in the reading zone <NM, N + M> as in (c) and (e), so that the reading of the barcode is abandoned and a signal indicating no output is output (step (17) )).

If Dmin <M, it means that a bar code as shown in FIGS. 6 (c) and 6 (e) exists, and the position coordinates <bi, ei> of the bar code are determined and output (step S1). (1
6)). As described above, the reading zone <NM, N +
M> can be specified.

It should be noted that the present invention is not limited to the above-described embodiment.
It can be easily extended and applied to dimensions. At this time, as shown in FIG. 7, the distances Di, D from the center X to the closest part are set as the distances between the character strings i, j and the center X of the scanning range.
Just set j. However, in practice,
When reading horizontally written characters, there is a possibility that the target character string may be away from the center by a distance D up or down, and the distance D may be left or right.
The former is clearly more likely than the possibility of leaving. Conversely, there is a high possibility that a character string distant to the left or right is in the field of view contrary to intention. Therefore, when calculating the distance from the center, the weight should be changed between the horizontal component and the vertical component. For example, the distance Di between the center X = <NH, Nv> and the character string i is represented by Di = m (bvi-Nv), where m is a weighting coefficient (0 <m <1), and the distance Dj between the center X and the character string j. is Dj = {m (evj-Nv ) 2 + (NH -eHj) 2} 1/2
Is more preferable. Here, bvi is the ordinate of the lower end Pi of the character string i, and evj is the character string j.
Is the ordinate of the upper right end Pj, and eHj is the abscissa of the upper right end Pj of the character string j.

Various other design changes can be made without departing from the scope of the present invention.

[0023]

As is evident from the foregoing description, according to the optical reading apparatus according to claim 1, in a range of the central portion of the scanning range, if there is at least some symbols image, it recognizes the symbol, scanning When the symbol image is not included in a certain area in the center of the area, the symbol is not recognized, so that a plurality of symbols can be scanned.
At a distance from the center of the scanning range even when entering
Certain symbols can be excluded from reading.
The reading work efficiency by the optical reading device can be improved.
Become so. According to the optical reading device of the second aspect,
Symbolic image at the center of the scanning area or at the center of the scanning area
Since the closest symbol image can be specified, always
Only the symbol intended by the user can be read. did
Therefore, the reading of the symbol by the optical reading device is ensured.
To improve reading efficiency.
become.

[Brief description of the drawings]

FIG. 1 is a main block diagram of an electric circuit of an optical reading device according to the present invention.

FIG. 2 is a perspective view showing the internal structure of the optical reading device.

FIG. 3 is a diagram illustrating a scanning range of the optical reading device.

FIG. 4 is a waveform diagram showing a synchronization signal S1 and an image signal S2.

FIG. 5 is a flowchart illustrating a processing procedure of a symbol image specifying unit.

FIG. 6 is a diagram illustrating a positional relationship between a scanning range of the optical reading device and a barcode image.

FIG. 7 is a diagram showing a positional relationship between a two-dimensional scanning range and a character string.

FIG. 8 shows a BC for reading bar codes attached to a plurality of products.
It is a figure showing R.

[Explanation of symbols]

 Reference Signs List 1 housing 2 laser oscillation device 6a, 6b barcode surface 7 light receiving element 9a, 9b processing unit 12 scanning detection light receiving element 91 symbol position detecting unit 92 symbol image specifying unit 93 symbol recognizing unit

Claims (2)

(57) [Claims] An optical reading device for reading a symbol attached to a target surface by irradiating light output from a light source to the target surface and forming reflected light from the target surface into an image within a scanning range of a scanner. Symbol position detecting means for detecting a position where the image of the symbol obtained by the scanning is present in the scanning range; and at least a part of the symbol image detected by the symbol position detecting means within a certain range in the center of the scanning range. If there exist, to identify the symbol image, and symbols image specifying means not identify the symbol image if the symbol image detected by the symbol position detecting means is not included in a range of the central portion of the scanning range, the symbol A symbol recognition unit for recognizing the contents of the symbol specified by the image specifying unit. 2. A method according to claim 1, wherein said symbol image specifying means includes a plurality of symbol images.
If there are several, the symbol image at the center of the scanning range
The symbol image or the symbol image closest to the center of the scanning range is 1
2. The optical reading device according to claim 1, wherein
Place.