JP4175223B2 - Optical information reader - Google Patents

Description

  The present invention provides optical information including marker light irradiation means for irradiating marker light for indicating a reading center to a reading target in which a barcode (one-dimensional code), a QR code (two-dimensional code), or the like is recorded. The present invention relates to a reading device.

As this type of optical information reader, a barcode reader having a configuration in which two spot lights having different emission colors are irradiated so as to intersect at a reading point from a head equipped with a barcode reading mechanism is considered. . According to such a configuration, although the operator can easily be notified of the optimum distance between the reading target on which the barcode is recorded and the head, that is, the best focus position, the operator can determine the visual field range of the barcode reader. There was a defect that could not be notified.
JP-A-11-250172

  Therefore, Japanese Patent Application Laid-Open No. 11-250172 relating to the application of the present applicant describes three spot lights on the left, right, and center to visually inform the operator of the reading range in which the information symbol can be read and the optimum reading depth. An information symbol reading apparatus configured to irradiate guide light consisting of the above from a reading port portion is shown. In this case, the optimum focus position is obtained when the marker light is clearly imaged on the surface to be read, and proper reading is performed by aligning the information symbol with the position between the left and right guide lights. It can be done.

  By the way, the reading optical axis and the marker optical axis may be slightly shifted due to dimensional errors or assembly errors of the components. As such a deviation, there is a deviation in the up-down direction or the left-right direction, and when a deviation in the up-down direction occurs, when reading the barcode label, as shown in FIG. 8, a range adjacent to the barcode to be read. In such a case, the barcode does not exist and a reading error occurs.

On the other hand, when a horizontal shift occurs as a shift, when reading only a desired two-dimensional code (second from the right in the example of FIG. 9) from a plurality of two-dimensional codes, There is a possibility that the code (third from the right in the example of FIG. 9) may be erroneously read.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical information reading apparatus capable of reliably reading a desired code located in a reading range or a reading center indicated by a marker light. .

According to the first aspect of the present invention, the measuring means measures the amount of deviation between the visual field center of the reading means and the reading center irradiated from the marker light irradiation means, and the correcting means is measured from the reading center of the reading means by the measuring means. Since the reading center in use is set at a position displaced by the measured deviation amount, the code can be reliably read without being affected by the deviation amount .

When the assembly of the optical information reader is completed, the measuring means is operated with the plane positioned at a representative reading distance within the reading depth. Then, the measuring unit measures the deviation amount by actually measuring the center of the visual field of the reading unit with respect to the plane and the reading center indicated by the marker light emitted from the marker light irradiation unit with respect to the plane. This makes it possible to obtain a representative amount of deviation, which is effective when the difference in the amount of deviation corresponding to the reading distance within the reading depth is small and can be corrected with the representative amount of deviation.

According to the second aspect of the present invention, even if the reading depth is deep and correction is not possible with a typical deviation amount, a reading distance within the reading depth is obtained by obtaining a calculation formula for obtaining a deviation amount according to the reading distance. Even if there is a large difference in the amount of deviation according to the above, the amount of deviation can be corrected appropriately.
According to the invention of claim 3, when reading a two-dimensional code, a desired two-dimensional code can be reliably read.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. First, FIG. 3 schematically shows an internal configuration of the code scanner 1 as an optical information reading device. This code scanner 1 is called a handy terminal that is operated by an operator by hand. Various types of codes such as a one-dimensional code such as a bar code, a two-dimensional code such as a QR code, and characters for OCR reading. The code can be read. In addition to reading the code, it also has functions of processing (decoding processing) and storing the read code data, data communication with the management computer, and the like.

The code scanner 1 is configured by incorporating a reading mechanism 3 for optically reading a code, a control device 4 (see FIG. 1), and the like in a case 2. Further, as shown in FIG. 3, the case 2 is bent so that the base end side is a grip portion, the front end side is slightly inclined downward, and a reading window portion 2a is provided at the front end portion.
A key input unit 5 including a plurality of key switches 5a is provided on the upper surface of the case 2 so that a program to be installed can be selected and a type of code to be read can be specified by an operator's operation. It has become. Further, a trigger switch 6 for reading (see FIG. 2) is provided on both side surfaces of the case 2. Furthermore, a display unit 7 made of, for example, an LCD is provided on the upper surface of the case 2. Note that the key switch 5 a, the display unit 7, the control device 4, and the like are mounted on a printed circuit board 8 disposed in the case 2. Further, in the case 2, a secondary battery (not shown) serving as a power source is incorporated.

  On the other hand, the reading mechanism 3 is provided in an area sensor (corresponding to a two-dimensional reading means) 9 composed of a CCD two-dimensional image pickup device provided in the center of the inner portion of the reading window portion 2a, and in front of the area sensor 9. The imaging lens 10, a plurality of illumination LEDs 11 (see FIG. 1) that are provided in the vicinity (upper side) of the periphery of the imaging lens 10 and serve as an illumination light source at the time of code reading, and are positioned in front of these illumination LEDs 11 An illumination lens (not shown) is provided. At this time, the area sensor 9 has, for example, 600 horizontal pixels and 400 vertical pixels, and has a two-dimensional reading field F as shown in FIG. The illumination LED 11 and the illumination lens illuminate the entire reading field F evenly.

  With such a configuration, the operator brings the reading window portion 2a of the code scanner 1 close to the reading target (for example, the label L shown in FIG. 2) on which the code (for example, the barcode C shown in FIG. 2) is recorded. By performing a reading operation, that is, turning on the trigger switch 6 at an optimum reading distance (for example, 90 mm), the reading target is illuminated by the illumination LED 11, and the reflected light is imaged by the area sensor 9 to read the code. It is done. Although not shown, the code may be a two-dimensional code such as a QR code, a character for OCR reading, or the like, and there are various types of codes such as slips and catalogs.

The image captured by the area sensor 9 is output to the control device 4. Based on the image captured by the area sensor 9 in the lighting state of the marker LED 13 (see FIG. 1), the control device 4 The irradiation position of the marker light in the entire field of view of the area sensor 9 can be recognized.
As shown in FIG. 4, the reading mechanism 3 portion is arranged at a marker LED 13 constituting marker light irradiating means for irradiating two marker lights for indicating a reading range with respect to an object to be read and a front portion thereof. The projected lens 14 is provided. The marker LED 13 and the light projecting lens 14 are provided in the vicinity of the periphery of the imaging lens 10 and irradiate marker light composed of spot light.

  In the present embodiment, as shown in FIG. 4, the marker light is composed of two marker lights M indicating the range of the reading visual field F, that is, the left and right ends. Further, the marker light M is clearly imaged on the surface of the reading object when the reading object is at an appropriate focal position (range) with respect to the reading mechanism 3, and the distance deviated therefrom. The image of the marker light M on the reading target surface is blurred.

These two marker LEDs 13 are controlled by the control device 4 as shown in FIG. 1, and the control device 4 controls the left and right marker LEDs 13 to blink at a predetermined cycle. To do.
Here, when a predetermined special operation is performed, the control device 4 automatically measures the deviation between the center of the field of view of the area sensor 9 and the reading center indicated by the marker light M as described later by the deviation measurement program. It is supposed to be.

  FIG. 1 schematically shows the electrical configuration of the code scanner 1. The control device (corresponding to measurement means and correction means) 4 is mainly composed of a microcomputer, and performs decoding processing of signals from the reading mechanism 3, control of the entire device, and the like. That is, the control device 4 controls the display of the display unit 7 according to the input of the operation signal from the key input unit 5 or the trigger switch 6, controls the lighting of the illumination LED 11, and as described above, The LED 13 is controlled.

  The control device 4 is input with the code image data read by the area sensor 9 and decoded. At this time, although not shown, an amplifier for amplifying the imaging signal of the area sensor 9, a binarization circuit for converting the binarized data, and the like are provided. An image memory 15 is provided connected to the control device 4 and the area sensor 9. Furthermore, the control device 4 is connected, for example, with a sound generating unit 16 that emits a buzzer sound when a code is read, and a data communication unit that performs data communication with an external device (for example, a management computer) using, for example, infrared rays. 17 is connected.

Next, the operation of the above configuration will be described.
When the assembly of the code scanner 1 having the above configuration is completed, it is necessary to correct a deviation between the center of the field sensor 9 and the reading center indicated by the marker light M. Such a shift is caused by a dimensional error or an assembly error of a component. In fact, even if the component accuracy or the assembly accuracy is increased, a slight error is inevitable.

FIG. 5 shows a deviation between the center of the visual field of the area sensor 9 and the reading center indicated by the marker light M. In FIG. 5, the deviation between the center of the field of view of the area sensor 9 and the reading center indicated by the marker light M is usually generated by superimposing the vertical deviation amount Za and the horizontal deviation amount Zb. .
Therefore, a predetermined special operation is performed on the code scanner 1 in a state where the reference reading target is positioned at a predetermined position of the reading depth of the code scanner 1.

  The control device 4 executes a deviation measurement program when a predetermined special operation is performed. That is, the control device 4 acquires an image from the area sensor 9 in a state where the marker LED 13 is lit, and the amount of deviation (the vertical direction deviation amount Za and the vertical direction deviation amount Za and the reading center indicated by the marker light M). The lateral displacement amount Zb) is measured, and the displacement amounts Za and Zb are stored in the internal memory.

Incidentally, the amount of deviation between the center of the field of view of the area sensor 9 and the reading center indicated by the marker light M changes according to the reading distance.
FIG. 6 shows the relationship between the visual field center of the area sensor 9 and the reading center indicated by the marker light emitted from the marker LED 13. As shown in FIG. 6, it can be seen that the longer the reading distance, the larger the deviation amount between the center of the field of view of the area sensor 9 and the reading center indicated by the marker light.

Here, when the reading depth is small, the difference in deviation amount according to the reading distance within the reading depth is small, so the deviation amount at the center of the reading depth is stored as a representative value.
When the above-described code scanner 1 is used to read a barcode (not shown) printed on, for example, a label to be read attached to a product (or directly on a product package), the operator Makes the reading window portion 2a of the code scanner 1 close to the reading object and turns on the trigger switch 6. Then, first, the marker LED 13 is turned on (flashes), and the marker light M is irradiated to the reading target.

  Therefore, when reading the one-dimensional code, the operator aligns the bar code C so as to be sandwiched between the left and right marker lights M as shown in FIG. Align to the distance to be imaged. As a result, it is possible to perform good reading at an appropriate focal position without causing the barcode C to deviate from the reading visual field F.

When the control device 4 irradiates the marker light M for a predetermined time, the control LED 4 turns off the marker LED 13 and then turns on the illumination LED 11. As a result, the reading target is illuminated, and the area sensor 9 reads (captures) the code.
Here, the control device 4 corrects the position shifted by the shift amounts Za and Zb stored in the internal memory from the center of the field of view of the area sensor 9 as the reading center in use, and the bar code C with the reading center as a reference. Perform a read of Thereby, even when the center of the visual field of the area sensor 9 and the reading center indicated by the marker light M are deviated, the barcode C positioned in the reading range indicated by the marker light M can be reliably read.
The completion of reading is notified by a buzzer sound from the sound generation unit 16.

  Similarly, when a two-dimensional code such as a relatively large QR code is read, the two-dimensional code is similarly positioned so as to be sandwiched between the marker lights M at the left and right ends, and each marker light is By aligning at such a distance that M is clearly imaged on the object to be read, good reading can be performed. The same applies when reading characters for OCR reading.

Incidentally, among codes that can be read by the code scanner 1, there is a code called a small micro QR code having a square shape with a side length of about several millimeters.
In the case where such small micro QR codes C are arranged in a horizontal row as shown in FIG. 9, when reading the desired micro QR code C, the reading indicated by the two marker lights M is performed. The reading operation may be performed by positioning so that the center is located at the desired code C. In this case, when the center of the field of view of the area sensor 9 and the reading center indicated by the marker light M are deviated. Even if an attempt is made to read a desired micro QR code C positioned at the reading center indicated by the marker light M, there is a possibility that the micro QR code positioned at the center of the field of view of the area sensor 9 may be read.

However, in the present embodiment, as described above, when the control device 4 reads the code, it is executed in a state in which the deviation between the field center of the area sensor 9 and the reading center indicated by the marker light M is corrected. The desired micro QR code positioned at the reading center indicated by the marker light M among the plurality of micro QR codes can be reliably read.
On the other hand, when the reading depth shown in FIG. 6 is large, the difference in the amount of deviation according to the reading distance within the reading depth is greatly different. Therefore, the amount of deviation at the intermediate position of the reading depth as described above is uniformly set as a representative value. When the correction is made, the difference from the actual deviation amount becomes large, and there is a possibility that reading of a desired code may fail. Therefore, when the reading depth is large as described above, the shift amount is corrected as follows.

  That is, as shown in FIG. 6, the corresponding shift amounts (Za1, Za2) and (Zb1, Zb2) are measured at the reading distances L1, L2 of at least two points at the reading depth, and the shift amounts (Za1, Za2) are respectively measured. , (Zb1, Zb2) is used to obtain an arithmetic expression indicating the correspondence between the reading distance L and the deviation amount, and when the code is read, the deviation amount corresponding to the reading distance L is obtained based on the arithmetic expression.

  Here, as a method of obtaining the reading distance L, as shown in FIG. 7, when the positions of the marker lights M at the reading distances L1 and L2 are measured, the marker light distances B1 and B2 are obtained, thereby obtaining the marker light distance and the reading distance. An arithmetic expression indicating a relationship with the distance L is obtained, and a reading distance L corresponding to the marker light interval B is obtained based on the arithmetic expression. Accordingly, by substituting the read distance L thus obtained into the arithmetic expression obtained as described above, the deviation amounts Za and Zb corresponding to the read distance L are finally obtained, and the deviation is corrected. To the reading center in use.

  According to such an embodiment, when the code scanner 1 is assembled, the deviation amount between the center of the field of view of the area sensor 9 and the reading center indicated by the marker light M is measured and stored, and when reading the code, Since the position where the deviation amount stored in advance is corrected is used as the reading center in use, the reading range indicated by the marker light M is different from the conventional example in which the code is read with reference to the center of the field of view of the area sensor. The positioned one-dimensional code can be reliably read, and the two-dimensional code positioned at the reading center indicated by the marker light M can be reliably read.

In addition, the amount of deviation is fixed to a representative value according to the size of the reading depth, or an arithmetic expression indicating the relationship between the reading distance and the amount of deviation is obtained, so a method suitable for the size of the reading depth The amount of deviation can be corrected with.
It is conceivable that the reading center is obtained from the position of the marker light just before reading the code, and the one-dimensional code located in the reading range is read at the time of reading the code, or the two-dimensional code located at the reading center is read. However, in such a method, unlike the reading target serving as a reference for correcting the deviation, the marker light may not be read depending on the surface state of the reading target, which is difficult to implement.

(Other embodiments)
The present invention is not limited to the above embodiment, and can be modified or expanded as follows.
The marker light may be irradiated so as to indicate the center of the visual field of the area sensor 9 or may be irradiated so as to indicate the corner of the reading visual field.
For example, the optical information reader according to the present invention is not limited to a so-called handy terminal, but is a handy type connected to a host computer, that is, a type in which only data is read and data processing is performed on the host computer side. For example, the present invention may be applied to a QR code reading-only device. Further, the marker light irradiation means is not limited to the LED, and a laser or the like can be used, and various modifications can be considered as the configuration of the reading mechanism (optical system). It can be implemented.

The block diagram which shows the electric constitution of the code scanner in one embodiment of this invention Top view of the code scanner shown in the marker light projection state Code scanner vertical section Figure showing the reading field of view of the area sensor The figure which shows the shift | offset | difference of the visual field center of an area sensor, and the reading center which marker light shows Diagram showing the relationship between reading distance and deviation The figure which shows the relationship between the space | interval of marker light, and reading distance The figure which shows the shift | offset | difference at the time of reading the one-dimensional code in a prior art example The figure which shows the shift | offset | difference at the time of reading the two-dimensional code in a prior art example

Explanation of symbols

Reference numeral 1 denotes a code scanner (optical information reading device), 4 denotes a control device (measurement means, correction means), 9 denotes an area sensor (two-dimensional reading means), and 13 denotes a marker LED (marker light irradiation means).

Claims (3)

An optical system comprising: a two-dimensional reading unit that optically reads a one-dimensional or two-dimensional code recorded on a reading target; and a marker light irradiation unit that irradiates a marker light for indicating a reading center with respect to the reading target. In the formula information reader,
Measuring means for measuring the amount of deviation between the center of the visual field of the reading means and the reading center indicated by the marker light emitted from the marker light irradiation means;
Correction means for setting a reading center for use at a position displaced from the center of the visual field of the reading means by the amount of deviation measured by the measuring means ;
The measuring means operates in a state in which a plane is positioned at a representative reading distance within a reading depth, and a marker irradiated from the marker light irradiation means to the plane center of the reading means with respect to the plane and the plane. An optical information reading apparatus for measuring a deviation amount by actually measuring a reading center indicated by light . An optical system comprising: a two-dimensional reading unit that optically reads a one-dimensional or two-dimensional code recorded on a reading target; and a marker light irradiation unit that irradiates a marker light for indicating a reading center with respect to the reading target. In the formula information reader,
Measuring means for measuring the amount of deviation between the center of the visual field of the reading means and the reading center indicated by the marker light emitted from the marker light irradiation means;
Correction means for setting a reading center for use at a position displaced from the center of the visual field of the reading means by the amount of deviation measured by the measuring means;
The measuring means operates in a state in which a plane is positioned at at least two reading distances within a reading depth, and a marker irradiated from the marker light irradiation means to the plane center of the reading means with respect to the plane and the plane. Measure the reading center indicated by the light, and obtain a calculation formula for obtaining the deviation amount according to the reading distance based on the measured data,
The optical information reading apparatus characterized in that the correction means calculates a reading center in use at an actual usage distance based on a calculation formula by the measurement means . 2. The code according to claim 1 , wherein when the reading unit determines that there are a plurality of codes in the reading field, the code closest to the reading center in use is set as the highest priority code or the only reading target code. 3. The optical information reader according to 2.

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