JPH06274675A - Bar code symbol reader - Google Patents

Abstract

PURPOSE:To provide the low-priced bar code symbol reader which can eliminate the shake of a bar code. CONSTITUTION:A controller 20 calculates the moving speed of a moving object 14, to which a label 10 writing the bar code symbol is stuck, while moving on a conveyer belt 12 from the time taken for passage between two photointerrupters 16 and 18 and also from a distance between both of photointerrupters 16 and 18. Then, a read sensor 22 is turned or parallelly moved in the previously recognized moving direction of the object 14 at the calculated moving speed. A decoder part 26 decodes the output of the read sensor 22 just during this turn or parallel move.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bar code symbol reading device for reading a bar code symbol, and more particularly to a method for reading a bar code symbol attached to a moving object or a bar code symbol subject to camera shake. It is a thing.

[0002]

2. Description of the Related Art Conventionally, various bar code symbols are
It is widely used to manage goods and luggage. For example, IT
Many companies use the F code as their own symbol for physical distribution, including the standard physical distribution symbol. As a way of using for logistics, for example, a label having a bar code symbol indicating a destination district number is attached to a package and the bar code symbol is read to enable sorting. Also, in stores, JAN codes are used and products are sold and inventory is managed by a POS (Point of Sales) system.

As a method of reading such a bar code symbol, an image of a bar code is read by an image pickup device such as a CCD, and it is judged whether each point of the image is a bar or a space from the brightness information of the image, and the bar code is read. There is one that decodes the information written in the code symbol. Alternatively, there is also a method in which a laser beam is scanned over a bar code symbol, the reflected light is detected, it is determined whether the reflected portion is a bar or a space, and the information written on the bar code symbol is decoded.

However, when the package is collected and delivered, the package is often moved by a conveyor belt or the like. When reading a label attached to a moving baggage in this way, the distance the label moves within the reading time becomes a blur amount, which causes a reading error. Further, even when the operator places the label on the front surface of the scanner and reads it, the camera shake of the operator causes the scanner or the label to shake, which causes a reading error.

As a method for solving such a problem, for example, a method of reading using a flash as shown in the side view and the top view of FIGS. 8A and 8B is known. In these drawings, the reading sensor 100 can read the image of the label 102 on which the bar code symbol is written, and can be configured by an image pickup unit such as a CCD and an optical system. The label 102 is attached to the moving object 106 by, for example, the conveyor belt 104. When the object 106 crosses the detection beam of the photo interrupter 108, the control device 110 detects that the object 106 has come under the reading sensor 100, that is, the label 102 has entered the imaging area 112 of the reading sensor 100. , Flash 114 is emitted. Read sensor 1
Since the exposure sensitivity of 00 is lowered by, for example, narrowing the diaphragm, only the image within the time when the flash 114 is emitting light is read by the reading sensor 100. Here, if the flash 114 has a light emission time of 0.1 ms, the blur amount is set to 50
If it is necessary to keep it within μm, an object moving speed of 0.5 m / s or less is allowed. By doing so, the image can be read by the reading sensor 100 without blurring. The read image is decoded by the decoder unit 116, and the information is read.

As another conventional method, a method of reading using a shutter as shown in FIG. 8C is known. The difference from the conventional example of (A) and (B) of the figure is that instead of the flash 114, the lighting device 11 that is always lit
8 and the shutter 120 are used. That is, the label 102 is affixed to the moving object 106 by the conveyor belt 104 or the like as in the conventional example. When the object 106 crosses the detection beam of the photo interrupter 108, the controller 110 causes the object 102 to read the sensor 1
The shutter 120 is opened and closed for a moment when it senses that it is under 00. Only the image within the time when the shutter 120 is open is read by the reading sensor 100. If the shutter 120 is open for 0.1 ms and the blurring amount needs to be kept within 50 μm as in the case of the conventional example, an object moving speed of 0.5 m / s or less is required. forgiven. The shutter 120 can be realized by either a mechanical shutter or an electronic shutter. The image thus read is decoded by the decoder unit 116, and the information is read.

[0007]

However, in the former method of capturing a momentary image of a moving bar code symbol using the flash 114, a flash having a large amount of light emission and a short lighting time is required. Since such a flash emits light by using a high voltage, it is necessary to charge the voltage, and continuous light emission is difficult. Further, even if the lamp can emit light continuously, the lamp that emits light has a life and needs maintenance.

Further, in the latter method of capturing an image using the shutter 120, an illumination having a short lighting time is not required, but a shutter having a high shutter speed is required. By adding such a shutter function with a high shutter speed to a camera having the reading sensor 100 and the shutter 120, the price of the camera increases. Also,
Since the exposure time is shortened as the shutter speed is increased, the illumination light source 118 that emits as much light as the flash 114 described above is required.

The present invention has been made in view of the above points, and provides a bar code symbol reading apparatus which can use an inexpensive camera without using a flash or a shutter and can eliminate the influence of a blur of a bar code symbol. With the goal.

[0010]

In order to achieve the above object, a bar code symbol reader according to the present invention images a moving bar code symbol or a medium with a bar code symbol at a predetermined position. And a sensor for moving the read sensor means in the same direction and speed as the moving speed and direction based on the previously known or detected moving speed and direction of the barcode symbol or the medium. It is characterized by comprising a moving means and a reading control means for causing the reading sensor means to take an image of the bar code symbol or the medium during the movement by the moving means.

[0011]

That is, according to the bar code symbol reading apparatus of the present invention, the sensor moving means includes the moving speed and direction of the moving bar code symbol or the medium to which the bar code symbol is attached, which is known or detected in advance. Based on the above, the reading sensor means for imaging the barcode symbol or the medium at a predetermined position is moved in the same direction and speed as those moving speeds and directions. Then, the reading control means
The reading sensor means is caused to capture an image of the bar code symbol or medium during movement by the moving means. In other words, the camera is also moved so that the image blur does not occur even if the barcode symbol moves within the exposure time.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS. 1A and 1B are a side view and a top view of a bar code symbol reading apparatus according to a first embodiment of the present invention.

Label 10 on which a bar code symbol is written
Is an object 14 moving by the conveyor belt 12.
Affixed to. In this reading apparatus, two sets of photo interrupters, a photo interrupter "A" 16 and a photo interrupter "B" 18, are arranged. That is, the distance between these two sets of photo interrupters 16 and 18 is divided by the time from when the object 14 crosses the first photo interrupter "A" 16 to when it crosses the next photo interrupter "B" 18, The moving speed of is obtained. These calculations are performed in the control device 20. Then, as soon as the moving speed of the object 14 is known, the control device 20 causes the reading sensor 22 to move in the direction of the arrow 24 in the drawing by a moving mechanism (not shown).
Rotate to. That is, the reading sensor 22 is controlled by the controller 20 so that the moving object 14 can always be caught at the same position on the sensor at the moving speed of the object measured using the two sets of photo interrupters 16 and 18. Move. Here, instead of rotating the reading sensor 22, as shown in FIG. 1C, the reading sensor 22 may move in parallel with the moving direction of the moving object 14. By doing this,
An image without blur can be read by the reading sensor 22. The read image is decoded by the decoder unit 26 and the information is read. The barcode symbol reading device having such a configuration operates as shown in the flowchart of FIG.

That is, when the photo interrupter "A" 16 detects the moving object 14 to which the label 10 is attached (step S11), the control unit 20 starts an internal timer (not shown) (step S12), and thereafter. When the photo interrupter "B" 18 detects the moving object 14 (step S13), the timer is stopped (step S14). That is, the time from when the object 14 crosses the first photo interrupter "A" 16 to when it crosses the next photo interrupter "B" 18 is measured.

Next, the moving speed A of the object 14 is calculated by dividing the previously known distance between the two sets of photo interrupters 16 and 18 by the time counted by this timer (step S15). Then, the moving speed (rotation or parallel movement) of the reading sensor 22 is set so that the moving speed of the imaging area 28 of the reading sensor 22 becomes the moving speed A calculated above (step S16), and this is set by a moving mechanism (not shown). The reading sensor 22 is moved at the moving speed (step S17), and the label 10 is imaged (step S1).
8).

The image pickup data from the reading sensor 22 is transferred to the decoder unit 26 (step S19), is decoded (step S20), and the decoding result is output to a host device (not shown) or the like (step S21). Then, when another barcode symbol is continuously read (step S22), the process returns to step S11 to repeat the above process.

When the imaging optical system is arranged in front of the reading sensor 22 and a camera integrated with the sensor is used, when the reading sensor 22 is rotated as in this method, the distance between the sensor and the object 14 is reduced. Change. If this change in distance poses a problem, it is necessary to use a method such as autofocus or autozoom.

To measure the moving speed of the object 14, a roller 30 as shown in FIG. 3A is pressed against the conveyor belt 12 instead of the two sets of photo interrupters 16 and 18 as described above. The moving speed of the belt 12 may be detected by rotating the belt 12 and measuring the number of rotations. At this time, one photo interrupter is used and the reading sensor 22
Is used as a trigger for the start of moving.

Further, instead of rotating the reading sensor 22,
When moving in a direction parallel to the conveyor belt 12 as shown in FIG. 1C, it is not necessary to use a technique such as autofocus or autozoom.

Further, if the moving speed of the conveyor belt 12 is constant, it is not necessary to measure the moving speed of the belt 12 as described above, and one photo interrupter is used as a trigger for moving the reading sensor 22, Reading sensor 22
May be rotated or moved in parallel at a constant speed.

Further, although the photo interrupters 16 and 18 are used for detecting the moving object 14, the present invention is not limited to this, and for example, a micro switch or the like is arranged to detect the object when the object 14 comes into contact therewith. You may do it. (Second Embodiment) FIG. 3B is a side view of a second embodiment of the present invention in which neither a flash, a shutter nor a photo interrupter is used.

The label 10 is attached to the moving object 14 by the conveyor belt 12 or the like as in the first embodiment. In the present embodiment, the reading sensor 22 is arranged diagonally above in the moving direction of the moving object 14. This position does not have to be diagonally upper, but may be diagonally left and right, and in short, it may be any relationship as long as the object 14 does not collide with the reading sensor 22 even if it goes straight ahead.

Here, if the depth of field of the reading sensor 22 is made shallow, the image of the label 10 is formed for an instant.
Therefore, the movement of the object 14 is not affected by the imaging, and a label image without blur is sent to the decoder unit 26 and decoded,
The information is read.

As shown in FIG. 3C, if the conveyor belt 12 is bent to change the traveling direction of the moving object 14, the reading sensor 28 is arranged in front of the moving direction of the moving object 14. be able to.

Even with this configuration, when the reading sensor 22 is read with a shallow depth of field, the image is formed in the label 10 for a moment, as in the case of the configuration shown in FIG. The movement of the object 14 is not affected by the imaging, and it is possible to obtain a label image without blurring. Moreover, the inclination of the label 10 with respect to the optical axis is smaller than that in the configuration of FIG.
A high-quality label image can be captured. Figure 4
4 is a flowchart for explaining the operation in the configuration of (B) or (C) of FIG. That is, the reading sensor 22 captures an image (step S31) and transfers the captured image data to the decoder unit 26 (step S32).

The decoder unit 26 judges from the image pickup data transferred from the reading sensor 22 whether or not a part or the whole of the picked-up image can be recognized as a bar code symbol (step S33), and the bar code symbol is recognized. If not, the process returns to step S31.

If it can be recognized as a bar code symbol, decoding is performed (step S34), and the decoding result is output to a host device (not shown) or the like (step S35). Then, when another bar code symbol is continuously read (step S36), the process returns to step S31 and the above process is repeated.

According to such a method, when the speed of the conveyor belt 12 is high, not only the image at the time of focusing but also the image at the time of defocus is captured. However, the image at the time of defocus is a low-pass filtered image at the time of focusing, and although there is some deterioration of the image due to the overlapping of the defocus images, it is possible to perform the decoding process.

Although the first and second embodiments have described the case where the object 14 is moved by the conveyor belt 12, it goes without saying that an object that moves by another method, or
The above method can be applied to a blurred object or the like.
For example, as shown in FIG.
You may move. Further, the object 14 described above can be replaced with any object such as a box such as a cardboard box, a card and a sheet. (Third Embodiment) FIG. 6 is a side view of a third embodiment of the present invention in the case of an apparatus in which the label 10 is placed on the front surface of the reading sensor (scanner) 22 and read by the operator.

In this embodiment, the pyroelectric sensor 34 is used. That is, the pyroelectric sensor 34 is a kind of infrared sensor capable of detecting a weak infrared ray emitted by a person, and the pyroelectric sensor 34 allows the pyroelectric sensor 34 to be located below the reading sensor 22, that is, within the sensing area 36 of the pyroelectric sensor 34. Detect if there is a hand.

With such a configuration, while the operator is inserting the label 10 under the reading sensor 22, the hand does not read the image of the label 10 and the hand reads the reading sensor 22.
The bar code symbol image can be read only when it is separated from the bottom. The image captured in this way is an image free from camera shake. Then, the barcode symbol image without blurring is sent to the decoder unit 26 and decoded, and the information is read out. FIG. 7 shows an operation flowchart of this embodiment.

That is, when the reading sensor 22 takes an image (step S41), while the pyroelectric sensor 34 detects the hand of the operator (step S42), the reading sensor 22 takes an image on the decoder section 26. Do not transfer data.

When the operator's hand is no longer detected in step S42, the image data is transferred from the reading sensor 22 to the decoder section 26 (step S43). The decoder unit 26 decodes this (step S4
4) The decoding result is output to a host device (not shown) or the like (step S45). Then, when another bar code symbol is continuously read (step S46), the process returns to step S41 and the above process is repeated. Instead of the pyroelectric sensor 34, a photo interrupter may detect the hand of the operator around the imaging area.
Further, it goes without saying that the first to third embodiments can be carried out individually or in combination.

Furthermore, as in the first embodiment, the moving object 14
If it can be determined that the blur amount that occurs when the image is picked up at that speed does not hinder the decoding of the bar code symbol, then the decoding can be performed without performing the processing described above. .

[0035]

As described in detail above, according to the present invention,
It is possible to provide a barcode symbol reading device that can eliminate the influence of the blurring of barcode symbols without using a flash or a shutter.

That is, it is possible to provide a bar code symbol reader capable of reading and decoding a bar code without being affected by the blur even in a situation where the blur occurs.

[Brief description of drawings]

1A and 1B are a side view and a top view of a barcode symbol reading apparatus according to a first embodiment of the present invention, respectively, and FIG. 1C shows a characteristic portion of a modification of the first embodiment. FIG.

FIG. 2 is an operation flowchart of the first embodiment.

FIG. 3A is a diagram showing a characteristic part of still another modification of the first embodiment, FIG. 3B is a side view of a bar code symbol reading apparatus of a second embodiment of the present invention, and FIG. 8] is a side view of a modification of the second embodiment.

FIG. 4 is a flowchart for explaining the operation in the configuration of FIG. 3 (B) or (C).

FIG. 5 is a diagram showing another example of an object moving mechanism applicable to the first and second embodiments.

FIG. 6 is a side view of a barcode symbol reading device according to a third embodiment of the present invention.

FIG. 7 is an operation flowchart of the third embodiment.

8A and 8B are a side view and a top view of a conventional bar code symbol reading device using a flash, and FIG. 8C is a conventional bar code symbol reading device using a shutter. It is a side view.

[Explanation of symbols]

10 ... Label, 12 ... Conveyor belt, 14 ... Moving object, 16, 18 ... Photointerrupter, 20 ... Control device, 22 ... Read sensor, 24 ... Read sensor rotation direction, 2
6 ... Decoder part, 28 ... Imaging area, 30 ... Roller, 3
2 ... Drive roller, 34 ... Pyroelectric sensor, 36 ... Sensing area.

Claims (1)

[Claims] 1. A reading sensor means for imaging a moving bar code symbol or a medium with a bar code symbol at a predetermined position, and a previously known or detected movement of the bar code symbol or medium. Sensor moving means for moving the reading sensor means in the same direction and speed as the moving speed and direction based on the speed and direction; and the bar code symbol or medium for the reading sensor means during the movement by the moving means. A bar code symbol reading device, comprising: