JPH0721300A - Bar-code reader - Google Patents

Abstract

PURPOSE: To provide a bar code reader with which a bar code added onto any face of merchandise moving on a carrier path is automatically read by one image pickup device. CONSTITUTION: This device is provided with plural reflection mirrors 5 for guiding images from the various directions of merchandise 3 to an image pickup device 2 and an image switching means provided with a shutter system 6 for successively inputting the images from the respective reflection mirrors to the image pickup device 2 frame by frame. After a bar code detecting means 16 detects the position and direction of the bar code from the image data received at the image pickup device 2, bar code data are extracted from source image data based on these position data, and the bar code is decoded from the extracted data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bar code reader using an image pickup device. In particular, the present invention relates to a bar code reading device that automatically reads a bar code from a product moving on a transport path.

[0002]

2. Description of the Related Art A bar code reader using an image sensor is disclosed in Japanese Patent Application Nos. 48-92573 and 5-5.
Many inventions are disclosed in Japanese Patent Publication No. 1-97235. However, in these inventions, the barcode cannot be read unless the surface with the barcode passes through the front of the image pickup apparatus. Therefore, when the product is placed on the transport path, the product must be arranged so that the surface with the barcode faces the imaging device.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a bar code which can be read by a single image pickup device regardless of whether the bar code is attached to the front, rear, left, right or top surface of an article such as a product. An object is to provide a code reading device. Further, according to the present invention, the position where the barcode is attached and the orientation of the barcode are detected by the imaging device,
An object of the present invention is to provide a bar code reading apparatus with improved reading accuracy by limiting the scanning range of a single beam scanner based on the detection data.

[0004]

According to the present invention, a bar code reading device for reading a bar code attached to a surface of an article moving along a conveying path is provided with an image pickup device provided adjacent to the conveying path. A light source, a plurality of reflecting mirrors for guiding the image of each surface of the moving article onto the image pickup device, and an image of an object from each of the reflecting mirrors in order of 1
From the image switching means for projecting the image on the image pickup device one by one, the detecting means for detecting the barcode from each image information output from the image pickup device, and the decoding means for decoding the detected barcode. The above object was achieved by the configuration.

Further, a bar code reading device for reading a bar code attached to the surface of an article moving along the conveying path, an image pickup device provided adjacent to the conveying path, a light source, and the moving article. A plurality of reflecting mirrors for guiding the image of each surface of the image pickup device onto the image pickup device, image switching means for projecting one image of the object from each of the reflecting mirrors in sequence onto the image pickup device, and the image pickup device. Bar code detecting means comprising a detecting means for detecting the position and direction of the bar code from each image information output from the device,
In order to read the barcode attached to the object, a plurality of barcode scanners provided at a position rearward of the barcode detecting means of the conveying path, and the position of the barcode detected by the barcode detecting means. And a reading control device that controls the bar code scanner corresponding to the bar code position based on the data regarding the direction and the direction so as to read the bar code at an optimum timing, thereby improving the reading accuracy. Was achieved.

[0006]

According to the present invention, the plurality of reflecting mirrors and the image data from the reflecting mirrors are sequentially switched and projected on the image pickup device to prevent the images on the respective surfaces of the article from overlapping with each other. Even the barcode attached to the surface can be read.

In addition, the image pickup device detects the bar code position and direction in advance and aims at that position to set the laser beam.
Since the beam can be scanned, the reading accuracy can be improved.

[0008]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual diagram showing a first embodiment of the bar code reading apparatus of the present invention. In FIG. 1, 2 is an image pickup device, and 3
Is an article such as a product having a barcode on its surface. Four
Is a conveyance path for conveying the article 3 by a belt conveyor, and
Is a plurality of reflecting mirrors for guiding the image from each direction of the article 3 passing on the transport path 4 to the image pickup device 2. Reference numeral 6 denotes a shutter device for projecting an image of the article from each reflecting mirror 5 on the image pickup device for each image. Reference numeral 7 is a sensor for detecting the article 3 on the conveyance path, and 8 is a flash light source for irradiating the article with light.

The operation will be described. The article 3 is the transport path 4
When moving up, the article 3 is detected by the sensor 7 and the article detecting means 10. The detection signal from the article detection means 10 is transmitted to the synchronization means 12. By receiving the detection signal, the synchronization means 12 calculates the optimum position for reading the bar code attached to the article, and when the article reaches that position, drives the light source driver 14 to activate the flash light source 8. Let At the same time, the synchronizing means 12 also sends a synchronizing signal to the image switching means 9 and the bar code detection processing means 16 to synchronize these operations. The image information input to the image pickup apparatus 2 is image-processed by the barcode detection processing means 16 to detect a barcode from the image information,
Further extract it. The extracted barcode data is sent to the decoding means 18 and the barcode is read. In this embodiment, three kinds of reflecting mirrors are provided.
In order to input and read the images from the respective reflecting mirrors into the image pickup device, at least three flash emission and bar code reading operations are required.

Next, the reflecting mirror 5, the shutter means 6 and the image switching means 9 will be described in detail with reference to the drawings. First, the shutter means 6 will be described with reference to FIG. Figure 2
FIG. 3 is a side view showing the configuration of shutter means 6. The shutter means 6 has a hollow spherical outer shell 20 and a hollow inner shell 22, and the inner shell 22 is rotated in the arrow direction inside the outer shell by a rotation driving means (not shown). The outer shell 20 is provided with three openings 24a to 24c toward the respective reflecting mirrors 5. The inner shell 22 is also provided with one opening 26 having the same shape as the outer shell opening 24 at a position substantially the same height as the outer shell 20. Inside the hollow inner shell 22, an internal reflecting mirror 28 or a prism is provided at a position substantially in the center of the hollow inner shell 22, and is rotating together with the inner shell 22. This inner reflecting mirror 28 has a structure in which the opening 24 of the outer shell 20 is rotated by rotating the inner shell 22.
Only when the positions of the opening 26 of the inner shell coincide with each other, the image from the outer reflecting mirror 5 is projected. Therefore, the images from the external reflecting mirrors 5 are sequentially switched by the rotary shutter means 6 and projected on the internal reflecting mirrors. When such a rotary shutter means is used, a coincidence pulse is generated each time the positions of the outer shell opening 24 and the inner shell opening 26 are coincident with each other, and the coincident pulse is transmitted to the synchronizing means 12 to flash the light source and detect the bar code. Need to be synchronized with. In addition,
In the present embodiment, the example in which the spherical inner shell 22 is rotated as the shutter means 6 has been shown, but it is also possible to make the shape cylindrical and change the number of apertures, that is, the number of shooting locations and the number of times of shooting as necessary. is there. Also, a normal shutter and its control means such as those used in a camera may be used.

The image projected on the internal reflecting mirror 28 is further reflected and projected on the image pickup device 32 of the image pickup device 30 provided on the upper portion thereof. The image information on the image pickup device is converted into an image signal composed of an electric signal by the image pickup device and transmitted to the barcode detection processing device 16 as image data.

Before describing the bar code detection processing operation, the image of the article 3 reflected and projected by the reflecting mirrors 5A to 5C and its limit will be described with reference to FIGS. 1, 3, 4 and 5. To do. FIG. 3 is a perspective view showing each side of the article. Since the reflecting mirror 5A is attached to the upper right portion of the transport path 4 at an angle that slightly reflects the upstream direction, as shown in FIG.
The images of the article 3 projected by the reflecting mirror 5A are the top surface a, the right side surface b, and the front surface d of the article. Similarly, reflector 5B
Are provided in the upper left portion, and therefore are the upper surface a, the left side surface c, and the front surface d. On the other hand, since the reflecting mirror 5C is attached to the upper center of the transport path 2 so as to project the downstream direction, the upper surface a and the rear surface e of the article 3 are projected. As can be seen, all the reflecting mirrors 5 are attached to the upper surface a of the article.
The images are captured at A to 5C, and two images can be detected on the front surface d.

FIG. 4 is a view showing an image pickup range by the reflecting mirrors 5A and 5B provided on both side surfaces of the upper portion of the transport path.
Indicates an imageable range of the reflecting mirror 5C. In both FIGS. 4 and 5, (A) is a view seen from the direction of arrow A in FIG. 1, and shows the readable range in the lateral and height directions of the transport path 4. (B) is a view as seen from the direction of arrow B in FIG. 1, and shows the imaging limit in the traveling direction and the height direction of the transport path.
If the article 3 enters the range, the image of the article 3 can be captured, and the barcode attached to any surface can be read. These imaging limits are basically determined by the focal length of the lens system used in the imaging device and others and the position / angle of the reflecting mirror.

Next, the barcode detection and extraction processing by the barcode detection processing means 16 will be described with reference to FIG. FIG. 6 is a diagram showing a processing procedure of the barcode detection processing means 16 and an outline of image data for each processing.
The image data transmitted from the image pickup apparatus 2 is first divided into barcode detection data and decoding data, and preprocessing is performed according to each purpose (S1). This kind of pre-processing is performed to remove the information (bar code in this case) that the image has, because the image data generally contains various types of noise and distortion. is there. These include contrast enhancement, noise removal, geometric distortion correction, and the like. In particular, in the present invention,
Since the purpose of the barcode is to detect and read an image with clear contrast, it is effective to enhance the contrast. The barcode detection data is further processed to extract the contour of the image (S2). To extract the edge of an image, the first derivative (gradient) or second derivative of the image data is used.
(Laplacian) processing is performed. As a result, only the contour of the object or the contour of the pattern such as the barcode is extracted from the image. Next, labeling is performed on the contour line (connected component) (S
3). In this process, pixels in which pixels representing the contours of image data are connected to each other (connected components) are set as one set (contour line), and a different label is given to each set (contour line).

Next, in view of the purpose of detecting the bar code, only those with high linearity are selected from these connected components and are subjected to the subsequent processing. That is, the contour of a circular object or the contour of a rounded character is removed in the subsequent processing. After that, the individual connected components of the linear contour line are compared with the connected components around it by pattern matching or the like to calculate the degree of correlation (similarity) of each contour line (S4). Briefly, two components are superposed, and the higher the degree of overlap, the higher the degree of correlation. There are not many contours of objects with the same shape in the periphery, but in a group of parallel striped lines such as a barcode, for one connected component that is one bar,
Since many similar objects exist at substantially parallel positions, the respective correlation (similarity) coefficients have high values. It is determined that the area of the collection of labels in which those having a high degree of correlation are concentrated is the area of the barcode. In this case, since the vertical direction is the arrangement of the barcodes with respect to the parallel direction of the set of contours, the position and orientation of the barcode can be determined as the coordinates on the image (S5). When the coordinates of the bar code are known, the data of the bar code portion is extracted from the decoding data preprocessed previously based on this coordinate data (S6). By decoding the one-dimensional data string of pixels in the direction across the extracted barcode,
The barcode can be decoded. Therefore, the barcode can be read by transmitting the one-dimensional data string of the barcode to the decoding means 18. These decodings are well known in the art and will not be described further.

Next, a second embodiment of the present invention will be described. FIG. 7 shows an external view of the second embodiment of the present invention. Second
Also in this embodiment, the image recognition processing using the same image pickup apparatus as in the first embodiment is performed. The difference is that the bar code is not read from the image data, only the position and orientation of the bar code is detected, and that data is transmitted to the bar code reader located downstream of the conveyance path. The point to read. An expensive high-performance image pickup device with a large number of pixels is required for reading with an image pickup device. However, this has the advantage that an image pickup device with a smaller number of pixels can be used compared to reading a barcode. Have. Further, since the position where the bar code exists can be intensively scanned, the reading accuracy can be greatly improved as compared with scanning the entire surface of the article without detecting the position of the bar code and the like.

In the second embodiment, the scanners 42A ...
The 42C preferably uses a single beam scanner, and each scanner is configured to change its beam irradiation angle in order to aim at a bar code. FIG. 8 illustrates the irradiation possible angles of the scanners 42A to 42C. The barcode position and orientation detected by the barcode detection processing means 16 are output to the scanner control means 40. The scanner control means 40 selects the most suitable scanner for reading from the plurality of barcode scanners 42A to 42C according to the surface to which the barcode is attached and the position thereof, and directs the scanner to the barcode. When the barcode moves to the optimum reading position, scanning for reading is started. The data obtained by the barcode scanning is decoded by a decoding means (not shown).

[0018]

According to the present invention, the bar code can be read regardless of whether the bar code is attached to the front, rear, left, right, or upper surface of the product, so that the position of the bar code when the products are lined up in the conveying path. There is no need to check. Therefore, the products can be arranged on the conveying path at a high speed, and the processing capacity per reading device is improved.
Further, according to the device for reading a barcode with the single beam scanner after confirming the barcode position of the present invention, the position and direction of the barcode can be determined without increasing the resolution of the image pickup device. Further, if the position and direction of the bar code are known, a single beam scanner with a deep reading depth can be aimed and read, so that the reading accuracy can be improved.

[Brief description of drawings]

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

FIG. 2 is a side view showing a configuration of a shutter device used in the barcode reading device of the present invention.

FIG. 3 is a perspective view showing each side of an article 3 to which a barcode is attached.

FIG. 4 is a diagram showing an imageable range of reflecting mirrors 5A and 5B.

FIG. 5 is a diagram showing an imageable range of a reflecting mirror 5C.

FIG. 6 is a diagram showing a processing procedure of the barcode detection processing means 16 and image data for each processing.

FIG. 7 is a block diagram showing an external appearance and a partial configuration of a bar code reading apparatus according to a second embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a reading range of a barcode by the upper scanner.

[Explanation of symbols]

 2 image pickup device 4 conveying path 5 reflecting mirror 6 shutter device 8 light source 9 image switching means 16 bar code detection processing means 18 decoding means 42 bar code scanner

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takayuki Hatanaka 1-10-1 Korai, Oiso-cho, Naka-gun, Kanagawa Japan NRC R Co., Ltd. Oiso Kai Development Headquarters (72) Inventor Takao Kumazawa Kanagawa 1-10-1 Korai, Oiso-machi, Naka-gun Japan NRC R Co., Ltd. Oiso Development Manufacturing Headquarters

Claims (2)

[Claims] 1. A bar code reading device for reading a bar code attached to a surface of an article moving along a transport passage, comprising: an image pickup device (2) provided adjacent to the transport passage (4); (8), a plurality of reflecting mirrors (5A ~ 5C) for guiding the image of each surface of the moving article (3) on the imaging device (2), from the reflecting mirrors (5A ~ 5C) Image of object (3)
Image switching means (6, 9) for projecting on the image pickup device (2) one by one, and detection means (16) for detecting the bar code from each image information output from the image pickup device (2). And a decoding means (1
8) A barcode reader consisting of and. 2. A bar code reading device for reading a bar code attached to the surface of an object moving along a transportation path, comprising: an imaging device (2) provided adjacent to the transportation path (4);
A light source (8), a plurality of reflecting mirrors (5A to 5C) for guiding the images of the surfaces of the moving object onto the image pickup device, and the reflecting mirrors.
Image switching means (6, 9) for projecting an image of an object from (5A to 5C) one by one onto the image pickup device (2) in sequence, and image information output from the image pickup device (2) Bar code position detecting means consisting of a detecting means (16) for detecting the position and direction of the bar code from among, and for reading the bar code attached to the object, the bar code of the conveying path (4) A plurality of barcode scanners (42A to 42C) provided at a position rearward of the detection means (2), and based on the data regarding the position and direction of the barcode detected by the barcode position detection means, the barcode position And a bar code reader (40) for designating the bar code scanners (42A to 42C) corresponding to, and controlling to read the bar code at an optimum timing.