JP2891821B2 - Barcode identification method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a barcode identification method capable of removing unnecessary background and noise from an image of a region including a barcode symbol and identifying and extracting only a necessary barcode symbol. It is about.

[0002]

2. Description of the Related Art Various reading methods have been proposed and developed for reading barcode symbols recorded on barcode labels. For example, a general method of reading the barcode symbol includes a method of sequentially reading and scanning light from a light source in an area where a barcode symbol exists, and a method of reading an area including a barcode symbol. It is known that a part is imaged by a CCD camera (area sensor) or the like, and a barcode symbol part is identified and read from the imaged image.

[0003]

In the former reading method, there is no particular problem in the former method. However, in the latter method, if the captured image contains many backgrounds and noises, A barcode symbol is erroneously recognized, and reading becomes impossible or a reading error occurs, which is a problem. In view of the above-described conventional disadvantages, the present invention provides a barcode recognition method capable of accurately recognizing only a barcode symbol even when there is a background or noise around the barcode symbol. It is intended for.

[0004]

That is, according to the barcode identification method of the present invention, for a continuous black pixel in an image, a thickening process of changing an adjacent white pixel to a black pixel is performed, and the thickened processing is performed. The area of each connected black pixel region in the image is determined, the largest one of these black pixel regions is recognized as a barcode symbol region, and each of the barcode symbol region and the original image in the processed image is A logical product of the pixels is obtained, and a bar code is identified from the obtained black pixels.

[0005]

According to the present invention, the area of each black pixel region obtained by the thickening process is obtained, and the largest of these black pixel regions is recognized as a barcode symbol region including a barcode symbol. Next, the logical product of each corresponding pixel in the bar code symbol area and the original image is obtained, thereby accurately recognizing the shape of the bar code symbol.

[0006]

An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a method of identifying a barcode according to the present invention.
It consists of step 5. In the first step 1,
Using an imaging means such as a CCD camera (area sensor) or the like, the barcode is photographed in a state where the entire barcode symbol 1 is completely included as shown in FIG. And
The thickening process described below is performed on the photographed original image α. This thickening process means, for example, replacing all white pixels with black pixels around each black pixel (for example, point P (10, 11)) in FIG. 4). It should be noted that the pixel to be replaced with the black pixel is not particularly limited to the eight pixels. For example, in FIG.
CEG). In FIG. 2, for the sake of convenience, each ruled line is attached so as to divide a region of two pixels vertically and horizontally, and therefore, it is assumed that there are actually pixels corresponding to four times the mesh.

In a second step 2, a thickening process is performed on all the black pixels in the first step 1, and in the processing image β thus obtained shown in FIG.
Determining the area of ₁ to S ₈ (or the number of black pixels). Note that in FIG. 5 as well, each ruled line is attached to indicate a unit area of two pixels vertically and horizontally for convenience. In the third step 3, out of the black pixel area S ₁ to S ₈ obtained in processing the image β shown in FIG. 5 recognizes the S ₃ the largest area as a bar code symbol region. In a fourth step 4, each pixel in the recognized area as a bar code symbol area S ₃ in the processed image beta, between each pixel in the original image alpha, a logical product in other words the corresponding pixel to each other at the same position Take. For example, a black pixel is set to 1 and a white pixel is set to 0 to perform an operation as shown in the following table. As a result, only the pixel whose logical product is 1 is determined as a black pixel, and this is determined as a pixel indicating a part of the true shape of the barcode symbol.

[0008]

[Table 1]

In a fifth step 5, only the pixel whose logical product obtained in the fourth step 4 is 1 is determined as a black pixel, and the shape given by this is identified as the shape of a barcode symbol.

[0010]

As described above, according to the bar code discrimination method according to the present invention, the area of each black pixel region obtained by the thickening process is obtained, and the largest one of these black pixel regions is obtained. Is recognized as a barcode symbol area including a barcode symbol, a logical AND operation is performed on the pixel at each corresponding position in the barcode symbol area and the original image, and the barcode symbol is determined from only those determined as black pixels. Because it recognizes the shape of, unnecessary background and noise can be removed,
Barcode symbols can be read accurately.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a barcode identification method according to the present invention.

FIG. 2 is an explanatory diagram showing an original image used in the identification method of the present invention.

FIG. 3 is an explanatory diagram showing a thickening method used in the identification method of the present invention.

FIG. 4 is an explanatory diagram showing a thickening method used in the identification method of the present invention.

FIG. 5 is an explanatory diagram showing a processed image after performing a thickening process in the identification method of the present invention.

Claims (1)

(57) [Claims] 1. A thickening process for changing an adjacent white pixel to a black pixel for each pixel in an image is performed, and an area of each connected black pixel region in the thickened processed image is obtained. Recognize the largest area of the area as a barcode symbol area, take the logical product of each pixel for the barcode symbol area in the processed image and the original image, and calculate the barcode symbol area from the obtained black pixels. A method of identifying a barcode, comprising: identifying a barcode.