Rectangular seal positioning method and device aiming at certificate image

A positioning method and positioning device technology, applied in the field of image recognition, can solve the problems of easy destruction of rectangular shape features, non-linear misdetection, and small number of votes on short sides, etc., achieve simple edge extraction and reduce the probability of false detection , Improve the effect of detection accuracy

Active Publication Date: 2012-12-26
京北方信息技术股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the application of seal detection, the length of the rectangular edge segment itself has certain limitations. The method of voting separately and connecting straight lines in multiple sub-images will cause the rectangular edge to be missed, and the rectangle cannot be detected.
[0012] In addition, in the seal image, the rectangular shape feature is easily destroyed
For example, due to the smearing of the stamp, the abrasion of the stamp itself, etc., the rectangle in the image will have

Method used

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  • Rectangular seal positioning method and device aiming at certificate image
  • Rectangular seal positioning method and device aiming at certificate image
  • Rectangular seal positioning method and device aiming at certificate image

Examples

Experimental program
Comparison scheme
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Example Embodiment

[0063] Example one

[0064] This embodiment provides a rectangle detection method for seal images, figure 1 The flowchart of the rectangle detection method for the seal image described in this embodiment is as follows: figure 1 As shown, the rectangle detection method for seal images provided in this implementation mainly includes the following steps:

[0065] S101, sequentially determining whether the color of each pixel in the original image is the color of the designated seal, and generating a binary image of the original image;

[0066] First, extract the specified seal color, such as red, define a ForegroundImage(i,j) equal in size to the original image, traverse the original image, take the RGB values ​​r, g, b of the current pixel, and find the average:

[0067] avrval = ( r + g + b ) 3

[0068] Calculate the color variance value of this pixel:

[0069] varval = ( r - avrval ) 2 + ( g - avrval ) 2 + ( b ...

Example Embodiment

[0119] Example two

[0120] This embodiment provides a rectangle detection device for seal images, image 3 It is the structural block diagram of the rectangle detection device for seal images in this embodiment, see image 3 , The rectangular detection device for seal images provided in this implementation includes:

[0121] Binary image generation module 301, which sequentially determines whether the color of each pixel in the original image is the color of the designated seal, and generates a binary image of the original image;

[0122] The judging whether the color of each pixel in the original image is the color of the designated seal includes: taking the RGB value of the current pixel, calculating the color variance value, judging whether the variance value is less than a preset variance threshold, and if so, judging The pixel point is a background point, otherwise it is determined whether the chromaticity value of the pixel point is within a preset chromaticity range, if it is...

Example Embodiment

[0129] Example three

[0130] This embodiment provides a rectangular seal positioning method for voucher images, Figure 4 It is the flowchart of the rectangular seal positioning method for the voucher image in this embodiment, such as Figure 4 As shown, the positioning method of the rectangular seal for the voucher image provided by this implementation is as follows:

[0131] S401, sequentially determining whether the color of each pixel in the original image is the color of the designated seal, and generating a binary image of the original image;

[0132] This step is the same as step S101 described in the first embodiment, and will not be repeated here.

[0133] S402: Generate an edge binary image EdgeImage(i, j) according to the binary image;

[0134] This step is the same as step S102 described in the first embodiment, and will not be repeated here.

[0135] S403. Set a square window with a side length of M, the initial position of the window is the upper left corner of the edge im...

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Abstract

The invention discloses a rectangular seal positioning method and a device aiming at a certificate image. The method comprises the following steps of: S1, sequentially judging whether a color of each pixel in an original image is the color of a specified seal, and generating a binary image of original image; S2, generating an edge binary image based on the binary image; S3, setting a window, judging whether a total amount of a foreground ponit in the window in the edge binary image is less than a preset noise threshold, if so, moving the window to rejudge in the edge binary image, if not, calculating a center of gravity of the foreground ponit, and determining whether the centre of gravity is within a preset area, if so, determining that positioning is carried out successfully, and recording the edge binary image in the window, if not, moving the window in the edge binary image and rejudgeing. According to the method and device, some characteristics of a seal image are considered, a foreground image with a specified color is extracted, and the window is set to slid to intercept a rectangle to initially judge a position of the rectangle in the whole image, so that rectangle detection aiming at the seal image in a later period can be carried out within a small scope, and probability of false detection and a calculated amount are reduced.

Description

technical field [0001] The present invention relates to the technical field of image recognition, in particular to a rectangular seal positioning method and device for voucher images. Background technique [0002] There will be stamps of various shapes and sizes in the voucher image. In the processing of the voucher image, it is necessary to use various shape detection methods to detect whether there is a stamp of a specified shape in the voucher image. In addition, while detecting, it needs to be distinguished from seals of other shapes. Among them, the rectangular seal is difficult to detect because of the uncertain rotation angle when stamping. [0003] Since a rectangle cannot be expressed by a single analytical formula like a circle, in the current general shape detection method, the detection of a rectangle must first be detected by a straight line. Generally, rectangle detection can be summarized as the following steps: [0004] First, extract the edge map. Edge d...

Claims

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Application Information

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IPC IPC(8): G06K9/32
Inventor 代克非高昊江刘冠强
Owner 京北方信息技术股份有限公司
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