Method for detecting and adjusting inversion of certificate image

Abstract

The invention discloses a method for detecting and adjusting the inversion of a certificate image, comprising the following steps: (1) acquiring a color certificate image by an image acquisition tool;(2) shrinking the certificate image according to a certain scale factor; (3) converting the RGB color space of the certificate image into HIS color space; (4) converting the HIS image into an binaryimage by utilizing the constraint condition of a human face skin color; (5) carrying out median filtering of the binary image to obtain a binary image only with a human face part; (6) cutting a humanface part image according to the human face part binary image; (7) obtaining a human face edge binary image by an RGB edge extraction method; and (8) utilizing horizontal projection statistics to detect the inversion of a certificate. The method for detecting and adjusting the inversion of the certificate image shrinks the image under the condition of keeping the human face outline information ofthe image constant so as to greatly reduce the pixel participating human face skin color positioning and outline extraction operation, thereby not only enhancing the arithmetic efficiency but also ensuring the high accuracy, robustness and reliability of arithmetic detection.

Description

technical field [0001] The invention relates to a method for detecting and correcting inversion of a document image, in particular to a method for determining whether an image is inversion by utilizing the skin color of a person's face and combining projection statistics. Background technique [0002] Obtaining relevant information from documents has increasingly appeared in many fields of social and people's livelihood. With the maturity of computer technology, image processing and optical character recognition algorithms, it has become possible to use computers to automatically identify and enter document information. The emergence of this means of obtaining information will greatly improve the efficiency of both sides of the business. The document information collection system based on computer OCR can be widely used in public security, banking, telecommunications, postal services, railways, civil aviation, securities, civil affairs, entry-exit, army, Internet cafes and h...

AI Technical Summary

Problems solved by technology

[0003] The document information acquisition system can be divided into five main steps: image acquisition, image preprocessing, document positioning, image segmentation, and character recognition. Document image inversion detection and correction is an important process between document positioning and image segmentation. The inversion phenomenon occurs due to the randomness of placement, which will not only bring difficulties to the next step of image segmentation, but even cause the document information to be incorrectly identified

[0004] The inversion detection and correction of the document image is an important topic in the document information acquisition system. In order to avoid the inversion of the document image as much as possible, some corresponding restrictions can be placed on the acquisition equipment, acquisition steps, and usage methods, but considering the robustness of the system and scalability (such as adapting to documents of different sizes), and at the same time give users the greatest degree of freedom in use, so it is difficult to prevent the image inversion of the document image, but if the corresponding inversion detection correction is not performed on the document, then The segmentation of information sub-blocks (such as avatar, name, certificate number, etc.) will bring great difficulties to the document image. The most significant problem is that character recognition and information will be caused by factors such as information loss and character deformation. extraction error

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