Method and device for measuring image inclination angle of business card

Abstract

The invention relates to a method and a device for measuring image inclination angle of a business card, which belong to the technical field of OCR. The method extracts the edge image of a business card image at first, searches the peripheral frame line of a business card in the edge image, judges if the image is inclined according to the inclination degree of the peripheral frame line, judges word editing direction thereof for the inclined picture, projects along the word editing direction and calculates the inclination angle of the image by projection characteristic. Judging the inclination of the image by collecting the peripheral frame line of the image, the invention can divide the images into an inclination type and an aclinal type quickly and process the two types respectively. The invention quickly judges the word editing direction by comparing the characteristics of projection histograms in the horizontal direction and the vertical direction. The determination of the word editing direction is greatly useful for calculating the inclination angle by projecting and analyzing the layout of the business card image.

Description

technical field [0001] The invention belongs to the technical fields of digital image processing and OCR (optical character recognition), and in particular relates to a method and a device for measuring the inclination angle of a business card image. Background technique [0002] In today's business activities, business cards are already an important information carrier for business partners, customers, etc. Faced with a large number of business cards, companies and individuals need a way to automatically and accurately collect and process information. Currently, OCR ( Optical Character Recognition) system to complete this function. In the business card OCR system, the input business card image may have a certain angle of inclination (generally less than 5°), which will have a negative impact on the layout analysis, character segmentation and character recognition of the business card. Angle for image correction. [0003] The existing tilt detection methods for document im...

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Problems solved by technology

[0006] The document "Rapid Slant Detection and Correction Method for Grayscale Business Card Image" ("Journal of Chinese Information Science" 2004, 01, pp. 63-70) proposes a method for detecting the inclination angle based on the four border lines of the business card in the scanned business card image. The method is simple and fast, but it is powerless for the case where there is no edge straight line in the business card image, and the accuracy of the angle calculated only based on the edge straight line is not very high

[0007] Using the projection method to calculate the inclination angle of the business card image, the calculation result is accurate, but it is a waste to calculate the business card image without inclination; the method of calculating the inclination angle by using the straight line of the business card frame in the image is simple and fast, but for the lack of a straight line in the frame In the case of , it loses its effect. For the case where the border line is polluted by noise, the calculation result is not accurate enough

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