Rapid correction method for scanning document image

A document image and scanning image technology, applied in the field of document image correction, can solve the problem of character gray value reduction, etc., achieve high accuracy and reliability, simplify calculation complexity, and high application value

Active Publication Date: 2010-12-29
山东山大鸥玛软件股份有限公司
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Problems solved by technology

In addition, document images are different from natural images. Document images have strong edge information. General interpolation methods (nei

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  • Rapid correction method for scanning document image
  • Rapid correction method for scanning document image
  • Rapid correction method for scanning document image

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The present invention will be described in further detail below in conjunction with the drawings and preferred embodiments.

Referring to Figure 1, this preferred embodiment selects A3 format, 100dpi scanned image (pixel size: 1500×1024), uses the edge characteristics of the image, and performs segmented scanning to reduce the number of straight-line fitting points during calculation, including horizontal line detection and vertical For line detection, the step length is used as a detection parameter, which is determined according to the size and efficiency and accuracy of the scanned image. The step length is taken to ensure that the edge points are not less than 100 effective points on each side. In the processing of four sides, the image is divided into four parts, up, down, left, and right to fully reduce the number of traversing the image. When a valid straight line mark point is detected, the scanning of the row or column ends, and the next row or column is continued. Colu...

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Abstract

The invention discloses a rapid correction method for scanning a document image. A detection step is calculated according to the size of the image; four lines are fixedly detected, and the maximum number of points of each line is 100, so the maximum number of characteristic points of a straight line is no more than 400; therefore, the calculated amount of Hough transformation during straight line detection is reduced and the stability is improved; the Hough transformation with a limited included angle is adopted to further improve the efficiency of the straight line detection; an inclined angle is calculated according to parallel lines, so the algorithm can process a trapezoidal document image; the calculation of an intersection is determined according to a parametric equation of two straight lines; when the image rotates, an effective image region is only processed, the process of interpolation calculation of a black background is avoided, and the processing efficiency is improved; and the document image is partitioned for processing, and the interpolation calculation is determined according to a partitioning characteristic so as to improve the execution efficiency of a correction algorithm; and quality optimization adopts a grey scale compensation method so as to achieve better visual effect.

Description

technical field The invention relates to a method for rectifying a document image, in particular to a method for quickly correcting a scanned document image. Background technique Inclination angle detection and correction technology is a very important part of document image processing, and is the basic work of image analysis and recognition, especially in the real-time system of cursor character recognition, the performance of recognition is directly related to the quality of image data, so make full use of The existing image processing means can solve the problem of inclination in the document image scanning process, which has important research significance in improving document information collection, input accuracy, reducing rejection rate, and improving product operability and reliability. There are five main types of existing tilt angle estimation methods: methods based on Hough transform, methods based on cross-correlation, methods based on projection, methods based...

Claims

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Application Information

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IPC IPC(8): G06T5/00G06T7/00
Inventor 马磊刘江
Owner 山东山大鸥玛软件股份有限公司
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