Image correction method

Abstract

An image correction method is provided. First, scan an all-white document and form a scanned image including a plurality of image pixels with each of them having a gray level value. Next, gather these gray level values statistically such that each of them has an image pixel quantity. Then the maximum gray level value and the minimum gray level value are selected and a middle gray level value is obtained accordingly. Following that, determine whether the reference gray level value is greater or smaller than the middle gray level value according to the document, select the gray level values from within the interval of (the reference gray level value ± a gray level value), and weight average the selected gray level values according to these selected gray level values and their corresponding image pixel quantities to obtain a corrected gray level value.

Description

[0001] This application claims the benefit of Taiwan application Serial No. 91120807, filed on Sep. 11, 2002. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The invention relates in general to an image correction method, and more particularly to an image correction method, which, according to the pattern of the document scanned, determines whether the necessary reference gray level value with a maximum image pixel quantity should be greater or smaller than the middle gray level value calculated from the maximum gray level value and the minimum gray level value. [0004] 2. Description of the Related Art [0005] Before scanning a document, a scanner normally proceeds with an image correction to avoid an undesirable image distortion of the scanned image. Among the many image correction methods available nowadays, the image correction method disclosed in Taiwan Patent Publication Serial No. 376648 will be used as an example for explanation in assistance with FIG. 1. [...

AI Technical Summary

Problems solved by technology

However, if blemishes on the all-white document are numerous or the scanner is interfered with: by external noises during scanning, the gray level values obtained and their corresponding image pixel quantities might results in a profile as shown in FIG. 3.

Furthermore, the corrected gray level value obtained by weight averaging the gray level values selected from the interval of (ME±ηS) would have enormous differences with expected results.

Therefore the above mentioned method cannot be applied to such a special condition.

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