Automatic Image Restoration Technique For Under/Over Exposed Region

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Date
2011-07
Authors
Zakaria, Mohd Firdaus
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Publisher
Universiti Sains Malaysia
Abstract
Many methods have been proposed to improve the clarity, quality and to compensate the underexposed or over-exposed regions of an image. In image restoration, the main goal is to improve the clarity in the image. Images with high clarity level contain a lot of information. The clarity is very easily affected by lighting, weather or equipments that have been used to capture the image. Some of these conditions such as inconsistent lighting lead to under-exposed or over-exposed conditions where the image may suffer information loss. Thus, this thesis puts forward an improved restoration method in order to retain the information in the image. This proposed method only performs image restoration on the under-exposed and over-exposed regions without degrading the correctly exposed ones. The tone mapping functions used in this method is inspired by a shunting characteristic of the centre surround cells of the spatial filtering output. This function is modulated differently for every pixel, according to its surround, thus minimizes the halo effect. It also has automatic functions to recognize the under-exposed or over-exposed regions, in which suitable correction is applied to restore these particular regions. The empirical results from series of experiments demonstrate that the proposed method successfully improves the image quality and clarity. The proposed method gives good results for entropy value and increases the detection rate in face detection system. This algorithm only requires around 0.43 seconds to process an image of size 704×576 using conventional personal computer.
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Keywords
Image Restoration Technique , Under/Over Exposed Region
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