Thin Dust Clouds Degradation Of Image Processing Research

The image we obtained in bad weather conditions is often significantly degraded by fog and mist. It greatly decreased the use of the image and make bad effect on the information processing in military, traffic, remote-sensing etc. As a result, the research on how to effectively process this kind of degraded images has very important meaning.First the degradation effect on the image by bad weather is presented, and the Oakley degradation model and the degradation model based on the atmosphere transfer function are analyzed. The restoration methods based on the degradation model are discussed in this paper, and its difficulties we met in practical application are also indicated. Based on the characteristic analysis of the image degraded by fog and mist, the simple and effective processing methods from the view of image enhancement are discussed.Satisfied results usually can not be got when processing color images degraded by fog and mist with the conventional enhancement algorithms such as histogram equalization and homomorphic filtering. If the image degraded by fog and mist is thought to be composed of two parts: One is the part effected by the atmosphere, and the other is the essential character of the scene, the process is to obtain the second part. This offers the probability to use Retinex theory. Then the paper lays strong emphasis on the discussion of the application of Retinex algorithm for processing the images degraded by fog and mist. The basic idea and the development of the Retinex algorithm are briefly introduced. For practical application, three kinds of algorithms which are Retinex algorithm based on pixel comparing , SSR and MSR(CR), Kimmel Retinex are chosen for their common use and easy implementation. These algorithms are improved when used for processing the images degraded by fog and mist. Satisfied results are got.