Study On Algorithm Of Digital Image Processing For Fog-degraded Image

Image restoration and enhancement can highlight some details of images, making it easier for observation and post-computer analysis and processing. Due to atmospheric particles, the air is filled with droplets in rainy and foggy weather, thereby the reflected light of real objects and ambient light are either scattered or absorbed, blurring images received by the receiver; at the same time, being sensitive to the weather, such optical media devices as video surveillances and target trackers are sensitively affected by the existence of those particles in the air.The enhancement and restoration of images in foggy weather is attracting more and more attention from scientists, and the relevant studies are now on the rise. It is earnestly demanded that adverse results caused by fog be the demand of the adverse effects caused by fog be removed. The sophisticated imaging process of objects in fog itself makes it difficult to produce a comprehensive description, so it still remains as a problem to be solved to process images in foggy weather.The main content of the paper contains the following:(1) An improved Retinex rainy day digital image enhancement method is proposed. Because the traditional convolution function determines the results of Retinex algorithm and the results poorly. Investigating its reason, we find it is the convolution algorithm is homomorphic filter function Gauss filter. In this paper, a self-adaption filter is adopted, when the image gray levels within a certain threshold we use a homomorphic filter processing the image;else it exceeds this threshold value, we use anisotropic filter. Meanwhile, the traditional multi-scale Retinex using the same weighting factor, my paper uses the self-adaption filter method with different weighting factors. Experiments show that this method enhances image detail features,;the contrast of image is markedly improved,; and the distortion and hole phenomena have been improved.(2) Study on Retinex image enhancement algorithm based on the modified method. Using non-linear methods modify the reflection and irradiation component of an image. Using a global contrast function to stretching the illumination of the image, it improves the overall contrast. A S-type function is used to alter the reflection of an image, it can largely changes the Intermediate value, while the higher and lower values change little, play a local image contrast enhancement purposes. Compared with traditional MSR (multi-scale Retinex) algorithm, the results show significantly enhancement, visual effects are improved, and the bright and dim part of the image is enhanced. Meanwhile, the algorithm processing fleetly, and the results is not present apparently whitening or distortion.