The Research Of Image Enhancement Algorithm

As an effective information carrier, image is the main source through which human acquire and exchange information. Researches have shown that eighty percent of surroundings information which is able to be perceptive by human is acquired through human visual system. So, the application of image processing must be involved in all aspects of human living and work. Image enhancement is located in the stage of image preprocessing, inherits the past and ushers in the future. It is one step of image processing in the sense of low-grade process, and plays an important role. The final enhancement result directly determines success or failure of the subsequent image processing in the sense of high-grade process. The purpose of image enhancement is to improve the quality of the image and visual effect, or transform the image into another pattern which is more adapted to the human observation or machine analysis and cognition, so as to acquire more valuable information from the image.Because image enhancement is closely related to the property of the interested target, the habit of observers and the specific processing goal, so, the image enhancement algorithm is only aimed at the given process goal, too. Though a variety of algorithms of image enhancement processing were proposed, however, there wasn't a universal algorithm coming into existence so far.This paper is developed according to the algorithm of image enhancement. After the fundamental methods of image enhancement processing are demonstrated, the following representative algorithms: image enhancement algorithm based on histogram equalization, image enhancement algorithm based on fuzzy set theory, image enhancement algorithm based on wavelet transform, image enhancement algorithm based on human visual property and image enhancement algorithm based on artificial neural network, are deeply and systematically investigated and compared. The advantage and defect of the above-mentioned algorithms as well as the suitable application situations of them are analyzed and pointed out, in order to conclude a set of effective application instructing rules.