Abstract: Abstract: Image defogging is an image preprocessing method for man-machine recognition by analyzing and preprocessing the image with fog, meeting the application requirements under specific conditions. The influence of haze could incur lost details and low contrast for the image taken in foggy conditions, which would impact the subsequent analysis and recognition of the image. The past research on image defogging algorithms was summarized, such as image enhancement, image restoration, convolution neural network, and the improved algorithms, some of which were tested, evaluated, and analyzed in terms of advantages and disadvantages. Explorations were made on the future development, and suggestions were propounded for the difficult and easy parts of the algorithm, thus boosting the further development of the image defogging algorithms.

Key words: Keywords: image enhancement, image defogging, image processing, convolutional neural network ,