A hybrid frequency-spatial domain infrared image enhancement approach evaluated by fuzzy entropy

摘要

Traditional homomorphic enhancement method is only attributed to the frequency domain processing, which could not enhance the image outline effectively. A better homomorphic algorithm could consider the dynamic range of image to compress and expand gray levels of the target and thus enhance image details. After the frequency domain enhancement, the deployment of mathematical morphology could smooth the outline of the image in spatial domain. This paper develops an effectively comprehensive approach to optimize the contrast of infrared image, utilizing non-linear filtering in frequency domain and top-hat and bottom-hat transforms in spatial domain. Besides, a fuzzy entropy scheme is defined to verify the improved infrared image enhancement effects. Experimental results indicate that, through the proposed method, the image details and contours can be better enhanced comparing with other methods.