Haze removal for image enhancement
Maria L. Groszek, Jan P. Allebach · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2005
We present a method to improve the quality of hazy digital images for digital photography applications. Most of the methods for haze removal that have been reported in the literature require either multiple images of the scene or auxiliary information, and are thus not suitable for digital photography applications. Our method is based on variable contrast enhancement. To determine where the enhancement should be applied, we find the location of the horizon. We use a ratio of luminance values to form an edge map, a connected components algorithm to find the sky set, and then finally a connected components algorithm to find any object extending over the horizon. The ground cover is then contrast enhanced with a modified piecewise linear function, with more enhancement at the horizon than at the bottom of the image. We demonstrate the capability to improve image quality with several images.