An Edge-preserving Filtering Framework for Visibility Restoration
Linchao Bao, Yibing Song, Qingxiong Yang, Narendra Ahuja · 2012
In this paper, we propose a new framework for edgepreserving texture-smoothing filtering to improve the visibility of images in presence of haze or fog. The proposed framework can effectively achieve strong texture smoothing while keeping edges sharp, and any low-pass filter can be directly integrated into the framework. Our experiments with three popular low-pass filters (Gaussian filter, median filter and bilateral filter) show that our framework can better preserve the contrast around edges than the original filters. The visibility restoration algorithm based on our framework outperforms existing filtering-based algorithm without losing the speed advantage compared to non-filtering-based algorithms. transmission map and then refine it using soft matting algorithms. However, the common disadvantage of these three algorithms are that they are too slow to fulfil the demands of real-time applications. Based on these pioneering works, Tarel et al. [8] propose a fast algorithm which treats the problem as a filtering problem and thus can achieve much faster speed. The algorithm estimates the medium transmission map based on edge-preserving smoothing, and then restores the image using the medium transmission map. The core step is the edge-preserving smoothing step, where they utilize median filtering. 1.