A Second-Order Variational Framework for Joint Depth Map Estimation and Image Dehazing

Outdoor images captured in poor weather conditions (e.g., fog or haze) commonly suffer from reduced contrast and visibility. Increasing attention has recently been paid to single image dehazing, i.e., improving image contrast and visibility. It is generally thought that the dehazing performance highly depends on the accurate depth information. In this work, we first obtain the initial depth map by using the popular dark channel prior. A unified second-order variational framework is then proposed to refine the depth map and restore the haze-free image. The introduced second-order framework has the capacity of preserving important structures in both depth map and haze-free image. Furthermore, the proposed framework performs well for several different types of haze situations. The resulting optimization problems related to depth map estimation and latent image restoration can be effectively handled using the primal-dual algorithm under a two-step numerical framework. The effectiveness of our proposed method has been demonstrated by comparing the imaging performance with several state-of-the-art dehazing methods.