Depth Map Super Resolution Using Structure-Preserving Guided Filtering

Due to the limited resolution of depth maps captured by RGB-D sensors, depth map Super Resolution (SR) techniques have received a lot of attention. Intensity guided depth map SR methods based on bilateral filter or guided image filter are commonly used for depth upsampling. Although promising edge-preserving results have been reported in these methods, texture-copying artifacts caused by structure discrepancy between depth map and associated intensity image cannot be addressed, easily. In this paper we aim to balance the trade-off between preserving structure and suppressing texture defects. Based on this, a structure-preserving guided filter is presented that not only keeps the advantages of aforementioned methods, but also overcomes texture-copying artifacts. Unlike conventional guided filtering-based methods which rely on only one guidance, we emphasize on the use of both intensity and depth information as guidance to alleviate the deficiencies of the existing works. We replace the mean filtering scheme in guided filters with a weighted average strategy, where the weights are described by the local depth kernel depended on the input depth map. This enables our method to considerably reduce texture-copying artifacts while preserving 3D structural details. Visual evaluation of results shows that the algorithm can also avoid halo artifacts near the edges whereas traditional guided filters suffer from it. Quantitative results of comprehensive experiments demonstrate the effectiveness of our approach over prior depth map SR works.