Removing depth map coding distortion by using post filter set

Abstract

We propose a fast post filter set for removing coding distortions of depth maps. Lossy coding generates various distortions, such as mosquito and block noises, edge blurs, and over quantization. These distortions seriously deteriorate image quality of synthesized views in free viewpoint image rendering. Thus, we propose the post filter set which includes median filter, Gaussian filter, min-max blur remove filer, and binary weighted range filter to remove these noises. In experiments, we use various codecs, which are JPEG, JPEG-LS, JPEG2000, and H.264/AVC, for depth map coding, and synthesize views with the coded depth maps. Experimental results show that our post filter set can improves every codecs performance. Improvement of PSNR is larger than the conventional post filter, and especially JPEG is large. The computational time of the filter set, which is implemented by C++ with SIMD optimization, is within 5.2 ms at high bit rate cases, and within 15.3 ms at low bit rate cases.

Effective Implementation of Edge-Preserving Filtering on CPU Microarchitectures

“…The representatives of the filters include bilateral filtering [1,2], non-local means filtering [3] and guided image filtering [4][5][6]. These filters are used in various applications, such as image denoising [3,7], high dynamic range imaging [8], detail enhancement [9][10][11], free viewpoint image rendering [12], flash/no-flash photography [13,14], up-sampling/super resolution [15,16], alpha matting [5,17], haze removal [18], optical flow and stereo matching [19], refinement processing in optical flow and stereo matching [20,21] and coding noise removal [22,23].…”