Pseudo-Quadtree Structure

Minsik Kim, Minyong Sung, Minwoo Kim, and Won Woo Ro, "Exploiting Pseudo-Quadtree Structure for Accelerating HEVC Spatial Resolution Downscaling Transcoder," in TMM

Minsik Kim

In this paper, a novel method to accelerate the spatial resolution downscaling transcoding operation for high efficiency video coding (HEVC) is proposed. The proposed transcoder first extracts the information about the coding unit (CU) structure during the decoding process and analyzes it to construct a pseudo-quadtree of the target resolution. By utilizing the constructed pseudo-quadtree, the encoder process is accelerated by searching only the optimal depth in the quadtree structure. To evaluate the performance of the proposed transcoding method, its transcoding time and bitrate loss are measured and compared with those of the HEVC reference encoder and decoder. Also, a comparison with state-of-the-art fastCUsize decision methods and spatial resolution downscaling transcoding methods for HEVC is presented. The proposed method achieves an average speedup of 1.65 with an average bitrate loss of 2.06%.

Separable Median Filter

Minsik Kim, Deokho Kim, Minyong Sung, and Won Woo Ro, "An Accelerated Separable Median Filter with Sorting Networks," in ICIP 2015

Minsik Kim

Since the computer vision technologies are used to extract features from the edges of images, the median filter is frequently used as a pre-processing operation to improve the quality of feature objects. However, the median filter algorithms still have the limitation on integrating with the mobile systems due to the large computation overhead. Since the median filter accounts for a large proportion of total computation, this paper proposes a separable median filter to resolve the limitation. The proposed separable median filter is implemented with the sorting network, and reuses the data sorted at neighbor pixels, reducing duplicated comparisons.