Kyungmin Lim

Fast PU Skip and Split Termination Algorithm for HEVC Intra Prediction

High Efficiency Video Coding (HEVC) is developed for next-generation video coding, which achieves significant improvements in coding efficiency compared with H.264/Advanced Video Coding by adopting various tools including a quadtree-based block partitioning structure. However, this causes high encoding complexity for exhaustive rate-distortion (RD) cost computation of the extended prediction unit (PU) searching. In this paper, a fast PU skip and split termination algorithm is proposed. The proposed method consists of three algorithms: 1) early skip; 2) PU skip; and 3) PU split termination. The early skip algorithm allows immediate skipping of the RD cost computation for large PUs according to the neighboring PUs. Based on Bayess rule, the PU skip algorithm allows skipping of the full RD cost computation, and the split termination algorithm terminates further PU splitting using the RD cost of rough mode decision (RMD). The decision parameter for the PU skip and the split termination is presented as the ratio of the RMD RD costs between the current PU and the spatially adjacent or upper depth PU. The simulation results show that the proposed algorithm achieves a saving of 53.52% encoding time while maintaining almost the same RD performances as the HEVC reference software.

Fast block size and mode decision algorithm for intra prediction in H.264/AVC

The H.264/AVC standard achieves high compression performance compared to existing video coding standards by employing the rate distortion optimization (RDO) technique. All possible combinations of modes are calculated to find the minimum rate distortion cost which results in significant computational complexity. In this paper, we propose a fast block size and mode decision method for intra prediction, which can effectively reduce computational burden. For fast block size decision, intra16x16 is selectively searched based on the homogeneity of inner-8x8 block of macroblock (MB). For fast mode decision, the search of intra16x16 and intra4x4 prediction modes is restricted by the similarity of the reference pixels. Moreover, by considering the similarities of the upper reference pixels and left reference pixels separately, considerable reduction of computational complexity is achieved. The results of simulations demonstrate maxima of 79% and 77% average time savings with negligible loss in PSNRY and bitrate.

Fingertips detection and tracking based on active shape models and an ellipse

Detecting and tracking fingertips are significant techniques for recognizing hand gestures. Many patterns and skin color information are used to extract and trace features [1, 2]. However, to find correct shapes is difficult and there is limitation to express the diversity of models. In this paper, we describe a method of detecting and tracking fingertips based on Active Shape Models (ASMs) and an ellipse equation. ASM is an effective tool to obtain features of a specific object in images by using a trained model. The ellipse equation helps a template follow the object without skin color information. We show how well fingertips are extracted and traced through some experiments.

Fast intermode decision algorithm based on general and local residual complexity in H.264/AVC

The state-of-the-art video coding standard H.264/AVC achieves significant coding performance by adopting variable block sizes for motion estimation (ME) and mode decision. However, this technique brings out high computational complexity since the optimal mode is determined by exhaustively performing rate-distortion optimization (RDO) on each coding mode with different block sizes. In this paper, the fast intermode decision algorithm is proposed to reduce the computational complexity. Based on the high correlation between the residual error of ME and the optimal block size, general residual complexity (GRC) and local residual complexity (LRC) are defined. According to MB activity evaluated on GRC and LRC, candidate intermodes are determined and RDO processes are only performed on selected intermodes. The experimental results demonstrate that the proposed algorithm achieves time saving by 63% on average with negligible degradation of coding efficiency.

The effect of bilateral trainings on upper extremities muscle activation on level of motor function in stroke patients

[Purpose] This study was conducted in order to compare muscle activation level on the affected and unaffected limb according to the recovery level of upper limb between bilateral activity with hands clasped and bilateral activity with pilates ring. [Subjects and Methods] Twenty inpatient who have had a stroke were recruited. Subjects were divided into two groups by the Fugl-Meyer Assessment of Motor Function score of moderately recovered group and well recovered group. The muscles activation of upper extremity and Co-Contraction Ratio (CCR) were analyzed. [Results] In the muscles activation of the well group, trapezius, anterior deltoid, and triceps muscles of affected side and biceps muscles of both sides were significantly higher when activity with pilates ring than activity with hands clasped. CCR of both side in the well group was significantly decreased during activity with pilates ring and in the moderate group, CCR of affected side was significantly decreased during activity with pilates ring. [Conclusion] Bilateral activity with a pilates ring is more effective than activity with hands clasped for the facilitation of muscle activation and coordination in stroke patients.

Low-delay stream switch method for real-time transfer protocol

With wide spread of smartphones and high speed mobile communication technology, mobile broadcasting market is growing rapidly. Bit stream change during Video-on-Demand service causes large delay of video and audio playback, which makes user inconvenience. To avoid large delay, a method for low-delay stream switch is proposed and implemented on Android platform. Experimental result shows 72.71ms of stream change time on average when bit stream change occurred.