caa a22 4500 606206582 CHVBK 20210128101012.0 cr unu---uuuuu 210128e20150201xx s 000 0 eng 10.1007/s00034-014-9870-x doi (NATIONALLICENCE)springer-10.1007/s00034-014-9870-x A Shape-Adaptive Low-Complexity Technique for 3D Free-Viewpoint Visual Applications [Elektronische Daten] [Kuan-Hung Chen, Cheng-Hao Chen, Chih-Hao Chang, Jun-Yu Liu, Ching-Lung Su] View synthesis (VS) and depth map generation (DMG) are two of the most crucial operations for facilitating the development of free-viewpoint 3D video systems. This demand for high computational complexity has motivated the development of the proposed design. Conventional designs have directly adopted dedicated hardware to increase the speed of these operations independently, which has resulted in algorithmic-level redundancies. Thus, the conventional per-pixel computation results in high redundancy in both VS and DMG operations. Accordingly, this paper proposes a shape-adaptive low-complexity (SALC) technique for removing such algorithmic-level redundancies for both VS and DMG operations. Moreover, adopting shape-adaptive searching blocks can improve the accuracy of stereo matching (SM), which subsequently enhances the resulting VS. To overcome the problem of border misalignment in VS, a novel edge alignment technique is presented for detecting and aligning misaligned borders. In addition, an unreliable region repairing (URR) technique was adopted to enhance the accuracy of DMG operations, thereby optimizing the image quality. The proposed SALC technique was verified using $$C$$ C /Matlab simulations. Through the presented complexity reduction without any hardware acceleration, this design can achieve a high performance of 48 fps for synthesizing the virtual views of the CIF format (352 $$\times $$ × 288) based on a portable platform equipped with a 1 GHz ARM Cortex-A9 RISC processor only. The experimental results revealed that the proposed SALC technique saves up to 96% computational complexity for VS, and the computation time of DMG operations is reduced to approximately 2% of that required for conventional SM. The average improved image quality was 32.46 dB (i.e., 7.33% improvement from the original 30.46 dB) when using the presented edge alignment technique. When considering the overall efficiency evaluation, the proposed SALC-based SM method is 172 times more efficient than the conventional fixed block-sized SM based on the combined indices of the BPCT product. Compared with the designs of previous studies, the proposed SALC-based design obtained superior efficiency in both VS and DMG as a result of the computation reuse property. Springer Science+Business Media New York, 2014 Depth map generation (DMG) nationallicence Disparity estimation (DE) nationallicence Free-viewpoint nationallicence Stereo matching (SM) nationallicence Three-dimensional imaging nationallicence View interpolation nationallicence View synthesis (VS) nationallicence Chen Kuan-Hung Department of Electronic Engineering, Feng-Chia University, 100 Wen-hwa Rd., Sea-twen, 40724, Taichung, Taiwan, ROC aut Chen Cheng-Hao Department of Electronic Engineering, Feng-Chia University, 100 Wen-hwa Rd., Sea-twen, 40724, Taichung, Taiwan, ROC aut Chang Chih-Hao Department of Electronic Engineering, Feng-Chia University, 100 Wen-hwa Rd., Sea-twen, 40724, Taichung, Taiwan, ROC aut Liu Jun-Yu Department of Electronic Engineering, Feng-Chia University, 100 Wen-hwa Rd., Sea-twen, 40724, Taichung, Taiwan, ROC aut Su Ching-Lung Department of Electronic Engineering, National Yunlin University of Science and Technology, 123 University Road, Section 3, Douliou, 64002, Yunlin, Taiwan, ROC aut Circuits, Systems, and Signal Processing Springer US; http://www.springer-ny.com 34/2(2015-02-01), 579-604 0278-081X 34:2<579 2015 34 34 https://doi.org/10.1007/s00034-014-9870-x text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00034-014-9870-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Chen Kuan-Hung Department of Electronic Engineering, Feng-Chia University, 100 Wen-hwa Rd., Sea-twen, 40724, Taichung, Taiwan, ROC aut NATIONALLICENCE 700 1- Chen Cheng-Hao Department of Electronic Engineering, Feng-Chia University, 100 Wen-hwa Rd., Sea-twen, 40724, Taichung, Taiwan, ROC aut NATIONALLICENCE 700 1- Chang Chih-Hao Department of Electronic Engineering, Feng-Chia University, 100 Wen-hwa Rd., Sea-twen, 40724, Taichung, Taiwan, ROC aut NATIONALLICENCE 700 1- Liu Jun-Yu Department of Electronic Engineering, Feng-Chia University, 100 Wen-hwa Rd., Sea-twen, 40724, Taichung, Taiwan, ROC aut NATIONALLICENCE 700 1- Su Ching-Lung Department of Electronic Engineering, National Yunlin University of Science and Technology, 123 University Road, Section 3, Douliou, 64002, Yunlin, Taiwan, ROC aut NATIONALLICENCE 773 0- Circuits, Systems, and Signal Processing Springer US; http://www.springer-ny.com 34/2(2015-02-01), 579-604 0278-081X 34:2<579 2015 34 34