Manuscript received October 10, 2023; revised November 24, 2023; accepted December 5, 2023; March 21, 2024

Abstract—Graph-based Light Field coding using the concept of super-rays is powerful to exploit signal redundancy along irregular shapes and achieves good energy compaction, compared to rectangular block -based approaches. However, its main limitation lies in the high time complexity for eigen-decomposition of each super-ray local graph, a high number of which can be found in a Light Field when segmented into super-rays. This paper examines a grouping scheme for super-rays in order to reduce the number of eigen-decomposition times, and proposes a novel coding architecture to handle the signal residual data arising for each super-ray group, as a tradeoff to achieve lower computational time. Experimental results have shown to reduce a considerable amount of decoding time for Light Field scenes, despite having a slight increase in the coding bitrates when compared with the original non-grouping super-ray-based approach. The proposal also remains to have competitive performance in Rate Distortion in comparison to HEVC-based and JPEG Pleno -based methods.

Keywords—light field, compression, super-ray, over-segmentation, graph transform, eigen-decomposition

Cite: Nguyen Gia Bach, Chanh Minh Tran, Nguyen Duc Tho, Phan Xuan Tan, and Eiji Kamioka, "Super-Rays Grouping Scheme and Novel Coding Architecture for Computational Time Reduction of Graph-Based Light Field Coding," Journal of Image and Graphics, Vol. 12, No. 1, pp. 90-102, 2024.

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