Santos, Joao M.Thomaz, Lucas A.Assuncao, Pedro A. A.Cruz, Luis A. da SilvaTavora, Luis M. N.Faria, Sergio M. M. de2025-07-162025-07-162020-12J. M. Santos, L. A. Thomaz, P. A. A. Assuncao, L. A. da Silva Cruz, L. M. N. Tavora and S. M. M. Faria, "Disparity compensation of light fields for improved efficiency in 4D transform-based encoders," 2020 IEEE International Conference on Visual Communications and Image Processing (VCIP), Macau, China, 2020, pp. 112-115, doi: https://doi.org/10.1109/VCIP49819.2020.9301829.978-1-7281-8069-4978-1-7281-8068-71018-8770http://hdl.handle.net/10400.8/13672EISBN - 978-1-7281-8068-7Article number - 9301829; Conference date - 1 December 2020 - 4 December 2020; Conference code - 166231Efficient light field en coders take advantage of the inherent 4D data structures to achieve high compression performance. This is accomplished by exploiting the redundancy of co-located pixels in different sub-aperture images (SAIs) through prediction and/or transform schemes to find a m ore compact representation of the signal. However, in image regions with higher disparity between SAIs, such scheme's performance tends to decrease, thus reducing the compression efficiency. This paper introduces a reversible pre-processing algorithm for disparity compensation that operates on the SAI domain of light field data. The proposed method contributes to improve the transform efficiency of the encoder, since the disparity-compensated data presents higher correlation between co-located image blocks. The experimental results show significant improvements in the compression performance of 4D light fields, achieving Bjontegaard delta rate gains of about 44% on average for MuLE codec using the 4D discrete cosine transform, when encoding High Density Camera Arrays (HDCA) light field images.eng4D light field codecsdisparity compensationLight field compressionconference paper10.1109/vcip49819.2020.93018292642-9357