Interpolation-free subpixel refinement for block-based motion estimation

T-K Chiew, J Chung-How, TH James, DR Bull, CN Canagarajah

Research output: Chapter in Book/Report/Conference proceedingConference Contribution (Conference Proceeding)

5 Citations (Scopus)


This paper proposes a low-complexity sub-pixel refinement to motion estimation based on full-search block matching algorithm (BMA) at integer-pixel accuracy. This algorithm eliminates the need to produce interpolated reference frames, which is may be too memory- and processor- intensive, for some real-time mobile applications. The algorithm assumes the BMA is done at pixel resolution and the (sum-of-absolute-differences) SADs of the candidate motion vector and its neighbouring vectors are available for each block. The proposed method than models the SAD distribution around the candidate motion vector and its neighbouring points. Actual minimum point at sub-pixel resolution is then computed according to the model used. 3 variations of the parabolic model are considered and simulations using the H.263 standard encoder on several test sequences reveal an improvement of 1.0 dB over integer-accuracy motion estimation. Albeit its simplicity, some test cases come close to the results obtained by actual interpolated reference frames.
Translated title of the contributionInterpolation-free subpixel refinement for block-based motion estimation
Original languageEnglish
Title of host publicationSPIE - Visual Communications and Image Processing 2004
PublisherSociety of Photo-Optical Instrumentation Engineers (SPIE)
Pages1261 - 1269
Number of pages9
Publication statusPublished - 20 Jan 2004


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