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Iterative Frame Decimation and Watermarking for Human Motion Animation
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Iterative Frame Decimation and Watermarking for Human Motion Animation

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Iterative Frame Decimation and Watermarking for Human Motion Animation …

Iterative Frame Decimation and Watermarking for Human Motion Animation

Shiyu Li and Masahiro Okuda

Faculty of Environmental Engineering, The University of Kitakyushu, 1-1, Hibikino, Wakamatsu-ku, Kitakyushu, Fukuoka, Japan


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  • 1. Iterative Frame Decimation and Watermarking for Human Motion Animation Shiyu Li, Masahiro Okuda Faculty of Environmental Engineering, The University of Kitakyushu 1-1,Hibikino, Wakamatsu-ku, Kitakyushu, Fukuoka, Japan [lishiyu, okuda-m]@env.kitakyu-u.ac.jp http://vig.is.env.kitakyu-u.ac.jp/
  • 2. PRELIMINARY Body Skeleton Configuration root terminator end effector link
  • 3. Introduction- Why Motion Coding ?
    • Reuse motion data (storing)
    • Motion data retrieval
    • Motion editing
    • Real time transmitting
  • 4. Introduction- Two methods
    • Reduce motion sample density
    • -key-frame, interpolation
    • Reduce size of database
    • -compression of each sample itself
  • 5. Reduce motion sample density
    • key-framing
    • Shiyu Li, Masahiro Okuda and Shin-ichi Takahashi, “ Embedded Key-frame Extraction for CG Animation by Frame Decimation ”, Proceed­ing of IEEE Int. Conference on Multimedia & Expo (ICME05)
    • Watermarking
    • Shiyu Li, Masahiro Okuda, “ Watermark for Progressive Human Motion Animation ”, Proceed­ing of IEEE Int. Conference on Multimedia & Expo (ICME07)
  • 6. Reduce size of database
    • Wavelet transform based
    • Shiyu Li, Masahiro Okuda, Shin-ichi Takahashi, “ Hierarchical Human Motion Compression with Constraints on Frames ”, 47th MWSCAS, Hiroshima, Japan, pp. I-253- I-256, Jul. 2004.
    • Using the Reduction of Inter-Joint Correlation
    • Shiyu Li, Masahiro Okuda, Shin-ichi Takahashi, “ Kinematics-based motion compression for human figure animation ”, 30th ICASSP, Pennsylvania, United States, vol.II, pp.1077-1080, Mar. 2005.
  • 7. Embedded Key-frame Extraction for CG Animation by Frame Decimation
    • Previous method: motion curve simplification
    • Our method: All the frames are ranked by their importance, and thus users can specify any number of key-frames from one data set.
  • 8. Watermark for Progressive Human Motion Animation
    • A progressive coding based watermarking scheme
    To embed the watermark in the encoder: The sequence E is broken up into blocks. We use 50 frames per block. To calculate the variance Var(E) of the signal E in each block: (1). if the value of a frame is larger than Et , Et is subtracted from this frame. Fig.2(b) represents the signal after this preprocessing. (2). to produce a sequence which is zero-mean, the mean of each block is subtracted from each frame. Calculate the variance Var(E) of each block. Calculate the variance Var( w ) of the watermark w by the Var(E) . Generate a pseudo random sequence w with the same length as the blocks of sequence E , assume E and w are independent. See Fig2.(c) Store E’ = E+ w as the watermarked signal. See Fig2.(d) The watermarked signal E’ is sent to the decoder. In the decoder: Rank the frames by the value of E’ . R eceive the key-frames progressively as this order. After applying interpolation to the key-frames, the motion can be reconstructed approximatively. To detect if the watermark exists , the original Et is necessary : Calculate the variance of E’ after the same preprocessing in the encoder, i.e. if the value of a frame is larger than Et , Et is subtracted from this frame. Estimate the variance of w, assuming Var(E’)=Var(E) +Var( w ) . Var(E) is calculated by the same method in step1. Regenerate w using the same seed value. Calculate Z=Σ(w* E’) Declare E’ watermarked if Z > n Var( w ) / 2
  • 9. Hierarchical Human Motion Compression with Constraints on Frames Data Compensation for joint i+ 1 Input : joint i Wavelet Transform: c 0 ,w 0 ,w 1 ,...,w j -1 ,c j -1 Max-Shift for Constraint frames (Scale up) Entropy Coding Hierarchical Quantization Dequantization Hierarchically Inverse Operation (Decoder) Inverse Wavelet Transform: c 0 ,w 0 ,w 1 ,...,w j -1 ,c j -1 Max-Shift for Constraint frames (Scale down) Entropy Decoding Input bits Convert to Euler- angle format Output : joint i Convert to two- angle format Output bits Encoder Decoder
  • 10. Kinematics-based motion compression for human figure animation Endcoder Decoder Entropy decoding dequantization Position calculation Prediction by IK Compressed   angles of previous frame Converted Two angles Angle conversion Bits of end- effectors Entropy decoding dequantization Convert all joints to original angle format Bits of general other joints Orientation Angle retrieval General other joints Position calculation quantization Entropy coding decoding Com- pressed position Prediction by IK Calculate prediction error quantization decoding End effectors Simple prediction Compressed   angles of previous frame Orientation calculation Entropy coding Simple prediction Converted format