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Multi-View Super Vector for Action Recognition. Shenzhen Institutes of Advanced Technology, CAS Chinese University of Hong Kong. Limin Wang. Zhuowei Cai. Xiaojiang Peng. Yu Qiao. Content. Motivation M-PCCA model & MVSV representation Experimental Results. Content. Motivation
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Multi-View Super Vector for Action Recognition Shenzhen Institutes of Advanced Technology, CAS Chinese University of Hong Kong Limin Wang Zhuowei Cai Xiaojiang Peng Yu Qiao
Content • Motivation • M-PCCA model & MVSV representation • Experimental Results
Content • Motivation • M-PCCA model & MVSV representation • Experimental Results
Actions in Video Clips can be captured by ... *Video from chalearn looking at people chanllenge HOG HOF MBHx/MBHy static feature dynamic features
Feature Fusion - Concatenation HOG HOF Concatenation before GMM : HOG + HOF Defect : features presumed to be strongly correlated
Feature Fusion - Kernel Average HOG HOF CodeHOF CodeHOG Concatenation after GMM : CodeHOG + CodeHOF Defect : features presumed to be mutually independent
Decomposition HOG HOF HOG-Specific HOG/HOF-Shared HOF-Specific
HOG-Specific HOG/HOF-Shared HOF-Specific Merit : features are decomposed into relatively independent components
HOG-Specific HOG/HOF-Shared HOF-Specific M-PCCA Mixture of Probabilistic Canonical Correlation Analyzers
Content • Motivation • M-PCCA model & MVSV representation • Experimental Results
Mixture of Probabilistic Models Latent Variable Models V = WZ + Zv Z ~ N(0, I), Zv ~ N(μ, Φ) Probabilistic Principal Component Analysis: Φ = σI. *M. Tipping, C. Bishop Probabilistic Factor Analysis: Φ is diagonal. Probabilistic Canonical Correlation Analyzer.*B. Francis, M. Jordan; K. Arto, S. Kaski X = Wx Z + Zx Y = Wy Z + Zy Z ~ N(0, I), Zx ~ N(μx, Φx),Zy ~ N(μy, Φy). Mixture Version: M-PPCA *M. Tipping, C. Bishop, M-FA *G. Zoubin, G. Hinton
M-PCCA EM Learning Algorithm
M-PCCA X = Wx Z + Zx Y = Wy Z + Zy
M-PCCA Z2 Z1 Z3 = Shared Part
M-PCCA gx = Private Part gy
M-PCCA Shared Part + = Multi-View Super Vector gx gy Private Part
Content • Motivation • M-PCCA model & MVSV representation • Experimental Results
MVSV with SVM classifier on HMDB51 with various configurations Performance w.r.t number of Components Performance w.r.t Latent Dimension
Results #components = 256, dimension = 45
Descriptor-level X Fusion GMM SVM Score Y GMM (linear) Kernel-level X Fusion SVM GMM Score Y GMM SVM Score-level X Score Fusion Score GMM SVM Score Y MVSV X M-PCCA SVM Fusion Score Y