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Unformatted text preview: Global Flow Global Flow • Dominant Motion in the scene • Motion of all points in the scene • Motion of most of the points in the scene • A Component of motion of all points in the scene • Global Motion is caused by • Motion of sensor (Ego Motion) • Motion of a rigid scene • Estimation of Global Motion can be used to • Video Mosaics • Image Alignment (Registration) • Removing Camera Jitter • Tracking (By neglecting camera motion) • Video Segmentation etc. Global Flow Application: Image Alignment Estimation of Global Flow James R. Bergen, P. Anandan, Keith J. Hanna, Rajesh Hingorani: “Hierarchical ModelBased Motion Estimation," ECCV 1992: 237252 Assume Affine Flow: 2 4 3 1 2 1 b y a x a v v b y a x a v u B y x A v u y x + + = = + + = = + = = 2 4 3 1 2 1 1 1 b a a b a a y x y x v u Xa U = Estimation of Global Flow ( 29 = + ∇ t T I v u I (Optical Flow Constraint Equation) ( 29 = + ∇ t T I I Xa ( 29 [ ] ( 29 , 2 = + ∇ ∑ ∈ 2200 I y x t T I I Xa ( 29 [ ] ( 29 ∑ ∈ 2200 + ∇ I y x t T I I , 2 min Xa ( 29 ( 29 ( 29 ( 29 ∑ ∑ ∈ 2200 ∈ 2200 ∇ = ∇ ∇ I y x T t I y x T T I I I I , , X a X X B Aa = Estimation of Global Flow Single Iteration Image ‘t’ Image ‘t+1’ Warp by a B Aa = Solve Compute A and B Estimation of Global Flow Iterative Image ‘t’ Image ‘t+1’ Warp by a Initial Estimate [ ] T b a a b a a 2 4 3 1 2 1 = a B a A = δ Solve Compute A and B Warp by a δ Estimation of Global Flow...
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This note was uploaded on 06/12/2011 for the course CAP 5415 taught by Professor Staff during the Fall '08 term at University of Central Florida.
 Fall '08
 Staff

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