report 1: optical flow and sift
DESCRIPTION
Report 1: Optical Flow and Sift. Billy Timlen. Lucas Kanade. ( u,v ) = inv(A t A)* A t *F t Derived from f x *u +f y *v = -f t (after taking the partial derivative in terms of each variable x,y,t Analyze the pixels around the point of interest Requires a degree of padding - PowerPoint PPT PresentationTRANSCRIPT
Report 1: Optical Flow and Sift
Billy Timlen
(u,v) = inv(AtA)*At*Ft◦ Derived from fx*u +fy*v = -ft (after taking the partial derivative in terms of
each variable x,y,t Analyze the pixels around the point of interest
◦ Requires a degree of padding Works for slow motion and small areas
Lucas Kanade
Results
Reduces the original image into different levels◦ Impyramid(image, ‘reduce’)
Computes Optical flow for each level◦ Shifts derivative mask by u and v of prior level
Add the optical flows of each level Should record more detailed results of
motion
Optical Flow with Gaussian Pyramids
Code
Results
Input: 18x18 patch, keypoint and orientation angle Outputs a descriptor
◦ Histogram of orientation magnitudes Results vary according to the Gaussian used (for
smoothing) and the sigma used (which affects the Gaussian)
Sift
Result
Work with different types of masks
Use different forms of interpolation◦ MatLab has their own function
Use another form of rounding the non-integer indices from u and v◦ Gonzalo sent us a bilinear function to look at
What Next?
Optimal Algorithms for Topologically Constrained Correspondence
Bayesian Formulation for Event Recounting given Event Label
3D Joint Localization for Gesture Recognition
GPS-Tag Refinement
Possible Projects