Computer Vision Motion C Division Home计算机视觉的运动 CS分回家.pptVIP

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 Estimation of Global Flow Estimation of Global Flow Estimation of Global Flow Estimation of Global Flow Estimation of Global Flow Estimation of Global Flow Iterative Refinement Coarse-to-fine global flow estimation Coarse-to-fine global flow estimation Coarse-to-fine global motion estimation Basic Components Pyramid Construction Motion Estimation Image Warping Coarse to Fine Refinement Video Mosaic Image Warping Image Warping Interpolation Interpolation Interpolation Interpolation Image Warping Motion Tracking Motion tracking Suppose we have more than two images How to track a point through all of the images? Feature Detection Tracking features Feature tracking Compute optical flow for that feature for each consecutive H, I Handling large motions L-K requires small motion If the motion is much more than a pixel, use discrete search instead Given feature window W in H, find best matching window in I Minimize sum squared difference (SSD) of pixels in window Solve by doing a search over a specified range of (u,v) values this (u,v) range defines the search window Tracking Over Many Frames Feature tracking with m frames Select features in first frame Given feature in frame i, compute position in i+1 Select more features if needed i = i + 1 If i m, go to step 2 Incorporating Dynamics Idea Can get better performance if we know something about the way points move Most approaches assume constant velocity or constant acceleration Use above to predict position in next frame, initialize search * Application: Image Ali