Homography-Based 3D Scene Analysis of Video Sequences *

Abstract We propose a framework to recover projectivedepth based on image homography and discuss itsapplication to scene analysis of video sequences.We describe a robust homography algorithmwhich incorporates contrast/brightness adjustmentand robust estimation into image registration. Wepresent a camera motion solver to obtain the ego-motion and the real/virtual plane position fromhomography. We then apply the Levenburg-Marquardt method to generate a dense projectivedepth map. We also discuss temporal integrationover video sequences. Finally we present theresults of applying the homography-based videoanalysis to motion detection. 1 Introduction Temporal information redundancy of videosequences allows us to use efficient, incrementalmethods which perform temporal integration ofinformation for gradual refinement.Approaches handling 3D scene analysis of videosequences with camera motion can be classifiedinto two categories: algorithms which use 2Dtransformation or model fitting, and algorithmswhich use 3D geometry analysis. Video sequencesof our interest are taken from a moving airborneplatform where the ego-motion is complex and thescene is relatively distant but not necessarily flat;