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Robot Navigation. Avneesh Sud Vaibhav Vaish under the guidance of Dr. Subhashis Banerjee. Problem Description. The aim is to enable a robot to move around on the ground plane by visually detecting and avoiding obstacles. Stages Involved (Existing). Camera Calibration
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Robot Navigation Avneesh Sud Vaibhav Vaish under the guidance of Dr. Subhashis Banerjee
Problem Description The aim is to enable a robot to move around on the ground plane by visually detecting and avoiding obstacles.
Stages Involved (Existing) • Camera Calibration • Edge & Corner Detection • Finding Correspondences • 3-D Reconstruction • Path Planning • Navigating the Path
Camera Calibration lm = Ai [Ri|ti] M • A co-ordinate system for each camera • 4+3+3 = 10 unknowns
World Point X x x’ Y Y’ l’ Z Z’ C C’ e e’ Left optical center Right optical center X X’ Right Image plane Left Image plane R,T Essential & Fundamental Matrices • F = C’-TEC-1 • x’TFx = 0 • l’ = Fx • E = [T]XR • X’TEX = 0 Base Line
Corner Detection • Edges are determined • Line Map is fit on the edges • Junctions of the lines are found Toolkit used : horatio
Finding Correspondences (Lines) • Candidate Lines should have similar orientation • Images of end-points are got using the epipolar constraint • An new approach considers orientation of nearby lines (Amit Garg)
Reconstruction Mid-point of shortest distance
Locating Obstructions • The reconstructed scene is projected on the ground plane. • Clustering is done, by deleting long edges in MST • Each cluster is bounded by its convex hull TO BE DONE Identification of ground plane. Current implementation projects onto xz plane of camera co-ordinate system.
Needed for Navigation • Hand-eye calibration: to locate robot w.r.t. co-ordinate system • Visual Servoing: using visual feedback for correction in motion • Path Planning: Simple backtracking algorithm OUR TARGET To complete the above by the end of the semester
New Approaches Avoid Calibration by: • Self-Calibration this was attempted by Amit Garg & Deepak Verma, without much success. • Inner Camera Invariants this will let us handle varying or unknown internal parameters of the camera.
References • Three Dimensional Computer Vision O. Faugeras • The Geometry of Multiple Views Andrew Zissermann • A Versatile Camera Calibration Technique Roger Tsai (IEEE J. of Rob. & Aut., 1987) • Inner Camera Invariants & Applications S. Banerjeeet al.