Ordinal depth from SFM and its application in robust scene recognition

Ph.DDOCTOR OF PHILOSOPH

Measuring Time-To-Contact Using Active Camera Control

. In this paper we use a simple, active-camera model to estimate the time-to-contact (TTC) of a moving object. We estimate TTC by enforcing a "uniform scale" constraint on the moving object. By actively adjusting the focal length of the pinhole model, the projected object maintains a fixed image scale regardless of its motion. These adjustments on the ideal pinhole focal length are translated into changes of the actual zoom and focus settings of a real camera system. We obtain improvements over a fixed-camera approach because the scale adjustment (zoom) improves image divergence measurements. We show experimental results indicating that our active method can reduce errors over a larger distance range than fixed-camera methods of estimating time-to-contact. 1 Introduction The intent of active camera control is almost always to create additional constraints and more favorable imaging situations. Extrinsic parameters, which control the position and orientation of the camera, determine th..