NEW DYNAMIC ESTIMATION OF DEPTH FROM FOCUS IN ACTIVE VISION SYSTEMS - Data Acquisition, LPV Observer Design, Analysis and Test

Abstract

In this paper, new methodologies for the estimation of the depth of a generic moving target with unknown dimensions, based upon depth from focus strategies, are proposed. A set of measurements, extracted from real time images acquired with a single pan and tilt camera, is used. These measurements are obtained resorting to the minimization of a new functional, deeply rooted on optical characteristics of the lens system, and combined with additional information extracted from images to provide estimates for the depth of the target. This integration is performed by a Linear Parameter Varying (LPV) observer, whose syntesis and analysis are also detailed. To assess the performance of the proposed system, a series of indoor experimental tests, with a real target mounted on a robotic platform, for a range of operation of up to ten meter, were carried out. A centimetric accuracy was obtained under realistic conditions.