Automatic planning of light source and camera placement for an active photometric stereo system

Abstract

An automatic planning method of light source and camera placement for an active photometric stereo system is presented. Since photometric stereo systems normally use multiple light sources fixed to the environment, they cannot avoid shadows caused by surrounding objects. Using a movable light source and adapting its placement actively to the task environment eliminates shadows. Candidate positions for light source placement are obtained based on a three-dimensional model of the environment and image processing of a virtual sphere around the target objects. Possible combinations are evaluated using the combined criteria of reliability and detectability of the measurement. Experimental results obtained using a light source affixed to a manipulator demonstrate the usefulness of the method. To improve the detectability of the active photometric stereo system, an extension has been made by using a movable camera in place of a fixed camera.