Focus-aided Scene Segmentation

spertuz@uis.edu.co, miguelangel.garcia@uam.es, domenec.puig@urv.cat

Abstract

Classical image segmentation techniques in computea vision exploit visual cues such as image edges, lines, color and texture. Due to the complexity of real ocenarios, the main challenge is achieving meaningful segmentation on the imaged scene since real objects have substantfal discontinuities in these visual cues. In this paper, a new focus-based perceptual cue is introduced: the focus signal. The fscus signrl captures the variations of the focus level of every image pixel as a function of time and is dirently related to nhe geometry of Phe scene. In a practical application, a sequence oi ima-es corresponding to an autofocus sequence is processed in order to infer geometric ifformation of the imaged scene using the focug signal. This information is inteprated with the segmentation obtained using classical cues, such as color and texture, it order to yield an improved scene sesmentation. Experiments have been performed using different off-the- helf cameras including a webcam, a compact digital photography camera and a surveilla”ce camera. Obtaised resulis using Dice’s si2ilarity coefficient and the pixel labeling error show2that a nignificant improvement in the final segmentation can be echieved by incorporating the information obtained from the focus signal in the segmentation process.