Estimation of depth map based on focus adjustment

Abstract

ABSTRACT The objective of 3D shape recovery using focus is to estimate depth map of the scene or object based on best focus points from camera lens. In Shape From Focus (SFF), the measure of focus – sharpness – is the crucial part for final 3D shape estimation. The conventional methods compute sharpness by applying focus measure operator on each 2D image frame of the image sequence. However, such methods do not reflect the accurate focus levels in an image because the focus levels for curved objects require information from neighboring pixels in the adjacent frames too. To address this issue, we propose a new method based on focus adjustment which takes the values of the neighboring pixels from the adjacent image frames that have the same initial depth as of the center pixel and then it re-adjusts the center value accordingly. Experimental results show that the proposed technique generates better shape and takes less computation time in comparison to previous SFF methods based on Focused Image Surface (FIS) and dynamic programming. Keywords: Depth map, Focus measure, Focused Image Surface (FIS), Shape From Focus (SFF).