  Existing shape from focus (SFF) techniques cannot preserve depth edges and
fine structural details from a sequence of multi-focus images. Moreover, noise
in the sequence of multi-focus images affects the accuracy of the depth map. In
this paper, a novel depth enhancement algorithm for the SFF based on an
adaptive weighted guided image filtering (AWGIF) is proposed to address the
above issues. The AWGIF is applied to decompose an initial depth map which is
estimated by the traditional SFF into a base layer and a detail layer. In order
to preserve the edges accurately in the refined depth map, the guidance image
is constructed from the multi-focus image sequence, and the coefficient of the
AWGIF is utilized to suppress the noise while enhancing the fine depth details.
Experiments on real and synthetic objects demonstrate the superiority of the
proposed algorithm in terms of anti-noise, and the ability to preserve depth
edges and fine structural details compared to existing methods.
