Sharpness is one of the most determining factors in the perceptual
assessment of image quality. Objective image sharpness
measures may play important roles in the design and optimization
of visual perception-based auto-focus systems and
image enhancement, restoration and compression algorithms.
Here we propose a new sharpness measure where sharpness
is identified as strong local phase coherence evaluated in the
complex wavelet transform domain. Our test using the LIVE
blur database shows that the proposed algorithm correlates
well with subjective quality evaluations. An additional advantage
of our approach is that other image distortions such
as compression, median filtering and noise contamination that
may affect perceptual sharpness can also be detected