Anisotropic filter (Greenberg et.al, Yang et.al)
Very fast but cannot handle creases, wide breaks and poor quality images
Pseudo Matched filtering (Wilson, Grother Candela et. al)
Increases SNR but can lead to artefacts due to isotropic filtering.
Directional Filtering (Sherlock,Monro et. al.)
Very robust even near regions of high curvature but marked by large storagerequirements. Frequency of ridges is assumed to be constant.
Gabor filter bank(Hong et. al)
Filter has optimal joint directional and frequency resolution but does not handlehigh curvature regions well due to block wise approach. Angular and radialbandwidths are constant.
Proposed approach
A single algorithm is used for contextual analysis and enhancement.
Utilized full contextual information. Adapts both frequency and angularbandwidth based on block properties.
Adapts to high curvature regions reducing blocking artifacts.
However, using full contextual information leads to processing complexity.