Whether phase congruency and phase coherence terms are same or different?
Phase congruency is where the phases of a quadrature filter responses at different scales are similar.

Some links:


http://homepages.inf.ed.ac.uk/rbf/CVonline/LOCAL_COPIES/OWENS/LECT7/node2.html
http://www.csse.uwa.edu.au/~pk/research/pkpapers/phasecorners.pdf


Papers:


Oppenheim, A. V., &amp; Lim, J. S. (1981). The importance of phase in signals.
Kovesi, P. (1995). Image Features From Phase Congruency.
Kovesi, P. (1996). Invariant measures of image features from phase information.
Kovesi, P. (1997). Symmetry and asymmetry from local phase.
Kovesi, P. (1999). Image features from phase congruency.
Kovesi, P. (2002). Edges are not just steps.
Kovesi, P. (2003). Phase congruency detects corners and edges.
Morrone, M. C., &amp; Burr, D. C. (1988). Feature detection in human vision: a phase-dependent energy model. 
Morrone, M. C., &amp; Owens, R. a. (1987). Feature detection from local energy.
Perona, P., &amp; Malik, J. (1990). Detecting and Localizing Edges Composed of Steps, Peaks and Roofs.
Reisfeld, D. (1996). Constrained phase congruency: simultaneous detection of interest points and of their orientational scales.
Robbins, B., &amp; Owens, R. (1997). 2D feature detection via local energy.
Venkatesh, S., &amp; Owens, R. (1990). On the classification of image features.