Matching images by comparing their gradient fields.

Daniel Scharstein Matching images by comparing their gradient fields. 572-575 1994 ICPR (1) https://doi.org/10.1109/ICPR.1994.576363 https://doi.ieeecomputersociety.org/10.1109/ICPR.1994.576363 conf/icpr/1994-1 db/conf/icpr/icpr1994-1.html#Scharstein94