Finding Object Boundaries Using Guided Gradient Ascent1
Yvan G. Leclerc, Pascal Fua · 1987
In real world images, physical event discontinuities cannot be detected solely by their local statistical signature in the image due to the presence of noise and various photometric anomalies. Therefore all methods for finding discontinuities that use purely local statistical criteria are bound to make mistakes and miss some of the weaker parts of edges.