locked-fg
Inconsistent Parameterization
Different feature descriptors are parameterized differently.
It would be nice to have a full Java based API for settings parameters.
Some examples:
PHOG has Setters for bins and recursions, but not for canny.
setGradientSource seems to be a bit odd. There is an initial value, but after the first run() it becomes null, making the feature descriptor somewhat non-reentrant.
AutoColorCorrelogram on the other hand apparently cannot be configured at all from Java, but only via properties, meaning you can't use different parameterizations in the same run if you want to compare them.
Descriptors shouldn't be reused at all. Maybe this should be guaranteed by throwing an exception after the first run.
Different configurations can be compared easily: Create different instances and call the set Properties methods. The according property values are set implicitly.