Hello Hoody!



 Hoodythree:

Actually I mean treating these four classes in the above image(a) as one, cause they belongs to the same category semantically.


I believe that I did answer the question you asked (with a somewhat
simplified example).



 Hoodythree:

Is it possible to recognize images with very large intra-class variation


In my example, a class showing “very large intra-class variation” would
be “monarch”, with the intra-class variation being caterpillar vs. butterfly.
(“Swallowtail” would be another class showing large intra-class variation
for the same reason.)



 Hoodythree:

(such as one species within different life cycles)?


To be very specific, in my example “one species” would be monarch,
and the “different life cycles” would be caterpillar and butterfly.
(If your asking about building a binary classifier that recognizes
“monarch” vs. “not monarch” the logic of my previous post still applies.
You can imagine training a three-class classifier, “monarch caterpillar”
“monarch butterfly”, “neither”, that then learns to collapse the two
classes “monarch caterpillar” and “monarch butterfly” into a single
“monarch” class, leaving you with a two-class (binary) “monarch”
vs. “not monarch” classifier.)
Best.
K. Frank