I'm looking for solution to create a script for importing only one band from orthphotos, then reclassifying into 2 classes, subtracting them and export as polygons.
Orthophotos are from 2011 and 2014 and are stored in 2 directories (for example D:\2011\ and D:\2014\). Overlapping orthophotos have same name except the new ones have letter "A" at the end - the old one has name E063462.tif - Band_3 and the new one E063462A.tif - Band_3. The script should find identical orthophotos, load only one band and then run processes as it is shown in picture below.
So the question is... does the model work? If it does you can export the model to a python script. If it doesn't, then you will have to provide more information.
There are two paths you can go IMHO, implement iterators in ModelBuilder:
... or use Python code to solve it, using Create lists of data—Help | ArcGIS for Desktop