So, I have a raster image with 15 arcsecond resolution. I want to be able to extract roads and other linear features from it using ArcGIS. or any other extensions which are compatible with ArcGIS. Anyone can suggest how to go about it? Any help will be greatly appreciated.
If I am reading you correctly, 15 arcsec = 4 per arc min, which is approximately +400m per pixel.
What sort of imagery is this?
It is very unlikely that you will be able to identify features like roads from this data.
Have you looked at this imagery? What can you identify? If you can't see it with your eyes, no algorithm will help.
Extracting actual features from imagery is not for the faint hearted and is a bit of a black art.