image processing using c programming to detect square tunnel

i am in final year project, someone please help me..how should be start to programming c for image processing...please give me some idea or guidance..

step 1: if you aren't already fluent, learn C. this will likely take much longer than the remainder of the school year that you have
step 2: use google or some other search engine to find information about computer vision and image recognition.
step 3: write, test, and debug your code until it works the way you want it to.
step 4: come back here and ask for help with specific questions as they arrive.