Can C# be used for developing a real-time application that involves taking input from web cam continuously and processing the input?
You cannot use any main stream garbage collected language for “hard real-time systems”, as the garbage collect will sometimes stop the system responding in a defined time. Avoiding allocating object can help, however you need a way to prove you are not creating any garbage and that the garbage collector will not kick in.
However most “real time” systems don’t in fact need to always respond within a hard time limit, so it all comes down do what you mean by “real time”.
Even when parts of the system needs to be “hard real time” often other large parts of the system like the UI don’t.
(I think your app needs to be fast rather than “real time”, if 1 frame is lost every 100 years how many people will get killed?)