Change camera output in Mac OS 10.6

Is there any way to programatically change what the camera in Mac OS X outputs? Maybe apply a filter, so that all applications using the camera 开发者_开发百科will see the camera image plus the applied filter?

If not programatically, or if not by using Objective-C, is there any other way this can be achieved?

You'd have to create a custom driver of sorts, as many applications access the camera directly or with a low-level API, so forcing them to use your filtered stream would be hard to do.