I’m still not sure what you are asking. What do you mean by “recognize video signal”?
The Video Experimenter shield allows you to capture very low resolution monochrome frames, overlay text and graphics on a composite video signal, etc. See the project page for more ideas: http://nootropicdesign.com/ve/projects.html
I try to catch video signal from CMOS camera (RCA). I want use only a composite video input from arduino to processing. Can I make this with video experimenter shield?
If i understand your question, yeah you can share frame data through the serial port to communicate with processing. Use the right serial command. i think it is serialpol or polserial. My advice check the forum, some other posted questions might help.