1. object detection:
i want to detect human by robots , is there any sensor in Argos that sens human structure.if yes then which one and how ... it will be enough for me if i am able to detect any cylindrical or circular shape.
Camera filtering is very expensive in simulation, and simulating it efficiently for large swarms (>100 robots) is currently impossible. So no, ARGoS does not do this kind of stuff. You can add it yourself, but you'll have problems with scalability.
An alternative solution is to move a cylinder around. You can place an LED on top of a cylinder and let the robots detect that LED. This would be similar to having a human wearing devices such as AirLeash, which are routinely used for simple robots that follow humans.
2. flocking without tacking light:
i want that robots will move in flocking or fallow the leader. here is example of flocking of robots which move by tracking light ..if i remove light then they unable to move. if i select leader robot with yellow LED and follow that robots then flocking will disturbed some of robots will follow and other cannot...
Well, for that you can try Google Scholar
For instance, the top result if you type 'leader based flocking' is this:
http://people.virginia.edu/~zl5y/housheng/flocking.pdf.
I made ARGoS.