@startuml
skinparam monochrome true
start
while ()
	:searchArena?;
	:shouldSendImage = false;
	:Img img = camera.Grab();
	:arena = img.SearchArena();
	if (arena) then (nullptr)
		:msg = new Message(MESSAGE_ANSWER_NACK);
		:messageToMonitor!msg;	
	else () 
		:img = img.DrawArena(arena);
		:msg = new MessageImg(MESSAGE_CAM_IMAGE, img);
		:messageToMon!msg;
		:validateArena?arenaOk;
		if (arenaOk) then (false)
			:arena = nullptr;
		else (true)
		endif;
	endif;
	:shouldSendImg = true;
end while;
stop
@enduml