View Single Post
  #4   Spotlight this post!  
Unread 05-01-2009, 10:19
StevenB StevenB is offline
is having FRC withdrawal symptoms.
AKA: Steven Bell
no team
Team Role: College Student
 
Join Date: May 2005
Rookie Year: 2005
Location: Stanford, CA
Posts: 412
StevenB has a reputation beyond reputeStevenB has a reputation beyond reputeStevenB has a reputation beyond reputeStevenB has a reputation beyond reputeStevenB has a reputation beyond reputeStevenB has a reputation beyond reputeStevenB has a reputation beyond reputeStevenB has a reputation beyond reputeStevenB has a reputation beyond reputeStevenB has a reputation beyond reputeStevenB has a reputation beyond repute
Re: camera / vision system too laggy

Quote:
Originally Posted by martin417 View Post
Even without watching the video stream, the reaction of the robot to a change in target position was about 1/2 to 1 second behind, so I don't think it has anything to do with how you monitor the stream.
My only experience comes with hooking the camera directly up to the computer and using the provided software. My sister was goofing around with it and pointed it at the screen displaying the image. This created an infinite "picture within a picture" effect, with each sub-picture lagging the one enclosing it. This video sort of demonstrates it. When an object was waved in front of the camera, it moved sequentially through the frames. As the object moved into the smaller frames, the frame rate increased. When the whole frame (real life) changed, it took more than a second before we saw the change on the screen, but when the fifth sub-picture changed, it took a much shorter time. I'm sorry I don't have a video of it at the moment, as it is very interesting and instructive.

My theory is that this is entirely a problem with the camera's data rate, which is dependent on how much it can compress the frame. If the camera is watching a mostly stationary scene (like most webcams and security cameras are designed to do), it will perform ok. If the camera moves much at all, expect a painfully low frame rate.
__________________
Need a physics refresher? Want to know if that motor is big enough for your arm? A FIRST Encounter with Physics

2005-2007: Student | Team #1519, Mechanical Mayhem | Milford, NH
2008-2011: Mentor | Team #2359, RoboLobos | Edmond, OK
2014-??: Mentor | Looking for a team...
Reply With Quote