Go to Post They can build a robot in 6 hours, so they don't need to start meeting for months... - Karthik [more]
Home
Go Back   Chief Delphi > ChiefDelphi.com Website > Extra Discussion
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Reply
 
Thread Tools Rate Thread Display Modes
  #1   Spotlight this post!  
Unread 04-04-2012, 09:32
techhelpbb's Avatar
techhelpbb techhelpbb is offline
Registered User
FRC #0011 (MORT - Team 11)
Team Role: Mentor
 
Join Date: Nov 2010
Rookie Year: 1997
Location: New Jersey
Posts: 1,622
techhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond repute
Re: paper: How to Get Multiple Cameras on Robot

Quote:
Originally Posted by Kevin Sevcik View Post
This whitepaper is documenting how to attach a second camera and add it to the driverstation display. In this game, likely as a POV camera for ball hunting. As described in the whitepaper, this takes about 30 minutes or less of programming, and no particular expertise.

So I fail to see how adding an entire laptop with USB cameras is a more economical solution to this problem. (Axis cameras are about $125, by the way. Is that a $200 laptop?) And then there's the complication of the custom code on your laptop and interfacing that to the code on the driverstation to display the video from the cameras.

So, while a secondary laptop for image processing is a nifty idea, I don't think it has any relevance whatsoever to this (rather good) whitepaper.
3 Axis cameras at $125 each would be $375. I originally wrote:
"Consider how much 3 of those Axis cameras would cost versus the $25 webcams."

However, now that you've stated you've been getting them for $125 each can you tell us how? Last year when we bought them they were at least $150 each.

If you really want to send the video back to the driver's station from a webcam(s) attached to a robot mounted laptop there are quite a few ways to achieve that. Including but not limited to installing VideoLAN and streaming it from the laptop on the robot to the laptop at the driver's station.

Here's an example of how to do it in Linux (which is what the students had on our robot laptop) and even rebroadcast that to the Internet:
http://www.wikihow.com/Stream-Your-Webcam

BTW, this example uses UDP, not TCP, which might actually come in handy if you do start dropping packets.
This method gives you fine control over both ends of the streaming, including the compression methods, transmission protocols, and the communications stacks themselves (for example you can reduce the MTU, you can increase the receive window, etc).

There's no problem with the whitepaper at all it is great work. There is just more than one way to do this and there shouldn't be any problem with mentioning that considering the title of the topic in question is: "How to Get Multiple Cameras on Robot". Consider for archival sake what will happen if someone searches for that later when this topic is less recent.

Sorry if I've ruffled anyone's feathers wasn't my intent.

Last edited by techhelpbb : 04-04-2012 at 10:00.
Reply With Quote
  #2   Spotlight this post!  
Unread 05-04-2012, 09:50
techhelpbb's Avatar
techhelpbb techhelpbb is offline
Registered User
FRC #0011 (MORT - Team 11)
Team Role: Mentor
 
Join Date: Nov 2010
Rookie Year: 1997
Location: New Jersey
Posts: 1,622
techhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond repute
Re: paper: How to Get Multiple Cameras on Robot

A few other things about VideoLAN that might be relevant to using it like this:

Here's a way to overlay something on the video (like the privacy filter on the Axis cameras):
http://www.recipester.org/Recipe:Ove...yer_3 3186770

Here's a way to 'float' the video without the frames in an overlay.
http://vollnixx.wordpress.com/2011/1...rlay-with-vlc/

If you dig around in VideoLAN you'll also find that you can basically control all it's functions remotely from devices that can't even run VideoLAN itself. For example it can run a telnet server you can connect to and issue it directions.

Last edited by techhelpbb : 05-04-2012 at 09:58.
Reply With Quote
  #3   Spotlight this post!  
Unread 16-06-2012, 12:47
Gregor's Avatar
Gregor Gregor is offline
#StickToTheStratisQuo
AKA: Gregor Browning
no team
Team Role: College Student
 
Join Date: Jan 2012
Rookie Year: 2012
Location: Kingston, Ontario, Canada
Posts: 2,447
Gregor has a reputation beyond reputeGregor has a reputation beyond reputeGregor has a reputation beyond reputeGregor has a reputation beyond reputeGregor has a reputation beyond reputeGregor has a reputation beyond reputeGregor has a reputation beyond reputeGregor has a reputation beyond reputeGregor has a reputation beyond reputeGregor has a reputation beyond reputeGregor has a reputation beyond repute
Re: paper: How to Get Multiple Cameras on Robot

What kind of lag can be seen when adding a second camera? Is there a significant difference in your first camera when the second one is added? Is it a good idea to add a second camera, or will it tax the control system too much?
__________________
What are nationals? Sounds like a fun American party, can we Canadians come?
“For me, insanity is super sanity. The normal is psychotic. Normal means lack of imagination, lack of creativity.” -Jean Dubuffet
"Insanity is doing the same thing over and over again and expecting different results." -Albert Einstein
FLL 2011-2015 Glen Ames Robotics-Student, Mentor
FRC 2012-2013 Team 907-Scouting Lead, Strategy Lead, Human Player, Driver
FRC 2014-2015 Team 1310-Mechanical, Electrical, Drive Captain
FRC 2011-xxxx Volunteer
How I came to be a FIRSTer
<Since 2011
Reply With Quote
  #4   Spotlight this post!  
Unread 16-06-2012, 13:30
Joe Ross's Avatar Unsung FIRST Hero
Joe Ross Joe Ross is offline
Registered User
FRC #0330 (Beachbots)
Team Role: Engineer
 
Join Date: Jun 2001
Rookie Year: 1997
Location: Los Angeles, CA
Posts: 8,574
Joe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond reputeJoe Ross has a reputation beyond repute
Re: paper: How to Get Multiple Cameras on Robot

Quote:
Originally Posted by Gregor01 View Post
What kind of lag can be seen when adding a second camera? Is there a significant difference in your first camera when the second one is added? Is it a good idea to add a second camera, or will it tax the control system too much?
Assuming that you are only using the 2nd camera to display on the DS, the only thing it stresses is the driver station computer. Based on my experience, the classmate can't handle two cameras without degradation. By default, everything degrades equally (both camera's and robot communication). The easiest solution is to use a more capable laptop.
Reply With Quote
Reply


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 00:08.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi