Camera Image Delay

[taysonholzer]

We're experiencing a four second delay from our Axis camera to the Classmate PC. Is this a programming problem or is this just inherent to the operation of the camera? If it is a programming problem, how do we fix it in Windriver?

[buddyb]

Four seconds? That's *really* significant.

In your teleoperated loop, try placing a "Wait(0.05); //(50 ms)". It has an unnoticeable effect on the teleoperated mode, but allows other tasks to run EXTREMELY smoothly, which may greatly help image transfer. It can also make your program far more responsive.

[Mike Mahar]

If you install the new Mandatory DriverStation update, this should improve to about a 1/2 second delay. There was a modified Dashboard that was posted last week that removes several CPU hog functions from the Dashboard. We are using that Dashboard and there is almost no noticeable delay in the camera. You have to use the latest DriverStation but you can use any Dashboard.

[Greg McKaskle]

From my investigations, the large four or five second lag was typically caused by the laptop not keeping up with the cRIO pushing out images. Some of this overhead was due to some UI stuff in the DS itself related to the cypress I/O. The latest update cuts down the CPU resources needed by the DS, so the issue will likely go away. If it doesn't, run in Developer and look at the task manager to determine if there are other tasks which are contributing. As for comparing different dashboards, I haven't directly compared different ones for performance. If anyone has quantitative comparison, I'm all ears.

Greg McKaskle

[slavik262]

If you just want video and don't care about the rest of the dashboard for now, TheDominis has made a lightweight video dashboard. Read about it here:

http://www.chiefdelphi.com/forums/sh...ad.php?t=82422

I'm also making custom dashboard software that will support video in C++ with hardware rendering for maximum speed, but it's not out yet. You can read about it here:

http://www.chiefdelphi.com/forums/sh...ad.php?t=80561

Another thing you can do is get a USB to Ethernet connector and run the dashboard on a faster laptop.

[Greg McKaskle]

I certainly don't want to discourage anyone from making a dashboard framework. As long as your are learning and enjoying yourself ...

But until you've measured the speed of the IMAQ display, perhaps throwing around terms like HW accelerated or super-fast is a bit premature. The IMAQ stuff is used in industry and is quite optimized. There are always new and better ways to skin a cat, but that is also why NI pays people to take advantage of such things.

If you have some comparisons worth sharing, I'm always game. I know just who to show it to in order to get IMAQ improved.

Greg McKaskle

[slavik262]

By all means, I'm not discouraging anyone from making their own system. It's a great way to challenge yourself and get something that custom-fits what you need. If anybody wants to pursue their own dashboard system, feel free to contact me if you want any help. That's what the Chief Delphi community is for.

I'm also not saying that the system I'm developing is faster than IMAQ, just that it is fast. I use the term hardware-accelerated because my dashboard can use DirectX or OpenGL as a renderer. When I do benchmarks (eventually), I'll be sure to share them.

Matt Kline