Hey,
Our team is having some problems with the AXIS Camera.
Every time its turned on, Even if its from the browser, Our router lags a whole lot. Now I know that the QOS settings are “supposed to” prevent that, but I was wondering if there were any other fixes.
If not, Our plan was to use the kinect and a laptop we will strap to the robot.
The laptop will do all of the prcessing on RoboRealm and send the resulting information to the cRIO using Net Tables. My only problem there is that we have no idea how we are going to hook the kinect up to the power board.
If anyone has an answer, That would be great.
Lag is often caused by processing slower than you produce. The framerate of the camera will tell you roughly how long you have to process the image. Can you time how long the processing takes?
And if the generation is at 33ms and the processing takes 36, that may not sound like much, but after just a few seconds you are getting pretty far behind.
Generally, you either want to speed up the processing by leaving out a step, processing a smaller image, or using a different technique. Or you leave that alone and change the rate of the camera to 24 or 20 or something slower than the processing at least. Another approach is to identify the minimum frames you need to succeed and hold yourself to that.
Greg McKaskle
The thing is, Even when I have the code for vision processing disabled, and I don’t even address the camera in Begin.vi, It still lags the robot when I go to the cameras web page. I have even tried with tethering my laptop to the router, and the robot still lags.
What is the framerate or fps of the camera? What are the size and compression settings too?
Greg McKaskle
Compression is upwards of 60%
FPS is set at 10
Resolution: 320 x 240
Those seem like good settings. Are those the settings for the dashboard and the robot? What is the Mbps readout of the dashboard?
Greg McKaskle
Sorry, I can’t tell you until Saturday. Don’t have camera or cRIO or router to test with.
You’re not trying to make your laptop work too hard, are you?
You say the lag happens when you view the camera from the browser, and that shouldn’t have any effect on what the cRIO is doing. However, it could make the Driver Station laptop slow down. Check the laptop’s CPU usage, both when things are working okay and when the problem is happening.
Well
Intel i7 2.2GHz
4GB RAM
Don’t think that is the problem, that max it’s ever used when using the camera and driver station is 20%.
As for the bandwidth, it stays around 1-2Mbps.
You may want to write a simple test program to measure the lag so that we can quantify it compared to what others are seeing.
Click on My computer in the project, then press Ctl-N to create a new VI. In that VI, wire the Millisecond Tick Count to an indicator and add a delay of 1ms to the loop. On the same panel, read from the camera and display it in an image indicator. When you run the VI, you point the camera at the computer screen so that the camera captures and displays the ms counter.
Then, with this VI running, press the print screen key. The screen you captured will have the current ms count and in the image display next to it, it will show the screen as most recently captured by the camera. The difference between the ms tick count and the camera version will indicate the lag. You can take a few more screen captures to get a better statistical sample since the camera will not update but every 100ms based on your camera settings.
The attached image shows the core of the measurement VI.
Greg McKaskle
