mjpg-streamer now with OpenCV input plugin (+filtering)

[jrw]

Originally Posted by virtuald

We used it on our robot today with a python script to do image processing and networktables operations (Lifecam 3000, 320x240, 15fps, 30 quality), and it seemed to be about 20% CPU usage. Not too shabby.

Did you ever use the exposure parameter (-ex)? We have the same webcam, but cannot get the stream with the correct exposure. It is definitely calling the opencv filter, because the image has the result of our processing (eg detected contours), but the exposure is stubbornly refusing to be set.

[virtuald]

Originally Posted by jrw

Did you ever use the exposure parameter (-ex)? We have the same webcam, but cannot get the stream with the correct exposure. It is definitely calling the opencv filter, because the image has the result of our processing (eg detected contours), but the exposure is stubbornly refusing to be set.

Yeah, OpenCV doesn't set exposure properly. See this bug report (looks like a fix was merged, so maybe next year it'll work!).

To set exposure correctly, we use the v4l-ctl executable. I thought I had documented it somewhere, but I can't seem to find it. Anyways, we found it useful to be able to switch the exposure dynamically via NetworkTables, so I created an object to manage that.

You'll have to search the forums, but I remember seeing that the lifecam-3000 only supports certain exposure setting values (like 5 and 10), and for all others it just does full exposure. We use 5 I think.