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jvcleave / ofxRPiCameraVideoGrabber

development of ofxRPiCameraVideoGrabber, an addon to control the native Raspberry Pi camera in openFrameworks
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question on camera control #1

Open orgicus opened 10 years ago

orgicus commented 10 years ago

Hello Jason,

I've just tested your addon and it works great! Love the shell command options as well, quite handy.

Is the image retrieved as YUV or RGB ? If I want to retrieve the U channel in openframeworks, how would I do that ? I want to use call OpenCV's minMaxLoc function on the U channel.

Thanks, George

jvcleave commented 10 years ago

I believe the camera receives only outputs RGB. If you find something that says different let me know

orgicus commented 10 years ago

Had a quick look at https://github.com/raspberrypi/firmware/blob/master/opt/vc/include/IL/OMX_Broadcom.h and noticed YUV structs there, but I'm not a c++ whiz and haven't used OMX before so not sure how to tap into that.

Using this guide(http://thinkrpi.wordpress.com/2013/05/22/opencvpi-cam-step-6-video/) I've got some basic brightness going with the C API for OpenCV and I thought by default the frames are sent in YUV.

oF is so much nicer to use and I'd like to the same brightness tracking on U channel there rather using C (which I'm 'playing by ear' atm)

jvcleave commented 10 years ago

quickly looking - they are actually converting to RGB in this file (which with this grabber is already done for you) http://raufast.org/download/camcv_vid0.c

jvcleave commented 10 years ago

if you wanted to provide something that uses minMaxLoc and YUV I could see if I could make it work. I'll hopefully be working more with it the next few weeks

jvcleave commented 10 years ago

@orgicus The camera is using OMX_COLOR_FormatYUV420PackedPlanar by default - I believe it is being converted to RGB through the egl_render component when it is written to the texture