Real time video capturing

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1

hello!!
I have installed openCV in the beagle board runing Anstrong 2.31. but
the capture is too slow, about 4 fps in VGA resolution. Does anyone
know how can i speed up the video capturing?

Thank you very much

2

hello!!
I have installed openCV in the beagle board runing Anstrong 2.31. but
the capture is too slow, about 4 fps in VGA resolution. Does anyone
know how can i speed up the video capturing?

Have you tried using gstreamer with the ti plugins and codecs?

3

What is angsrong 2.31?

4

Because of that problem, I used SDL for the capture, then used OpenCV 1.x for the image processing.

Jose Antonio wrote:

5

i have the same problem, but my framerate is limited to 7fps in
640x480. I'am doing some circle detection in the image and the
framerate drops to 2fps. How do you use SDL to do capture and then
opencv for video processing. Does SDL capture an iplImage ?

6

The SDL structure is different from the OpenCV structure, but the actual pixel data will be in whatever standard format you set up. First create an OpenCV image header:

IplImage* frameA = cvCreateImageHeader (sizeCV, IPL_DEPTH_8U, 4);

Then let the OpenCV header point to the captured SDL frame, where videoIn is the SDL image structure:

cvSetImageData (frameA, videoIn->framebuffer, 4*videoIn->width);

Then cvSplit can be used to extract Y values.

I used the above two statements with SDL capturing in YUYV format from a Logitech 9000. Even better performance was obtained by directly copying the Y values directly into an OpenCV grayscale image instead of using cvSetImageData.

jpiat wrote:

7

Thanks John for your answer. And How many fps do you get doing that?

8

As I recall, it was on the order of 7-10 fps. There was quite a bit of OpenCV processing for optical flow, so the resolution had to be reduced to 320x240 in order to achieve this rate.

The full CV application was implemented by a graduate student for a humanoid robotics contest in Bangalore a few months ago. The robot performed well, I am told.

Jose Antonio wrote:

9

I've tried gstreamer without TI plugins, and the capture is also too
slow. Did sb try gstreamer with DMAI?

10

I've tried gstreamer without TI plugins, and the capture is also too
slow. Did sb try gstreamer with DMAI?

DMAI can improve the encoding performance, but I doubt that it will
improve capturing speed. Are you sure that you camera can deliver
higher framerate with VGA resolution?