I've seen from the sample how to display an image from the webcam, but how do I get the image captured as an array?
import cv
capture = cv.CaptureFromCAM(0)
img = cv.QueryFrame(capture)
img.tostring() gives me weird caracters. Thanks in adv.
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why do you want to capture it in array? whats the exact requirement?Ankit Jaiswal– Ankit Jaiswal2010-08-20 07:22:32 +00:00Commented Aug 20, 2010 at 7:22
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4 Answers
I think this is what you're looking for:
img=cv.LoadImage("asd.png")
mat=cv.GetMat(img)
mat[3,1]
(83.0, 88.0, 89.0)
anyway, you should check opencv python cookbook for use with PIL and NUMPY packages.
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Be sure to get an opencv with numpy support included. The sequence that works for me is capture an IPL, convert to cvMat, convert to numpy:
import cv, numpy, pylab
capture = cv.CaptureFromCAM(0)
img = cv.QueryFrame(capture)
mat=cv.GetMat(img)
a = numpy.asarray(mat)
pylab.imshow(a)
Note that the representation of color is different from what pylab assumes. But there comes opencv documentation to your help!
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I believe your problem might be the way you are printing/displaying the contents of the array.
Nevertheless, this blog post shows how to capture frames from a webcam on linux using python.
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According to the docs, QueryFrame returns an IplImage. IplImage can be treated as an arbitrary array. It looks like you'll want to use the "Get" set of functions to access array elements.
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PuercoPop
Thanks, I didn't knew how to manipulate it. I had found a way to convert it to a PIL image and then accesses as an array. img_array = Image.fromstring("RGBA",cv.GetSize(img), img.tostring() )
