A simple question on cvtColor

cvtColor

asked 2013-04-22 15:36:01 -0600

hayden
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Hello Every body, I have a simple question. If the image is already grey scale image, do I still need to use cvtColor(img, gray, CV_BGR2GRAY) for further processing?

Thanks in advance.

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answered 2013-04-22 15:51:58 -0600

berak
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in general, no.

but beware, the default flag for imread(img_path, flag) is CV_LOAD_IMAGE_COLOR(==1), so that would leave you with 3 identical channels, even if your img is 1-channel gray on disk.

to avoid that problem, call imread(path, CV_LOAD_IMAGE_GRAYSCALE) // or 0 for the flag

if you want a 1-channel img here