Best way of masking on warpAffine?

warpAffine

asked 2013-05-29 16:52:17 -0600

Papercut
71 ●3 ●6

updated 2013-05-29 18:05:56 -0600

Hi,

Just like using mask when copying image:

image1.copyTo(image2, mask)

I just want to apply warpAffine only on a particular region because I only need a small part of image for example mouth. But existing warpAffine methods do not seem to accept any masks. Therefore I need to find a smart and easy way to do masking warpAffine method in order to reduce running time. Has anyone here thought about it before? Please give me some tips!

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answered 2013-05-30 07:30:37 -0600

Guanta
6736 ●6 ●25 ●79

If you have the ROI-coordiantes of the mouth, then you could apply warpAffine only onto that. Example:

// x0,y0,x1,y1 are the bounding coordinates of your mouth-region
// of course the same could be achieved with cv::Rect()
cv::Mat mouth_roi(whole_image, cv::Range(y0,y1), cv::Range(x0,x1));
// don't know if warpAffine works in-place, but give it a try:
cv::warpAffine(mouth_roi, mouth_roi, M, mouth_roi.size());

If that doesn't work you have to apply warpAffine to a different destination matrix and copy it back to mouth_roi. If they have different sizes it's getting slightly more complicated but the principle is the same.