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The relationship between Homography matrix and scaling images

asked 2014-01-06 21:37:41 -0500

我干过豪哥 gravatar image

I have compute the Homography matrix H1 between two images,after that I just use function "resize(orign_image,img,Size(),workscale,worscale)".finally I want to get a H'to apply to the img which has been resized,but the H1 or H'(H1 *workscale)cann't work.So I hope someone can help me get correct H' that can be applied to resized imgs.^_^

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answered 2014-01-06 22:02:55 -0500

Nghia gravatar image

updated 2014-01-06 22:03:30 -0500

You probably want

Mat H2 = S * H1 * inv(S);

Where S is

Mat S = Mat::eye(3,3,CV_64F);

S.at<double>(0,0) = scale_x;
S.at<double>(1,1) = scale_y;
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Thanks Bro!! your answer is correct,I have solved it^_^

我干过豪哥 gravatar image我干过豪哥 ( 2014-01-07 22:25:55 -0500 )edit
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answered 2014-01-06 23:56:53 -0500

updated 2014-01-07 00:03:40 -0500

After computing the homography matrix you must use the perspectiveTransform function instead of the resize function.For more information please see this link.

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Asked: 2014-01-06 21:37:41 -0500

Seen: 2,953 times

Last updated: Jan 07 '14