How do i calculate hessian matrix for an image?
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suresh G
le 20 Mar 2013
Commenté : Ismail Zouaoui
le 23 Juil 2019
i need to calculate hessian matrix manually.can anyone help?
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David Legland
le 20 Mar 2013
Hi, you need to compute second derivatives in each direction, using something like:
[gx, gy] = gradient(double(img));
[gxx, gxy] = gradient(gx);
[gxy, gyy] = gradient(gy);
The coefficients of the hessian matrix for each pixel are given by gxx, gxy and gyy.
regards
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Zirui WANG
le 11 Jan 2019
Thanks a lot for the answer, but I think there is a small order issue in the last line?
I think the last line should be
[gyx, gyy] = gradient(gx)
instead of
[gxy, gyy] = gradient(gx)
?
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Yongkai liu
le 24 Déc 2018
Thanks! It seems that in practice, we use the second derivative of gassian filter convoluted on image to get the hessian matrix feature of image.
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