construct and apply affine transformation matrix

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Fatma Elzahraa Ahmed 2015-9-14

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https://ww2.mathworks.cn/matlabcentral/answers/242828-construct-and-apply-affine-transformation-matrix

Hello, I am trying to construct affine transformation matrix through a parameter vactror of rotation angle, scaling, shearing and displacement values. The vector is organized as follow:

phai=[rotationAngle, scalingCoefX, scalingCoefY, shearingCoefX, shearingCoefY, translationCoefX, translationCoefY]';

To construct the affine transformation matrix I apply the following code:

rotation=[cos(phai(1)) sin(phai(1)) 0; -sin(phai(1))cos(phai(1)) 0; 0 0 1];
scaling=[phai(2) 0 0; 0 phai(3) 0; 0 0 1];
shearingY=[1 0 0; phai(5) 1 0; 0 0 1];
shearingX=[1 phai(4) 0; 0 1 0; 0 0 1];
translation=[1 0 0; 0 1 0; phai(6) phai(7) 1];
T=rotation*scaling*shearingY*shearingX*translation;
T = maketform('affine',T);

Then to apply the result to an image (c) I use the perform:

c=imtransform(c,T);

My question is: is this code right because it takes a lot of time to be executed? is there any suggestions to speed up the execution in the case that the code is right?

Thank you very much