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Motion matrices in homogeneous coordinates (need help)
Posted:
Jul 10, 1996 12:10 PM


I have to rotate some images. The usual rotation matrix in homogeneous coordinates is
cos(angle) sin(angle) 0 sin(angle) cos(angle) 0 0 0 1
In this case, the rotation center is (0,0) which is in the top left corner of the image. I'd like the rotation center to be (a, b) and I tried to combine : a translation (a, b), the rotation and a translation (a, b). This gives:
cos(angle) sin(angle) a( cos(angle)1 )  bsin(angle) sin(angle) cos(angle) b( cos(angle)1 )  asin(angle) 0 0 1
This doesn't seem to work! Could you help me?



