Axis-Angle from Matrix
{"Image DocumentName": "Axis-Angle from Matrix", "Image ImageDescription": "The rotation axis, r, is obtained from the skew-symmetric part of the matrix: Another useful relation gives us the magnitude of the rotation, q, in terms of the trace of the matrix, aii: , therefore, cos \uf071 = 0.5 (trace(a) \u2013 1). See the slides on Rotation_matrices for what to do when you have small angles, or if you want to use the full range of 0-360\u00b0 and deal with switching the sign of the rotation axis. Also, be careful that the argument to arc-cosine is in the range -1 to +1 : round-off in the computer can result in a value outside this range.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}