Mercurial > hg > orthanc-stone
comparison Resources/Computations/ComputeShearParameters.py @ 191:46cb2eedc2e0 wasm
ShearWarpProjectiveTransform
| author | Sebastien Jodogne <s.jodogne@gmail.com> |
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| date | Fri, 16 Mar 2018 15:01:52 +0100 |
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| children |
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| 190:465b294a55f0 | 191:46cb2eedc2e0 |
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| 1 #!/usr/bin/python | |
| 2 | |
| 3 from sympy import * | |
| 4 import pprint | |
| 5 | |
| 6 init_printing(use_unicode=True) | |
| 7 | |
| 8 s13, s23, s43 = symbols('s13 s23 s43') | |
| 9 x, y, z, w = symbols('x y z w') | |
| 10 | |
| 11 A = Matrix([[ 1, 0, s13, 0 ], | |
| 12 [ 0, 1, s23, 0 ], | |
| 13 [ 0, 0, 1, 0 ], | |
| 14 [ 0, 0, s43, 1 ]]) | |
| 15 | |
| 16 print('\nLacroute\'s shear matrix (A.14) is:') | |
| 17 pprint.pprint(A) | |
| 18 | |
| 19 # At this point, we can write "print(A*p)". However, we don't care | |
| 20 # about the output "z" axis, as it is fixed. So we delete the 3rd row | |
| 21 # of A. | |
| 22 | |
| 23 A.row_del(2) | |
| 24 | |
| 25 p = Matrix([ x, y, z, 1 ]) | |
| 26 | |
| 27 v = A*p | |
| 28 print('\nAction of Lacroute\'s shear matrix on plane z (taking w=1):\n%s\n' % v) | |
| 29 | |
| 30 print('Scaling = %s' % (1/v[2])) | |
| 31 print('Offset X = %s' % (v[0]/v[2]).subs(x, 0)) | |
| 32 print('Offset Y = %s' % (v[1]/v[2]).subs(y, 0)) |