[Insight-users] VersorRigid3DTransform Translation

[Matt Robert]

Hi,

I am using VersorRigid3DTransform to register two 3D volumes with
MutualInformationImageToImageMetric. The parameters I am setting are as
follows:

  metric->SetFixedImageStandardDeviation( atof(argv[7])  ); //0.4
  metric->SetMovingImageStandardDeviation( atof(argv[8]) ); //0.4
  metric->SetNumberOfSpatialSamples( atof(argv[9]) ); // 100

  typedef OptimizerType::ScalesType       OptimizerScalesType;
  OptimizerScalesType optimizerScales( transform->GetNumberOfParameters() );
  const double translationScale = 1.0 / atof(argv[11]); // was 1000

  float optimizerScale = atof(argv[10]); // was 1

  optimizerScales[0] = optimizerScale;
  optimizerScales[1] = optimizerScale;
  optimizerScales[2] = optimizerScale;
  optimizerScales[3] = translationScale;
  optimizerScales[4] = translationScale;
  optimizerScales[5] = translationScale;

  optimizer->SetScales( optimizerScales );

  optimizer->SetMaximumStepLength( atof(argv[4]) ); //was 0.2000
  optimizer->SetMinimumStepLength( atof(argv[5]) ); //was 0.0001

  optimizer->SetNumberOfIterations( atoi(argv[6]) ); //was 200

  optimizer->MaximizeOn();


I am using CenteredTransformInitializer to initialize center for
registration. When registration is perfomed, only rotation parameters are
changed during registration, however only fractional translation such as
0.01 is observed. I tried changing translation scale maximum and minimum
step length but it is not translating at all and only rotation is effected
by change of these paremeters.

I used following parameters

Fixed.mha Moving.mha Registered.mha  0.1 0.01 100 0.4 0.4 2000 1 1
0.1 = Max Step Length
0.01 =  Min Step Length
100 = Iterations
0.4 = Fixed SD
0.4 = Moving SD
2000 = bins
1 = translation scale
1 = optimizer scale

Which resulted in no chnage in translation

0   0.0646858   [-0.0125372, -0.0222413, 0.0704458, -9876.84, -9834.56,
9869.13]

1   0.0575174   [-0.00579253, -0.0163355, 0.0340948, -9876.84, -9834.56,
9869.13
]
2   0.0579627   [-0.0332293, 0.00705638, 0.0237937, -9876.84, -9834.56,
9869.13]

3   0.05574   [-0.0502068, 0.0262169, -0.0035953, -9876.84, -9834.56,
9869.13]
4   0.070265   [-0.0734341, 0.0536047, -0.0140631, -9876.84, -9834.56,
9869.13]
5   0.0551803   [-0.0578176, 0.0849285, -0.000649574, -9876.84, -9834.56,
9869.1
3]
6   0.0417816   [-0.0477029, 0.0848597, 0.0354581, -9876.84, -9834.56,
9869.13]
7   0.0451694   [-0.0409363, 0.090942, 0.0190652, -9876.84, -9834.56,
9869.13]
8   0.0616735   [-0.0335143, 0.0856553, 0.0211531, -9876.84, -9834.56,
9869.13]
9   0.0351133   [-0.0260303, 0.0912713, 0.021662, -9876.84, -9834.56,
9869.13]

I changed translation scale from 0.0001 to 1000 and same for optimizer scale
but no difference. Any suggestion.

Matt
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://public.kitware.com/pipermail/insight-users/attachments/20060822/26663941/attachment.html