[Insight-users] ICP Registration.Need help ASAP!!!! Please

[Smriti Raghunathan]

Hi,

I am trying to register two sets of 3D images using
IterativeClosestPoint2.cxx. In order to understand the final output
result better I tested the algorithm by first taking an image set,
mathematically translating it by 10 pixels and then trying to register
it with the non translated original image. This worked perfectly.

I then tried to take the same image and mathematically rotate it by 5
degrees about the z-axis and then registering it to the non rotated
image set. When I tried doing this I got the following message:

vnl_levenberg_marquardt: too many iterations
vnl_levenberg_marquardt: 286 iterations, 2003 evaluations, 7
residuals. RMS error start/end 8.21149/6.63919

Solution = [-0.0378734, -0.00286702, -0.0183505, -3.65209, 3.49051, 0.0378646]

I have the following questions:

1) what does this error message mean?

2) I understand that for the solution, the last three numbers are
translations in X, Y, and Z. What are the first three numbers? Are
they rotations about the x,y and z axes? If yes, then are the numbers
in radians or degrees. etc? Please help me interpret.

I have tried reading the ITK manual over and over again but I am
unable to figure it out. Any kind of help will be appreciated.

Thanks

Smriti