[vtkusers] vtkImageReslice config problem

[Dean Inglis]

Hi 

I am developing a MPR application and am having some difficulty

getting vtkImageReslice configured properly. I have a set of

"layout lines" interactively defined on a slice through the original 

image data set. The user can set the number of slices, spacing (output slice


thickness ) and length of the lines (in-plane FOV of the slices) as well

as the in-plane pixel dimensions (see attached jpeg). When I set

the vtkImageReslice, I use the following settings:

// r, s and t define the the output axes unit vectors

this->Reslice->SetResliceAxesDirectionCosines(

r[0],r[1],r[2],s[0],s[1],s[2],t[0],t[1],t[2]);

// turn off transformation of the input spacing origin and extent

// so we can use our own

this->Reslice->TransformInputSamplingOff();

// p0 corresponds to the origin of the output axes unit vectors

// and would correspond to one of the corners of the preview

// plane shown in the figure when that plane was on the first

// of the layout lines

this->Reslice->SetResliceAxesOrigin(p0[0], p0[1], p0[2]);

// neither of the following choices work!

// this->Reslice->SetOutputOrigin( p0[0], p0[1], p0[2] );

this->Reslice->SetOutputOrigin( 0.5*r_sp, 0.5*s_sp, 0.5*t_sp );

// r_sp, s_sp and t_sp are user specified spacings

this->Reslice->SetOutputSpacing( r_sp, s_sp, t_sp );

// w_ext is calculated from the specified spacings, the length of

// the layout lines, the distance they span, and the necessary height

// of the output slices so that none of the input data is truncated.

// w_ext[0], w_ext[2], w_ext[4] are all 0. 

this->Reslice->SetOutputExtent(w_ext);

When I update the reslice, the output slices do not appear positioned

with respect to the requested origin. Is there some transform I have to 

apply to get the correct origin? Would I have to transform the extent?

Dean 

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