No subject

observed that if you compose transforms, you might observe artifacts
such as torsional twisting of geometry.

This torsional twist happens due to the geometry of the image object
in 3D from which two consecutive slices of a 3D object are drawn. The
slices hold slightly different geometries that cause a very small
rotation. This rotation bias builds up as you compose.

Kishore

On Thu, Oct 15, 2009 at 5:20 PM, Darren Weber
<darren.weber.lists at gmail.com> wrote:
>
> We have a series of several thousand 2D microscope images:
>
> img0001 ... imgN
>
> A simple ITK program uses itkImageSeriesReader to stack the sequential
> images into a 3D volume for output to a .vtk file.=A0 Without any
> coregistration of the image series, the result is a mess (as expected).
>
> Another ITK program runs registration algorithm(s) on consecutive pairs o=
f
> images in the 2D image series (each pair of images is registered
> independently of any other images in the series).=A0 It outputs a transfo=
rm
> file for each image registration, using file names something like:
>
> img0002to0001.xfm
> img0003to0002.xfm
> etc.
>
> What is an efficient way to combine and apply these transforms using an I=
TK
> pipeline to 'concatenate' the image series into a 3D stack?
>
> My conception of how this might work, in outline, is:
>
> a)=A0 begin with img0001
> apply transform: none
>
> b) add img0002 to the stack
> apply transform: img0002to0001.xfm
>
> c) add img0003 to the stack
> apply transform: img0002to0001.xfm
> apply transform: img0003to0002.xfm
> (How to concatenate transforms without resampling image data?)
>
> d) add img0004 to the stack
> apply transform: img0002to0001.xfm
> apply transform: img0003to0002.xfm
> apply transform: img0004to0003.xfm
> (How to concatenate transforms without resampling image data?)
>
> etc.
>
>
> In this conception of the problem, the pair-wise registration transforms =
are
> 'concatenated' to propagate the registration through the entire series.
> What is the most efficient way to do that in ITK?
>
> Is it possible (or reasonable) to associate a transform object (or file)
> with each 'element' of an itkImageSeriesReader?=A0 If not, is there anoth=
er
> convention for creating an ITK filter pipeline or registration pipeline?
>
> TIA and take care,
> Darren
>
>
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