[Insight-users] suppress shearing

[Luis Ibanez]

Hi Erik,

Thanks for the clarification.

The class that you may want to use then is the

       itkScaleSkewVersor3DTransform.h

http://www.itk.org/Doxygen/html/classitk_1_1ScaleSkewVersor3DTransform.html


and follow your original plan of using the parameter
scaling in order to disable (or at least attenuate) the
modification of the Skew and Rotation parts.


Regards,


      Luis


------------------------------------------------------------------------
On Sat, Apr 10, 2010 at 5:18 AM, Erik Türke <tuerke at cbs.mpg.de> wrote:

>  On 04/09/2010 11:48 PM, Luis Ibanez wrote:
>
>
> Hi Erik,
>
> A transform that allows for rotation and for anisotropic scaling
> is indirectly allowing for Skewing (or Shearing).
>
> In short,
> it is a transform that does not preserve the angles
> between two straight lines.
>
>
> In that case, the Affine Transform is what you need.
>
>
> However,
> you may want to look at the
>
>                   itkScaleSkewVersor3DTransform
>
>
> http://public.kitware.com/Insight/Doxygen/html/classitk_1_1ScaleSkewVersor3DTransform.html
>
>
> Just in case
> your definition of "shearing" is a bit more specific....
>
>
>
>      Regards,
>
>
>            Luis
>
>
>
>
> --------------------------------------------------------------------------------
> On Fri, Apr 9, 2010 at 10:32 AM, Erik Tuerke <tuerke at cbs.mpg.de> wrote:
>
>> Hi!
>>
>> Thanks for the reply!
>>
>> Unfortunately i can not rely on an isotropic scaling. Sometimes it will be
>> enough, but the best would be to apply an anisotropic scaling.
>>
>> cheers
>>
>> ----- Original Message -----
>> From: "Bill Lorensen" <bill.lorensen at gmail.com>
>> To: "Erik Tuerke" <tuerke at cbs.mpg.de>
>> Cc: "insight-users" <insight-users at itk.org>
>> Sent: Friday, April 9, 2010 2:52:51 PM GMT +01:00 Amsterdam / Berlin /
>> Bern / Rome / Stockholm / Vienna
>> Subject: Re: [Insight-users] suppress shearing
>>
>> itkSimiliarity2DTransform and itkSimilarity3DTransform ally rotation,
>> translation and isotropic scaling.
>>
>> Is your scaling isotropic?
>>
>> On Fri, Apr 9, 2010 at 4:39 AM, Erik Tuerke <tuerke at cbs.mpg.de> wrote:
>> > Ahh...sorry for the double post but i am used to push strg-s to save a
>> text but unfortunately this is assigned to sent.
>> >
>> > anyway...
>> >
>> > I am seeking a transform which is capable of applying a transformation
>> in a way of translation, rotation and scaling.
>> > Since i did not found such a transform, i thought taking the affine
>> transform and suppress the shearing.
>> > Is there any way to do so? Maybe setting the optimizer scale to 0 for
>> the respective parameters...but what are the shearing parameters?
>> >
>> > Thanks!
>> >
>> > --
>> > Erik Türke
>> > Department of Neurophysics
>> > Max-Planck-Institute for Human Cognitive and Brain Sciences
>> > Stephanstrasse 1A
>> > 04103 Leipzig
>> > Germany
>> > Tel: +49 341 99 40-2440
>> > Email: tuerke at cbs.mpg.de
>> > www.cbs.mpg.de
>> >
>> >
>> > _____________________________________
>> > Powered by www.kitware.com
>> >
>> > Visit other Kitware open-source projects at
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>>
>>  --
>>  Erik Türke
>> Department of Neurophysics
>> Max-Planck-Institute for Human Cognitive and Brain Sciences
>> Stephanstrasse 1A
>> 04103 Leipzig
>> Germany
>> Tel: +49 341 99 40-2440
>> Email: tuerke at cbs.mpg.de
>> www.cbs.mpg.de
>>
>>
>> _____________________________________
>> Powered by www.kitware.com
>>
>> Visit other Kitware open-source projects at
>> http://www.kitware.com/opensource/opensource.html
>>
>> Kitware offers ITK Training Courses, for more information visit:
>> http://www.kitware.com/products/protraining.html
>>
>> Please keep messages on-topic and check the ITK FAQ at:
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>
>  Hi!
>
> Thanks for your reply!
>
> Actually, what i want to do is ONLY a anisotropic scaling. The reason why i
> mentioned the translation and rotation is because i want to set these
> parameters gained from a rigid transform as a "initial parameters". But when
> applying the Scaling transform, rotation and translation should be fixed.
>
> Rigid Transform(rotation and translation) - > Scaling Transform(anisotropic
> scaling)
>
> So i want to perform the two transforms consecutively without having to
> resample the image after the rigid transform.
> So my idea was to use a simple affine transform and making the rotation,
> translation and shearing parameters fixed by setting the respective
> optimizer-scalings to 0. But my guess is now there are no seperate scaling
> parameters. :-(
>
> So i have to consider a different approach...
>
> cheers
>
>
>
>
>
>
>
>
>
> _____________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
>
> Kitware offers ITK Training Courses, for more information visit:
> http://www.kitware.com/products/protraining.html
>
> Please keep messages on-topic and check the ITK FAQ at:
> http://www.itk.org/Wiki/ITK_FAQ
>
> Follow this link to subscribe/unsubscribe:
> http://www.itk.org/mailman/listinfo/insight-users
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>
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