[Insight-users] Support for BiLinear and Bicubic Interploation types

[Luis Ibanez]

Hi Sharath,

It seems that you are referring to the order of the BSpline to be used
in the interpolation.

See
http://www.itk.org/Insight/Doxygen/html/classitk_1_1BSplineInterpolateImageFunction.html

You can set the Spline Order by calling the method:


                   SetSplineOrder()


See documentation at:
http://www.itk.org/Insight/Doxygen/html/classitk_1_1BSplineInterpolateImageFunction.html#6a31d975ca09b5b2765f8ef2fcdc5a4f


For example:


Cubic BSpline will be:

            interpolator->SetSplineOrder(3);

Linear BSpline will be:

            interpolator->SetSplineOrder(1);


Nearest Neighbor BSpline will be:

            interpolator->SetSplineOrder(0);



You can put set the Order to any integer value between 0 and 5.



     Regards,



        Luis



-------------------------
Sharath Venkatesha wrote:
> Hi Luis,
> 
> Thanks for the clarification on the bi-linear interpolation.
> 
> By bicubic, I mean extension of the cubic hermite spline method for interpolating points in a grid. In a simple implementation, I remember for bilinear we take the values of the neighbors and interpolate them; In bi-cubic, the value of the neighbours, and its second neighbors are also taken for interpolation, with a more complex equation to be solved, and hence finer interpolation.
> The complexity is greater than bilinear and less than bspline.
> 
> Thanks,
> Sharath
> 
> 
> 
> 
> 
> ----- Original Message ----
> From: Luis Ibanez <luis.ibanez at kitware.com>
> To: Sharath Venkatesha <sharath20284 at yahoo.com>
> Cc: Insight users <insight-users at itk.org>
> Sent: Wednesday, July 8, 2009 2:33:18 PM
> Subject: Re: [Insight-users] Support for BiLinear and Bicubic Interploation types
> 
> 
> 
> Hi Sharath,
> 
> 
> (a) Yes, the BSplineInterpolateImageFunction can be used
>     along with any Transform. It use is not limited to
>     deformable registration by any means.
> 
>     Note however, that is computationally more expensive
>     than the linear interpolator.
> 
> 
> (b) The LinearInterpolator in ITK is N-Dimensional.
> 
>     So, it will perform Bilinear interpolation in a 2D image
>     and it will perform Trilinear interpolation in a 3D image.
> 
> 
> 
> (c) What do you call a "Bicubic" type ?
>     Please clarify,
> 
> 
> 
>     Thanks
> 
> 
>        Luis
> 
> 
> 
> ---------------------------
> Sharath Venkatesha wrote:
> 
>>Hi,
>>
>>I am currently using LinearInterpolationFunction filter, and want to use a better interpolation for registration. The manual says that the next option is BSplineInterpolateImageFunction.
>>
>>(a) Can  BSplineInterpolateImageFunction be used with Rigid transformations? I have generally read that it is used with deformable transformations.
>>(b) Is there a support for simpler Bilinear and Bicubic types?
>>
>>Thanks,
>>Sharath
>>
>>
>>
>>     
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