[Insight-users] itkResampleImageFilter Up sample take too long?

[Lydia Ng]

Hi Feng,

The amount of work done by the ResampleImageFilter is proportional to
the output size. From your numbers,
=20
"upsample work"/ "downsample work"=20
=3D 512x512x251 / 64x64x50
=3D 321 (approx)

"upsample time" / "downsample time"
=3D 107.77 / 0.33
=3D 326 (approx)

So, the time taken to upsample is about what is expected since the
algorithm is linear with respect to output size.

- Lydia

> -----Original Message-----
> From: Feng Ma [mailto:mafeng at hotmail . com]
> Sent: Thursday, October 23, 2003 1:59 PM
> To: insight-users at itk . org
> Subject: [Insight-users] itkResampleImageFilter Up sample take too
long?
>=20
> Hi,
>=20
>   I am using itkResampleImageFilter to do resampling both down
sampling
> and
> up sampling. I found out that down sampling almost take no time, while
up
> sampling takes significantly longer. Attached is my test code, with
> results
> as below:
>=20
>=20
>        Start down sampling: 0
>        End down sampling: 0.33
>        Start up sampling: 0.33
>        End up sampling: 107.77
>=20
>   The code works as:
>=20
>    First downsample a volume 512x512x251 to 64x64x50. Then up sample
the
> small volume to original size.
>=20
>   Any idea about this?
>=20
>   Thanks a lot.
>=20
> -Feng
>=20
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