[Insight-users] Wierd metric value for subregion of image

[Bill Lorensen]

Your upper indices should be 255, not 256.

On Tue, Sep 22, 2009 at 6:19 PM, motes motes <mort.motes at gmail.com> wrote:
> I am trying to compute the metric value for 4 subregions in a 512*512
> image pair (fixed, moving). All regions have the size (256, 256) which
> gives the following 4 regions:
>
>
> Region 0 (lower left corner):
> start index = (0,0)
>
> Region 1 (lower right corner):
> start index = (256,0)
>
> Region 2 (Upper left corner):
> start index = (0, 256)
>
> Region 3 (Upper right corner):
> start index = (256, 256)
>
>
> The moving image is deformed increasingly for each region in the
> following order: D(R0) < D(R1) < D(R2) < D(R3) using a 8*8
> BSplineDeformableTransform:
>
>    0  0    0  0    0  0    0  0              0  0    0  0    0  0    0  0
>
>    0  0    20 20    20 20    0  0         0  0    40 40    40 40    0  0
>
>    0  0    20 20    20 20    0  0         0  0    40 40    40 40    0  0
>
>    0  0    0  0    0  0    0  0             0  0    0  0    0  0    0  0
>
>
>
>    0  0    0  0    0  0    0  0             0  0    0  0    0  0    0  0
>
>    0  0    0  0    0  0    0  0             0  0    10 10    10 10    0  0
>
>    0  0    0  0    0  0    0  0             0  0    10 10    10 10    0  0
>
>    0  0    0  0    0  0    0  0             0  0    0  0    0  0    0  0
>
>
> But when I compute the metric I get som rather unexpected values:
>
>
> subRegion = ImageRegion (0148EF70)
>  Dimension: 2
>  Index: [0, 0]
>  Size: [256, 256]
> value = 6490.59
>
>
> subRegion = ImageRegion (0148EF70)
>  Dimension: 2
>  Index: [0, 256]
>  Size: [256, 256]
> value = 704.728
>
>
> subRegion = ImageRegion (0148EF70)
>  Dimension: 2
>  Index: [256, 0]
>  Size: [256, 256]
> value = 9512.77
>
>
> subRegion = ImageRegion (0148EF70)
>  Dimension: 2
>  Index: [256, 256]
>  Size: [256, 256]
> value = 2481.78
>
>
> I would expect that the region starting in index (0,0) should almost
> be 0. This is also verified from the following images (fixed, moving
> and difference respectivily):
>
> http://img6.imageshack.us/img6/994/82602924.jpg
>
> Am I defining the start index in the fixed image wrong?
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