[Insight-users] Image registration error

[Daniel Mace]

Eric,

It means that your moving image doesn't line up with any pixels in your 
fixed image (i.e. you've rotated it completely off of the map).  You 
need to adjust your starting parameters so that at least some of the 
pixels are lined up.

It's probably easiest just to set your initial parameters to the 
rotation instead of rotating beforehand (unless you are trying to 
preprocess all your images for normalization).  Don't forget that in 
order to rotate your moving image by 90 degrees you actually have to set 
your initial rotation parameter to -90 (or -1.57, as it's in radians).   
The transformation parameters are all in terms of the fixed image, and 
not the moving image (e.g. a scale of 0.1 actually magnifies your moving 
image by 10, and a x translation of 50 actually moves your moving image 
-50 units).  This caused me a bit of confusion  starting out.

Cheers,
Dan

Eric John wrote:
>
> Hello all, I am trying to register two 3-d MRI images (.mhd). The 
> moving image was previously rotated 90 degrees so that both images 
> would be in the same orientation for ease of registration. Before 
> rotating, it caused no error, now I get this error:  
>
> ExceptionObject caught !
>
> itk::ExceptionObject (012AFBA4)
> Location: "unknown"
> File: 
> C:\InsightToolkit-2.8.1\Code\Algorithms\itkMeanSquaresImageToImageMetric.t
> xx
> Line: 369
> Description: itk::ERROR: MeanSquaresImageToImageMetric(01805120): All 
> the points
>  mapped to outside of the moving image
>
> Any explanation for this? btw, this is one of the registration 
> examples: ImageRegistration8
>  
> Thanks,
> Eric
>
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