[Insight-users] Reg 64X64 images

[Luis Ibanez]

Hi Prasad,

It is not surprising that your image lost most
information after the conversion.

If you converted floats to unsigned char just
by using C-style casting it is very likely that
you truncated the original float values.

Did you verified if the float values were in the
range [0,255] before casting them to unsigned chars ?


You should rather use a normalization filter,
like for example the

    itk::RescaleIntensityImageFilter
http://www.itk.org/Insight/Doxygen/html/classitk_1_1RescaleIntensityImageFilter.html


Examples on the use of this filter are available
on the SoftwareGuide:
http://www.itk.org/ItkSoftwareGuide.pdf
In the "Casting" section : 5.2, pdf-page 96.



In any case, there is not much that you can see
in a 64x64 image   :-)



I would suggest you to create a couple of synthetic
images of this resolution in order to test your
procedures, before you move into processing real
medical data. A typical example could be something
like a circle of radius 25pixels centered in the
64x64 image.



Regards,


    Luis


--------------------------
Prasad Sarma wrote:
> hi,
> 
>   I have 19 images downloaded from GE scanner which
> are of 64X64 resoultion with datatype as "float".The
> raw files are generated in unix. I converted them into
> "unsigned char" in unix using just typecast operator
> of c .
> when I copy this file to windows and run using
> ITK/VTK/FLTK,the image displayed is very bad just no
> structure ..only dots appear. I used MetaImageIO
> function in ITK. 
> 
> 
> 
> When I use MetaImageIO for an "unsigned char" image of
> 180X217X180 as dimension(z,y,x resprectively) the
> image is good.
> 
>  does the resolution matter? did anyone get good
> images with 64 X 64 resolution?
> Pl let me know. 
> Thanks
> 
> Prasad
> 
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