[Gate-users] Voxelized phantom and interfile format conversion

[Didier Benoit]

Hi Alex,

I have converted MOBY and others phantoms from 32 bits -> unsigned 16 
bits, or 8 bits -> unsigned 16 bits. You can do this with a simple C/C++ 
code.
In your previous mail, at the point 3, the limit of 'unsigned int' is 
not -32768 to 32767 but 0 to 4294967296, and 'int' is -2,147,483,647 to 
2,147,483,648.
For your information 'unsigned short' is 0 to 65,536, and 'short' is 
-32,767 to 32,768.

In this mail, you'll find a little program in C to convert 8 bits -> 
unsigned 16 bits.
When a number in 8 bits is -12, for instance, in unsigned 16 bits is 
65524, beware :).

(To compile: just 'make' )

I hope that helps you
Kind Regards,
Didier

On 09/30/2011 12:54 PM, Alex wrote:
> Hello:
>
> 1>  I think this question might have been raised before.  Nevertheless, I
> still struggle with it. Basically I want to convert the Zubal torso phantom
> (8bit unsigned raw) into the interfile format used by GATE (uint16).  Some
> has suggested using MATHLAB, others have suggested xmedcon.  The problem
> with xmedcon is that there is o uint16 output option (as far as I know).  So
> far, I have converted to signed 16 using xmedcon.  I am not familiar with
> MATHLAB but to convert from signed to unsigned 16, is it as simple as type
> casting into unsigned 16 such as below.
>
> intArray = uint16(array);
>
>
>
>
> 2>  One can accomplish the same thing with C/C++ by simple static cast?
> (assuming that int is 16 bit for my compiler)
>
> y = (unsigned int) x;
>
>
> 3>  Also, naively, since pixel value ranges for signed 16 goes from -32768 to
> 32767 and unsigned from 0 to 65535, can one simply convert by this simple C
> snippet:
>
>
> unsigned int y;   // -32768 to 32767
> int x = a;           // 0 to 65535
>
> y = (unsigned int) (x + 32768);
>
>
> 4>  If simple conversion by type casting is possible, I guess I can bypass
> xmedcon and simply convert directly from 8bit raw data to uint16?
>
> Thanks in advance,
>
> Alex
> ECU Medical Physics Student.
> _______________________________________________
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> Gate-users at lists.opengatecollaboration.org
> http://lists.opengatecollaboration.org/mailman/listinfo/gate-users


-- 
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Didier BENOIT, GATE Engineer
Imagerie et Modélisation en Neurobiologie et Cancérologie (IMNC)
IMNC – UMR 8165 CNRS – Université Paris 7 – Université Paris 11
Campus d’Orsay
Bâtiment 440
91406 ORSAY Cedex

Tél : (33) 1 69 15 68 76
E-mail : benoit at imnc.in2p3.fr
http://www.imnc.in2p3.fr
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