[Insight-users] Convert dicom image to other format

[Luis Ibanez]

Hi Frank,

You probably have some "unsigned short" pixel type on the way.


the range of "signed short" is

           -32768   to   32765



If you can see a pixel at value 60,000 that means that you
have accidentally converted the data to "unsigned short"
where the range is

               0    to  65535

In that case the image will look like binary because all the
values from 32676 to 65535 are those that should have been
in the range from -32768 to -1.


Please post the MetaImage header (just the text file .mhd).
It may have a pixel type such as MET_USHORT (where "U" stands
for unsigned. For a signed type, it should be MET_SHORT.



    Regards,


        Luis



-------------------
Frank Zhao wrote:

> 
> The volume type is:
> 
>  typedef signed short   PixelType;
>  typedef itk::Image< PixelType, 3 >                VolumeType;
> 
> The DICOM files is CT image data.
> 
> I use both snap and volview to view the result MetaImage file.
> 
> Accurely, it is not corrupted, it still show as a 3D image, but like a 
> biany image of the original one, I check the voxel value, it is not 
> biniary image. with some voxel value goes up to 60000 and some only 
> around 50, look like a bianary image.
> 
> I modified the ISIS demo source for DICOM files( project name: 
> APPLICATIONMODEL, following the cvs download provided by you), it 
> displays DICOM image correctly, I only  add the writer code after DICOM 
> image is loaded.
> 
> When DICOM is readed, it uses signed short as the image type.
> 
> Thank you Luis
> 
> Frank
> 
>> From: Luis Ibanez <luis.ibanez at kitware.com>
>> To: Frank Zhao <zhaofrank at hotmail.com>
>> CC: insight-users at itk.org
>> Subject: Re: [Insight-users] Convert dicom image to other format
>> Date: Tue, 22 Jun 2004 14:18:49 -0400
>>
>>
>> Hi Frank,
>>
>> What is the type:
>>
>>         "VolumeType"   ?
>>
>> What is the image modality contained in the
>> DICOM files ? (CT, MRI, PET )?
>>
>> What are you using for viewing the resulting
>> MetaImage file ? (and concluding that it is
>> corrupted ?).
>>
>>
>> It is very likely that you are using an
>> inappropriate pixel type for reading your
>> DICOM images.
>>
>> For example, trying to read 16 bits into an
>> image type of 8 bits...
>>
>>
>>
>> Regards,
>>
>>
>>    Luis
>>
>>
>> --------------------
>> Frank Zhao wrote:
>>
>>>
>>>  After I load 3d Dicom image series, it displays correctly. The image 
>>> is corrupted when I using following code to convert it into another 
>>> format. But it convert correctly when I load a 3D gipl file.
>>>
>>> What is the reason?
>>>
>>> Thank you
>>>
>>> Frank
>>>
>>> =========================================
>>>  typedef itk::ImageFileWriter< VolumeType > WriterType;
>>>  WriterType::Pointer writer = WriterType::New();
>>>  writer->SetFileName( "c:\\temp\\test_write.mhd" );
>>>  writer->SetInput( m_Reader->GetOutput() );
>>>  writer->Update();
>>>
>>> _________________________________________________________________
>>> Is your PC infected? Get a FREE online computer virus scan from 
>>> McAfee?Security. 
>>> http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963
>>>
>>> _______________________________________________
>>> Insight-users mailing list
>>> Insight-users at itk.org
>>> http://www.itk.org/mailman/listinfo/insight-users
>>>
>>
>>
>>
> 
> _________________________________________________________________
> Is your PC infected? Get a FREE online computer virus scan from McAfee® 
> Security. http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963
> 
> _______________________________________________
> Insight-users mailing list
> Insight-users at itk.org
> http://www.itk.org/mailman/listinfo/insight-users
>