[Insight-developers] GDCM2 transition testing

[Karthik Krishnan]

On Mon, Oct 6, 2008 at 8:57 AM, Luis Ibanez <luis.ibanez at kitware.com> wrote:
>
Thanks a lot Mathieu.

>
> 1) ITK doesn't have an official color space representation.
>   We have several filters intended for RGB images.
>
>   I would vote for "doing the right thing", particularly
>   when doing the wrong thing will involve loosing information
>   from a medical image.  :-/
>
>   Do we need a new type of image ?
>   E.g.
>   a YBRImage that will internally have a color lookup table ?

Multiple YBR images, I suspect to handle the various chroma
subsamplings as well.

Typically with JPEG/J2k compression, YCbCr is the best used color
space. This usually also involves chroma subsampling often 4:2:2,
since the luminance visually has more information than the color
components. So the memory organization for each pixel needs in 4:2:2
is

    Y Y Cb Cr Y Y Cb Cr ......

Or we can simplify and ignore chroma sampling and always store in
memory the duplicate Cb Cr images.

The list of Dicom Photometric interpretations is:
  http://www.medicalconnections.co.uk/wiki/YBR_FULL_422

>
>   Images with lookup tables has been a feature request for a
>   long time, but we have not hit a pressing need for them so far.
>
>
> 2) I'm not sure I understand the options here...
>   Does this refer to the process of writing out a DICOM image ?

It involves estimating the output image type before you've accessed
every pixel in the image, so as to know the true dynamic range after
shift-scale, I think.