Clarification about Pixel Spacing, Pixel Spacing Calibration Type and Nominal Scanned Pixel Spacing
Christian Fremgen
I need a clarification about the usage of Pixel Spacing, Pixel Spacing
Calibration Type and Nominal Scanned Pixel Spacing according to PS 3.3
- 2008 p.82 Basic Pixel Spacing Calibration Macro.
The information to this macro states that if Pixel Spacing and Nominal
Scanned Pixel Spacing are both present, it depends on their values
wether the image has been calibrated or not. In my opinion it is
definitely defined, that if their values are the same, the image has
not been corrected and therefore it is not save to present the user
with measurements without further manual calibration.
Now I have the problem, that I have SC images where Pixel Spacing and
Nominal Scanned Pixel Spacing are the same, and the user would like to
measure while applying Nominal Scanned Pixel Spacing. As I prohibit
measurements without manual calibration in this case, what would be
the correct way to specify the tags to allow automatic usage? Would
the presence of Pixel Spacing Calibration Type be appropriate to
decide about usage of Pixel Spacing or not?
I think this is somewhat similar to the discussion about Pixel
Spacing, Imager Pixel Spacing and Estimated Radiographic Magnification
Factor for projection radiography images. Is there an equivalent to
the pixel spacing test images to be found at
http://www.dclunie.com/images/pixelspacingtestimages.zip for SC
Images?
Thank you and kind regards
Christian