Losing image quality on "Extrapolate" mode

Google Groups archive
1

HI.
On the full mode i have a good quality of images, but metadata loads too slow.

So I have specified the following options:
“StudiesMetadata”: “Extrapolate”,
“StudiesMetadataExtrapolatedTags”: [“AcquisitionDate”],
“SeriesMetadata”: “Extrapolate”,
“SeriesMetadataExtrapolatedTags”: [
“BitsAllocated”,
“BitsStored”,
“Columns”,
“HighBit”,
“PhotometricInterpretation”,
“PixelSpacing”,
“PlanarConfiguration”,
“RescaleIntercept”,
“RescaleSlope”,
“Rows”,
“SOPClassUID”,
“SamplesPerPixel”,
“SliceThickness”
]

And it loads fast, but image quality is not the same as on full mode.

I use Ohif viewer

full_mode.png

ext_mode.png

2

Quality seems ok, sounds that you just lost the windowing preset…

3

Hi,

From your screenshots, it seems that the windowing parameters are not set correctly (WindowCenter, WindowWidth). If each image has a different WindowCenter and WindowWidth, Interpolation won’t work anyway.

You may also use the ExtraMainDicomTags as an alternative to “Extrapolate”.

Hope this helps,

Alain.

4

Thanks for reply. You are right, it’s because of window preset. But i can’t understand why on “Extrapolate” it’s different presets. Do you have any ideas?

вторник, 7 марта 2023 г. в 15:28:06 UTC+6, Alain Mazy:

5

These values can vary from one instance to the other. If they are listed in “Extrapolate”, Orthanc assumes that they have the same value for all the instances of a series.