Requirements for pyramid

[Alex Price]

Hello, I am having a hard time getting my dicom images to display on the wsi plugin for orthanc as a pyramid.  I can view them in the preview but they are red.  I am creating dcm files from tiling a .svs and can open the dcm files in micro dicom fine.  I have compared the tags of working dcm files and this one that is failing and everything seems to be in order but I keep getting the error "Cannot get the pyramid structure of series: ".  

What is required for the viewer to show a pyramid or what structure is required? 

Thank you.

[Alex Price]

I found out that I was not adding some tags correctly namely xoffset yoffset and the column and row positions.  After properly adding them I was able to view the image in orthanc.

[Sébastien Jodogne]

Glad to read that you solved your issue by yourself.

Nonetheless, are you aware of the fact that the Orthanc project provides a command-line tool called "OrthancWSIDicomizer" that can create compliant DICOM pyramids from SVS images?

http://book.orthanc-server.com/plugins/wsi.html#proprietary-file-formats

[Alex Price]

Yes that is what I am using as a sanity check for tags but I have extra requirements (speed, related images, special tags etc), which is forcing me to dicomize on my own.

 I have noticed that using that tool does not produce a frame comment tag with the resolution, how does orthanc know how the pyramid is organized if it does not know the resolution and x, y location of the frame i.e. (Key)FrameComments  (Value)Resolution: 0 X: 1 Y: 1?

Thank you for the tip.

[Alex Price]

Looks like Orthanc uses DimensionIndexValues tag 0020,9157 to determine the structure.  Is this right?  I see it is just rolls over when the column position goes over the total width.  But I still don't see how Orthanc knows the resolutions of the levels.

[Alex Price]

For everyone else's benefit, I looked through the .cpp and orthanc builds the pyramid off of the instance height and width.  The instances are all grabbed and sorted by total height and width with highest width and height being the most zoomed in level, level 0 I think.

[Sébastien Jodogne]

Yes, I confirm that your interpretation is correct.