Determining the actual scale factor ...

[Adam Goode]

On Thu, 02 Dec 2010 17:27 +0100, "Hauke Heibel"
<hauke.heibel at googlemail.com> wrote:
> On Thu, Dec 2, 2010 at 4:00 PM, Mitko Veta <mitko.veta at gmail.com> wrote:
> > Image up-sampling increases the spatial resolution (although no new
> > information is added). Yes, my example was for the opposite situation.
> > I would expect that if you use low magnification and fine sampling, a
> > lot of the information in the image will be redundant (the image will
> > be blurry). Again, I might be wrong.
> 
> And again, true, the scanner vendors could implement such
> functionality. Disregarding for a moment the fact that this would be
> scary and bad behavior, it would also mean that the actual objective
> power were not corresponding to the 0th pyramid level and thus
> indicating the need to store this additionally required information
> somewhere.
> 

Part of the reason this was never implemented in OpenSlide was because I
never found the metadata stored in the files to be terribly accurate or
trustworthy. I think Trestle was particularly bad with being off by a
factor of 2 with this measurement. I think this was related to the fact
that while the objective magnification was recorded, the "virtual
eyepiece" was not. Or something. It's all a little vague.

Also, according to DICOM (really Aperio, I think),
ftp://medical.nema.org/medical/dicom/supps/sup145_09.pdf
1X == 10 MPP. 2X == 5 MPP, etc.


Adam