Relation between mpp-{x,y} and {X,Y}Resolution

[kyuhyoung choi]

That is a great help.  Thanks a lot.

2017-04-12 2:17 GMT+09:00 Derek Magee <D.R.Magee at leeds.ac.uk>:

> The logic I use is (pseudocode):
>
>
>
> If tiff.ResolutionUnit==”centimetre” : numerator = 10000 // microns in CM
>
> Else : numerator = 25400 // Microns in Inch
>
> // I’m not totally sure what other values there can be (I’ve never seen
> anything but “centimetre”, and the standard uses numbers*), but assume it’s
> inches if not cm. Technically there’s
>
> // a third option of “No absolute unit of measurement.”, but rare enough
> not to worry about IMHO ….
>
>
>
> Mppx = numerator / tiff.XResolution
>
> Mppy = numerator / tiff.YResolution
>
>
>
> Where tiff.ResolutionUnit, tiff.XResolution, and tiff.YResolution come
> from openslide. These tags are standard and well documented:
>
>
>
> http://www.awaresystems.be/imaging/tiff/tifftags/resolutionunit.html
>
> http://www.awaresystems.be/imaging/tiff/tifftags/xresolution.html
>
> http://www.awaresystems.be/imaging/tiff/tifftags/yresolution.html
>
>
>
> HTH
>
>
>
> Derek
>
>
>
> *From:* openslide-users [mailto:openslide-users-bounces+d.r.magee=
> leeds.ac.uk at lists.andrew.cmu.edu] *On Behalf Of *kyuhyoung choi
> *Sent:* 11 April 2017 16:08
> *To:* openslide-users at lists.andrew.cmu.edu
> *Subject:* Relation between mpp-{x,y} and {X,Y}Resolution
>
>
>
> I have many WSIs from 7 different sources (medical centers)
>
> I want to scale the level 0 images of them to a standard resolution (given
> by me).
>
> So I thinking about using mpp-{x, y} to do that.
>
> However, for some of the slides, I can not access mpp-{x, y} properties
> when I open them with openslide.
> Instead I found I can get the properties of {X, Y}Resolution
> and ResolutionUnit.
>
> Is there any equation between {X, Y}Resolution and mpp-{x,y} ?
>
> If not, how can I scale all the slides to the same resolution?
>
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