Regarding aggregation at multiple levels

[Kent Johnson]

My understanding is that OpenSlide is just giving you the data from the SVS
file. So the difference in red is caused by whatever program wrote the
file, not OpenSlide.

Kent


On Wed, Nov 7, 2012 at 1:09 PM, Sriram Somanchi <ssomanch at andrew.cmu.edu>wrote:

> Hi,****
>
> ** **
>
> I am new to using virtual slides and openslide library to access these
> files. I have a few Aperio (.svs) files that I could open with open slide.
> ****
>
> ** **
>
> My question is how is the aggregation done at multiple levels. I see that
> the aggregation RGB of 4x4 grid is not the 1x1 grid at the higher level (my
> down sampling is ~4). I have attached a small snippet of the code for
> reference. Can someone please explain how the aggregation is done across
> multiple levels? ****
>
> Otherwise, can you please direct me to documentation which will help me
> understand this aggregation****
>
> ** **
>
> Thank you for your help.****
>
> ** **
>
> Sriram****
>
> ** **
>
> Code:****
>
> openslide_read_region(slide, buf, 0, 0, 0, 4, 4);****
>
> openslide_read_region(slide, buf1, 0, 0, 1, 1, 1);****
>
> ** **
>
> Output:****
>
> ** **
>
> 4x4 grid at level 0:****
>
> The level 0 width 107046, the height 87978****
>
> The alpha 255, red 239, green 239, blue 239****
>
> The alpha 255, red 239, green 239, blue 239****
>
> The alpha 255, red 239, green 239, blue 239****
>
> The alpha 255, red 239, green 239, blue 239****
>
> The alpha 255, red 239, green 239, blue 239****
>
> The alpha 255, red 239, green 239, blue 239****
>
> The alpha 255, red 239, green 239, blue 239****
>
> The alpha 255, red 239, green 239, blue 239****
>
> The alpha 255, red 239, green 239, blue 239****
>
> The alpha 255, red 239, green 239, blue 239****
>
> The alpha 255, red 239, green 239, blue 239****
>
> The alpha 255, red 239, green 239, blue 239****
>
> The alpha 255, red 239, green 239, blue 239****
>
> The alpha 255, red 239, green 239, blue 239****
>
> The alpha 255, red 239, green 239, blue 239****
>
> The alpha 255, red 239, green 239, blue 239****
>
> ** **
>
> 1x1 grid at level 1:****
>
> The level 1 width 26761, the height 21994****
>
> The alpha 255, red 241, green 241, blue 239****
>
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