I had a problem about "Adaptive Median Filter"

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C#

Dear

Recently I wrote some codes about Standard Median Filter and Center Weight filter.
I read an article about "Adaptive Median filter". And I am trying to program out how it works.
The problem is algorithm. I can not understand about the following sentence:
Adaptive Median Filter increases size of the window Sxy during filtering depending on certain conditions.

Zmin is minimum gray level value in window Sxy;
Zmax is maximum gray level value in Sxy;
Zmed is median of gray levels in Sxy;
Zxy is gray level value at (x,y);
Smax is maximum allowed size of Sxy.

Like Standard median filter and Center Weight median filter, I used 3x3 filtering windows.

What does it mean that windows size increase?
And what is the "Smax is maximum allowed size of Sxy." meaning?
Does it mean that filtering Window change by 3x3 to 5x5 ?

Best Regards,
Jacky Tai