How to find local extrema in matrices / 2D-arrays

[altenbach]

OK, I thought if we would sweep an array subset across all locations and take a histogram of all subset maxima locations, only the real maxima will have a significant count. Seems to work just fine, try it!

 

(would need small adjustments for non-square inputs, but the idea stays the same)

[Standardnutzer]

Thanks for your solution!