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Kirsch operator


The Kirsch operator or Kirsch compass kernel is a non-linear edge detector that finds the maximum edge strength in a few predetermined directions. It is named after the computer scientist Russell A. Kirsch.

The operator takes a single kernel mask and rotates it in 45 degree increments through all 8 compass directions: N, NW, W, SW, S, SE, E, and NE. The edge magnitude of the Kirsch operator is calculated as the maximum magnitude across all directions:

where z enumerates the compass direction kernels g:

The edge direction is defined by the mask that produces the maximum edge magnitude.

Original

Maximum gradient in the 8 directions

Image filtered with g(1)

Image filtered with g(2)

Image filtered with g(3)

Image filtered with g(4)

Image filtered with g(5)

Image filtered with g(6)

Image filtered with g(7)

Image filtered with g(8)


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