laplacian

Create negative laplacian 3x3 kernel matrix.

Creates laplacian kernel matrix using

I - image
Laplacian(I) =   
             [a/4,    (1-a)/4,   a/4]
   4/(a+1) * |(1-a)/4   -1   (1-a)/4|
             [a/4,    (1-a)/4,   a/4]

pure nothrow

Slice!(Contiguous, [2], T*)

laplacian

(

T = double

)

(

T a = 0.

)

if (

isNumeric!T

)

Examples

t
{
    assert(laplacian().flattened == [0, 1, 0, 1, -4, 1, 0, 1, 0]