LAPLACE

Performs a Laplacian convolution as an edge detector in a two-dimensional NDF

Description:

This routine calculates the Laplacian of the supplied two-dimensional NDF , and subtracts it from the original array to create the output NDF. The subtractions can be done a specified integer number of times. This operation can be approximated by a convolution with the kernel:

N N N N + 8N N N N N

where N is the integer number of times the Laplacian is subtracted. This convolution is used as a uni-directional edge detector. Areas where the input data array is flat become zero in the output data array.

Usage:

laplace in [number] out [title]

Parameters:

IN = NDF (Read)
Input NDF.
NUMBER = _INTEGER (Read)
Number of Laplacians to remove. [1]
OUT = NDF (Write)
Output NDF.
TITLE = LITERAL (Read)
The title for the output NDF. A null value will cause the title of the NDF supplied for Parameter IN to be used instead. [!]

Examples:

laplace a 10 b
This subtracts ten Laplacians from the NDF called a, to make the NDF called b. NDF b inherits its title from a.

Related Applications

KAPPA: SHADOW, MEDIAN; FIGARO: ICONV3.

Implementation Status: