Performs a Laplacian convolution as an edge detector in a two-dimensional NDF
$\begin{array}{ccc}\hfill N\hfill & \hfill -N\hfill & \hfill -N\hfill \\ \hfill N\hfill & \hfill +8N\hfill & \hfill -N\hfill \\ \hfill N\hfill & \hfill -N\hfill & \hfill -N\hfill \end{array}$
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.
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This routine correctly processes the WCS, AXIS, DATA, and VARIANCE components of an NDF data structure. QUALITY is propagated.
Processing of bad pixels and automatic quality masking are supported.
All non-complex numeric data types can be handled.