SHADOW - Enhances edges in a two-dimensional NDF using a shadow effect

Description:

This routine enhances a two-dimensional NDF  by creating a bas-relief or shadow effect, that causes features in an array to appear as though they have been illuminated from the side by some imaginary light source. The enhancement is useful in locating edges and fine detail in an array.

Usage:

shadow in out

Parameters:

IN = NDF (Read)

The two-dimensional NDF to be enhanced.

OUT = NDF (Write)

The output NDF containing the enhanced image.

SHIFT( 2 ) = _INTEGER (Read)

The shift in x and y pixel indices  to be used in the enhancement. If the x shift is positive, positive features in the original array will appear to be lit from the positive x direction, i.e. from the right. Similarly, if the y shift is positive, the light source will appear to be shining from the top of the array. A one- or two-pixel shift is normally adequate. [1,1]

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:

shadow horse horse_bas

This enhances the NDF called horse by making it appear to be illuminated from the top-right, and stores the result in the NDF called horse_bas.

shadow out=aash in=aa [-1,-1] title="Bas relief"

This enhances the NDF called aa by making it appear to be illuminated from the bottom left, and stores the result in the NDF called aash, which has the title "Bas relief".

Related Applications

KAPPA: LAPLACE, MEDIAN; FIGARO: ICONV3.

Implementation Status:

• This routine correctly processes the AXIS, DATA, QUALITY, VARIANCE, LABEL, TITLE, UNITS, WCS, and HISTORY  components of an NDF data structure and propagates all extensions.

• Processing of bad pixels and automatic quality masking are supported.

• All non-complex numeric data types can be handled.

• The output NDF will be trimmed compared with the input NDF by the shifts applied.

Click here to see an example plot (120k).