ICONV3-Convolve an image with a 3x3 convolution kernel

Description:

ICONV3 convolves an image with a 3x3 symmetric convolution kernel, defined by its central value and its edge value. So the image is convolved with a 9 element array that has the 8 edge elements all set to one value and the central element to another. For example, CENTER=-9, EDGE=-1 is a highpass filter, CENTER=0.1, EDGE=0.1 would be a lowpass filter, while CENTER=8, EDGE=-1 would be a Laplacian edge enhancement filter.

Parameters:

IMAGE

The image to be filtered.

CENTER

Central value of 3x3 convolution array.

EDGE

Edge value of 3x3 convolution array.

OUTPUT

The name of the resulting filtered image. This may be the same as IMAGE, in which case the filtering will be performed in situ, or different, in which case a new file will be created.

See also:

FIGARO: ISMOOTH, IXSMOOTH, MEDFILT.
KAPPA: CONVOLVE, FFCLEAN, GAUSMOOTH, MEDIAN.

Source comments:

 I C O N V 3

 Convolves an image with a 3x3 symmetric convolution kernel.
 This allows a variety of spatial filters to be applied to
 an image.  The 3 by 3 array convolved with the image is defined
 by two values, the central value and the single value used
 for the eight edge elements.  That is, if C is the central and
 E the edge value, the kernel array looks like

                   E  E  E
                   E  C  E
                   E  E  E

 Command parameters -

 IMAGE    The name of the structure containing the image.

 CENTER   The value for the kernel central element.

 EDGE     The value for the kernel edge element.

 OUTPUT   The name of the result of the operation.  This can
          be the same as for IMAGE.  If not, a new structure
          is created, with everything but the data a direct
          copy of the input.
                                  KS / AAO 30th Oct 1987