NAME

flatten -- Flatten images by dividing by a flat field

USAGE

flatten images flatfield

PARAMETERS

images

Images to be flattened.

flatfield

Flat field image to be divided into the images.

minflat = INDEF

All flat field pixels less than or equal to this value are replaced by unit response. If INDEF all the flat field pixels are used.

pixtype = "real"

The pixel datatype of the flattened image. The null string ("") defaults the pixel datatype to that of the original image before flattening. The other choices are "short", "integer", "long", and "real".

DESCRIPTION

Each of the images is flatten by dividing by the flatfield flat field image. The flattened images replace the original images. The pixel datatype of the flattened images is specified by the pixtype . The null string ("") leaves the datatype of the images unchanged. Low values in the flat field may be replaced by unit response by specifying a minflat value. All pixels in the flat field less than or equal to minflat are given unit response.

EXAMPLES

To flatten a set of two dimensional images excluding pixels below

	cl> flatten frame* flat minflat=0.2