Name
distortion - Distortion estimation
Synopsis
distortion [options]
Description
distortion estimates the distortion (vertical lines curvature or hori-
zontal lines curvature) by using images with bright curved lines along
x or y. The distortion is fitted as a 2nd degree 2d polynomial repre-
senting either the distortion along x or y. This polynomial is stored
in a TFITS table that can be used as is by the warping command.
Algorithm
The input file is an ASCII file containing either one image name (with
several curved lines) or a list of images (with in each one or more
curved lines). The command begins by averaging the list of files. The
arcs are then detected, their shape is precisely extracted, fitted, and
a general fit is then computed to obtain the final 2d polynomial. The
arcs can be horizontal or vertical, but this has to be specified with
the -O option (1 for vertical arcs, 0 for horizontal arcs).
Options
-i input
input is the name of the input ASCII file.
-o output
output is the name of the output TFITS table.
-O orientation
orientation is 1 if the curved arcs are vertical and 0 if hori-
zontal.
SEE ALSO
warping