ofixpix: Fix bad pixels using text file (proto V2.10.4)

Package: obsolete

Usage

ofixpix images badpixels

Parameters

image: List of two dimensional images to be modified.

badpixels: File containing the regions of bad pixels. A region is described by four whitespace separated numbers consisting of the first and last columns of the bad region and the first and last lines of the bad region.

verbose = no: Print the image names and the bad pixel regions?

Description

Bad pixel regions in the list of two dimensional images are replaced by linear interpolation using pixels bordering the bad pixel regions. The bad pixel regions are input in the specified file consisting of lines of coordinates (x1 x2 y1 y2) where x1 and x2 are the first and last columns of the bad region and y1 and y2 are the first and last lines of the bad region. The file may be STDIN to read from the standard input. The type of interpolation is determined as follows:

(1): If the bad region spans entire lines then the interpolation is from neighboring lines.

(2): If the bad region spans entire columns then the interpolation is from neighboring columns.

(3): If the bad region contains more lines than columns then the interpolation is from neighboring columns.

(4): If the bad region contains the same or more columns than lines then the interpolation is from neighboring lines.

If the bad region borders the edge of the image then the interpolation is by replication of the first good pixel in the direction of interpolation and otherwise linear interpolation between the bordering lines or columns is used. The verbose parameter may be used to produce of log of the pixel modifications.

Examples

A detector has bad lines 10 and 25 to 27 and a partial bad column at column 31 between lines 35 and 50. A bad region file is created containing the lines

1 100 10 10
1 100 25 27
31 31 35 50

The set of images "image*" are fixed by:

cl> ofixpix image* badpixfile

Revisions

OFIXPIX V2.11: This is the V2.10.4 and earlier version of PROTO.FIXPIX.

Bugs

This is a simple minded task which can be improved by using more sophisticated interpolation. The bad pixel file will eventually be replaced by image masks and bad pixel lists in the image. Be careful with image sections because the bad pixel regions are relative to the image section. Also if the image is trimmed or rotated then the bad pixel regions must be changed.