Purpose: Identifies bright peaks in the images, measures the background brightness in columns containing them, and then adjusts those levels to match the surrounding columns.

Author: Leonidas (Lexi) Moustakas (GOODS team)
Date Contributed: 14 Sep 2004
System Requirements: IDL

This software is not considered part of the pipeline and no installation support from IRSA should be expected. We are however very interested in your feedback in order to improve or replace the algorithm and are glad to work with you in test cases and analysis. Questions and comments should be directed to the Helpdesk.

Information and Download

Download the Column Pulldown Corrector (do_pulldown.pro) (PRO, 12 KB)

The IRAC pulldown corrector was written by Lexi Moustakis of the GOODS team and is provided "as is" for testing and usage by other observers. In short, it identifies bright peaks in the images, measures the background brightness in columns containing them, and then adjusts those levels to match the surrounding columns. To run the corrector, you can make an ASCII list of filenames (for example, bcds.lis) with BCD images, and then say

do_pulldown,'bcds.lis'

within IDL. You will get new files with the "bcd_fp" portion of the filenames replaced with "bcd_fpc" as well as pulldown masks called "bcd_fpm". The corrector will eventually be implemented in non-IDL tools for all observers. The important parameters can be adjusted near the bottom in the simple driver routine "do_pulldown". You could change the file naming convention, or the threshold for which columns to perform corrections and which sources to search for possible corrections. Please ignore the error message at the end of the execution (Program caused arithmetic error: Floating illegal operand). Also note that at this time the program does not work with channel 4 data.