OPHIR Pyrocam IIIHR, User Manual

Page: 34 / 42

Pyrocam III
HR
User Guide Document No. 50361-001 Rev E 7/18/2017 Page 34
APPENDIX C – BAD PIXEL CORRECTION
Bad Pixel Correction Overview
This procedure will assume that the user is familiar with the operation of the Pyrocam. This
procedure will outline how to go about locating a bad pixel, marking a pixel for correction, and
downloading an updated bad pixel map to the Pyrocam. This map will be permanently stored in
the Pyrocam’s flash memory. How to save the map to a file is also explained.
Pulsed and Chopped
The following procedure is common for both Chopped and Pulsed operating modes. However,
the Pyrocam stores separate bad pixel maps, one for Chopped mode and one for Pulsed
mode. The map being loaded or saved is based on the setting of the
Chopped / Pulsed
selector. Only one mode can be in effect at a time.
What is a bad pixel?
A bad pixel falls primarily into 3 categories. They are:
 A pixel that under responds to radiant energy
 A pixel that over responds to radiant energy
 A pixel whose response is intermittent
Good Neighbor Policy
Bad pixels can occur singly or they can occur in groups, often referred to as clusters. Bad
pixels are most successfully repaired when they have a number of good neighbors, where a
neighbor is any adjacent pixel (horizontally, vertically, or diagonally) that operates normally.
The more good neighbors there are, the cleaner the correction will appear. While marking
pixels for repair, it is a good idea to try and keep at least one good neighbor adjacent to
every marked pixel.
Factory Map Files
Every Pyrocam that is produced will have two factory installed bad pixel maps stored in its
flash memory; one for Chopped mode and one for Pulsed mode. These factory stored maps
form the starting point from which additional bad pixels can be added. Spiricon will also
provide you with a pair of files that contain these maps upon request. These files form a
backup source in case you accidentally delete or corrupt one or more of the original maps
from the Flash memory. The backup files can be obtained by contacting Spiricon Service
department.
Bad Pixel Correction Procedure
Before beginning a bad pixel correction process, setup the Pyrocam to operate and provide a
reasonably bright source of illumination. Laser beams of the correct wavelength make good