CHEETAH Hardware User’s Manual
Imperx, Inc.
Rev. 2.0.7
6421 Congress Ave.
7/7/2015
Boca Raton, FL 33487
+1 (561) 989-0006
71 of 152
2.
“
Hot
” – these are pixels, which in normal camera operation behaves as normal pixel
(the sensitivity is equal to the one of the adjacent pixels), but during long time
integration behaves as a high intensity bright pixel. In some cases this pixel will have
full response (completely bright). During final camera testing at the factory, up to
8192 hot pixels will be identified and will be automatically corrected, if hot pixel
correction is enabled.
2.18.1 Static Pixel Correction
Static defective and Hot pixel correction works with predetermined and preloaded
Defective and Hot pixel maps. During factory final testing, our manufacturing
engineers run a program specially designed to identify these ‘defective’ and “hot”
pixels. The program creates a map file which lists the coordinates (i.e. row and
column) of every defective pixel. This file, called the Defect Pixel Map, is then
downloaded into the camera’s non-volatile memory. Users may wish, however, to
create and to upload their own DPM file because of the uniqueness of their
operating environment or camera use. When ‘Defective Pixel Correction’ is
enabled, the camera will compare each pixel’s coordinates with entries in the
‘defect’ map. If a match is found, then the camera will ‘correct’ the defective
pixel. When ‘Hot Pixel Correction’ is enabled, the camera will compare each
pixel’s coordinates with entries in the ‘defect’ map. If a match is found, then the
camera will ‘correct’ the hot pixel. The "Defective/Hot Pixel Map" can be
displayed upon user request.
2.18.2 Dynamic Pixel Correction
Dynamic pixel correction works without preloaded pixel maps. When this option
is enabled, the camera determines which pixel needs correction and performs the
correction automatically. Static and Dynamic “Defective Pixel Correction” and
“Hot Pixel Correction” can be enabled independently or simultaneously. The
Dynamic Threshold can be set to have a value between 0 to 4096 (12-bit). This
threshold determines how much a pixel can deviate from neighboring pixels
(either brighter or darker) before a pixel is considered to be defective and
correction is applied to this pixel.