mical performs radiometric corrections to images acquired by the MER
MI camera. MI images taken during science operations have 1024 samples
and 1024 lines and are single bands. The pre calibration images are signed
word or 16 bit images. Subareas can be aquired but this was rarely done during
the mission.
mical has a number of parameters required to process MER MI image
data. Most of these parameters are read from an ISIS parameter defaults
file located in the mer directory specified in the IsisPreference file.
This file has the form:
$mer/calibration/mical.ker.xxx
where "xxx" is a positive number.
mical will search for the parameter file with the highest number and
load all its defaults needed to process MI images. Note that the
caller may explicity provide an alternative ISIS parameter defaults
file name in the "CALKERNEL" input parameter if they have their own
set of defaults that applies to MI data. See an existing calibration
file for details on how to configure this file.
The level of calibration output can be selected. by choosing one of the
output options, the user can choose to dark current correct, dark current and
flat field, or dark current, flat field and output in I/F values.
The dark current correction equation mical implements is as follows:
r = dn - (rpi + rpv) + (zei * zev) + (aai * aav)
Where:
r is the aver signal being generated at the focal plane
dn is the input pixel value
rpi is the referance pixel dn
rpv is the referance pixel correction value
zei is the zero exposure pixel dn
zev is the zero exposure correction value
aai is the active area pixel dn
aav is the active area correction value
The user can choose to not correct for the reference pixel, zero exposure
or active area by selecting or deselecting the RPCORRECTION, ZECORECTION,
or AACORRECTION checkbox. The program will also determain if these
corrections should be applied. If the ShutteEffectCorrectionFlag is set to "TRUE"
in the image labels, the reference pixel, and zero exposure will not be applied.
If a flat fielded output is chosen:
r = dn / f
where:
r is the corrected output value
dn is the input pixel that has been dark current corrected
f is a flat field pixel
if the "ShutteEffectCorrectionFlag is false and the exposure duration is greater
them zero and less them 1000 and the image is mot equal to 1024 samples, a
image smear correction is applied.