Odyssey THEMIS IR Calibrated Data Record (IRRDR)
IRRDR – Infrared Calibrated Data Record
Instrument: Thermal Emission Imaging System
PDS Data Set ID: ODY-M-THM-3-IRRDR-V1.0 (in data directories odtie1_****)DOI: 10.17189/1520332
For more information about THEMIS IRRDR products, see the Data Set Catalog File.
For more information about all THEMIS products, see the THEMIS Product SIS.
The Thermal Emission Imaging System (THEMIS) Calibrated Infrared Record (IRRDR) data products contain the radiometrically corrected thermal infrared radiance observations. Uses Digital Number (DN), gain, and offset values from raw image with the instrument response function and a calibration flag image to return a calibrated spectral radiance image in Wcm2str-1μm-1.
For IR data, the DN values represent the delta signal between the scene and internal reference calibration flag. After decompression, the data are converted to scene radiance by: (1) adjusting for the gain and offset values used during data collection; (2) correcting for drift or offset that occurs between observations of the calibration flag; and (3) converting signal to radiance using the instrument response function determined prior to launch.
THEMIS IR images are acquired at selectable image lengths and in combinations of ten selectable bands (enumerated in the table below). The image width is 320 pixels (32 km, based on the nominal 400 km mapping orbit) and the length is variable, in multiples of 256 line increments, with a minimum and maximum image lengths of 272 and 65,296 lines respectively (27.2 km and 6,530 km, based on the nominal mapping orbit). The IR focal plane is covered by ten ~1 μm-bandwidth strip filters, producing ten band images with bands 1 and 2 having the same wavelength range.
In addition to the typical infrared images, additional images called “reset” images are collected throughout each orbit for calibration purposes.
THEMIS available infrared bands:
|
Band Numbers |
Center (μm) |
FWHM* (μm) |
|
IR-1 |
6.78 |
1.01 |
|
IR-2 |
6.78 |
1.01 |
|
IR-3 |
7.93 |
1.09 |
|
IR-4 |
8.56 |
1.16 |
|
IR-5 |
9.35 |
1.20 |
|
IR-6 |
10.21 |
1.10 |
|
IR-7 |
11.04 |
1.19 |
|
IR-8 |
11.79 |
1.07 |
|
IR-9 |
12.57 |
0.81 |
|
IR-10 |
14.88 |
0.87 |
*Full-width, Half-maximum
THEMIS IRRDR products have the following file names:
annnnnsssRDR.QUB
where:
a = 1-letter description of the type of image collected
I = infrared image
R = infrared reset image
S = infrared shutter image
nnnnn = 5-digit mission orbit when the image was collected
sss = 3-digit image sequence number indicating the order that images were collected each orbit (001 = first image collected in the nnnnn orbit)
In ODE, IRRDR products have the following Product IDs:
ANNNNNSSSRDR