MISR Ancillary Radiometric Product (ARP)
Processing Summary Page
Last update: June 27, 2007

Contents

Overview

This page provides information to those familiar with MISR calibration algorithms and procedures. In particular, it provides a summary of calibration experiments, and calibration experiment results. More information can be obtained from the calibration literature, or by contacting the MISR Calibration Scientist. In addition, this page is mirrored at the data distribution center.

The MISR calibration team has been involved in an on-going effort to both validate and make incremental improvements to the radiometric accuracy of the Level 1B data products. Because the uncertainties in these products are well understood, those produced after April 15, 2002, are given the quality designation of "Validated."

Radiometric accuracy has been improved for data produced October 24, 2002 or later. The improvement was achieved by discovering and correcting an error in the code used to derive the radiometric calibration coefficients. A-Nadir camera data produced before this date may have had absolute errors as large as 10% (too bright) at the left/western edge of the scene, and -5% (too dim) at the right/eastern edge. Radiometry at the swath center, and for other cameras, has been in error to a lesser degree. Thorough descriptions of calibration uncertainties for current and older products can be found on the Calibration Page. The uncertainties at this time are listed below.


Table 1. Sources of Scene-Dependent Effects
PSF effects refer to scene-contrast reductions due to local scene inhomogeneity. The radiometry of one pixel is affected in proportion to the contrast difference and proximity of another pixel. This is a camera optical effect, and is measurable for objects that are within 6 km crosstrack distance of each other. The downtrack PSF effect is believed to be negligible.
Ghost-image refers to the presence of a secondary image, created as a reflection of a given target through the lens optical axis. This secondary ghost has been measured to be 0.3% of the primary image, and thus results in a negligible error except where the image of a bright target falls on a very dark scene.
L1B2 resampling is implemented by bilinear interpolation, and thus errors in this process are a function only of a sample's radiance value as compared to that of its immediate neighbors.
Illumination-level dependent errors are attributable to the goodness-of-fit of camera response data to a mathematical equation. The MISR cameras are described as having a linear relationship between incident radiance and camera output. For radiance levels less than 2% in equivalent reflectance, this assumption is valid to within 5% uncertainty. The error is considered negligible for larger input signals.
Detector uniformity of response errors occur when a set of detector elements are non-uniform in response (10% non-uniformity or greater), are image inhomogeneous scenes, and are DN-averaged as part of the on-board data compression (Global Mode) algorithm. Only a dozen detector regions (out of 13,000 such pixel blocks) are non-uniform, and these are identified by data quality indicators in the products. For conditions where bright scenes are adjacent to dark scenes, an additional radiometric error of 6% may result in pixel regions where the Data Quality Indicator level is given a value of 2.

 

MISR has challenging radiometric specifications of 3% absolute, and 1% band and camera-relative calibration. The radiometric calibration is facilitated by use of an on-orbit calibrator (OBC) experiment, which is utilized at bi-monthly intervals. During these experiments a diffuse panel reflects solar light into the cameras. The intensity of this light is measured with on-board photodiode "detector standards. With the measured incident radiance and output DN, radiometric calibration coefficients are computed. Following each experiment the coefficients are packaged into a file called the Ancillary Radiometric Product (ARP). This new ARP file is used for the next two months to produce the MISR Level 1B1 radiance product, and in turn the Level 1B2 geo-located product.

Ideally each investigator desires to have a data products derived from the best-available ARP coefficient file. To determine which ARP file was used to develop a given data product, you would use an HDF browser, such as HDF_Scan. (A unix-based procedure will also supply this information.) Read the metadata: annotation text that is part of the data file. Under Annotation Text: Input Data files, find the ARP filename used to produce your data, then compare it to the recommended ARP file listed in the tables below. If these files match, then you have the most current version of the radiometric calibration file. If the files have not been constructed using the best-available, a crude adjustment of your data can be made by following the procedure below.

Because of the challenging radiometric requirements, the calibration team at JPL has been researching various procedures for reducing the calibration data and producing coefficients. Calibration-algorithm changes have occurred over time, and thus the ARP time-series files have not been produced using a common algorithm. The history of this activity is reported in the table below.

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Instrument Degradation With Time (Trend Plots)

These plots show the degradation of the MISR cameras, as predicted by the DAAC ARP files.

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Radiance Calculations Versus ARP

Linear model

A few investigators may wish to determine radiances that would have been computed if a specific ARP had been used in the L1B1 or L1B2 data production. As an example, say that a L1B2 data product was produced with ARP T002_0004, but it is now recommended that ARP T002_0005 be used for that data acquisition time period but the reprocessing has not yet occurred. This is a simplified case in that the G0 and G2 coefficients were set to zero for both of these files.

We will define the ARP coefficients that were used in the data processing as G1_old coefficient, and the coefficients we wish had been used as G1_new. Since the MISR radiances are computed using

DN = G1_old * L_old
then
L_new = G1_old * L_old/ G1_new


One merely looks up the coefficients from the above tables to make the conversion. Note that there are some fine scale pixel-to-pixel corrections that will not be taken into account with this simplified algorithm. These corrections are on the order of 1%. To make corrections to this level of accuracy, the data must be reprocessed.

In our example

G1_old(An_blue) = 22.5434
G1_new(An_blue) = 20.4269
therefore
L1_new=L1_old * 1.10

That is, there is a 10% increase in the radiance with the ARP update. This process will have to be repeated for each of the 36 channels.

Quadratic Model

For a period of time (ARP T8-T12) a constrained quadratic was used as the MISR calibration equation. To convert the radiance values from one set of coefficients to another, a more generic equation is needed. The conversion for these files is:

DN = G0_old + G1_old * L_old + G2_old * L_old * L_old
then
L_new = -2[G0_new-DN]/{G1_new + sqrt(G1_new*G1_new - 4*G2_new*(G0_new-DN))}

The above equation is a variant to the usual quadratic inversion and is preferred for instances where G2 is small.

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Calibration Experiment Timeline

DAAC file delivery information Experiment information
Best available file version Original file delivery information        
Date Time (UT) Orbit Date,
Day-of-year		 Orbit/ Path Time, UT Instrument command
T46_1 June 28-2007
(DOY 179)		 01:00:34 40028

Jun-18-2007
DOY 169

39888/P198 10:24:01 Cal_North
39890/P230 14:41:29 Cal_South
39892/P029 18:15:06 Cal_Dark. Goniometer at -0.021 deg.
T45_1 May-01-2007
(DOY 121)		 00:23:28 39183

Apr-17-2007
DOY 107

38985/P196 10:15:20 Cal_North
38987/P228 14:33:08 Cal_South
38989/P027 18:06:13 Cal_Dark. Goniometer at 0.023 deg.
T44_1 Feb-28-2007
(DOY 059)		 00:11:21 38280

Feb-14-2007
DOY 045

38082/P194 10:09:25 Cal_North
38084/P226 14:28:09 Cal_South
38086/P025 17:53:30 Cal_Dark. Goniometer at 0.026 deg.
T43_1 Jan-15-2007
(DOY 015)		 01:25:13 37640

Dec-18-2006
352

37238/P204 11:13:58 Cal_North
37240/P003 15:32:09 Cal_South
37241/P019 17:18:51 Cal_Dark. Goniometer at 0.382 deg.
T42_1 Nov-15-2006
(DOY 319)		 00:16:38 36751

Oct-23-2006
296

36423/P212 11:59:42 Cal_North
36425/P011 16:17:32 Cal_South
36426/P027 18:08:09 Cal_Dark. Goniometer at -0.040 deg.
T41_1 Sep-06-2006
(DOY 249)		 00:54:00 35732

Aug-23-2006
235

35534/P201 10:45:21 Cal_North
35536/P233 15:03:15 Cal_South
35537/P016 17:00:21 Cal_Dark. Goniometer at -0.003 deg.
T40_1 Jul-21-2006
(DOY 202)		 01:37:18 35048

Jun-27-2006
178

34705/P218 12:22:11 Cal_North
34707/P017 16:44:43 Cal_South
34708/P033 19:50:12 Cal_Dark. Goniometer at -0.003 deg.
T39_1 May-18-2006
(DOY 138)		 01:36:55 33819

Apr-27-2006
117

33816/P207 11:21:39 Cal_North
33818/P006 15:39:20 Cal_South
33819/P022 17:37:18 Cal_Dark. Goniometer placed at -0.098 deg.
T38_1 Mar-21-2006
(DOY 080)		 00:59:46 33271

Mar-02-2006
061

33001/P 215 12:16:16 Cal_North
33003/P014 16:34:54 Cal_South
33004/P030 18:26:20 Cal_Dark. Goniometer placed at idiosyncrasy -6.937 deg.
T37_1 Jan-20-2006
(DOY 020)		 00:34:26 32397

Jan-04-2006
004

32171/P216 12:26:53 Cal_North
32173/P015 16:45:21 Cal_South
32174/P031 18:31:58 Cal_Dark. Goniometer placed at -0.044 deg.
T36_1 Nov-10-2005
(DOY 314)		 00:25:18 31363

Nov-02-2005
306

31253/P207 11:10:29 Cal_North
31255/P066 15:47:35 Cal_South
31256/P022 17:36:59 Cal_Dark. Goniometer placed at -0.049 deg.
T35_1 Sept-26-2005
(DOY 269)		 00:56:43 30707

Sept-01-2005
244

30350/P205 11:10:29 Cal_North
30352/P004 15:28:24 Cal_South
30354/P036 17:33:37 Cal_Dark. Goniometer placed at -0.068 deg.
T34_1 21-July-2005
(DOY 202)		 00:26:35 29732

July-06-2005
187

29520/P206 11:12:51 Cal_North
29522/P005 15:30:27 Cal_South
29523/P021 17:31:43 Cal_Dark. Goniometer placed at -0.687 deg.
T33_1 01-June-2005
(DOY 152)		 00:39:31 29004

May-05-2005
125

28615/P172 09:23:45 Cal_North
28618/P220 13:41:21 Cal_South
28620/P019 17:18:38 Cal_Dark. Goniometer placed at -0.312 deg.
T32_1 21-March-2005
(DOY 080)		 01:28:20 27956

08-March-2005
067

27773/P214 12:09:38 Cal_North
27775/P013 16:28:03 Cal_South
27776/P029 18:23:07 Cal_Dark. Goniometer placed at -0.129 deg.
T31_1 31-Jan-2005
(DOY 031)		 00:47:05 27242

11-Jan-2005
011

26956/P190 09:46:29 Cal_North
26958/P222 14:04:59 Cal_South
26960/P021 17:33:40 Cal_Dark. Goniometer placed at -0.5 deg.
T30_1 19-Nov-2004
(DOY 324)		 00:27:53 26237

09-Nov-2004
314

26039/P197 10:28:12 Cal_North
26041/P229 14:46:00 Cal_South
26042/P012 16:37:33 Cal_Dark. Goniometer placed at 0.546 deg.
T29_1 28-Sept-2004
(DOY 272)		 00:22:20 25435

15-Sept-2004
259

25238/P196 11:46:09 Cal_North
25241/P011 16:22:32 Cal_South
25242/P027 18:10:44 Cal_Dark. Goniometer placed at -0.612 deg.
T28_1 29-July-2004
(DOY 211)		 00:10:15 24533

19-July-2004
201

24394/P206 11:13:44 Cal_North
24396/P222 15:31:23 Cal_South
24397/P021 17:34:06 Cal_Dark. Goniometer placed at -0.54 deg.
T27_1 16-June-2004
(DOY 168)		 23:46:38 23921

19-May-2004
140
(Cal North and Cal Dark)

04-June-2004
156
(Cal South)

23505/P195 10:06:38 Cal_North
23741/P010 16:02:03 Cal_South
23509/P026 18:01:32 Cal_Dark. Goniometer placed at 39.001 deg.
T26_1 30-March-2004
(DOY 089)		 00:17:39 22771

17-March-2004
076

 22588/P202 10:55:31 Cal_North
22590/P001 15:13:46 Cal_South
22591/P017 17:09:51 Cal_Dark. Goniometer placed at -0.396 deg.
T25_1 02-February-2004
(DOY 034)		 10:48:50 21758

20-January-2004
020

 21758/P203 11:07:51 Cal_North
21760/P002 15:26:25 Cal_South
21761/P018 17:16:37 Cal_Dark. Goniometer placed at +0.044 deg.
T24_2 05-December-2003
(DOY 339)		 01:08:28 21023

24-November-2003
267

 20928/P204 11:14:31 Cal_North
20930/P003 15:32:32 Cal_South
20931/P019 17:22:55 Cal_Dark. Goniometer placed at +0.25 deg.
T23_3 21-October-2003
(DOY 232)		 00:19:32 20441

24-September-2003
267

 20040/ P209 11:38:27 Cal_North
20042/ P008 15:56:17 Cal_South
20043/ P024 17:52:42 Cal_Dark. Goniometer placed at -0.15 deg.
T22_3 20-August-2003
(DOY 232)		 01:03:31 19524

30-July-2003
211

 19224/ P201 10:34:00 Cal_North
19226/ P233 13:52:00 Cal_South
19227/ P016 15:31:00 Cal_Dark. Goniometer placed at -0.49 deg.
T21_4 09-June-2003
(DOY 112)		 00:14:54 18475

29-May-2003
149

 18321/ P199 10:31:10 Cal_North
18323/ P231 14:48:34 Cal_South
18325/ P030 18:30:16 Cal_Dark. Goniometer placed at -0.28 deg.
T20_3 22-Apr-2003
(DOY 112)		 00:15:25 17776

01-Apr-2003
091

 17476/ P193 09:58:59 Cal_North
17478/ P225 14:16:59 Cal_South
17480/ P024 17:53:45 Cal_Dark. Goniometer placed at -0.45 deg.
T19_3 18-Feb-2003
(DOY 049)		 01:08:38 16859

03-Feb-2003
034

 16646/ P194 10:11:22 Cal_North
16648/ P226 14:30:01 Cal_South
16650/ P025 18:00:25 Cal_Dark. Goniometer placed at -6.39 deg.
T18_4 12-Jan-2003 (DOY 012) 00:42:14 16320 10-Dec-2002
344		 15846/ P209 11:46:41 Cal_North
15848/ P008 16:04:39 Cal_South
15849/ P024 17:54:18 Cal_Dark. Goniometer placed at -0.47 deg.
T17_5 24-Oct-2002 (DOY 249) 00:41:19 15155

8-Oct-2002
281

 14927/ P184 09:04:31 Cal_North
14930/ P232 15:03:25 Cal_South
14931/ P023 16:58:09 Cal_Dark. Goniometer placed at -6.61 deg.
T16_3 06-Sep-2002 (DOY 249) 00:42:47 14456

13-Aug-2002
225

 14113/ P208 11:29:32 Cal_North
14115/ P007 15:47:18 Cal_South
14116/ P023 17:48:04 Cal_Dark. Goniometer placed at -6.88 deg.
T15_4 26-Jun-2002 (DOY 177) 01:33:03 13408

11-Jun-2002
162

 13196/ P215 12:10:53 Cal_North
13198/ P014 16:28:16 Cal_South
13199/ P030 18:31:29 Cal_Dark. Goniometer placed at -0.39 deg.
T14_3 25-Apr-2002 (DOY 110) 01:21:24 12505 10-Apr-2002
100		 12293/ P213 12:02:22 Cal_North
12295/ P012 6:19:50 Cal_South
12296/ P028 18:18:39 Cal_Dark. Goniometer placed at 0.24 deg.
T13_3 25-Feb-2002 00:05:41 11645

12-Feb-2002
42-43

 11455/ P086 23:03:32 Cal_North
11457/ P118 3:22:08 Cal_South
11458/ P134 5:14:11 Cal_Dark
T12_3 22-Dec-2001 01:02:03 10699

14_Dec-2001
348

 10590/ P226 13:33:56 Cal_North
10591/ P009 16:13:01 Cal_South
10592/ P025 18:02:33

Cal_Dark. Goniometer placed at -60.34 deg.
T11_3 19-Nov-2001 00:19:10 10218 16-Oct-2001
288/ 289		 9720/ 053 19:42:49 Cal_North
9723/ 101 01:39:19 Cal_South
9725/ 133 05:12:03

Cal_Dark
Goniometer moved to 54.6 deg (56.5 goal)
to be aligned with Da-diode. Repositioned to 56.75 on 17-Oct-01.
T10_3 26-Sep-2001 00:56:52 9432 17-Aug-2001
229 		8856/ 209 11:42:24 Cal_North
8858/ 008 16:00:02 Cal_South
8858/ 008 16:21:30 Cal_Dark
Goniometer moved to -57.5deg (-58.0
goal) to be aligned with Df-diode
T9_3 11-Jul-2001 01:27:11 8311 21-Jun-01
172		 8026/ 210 11:46:48 Cal_North
8028/ 009 16:04:05 Cal_South
8029/ 025 18:07:21 Cal_Dark
T8_3 17-May-2001 01:19:09 7510 23-Apr-01
113		 7169/ 012 15:27:58 Cal_North
7171/ 044 19:45:24 Cal_South
24-Apr-01
114		 7177/ 140 05:59:52 Cal_Dark
T7_3 07-Mar-2001 01:17:44 6476

22-Feb-01
053

 6296/ 024 16:49:33 Cal_North
6297/ 040 19:28:53 Cal_South
23-Feb-01
054		 6303/ 136 05:36:39 Cal_Dark
T6_3 19-Dec-2000 19:13:59 5351/ 049 19-Dec-00
354		 5351/ 049 19:29:18 Cal_North
5352/ 065 22:08:13 Cal_South
5353/ 081 22:36:11 Cal_Dark
T5_3 01-Nov-2000 20:53:25 4653/ 065 01-Nov-00
306		 4653/ 065 21:06:26 Cal_North
4654/ 081 18:29:27 Cal_South
4660/ 177 18:43:15 Cal_Dark
T4_3 29-Aug-2000 14:18:37 3717 29-Aug-00
242		 3717/ 001 14:24:46 Cal_North
3721/ 065 22:01:02 Cal_South
3721/ 065 22:21:13 Cal_Dark
T3_3 12-Jun-2000 4:13:51 2575 11-Jun-00
163		 2569/ 040 18:50:07 Local Mode/ Lunar Lake
2575/ 136 04:16:43 Cal_North
12-Jun-00
164		 2585/ 063 21:44:55 Cal_South
2585/ 063 ?? Data never found Cal_Dark
T2_7 24-Feb-2000 16:41:00 995 27-Apr-00
118 		1911/ 230 14:01:01 Cal_North
1912/ 013 16:39:15 Cal_South
17:01:02 Cal_Dark
        17-Mar-00 1314/ 231 14:09:48 Cal_North
15:27:05 Cal_Dark
        13-Mar-00 1259/ 050 19:31:21 Cal_North
1260/ 066 22:27:14 Cal_Dark
        01-Mar-00 1076/ 151 05:57:26 Cal_North
06:56:53 Cal_South
7:12:20 Cal_Dark
        27-Feb-00 1043/ 089 23:34:24 Cal_North
        28-Feb-00 00:33:53 Cal_South
00:49:04 Cal_Dark

(1) JPL internal file: /data/bank/anc/ARP_INFLTCAL/database/MISR_AM1_ARP_INFLTCAL_Txxxx_Fyy_zzzz.hdf.

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Algorithm Change Log

This table gives the time frame for which each ARP processing algorithm update was made. Additionally, MISR product version information can be found at
http://eosweb.larc.nasa.gov/PRODOCS/misr/Version/version_stmt.html#pge1


First Implementation
(ARP_INFLT files, unless otherwise specified)

 Algorithm change
T030_0001

ARPs produced from the software labelled CLR_ATMOS_BTB_FINAL include a significant adjustment in band-to-band calibration across all cameras, as well as a group of minor algorithmic fixes.

Description of Minor Fixes: The range of data used to compute G1 coefficients was modified. Instead of working on the quickly-changing thick atmosphere range of the calibration data, the G1 algorithm now operates on the slowly-changing clear atmosphere region. All other ARP parameters are still computed using the original data range. In addition, small bug fixes were made involving line time and angle to the input Calibration data and to intermediate datasets within ARPGEN.

Description of Band-to-Band Adjustment: The red band calibration was reduced by 3% relative to the calibration in use since the year 2000. The NIR band was reduced by 1.5%. Blue and Green band relative calibrations were not changed. The adjustment is made to the G1 coefficients under the control of a configuration file as the ARP is being converted to the HDF file format.

Description of Camera-to-Camera Adjustment: The calfactor file contains values derived from the Cal South panel only. A new BRF factor file was generated by the ifrcc science team and used (for the first time in this ARP) to accountfor the North/South panel differences. The -yn-pin diode was used to calibrate the AN camera and the appropriate (fwd/aft) D-pin di odes were used for the other cameras.

T026_0001 ARPs produced from the software labelled CLR_ATMOS_BTB_FINAL include a significant adjustment in band-to-band calibration across all cameras, as well as a group of minor algorithmic fixes.

Description of Minor Fixes: The range of data used to compute G1 coefficients was modified. Instead of working on the quickly-changing thick atmosphere range of the calibration data, the G1 algorithm now operates on the slowly-changing clear atmosphere region. All other ARP parameters are still computed using the original data range. In addition, small bug fixes were made involving line time and angle to the input Calibration data and to intermediate datasets within ARPGEN.

Description of Band-to-Band Adjustment: The red band calibration was reduced by 3% relative to the calibration in use since the year 2000. The NIR band was reduced by 1.5%. Blue and Green band relative calibrations were not changed. The adjustment is made to the G1 coefficients under the control of a configuration file as the ARP is being converted to the HDF file format.

T025_0001 ARPs produced from the software labelled CLR_ATMOS_BTB include a significant adjustment in band-to-band calibration across all cameras, as well as a group of minor algorithmic fixes.

Description of Minor Fixes: The range of data used to compute G1 coefficients was modified. Instead of working on the quickly-changing thick atmosphere range of the calibration data, the G1 algorithm now operates on the slowly-changing clear atmosphere region. All other ARP parameters are still computed using the original data range. In addition, small bug fixes were made involving line time and angle to the input Calibration data and to intermediate datasets within ARPGEN.

Description of Band-to-Band Adjustment: The red band calibration was reduced by 3% relative to the calibration in use since the year 2000. The NIR band was reduced by 1.5%. Blue and Green band relative calibrations were not changed. The adjustment is made to the G1 coefficients under the control of a configuration file as the ARP is being converted to the HDF file format.

T024_0001

ARPs produced from the software labelled CLR_ATMOS_BTB include a significant adjustment in band-to-band calibration across all cameras, as well as a group of minor algorithmic fixes.

Description of Minor Fixes: The range of data used to compute G1 coefficients was modified. Instead of working on the quickly-changing thick atmosphere range of the calibration data, the G1 algorithm now operates on the slowly-changing clear atmosphere region. All other ARP parameters are still computed using the original data range. In addition, small bug fixes were made involving line time and angle to the input Calibration data and to intermediate datasets within ARPGEN. These minor fixes change the calibration by less than 1%.

Description of Band-to-Band Adjustment: The red band calibration was reduced by 3% relative to the calibration in use since the year 2000. The NIR band was reduced by 1%. Blue and Green band relative calibrations were not changed. The adjustment is made to the G1 coefficients under the control of a configuration file as the ARP is being converted to the HDF file format.

T022_0001 Minor Bug Fix to T018 algorithm. Solar Angles on the diffuse panel are computed at the correct time, removing a 1.5 degree error; and the aft-camera BRF scale factors have been adjusted appropriately. The resulting change in the calibration is less than 1%.
T018_0001 Corrected code error (diode view angles converted from degrees to radians).Previous data are in error by less than 0.5%.
ARP_CONFIG F02_0003 New PSF kernels were published in ARP_CONFIG_F2_003 (12-Nov-2002). These were derived after balancing on-orbit PSF derived functions with those needed to reduce ringing at contrast boundaries. PSF deconvolution is implemented beginning with Product version F02_0016.
T017_0001 Off-axis corrected algorithm. An error in the BRF database indexing has been corrected in the code used to process MISR calibration coefficients.
T016_0001 Linear no trending/no weighting: All off-nadir cameras use the D diodes (Da-pin or Df-pin) instead of hqe. An camera uses -yn-pin. Cal factors use South panel only, BRF factors file used. QUAD_FIT flag added to control whether linear or quadratic fit with G0 constrained to zero is used. If LINEAR fit is used, trending of the G1 coefficient over time may be implemented through the choice of HSTFILE and PFGILE in the ARPGen User Input File.
T012_0001 BRF correction algorithm. Data from the on-board goniometer have been used to update the North calibration panel reflectance database. The D-pin photodiodes are used to calibrate all but the nadir camera; the -yn-pn photodiode was used for the An camera only.We believe this to correct an aft-to-fore camera bias; camera-relative uncertainties using this algorithm are believed to be less than 2%. Level 1 data produced using this ARP are Provisional Data Quality.
T011_0001 D-PIN photodiodes used to calibrate C and D cameras; HQE for all other cameras.
T010_0001 In an effort to study camera-to-camera relative calibrations, the D-PIN photodiodes were used to calibrate the C and D cameras (HQE photodiodes were used for other cameras). An evaluation of the camera-relative calibrations followed.
T009_0001 A 5% aft-to-fore camera-relative bias has been discovered. This bias is present for all data products produced through T011 (T012 has applied the final correction algorithm). For ARP T009, separate calibration coefficients have been developed for the photodiodes as they view the North panel (used for aft and AN-red, nir channels) and the South panel (used for the fore- and AN-blue, green channels). This change was expected to improve fore-aft camera biases. In practice, several additional updates were made in T010 though T012 to correct this problem. Photodiodes used for T009: D-PIN for D camera, HQE for others.
T008_0001

Beginning with this delivery, a quadratic calibration equation is being used to convert the sensor data from DN to radiances values. This algorithm may change the radiances reported over dark, or ocean targets, by a few percentage points. Radiances reported over bright scenes are believed to be invariant with algorithm. The calibration team has documented the basis and consequences of this change in several internal memorandum: [ SDFM#241 - calibration equation study] [sdfm#247 - radiance change versus equation]. Photodiodes used: HQE only.
T002_0005 Use was made of the June 11th Vicarious Calibration experiment to validate the Blue HQE photodiode. As a result of this study all radiances computed for MISR have been adjusted upwards by a factor of 1.10, irrespective of data acquisition time.
T002_0004 Use was made of the Blue HQE photodiode to establish the radiometic scale for all MISR channels.
T002_003 Mean G1 coefficient for each channel set to same as preflight channel mean. Pixel-to-pixel relative response determined from response to OBC diffuse panel. With this ARP, vignetting of the Af and Aa cameras is removed, as is a rippling (a small, ~1%, radiometric effect) that may be due to slight changes within the camera filters. In this ARP release we also replaced the preflight quadratic calibration equation with a linear form, and constrained the DN versus radiance regression to report the dark current signal output for dark illumination conditions. With these changes two of the 3 calibration coefficients have been set to zero (G0=G2=0). Photodiode standards used: average results from multiple photodiodes. For D-cameras, average HQE, D-PIN and Y-PIN.
T001 (preflight) Laboratory calibration


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References and internal memorandum

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Contact information

URL: http://www-misr.jpl.nasa.gov/mission/valwork/val_reports/arp.html
Author: Carol J. Bruegge