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11:00-11:45 AM Tuesday, 28 November 2006 Landsat Calibration Working Group (LCWG) Meeting

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Landsat-7 ETM+ Radiometry Instrument-Based Stability/Calibrationfor Level-OR Characterization & Correction

The Art and Precision of ETM+ Radiometry

3. Landsat Project Science Office (LPSO) IAS-Based Internal Calibrator (IC) Lamp Characterization

11:00-11:45 AM Tuesday, 28 November 2006 Landsat Calibration Working Group (LCWG) Meeting

At NASA Goddard Space Flight Center (GSFC, Bldg 33, Rm A128)

Greenbelt, MD 20771 USA

by

John L. Barker, Ph. D.

Landsat Associate Project Scientist, [email protected], 301-614-6610

LPSO:Land Cover Satellite Project Science Office, NASA/GSFC/614.4 Greenbelt, MD 20771 USA

and

Jennifer Sun

SSAI, [email protected], 301-614-6618

LPSO:Land Cover Satellite Project Science Office, NASA/GSFC/614.4 Greenbelt, MD 20771 USA

John Barker:

1)

2)

Agenda of Workshop on The Art and Precision ofLandsat-7 ETM+ Radiometry

- 9:00 1. Approach to On-Board Characterization of ETM+
- 10:00 2. Landsat-7 ETM+ MOC and PCD Telemetry
- 11:00 3. IAS-Based IC Lamp Characterization
- 12:00 Lunch
- 13:30 4. Path-Processing (PP) of ETM+ Background
- 14:30 5. PP-Based IC Lamp Characterization

John Barker:

1) IC trend is relatively linear/stable after 2.6 y, after 4.2y

2) Principle components, graying of all bands, internal IC optics ( Dichroics or ND filters) needs to be done to agree to Lamp-2

3_need sensitivity curves on orbit

Thanks for Multi-Year SupportTalk 3. IC Lamp-Based Modeling of IAS-Data

USGS EDC Image Assessment System (IAS)

Creating , filling and maintaining

the Landsat-7 IAS Oricle Database

Mission Operation Center (MOC)

Delta-I imaging collects & on-line telemetry access

LPSO Contract personnel

Jennifer Sun, Jeff Miller and Dave Landis

NASA support for LPSO

Analysis, modeling & algorithm development

Landsat Project Scientist

Recognizing need for team & continuity

John Barker:

1) IC trend is relatively linear/stable after 2.6 y, after 4.2y

2) Principle components, graying of all bands, internal IC optics ( Dichroics or ND filters) needs to be done to agree to Lamp-2

3_need sensitivity curves on orbit

Outline of Talk 3. IAS Database IC ModelingThe Art & Precision of ETM+ Radiometry

Pictures of ETM+

Why instrument-based lamp-based monitoring?

Why scene-base Image-Assessment-System (IAS) database?

LPSO Filtering of IAS Data (Lamp-1 &-2)

IAS-database scene availability as of 13OCT2006

Lamp-2 IC Rate of Change

Lamp-1 IC Characterization

Lamp-1 IC Normalization

John Barker:

1) IC trend is relatively linear/stable after 2.6 y, after 4.2y

2) Principle components, graying of all bands, internal IC optics ( Dichroics or ND filters) needs to be done to agree to Lamp-2

3_need sensitivity curves on orbit

Why Lamp-Based Characterization?Strengths Talk 3. IC Lamp-Based Modeling of IAS-Data

Higher short-term 15-day reproducibility of ± 0.1 % on trends

than ground observations or cross-calibration

Scan-based pulses (0.072 seconds/scan) allow checking for forward and reverse scan differences

Ability to monitor within- and between orbits

potentially correctable for slow-varying systematic trends

Ability to characterize individual detectors

not just band-average

John Barker:

1) IC trend is relatively linear/stable after 2.6 y, after 4.2y

3_need sensitivity curves on orbit

Why Lamp-Based Characterization? Limitations & Ameliorations Talk 3. IC Lamp-Based Modeling of IAS-Data

Lamps need to equilibrate (use only equilibrated data)

Lamp filaments degrade (source of most of IC change)

limit degradation by limiting use (Lamp-2)

normalize for: 1) lamp current, 2) temperature (IC vs Detectors), 3) point discontinuities, 4) lamp flares (between-band constancy) and 5) vacuum and/or zero-g on-orbit changes

cross-calibrate normalized lamps

Does not monitor fore-optics of ETM+

compare trends in sensitivity to solar panel

John Barker:

1) IC trend is relatively linear/stable after 2.6 y, after 4.2y

3_need sensitivity curves on orbit

Why Scene-Based Monitoring? Talk 3. IC Lamp-Based Modeling of IAS-Data

Landsat archive has been historically organized by scene

radiometrical path-processing is better

John Barker:

1) IC trend is relatively linear/stable after 2.6 y, after 4.2y

3_need sensitivity curves on orbit

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

Lamp-1 IC

Trends (TSL7) of

“Random” Collects

from IAS Database

John Barker:

1)

2)

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

Net IC Pulse (∆P)

Background (B)

Std. Dev. (SD_B)

High and Low Gain

John Barker:

1)

2)

B2D12 Lamp-1 IAS Input of ∆P, B & SD_B in H & L Gain

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

B8D27 Lamp-1 IAS Input of ∆P, B & SD_B in Low Gain

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

8-Step Filtering of IAS ScenesFilter-2 (25NOV2006)Talk 3. IC Lamp-Based Modeling of IAS-Data

1. Input of Raw Data from IAS-Database as of 13OCT06

“Clean” collects after fixing background filter

No LPGS data

2. Remove Side-B scenes

3. Filter out dates of cooldown after Delta-I maneuvers

4. Filter for TCFP = 91.4 K ± 2 SD

5. Hawkins outliers filter on SD_B

6. Common PCD telemetry temperatures

7. IC equilibration by t_on > 10 minutes

8. Common bands (except B7)

John Barker:

1) Tim and Emily and Dennis, 9:35

2)

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

∆PH_L1_B1D15 after SD_B outliers removed (Step-5)

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

∆PH_L1_B1D15 filtered for common-T (Step 6)

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

∆PH_L1_B1D15 filtered for t_on > 10’ (Step 7)

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

∆PL_L1_B7D9 filtered for t_on > 10’ (Step 7)

13OCT2006 Scenes Count in IAS Database

Lamp-1 Scenes Removed by 7-Step Filter-2 Talk 2. MOC & PCD Telemetry

13OCT2006 Scenes Count in IAS Database

Lamp-2 Scenes Removed by 7-Step Filter-2 Talk 2. MOC & PCD Telemetry

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

Lamp-2 IC

“Raw” “Random” Input

from

EDC IAS Database

John Barker:

1)

2)

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

B2D12 Lamp-2 IAS Input of ∆P, B & SD_B in H & L Gain

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

Lamp-2 IC

filtered for t_on > 10’

with linear fit

for TSL7 > 5.5 years

John Barker:

1)

2)

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

∆PH_L2_B1D15 >5.5y -0.29%/y (-7.1% from OIVP to 8y)

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

∆PL_L2_B1D15 >5.5y -0.20%/y (no OIVP in low gain)

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

∆PH_L2_B2D12 >5.5y -0.20%/y (-4.0% from OIVP to 8y)

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

∆PL_L2_B1D15 >5.5y -0.07%/y (-3.2% from OIVP to 8y)

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

∆PH_L2_B3D8 >5.5y -0.20%/y (-4.0% from OIVP to 8y)

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

∆PL_L2_B3D8 >5.5y -0.04%/y (-3.5% from OIVP to 8y)

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

∆PH_L2_B4D7 >5.5y +0.02%/y (+0.3% from OIVP to 8y)

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

∆PH_L2_B5D14 >5.5y -0.05%/y (-1.1% from OIVP to 8y)

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

∆PL_L2_B7D9 >5.5y -0.00%/y ( No OIVP B7 low gain)

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

∆PL_L2_B7D27 >5.5y +0.02%/y (-1.4% from OIVP to 8y)

John Barker:

1)

2)

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

Normalized Net Pulse

N∆P=

100(∆P-S ∆P)/S ∆P

John Barker:

1)

2)

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

Lamp-1 IC

N∆P Temperature-

Dependence on TPFP

John Barker:

1)

2)

John Barker: 7JUN2006

1) Add quantization width for temperature, 13c ref mpt 12C (use one temperature for the whole mission)

2) Add DN scale for both axes or scales alternate Y-axis, quantization of vertical lines is temperature quantization

3) Known SD of N delta P, average of 2 PCD data points. Every 16 second PCD. 1 DN = 0.117 C

John Barker:

1)Summary with no interpretation

2) No obvious correlation, control IC should have not effect. No detector effect in B5/B7 (constant 91.4K). Electronics of pre-amp on B5/B7 still stable. Therefore we should see no detector dependence temperature effect so the observed effect of 0.02 to 0.04 is either IC effect or effect on relay optics. Check relay optics tempeartures probalby correlated to TPFP.

3) Find another way to summary plot

Unequilibrated Current Sensitivityfor 1’ < t_on < 4’Talk 3. IC Lamp-Based Modeling of IAS-Data

Current Sensitivity

Normalizd Pulse (N∆P)

Lamp-1

vs Resampled Current

John Barker:

1)

2)

See PowerPoint File: 20060601 I Ieq step2_3.ppt Step 2: Current Equilibration of Pulse

John Barker: 5JUL2006

1) 1 < t_on < 4 minutes used, since for t_o > 4 minutes (1/2**4 = .0625) is only 6- % away from equilibration

2) Remove temperature on x-axis

3) Cycling is probably processing of 0.02TA0.01; try wider TA: 0.04TA0.01 and 0.05TA0.01 to reduce aliasing for ∆Q

Plot raw N∆P vs ∆I = I -I_15TA1 (t_on > 10 minutes) , put unaccounted for variance on separate line.

Plot resampled N∆P_.04TA.01 vs ∆I_.04TA.01, N∆P_.06TA.01 vs ∆I_.06TA.01, and wider until cycles go away

Lamp-1 Linear B1D15 Current Sensitivity (%/mAmp) of ∆ N∆PH vs ∆ I for 1’ < t_on <10’ (Traveling Average of current sampled every 0.01 mAmp)

John Barker:

1) Jen does fit in IDL; relative smooth curve

2) B8 is not average of B1-4. IAS-based Derivation of current sensitivity looks like smooth Blackbody, effective T of lamp

If current only was equilibrating, then all sensitivities should be positive,

therefore it is assumed that something else like IC Optics is also equilibrating

Rb1

Path-Based

L2 Current

Sensitivity,

Rb1=b1/b0

(% per mAmp)

Wavelength, (nanometers)

John Barker: Fr 9JUN2006

1) The table incorrectly contains Rb2 values of temperature sensitivity, not current sensitivity.

2) Need to do a regression fit for blackbody radiation vs wavelength

3) Correct spelling of processing in title

4) L1 and L2 don’t compare well, L2 range: 1< Rb1_L2 < 10, -2 Rb1_L1 < 3

Rb1

Path-Based

L1 Current

Sensitivity,

Rb1=b1/b0

(% per mAmp)

Wavelength, (nanometers)

John Barker:

1)

2)

John Barker:

1)

2)

All sensitivities are positive as expected

John Barker:

1) Still a wavelength dependence after current correction may still be uncorrected lamp filament temperature effects, but nothing to do with any band-specific change in detector sensitivity for re-calibrate

2)

Proposed Lamp-1 IAS IC Research Talk 3. IC Lamp-Based Modeling of IAS-Data

Review lamp-1 IC IAS scene-based results

Temperature sensitivity from equilibrated scenes

Current sensitivity from unequilibrated scenes

Equilibrated current sensitivity

Proposed lamp-1 IC IAS scene-based normalizations Temperature normalization to TREF (AVE SLC-Off)

Current normalization of equilibrated scenes

Current normalization of unequilbrated scenes

to test for t_on dependence of IC Optics

John Barker:

1) Tim and Emily and Dennis, 9:35

2)

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

Ave Paired Gross Pulse Gain Conversion

B1D15

QH = 0.0505 + 1.5004 QL

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

Pair-by-pair trend of gain conversion coefficients

Plot of A0 offset in DN for B1D15

Using Smoothed High & Low Gain Gross IC P

Suggests unlikely change in A0 from 0 with time

Landsat-7 ETM+ Radiometry Talk 3. IC Lamp-Based Modeling of IAS-Data

Pair-by-pair trend of gain conversion coefficients

Plot of A1 slope for Smoothed B1D15

Using High & Low Gain Gross IC P

Suggests unlikely change in A1

From 1.50 to 1.70

Observed IAS-IC Precision and TrendingTalk 3. IC Lamp-Based Modeling of IAS-Data

Temperature-Correction (within-band)

up to 0.3 %

Current-Equilibration (within-band)

up to 2 %

Current-Normalization (within-band)

-1 to +7 %

IC Between-Bands Normalization

up to 6 %

John Barker:

1) IC trend is relatively linear/stable after 2.6 y, after 4.2y

3_need sensitivity curves on orbit

Conclusions (1 of 2)Talk 3. IC Lamp-Based Modeling of IAS-Data

Lamps equilibrate to 0.1 % within ten minutes

Lamp-2 current is constant over mission lifetime

Lamp-2 trends less than any other calibrator

Lamp-1 shows linear current sensitivity,

Observed change in lamp current correctable

Lamp-1 shows linear temperature sensitivity

John Barker:

1) IC trend is relatively linear/stable after 2.6 y, after 4.2y

3_need sensitivity curves on orbit

Conclusions (2 of 2)Talk 3. IC Lamp-Based Modeling of IAS-Data

Forward scan pulses are moving into image

Forward and reverse scan pulses are nearly the same

Low to high gain conversions have an offset

also not exactly 1.5000x slope (gain) factor

Unconfirmed apparent change in conversion offset and gain factor with TSL7

IC and FASC both show B7 on-orbit equilibration

B4 and B8 on-orbit equilibration only in IC

John Barker:

1) IC trend is relatively linear/stable after 2.6 y, after 4.2y

3_need sensitivity curves on orbit

Operational IAS IC RecommendationsTalk 3. IC Lamp-Based Modeling of IAS-Data

For variables used in a quantitative manner for populating the IAS radiometric database

Use MOC instead of PCD telemetry

Use smoothing and fitting equations

Populate IAS Database with

Separate forward and reverse scan IC pulses

Populate IAS Database with daily scene-based collects

50 % random

50 % (at on-time = 10 minutes, and max on-time)

John Barker:

1) IC trend is relatively linear/stable after 2.6 y, after 4.2y

3_need sensitivity curves on orbit

IAS-IC Research Recommendations(1 of 3) Talk 3. IC Lamp-Based Modeling of IAS-Data

Characterize, normalize and cross-calibrate lamps for

1) lamp current,

2) temperature (IC vs Detectors),

use smoothed multi-date path-processing fits vs of t_on>10’ for MOC temperatures and IC for multiple linear regression of temperature sensitivity.

3) point discontinuities,

4) lamp flares (between-band constancy) and

5) vacuum and/or zero-g on-orbit changes, after other dependencies have been normalized out.

John Barker:

1) IC trend is relatively linear/stable after 2.6 y, after 4.2y

3_need sensitivity curves on orbit

IAS-IC Research Recommendations(2 of 3) Talk 3. IC Lamp-Based Modeling of IAS-Data

Quantify early on-orbit B7 equilibrations

for re-calibration of archived imagery

Quantify time-dependence of FWD, REV and AVE IC

Develop within-band models for IC normalization

to account changes in IC radiance patterns

Develop between-band models for IC normalization

to account for changes in IC optics and lamps

Develop path-processing alternative to current scene-based radiometric characterization.

John Barker:

1) IC trend is relatively linear/stable after 2.6 y, after 4.2y

3_need sensitivity curves on orbit

IAS-IC Research Recommendations(3 of 3) Talk 3. IC Lamp-Based Modeling of IAS-Data

For variables of potential value in modeling ETM+ radiometric performance, monitor binary (on/off) telemetry and develop smoothing and fitting equations for analog variables

Cross-validate fitted MOC and PCD telemetry

recommend IAS use of MOC telemetry

Cross-validate path-processing with scene-based IC

Develop linear gain conversion equations for calibration parameter file (CPF) with detector-specific offsets

Test H0: slope identical for each A/D converter

Test for time-dependence of offset and gain

John Barker:

1) IC trend is relatively linear/stable after 2.6 y, after 4.2y

3_need sensitivity curves on orbit

Agenda of Workshop on The Art and Precision ofLandsat-7 ETM+ Radiometry

- 9:00 1. Approach to On-Board Characterization of ETM+
- 10:00 2. Landsat-7 ETM+ MOC and PCD Telemetry
- 11:00 3. IAS-Based IC Lamp Characterization
- 12:00 Lunch
- 13:30 4. Path-Processing (PP) of ETM+ Background
- 14:30 5. PP-Based IC Lamp Characterization

John Barker:

1) IC trend is relatively linear/stable after 2.6 y, after 4.2y

3_need sensitivity curves on orbit