SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006 HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions Hyperspectral.

SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006

HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions

Hyperspectral SensorsCalibration, Operation and Maintenance

Jens Nieke, Daniel Schläpfer, Francesco Dell'Endice, Klaus Itten (RSL)

Koen Meuleman (VITO)

Michael Schaepman (WUR)



Introduction

• Calibration (cal/val) activities:– Pre-launch (laboratory), in-flight and vicarious

calibration, validation– Spectral, radiometric, spatial calibration– Higher product validation



Introduction

• Operations & Services:– Spaceborne sensors:

• ESA operations center ESRIN (e.g., CHRIS)

• U.S. Geological Survey (USGS): EROS data center (e.g., HYPERION)

– Airborne sensors: Vito, DLR, INTA, …

• Maintenance : – Spaceborne sensors: no maintenance required– Airborne sensors: frequent maintenance recommended (combined

with re-calibration activities)



Hyperspectral Sensors

– Methodology of Sensor Calibration• Calibration of HYPERION / CHRIS

– Pre-launch (TRW / SIRA)– Products: L1B, geocorrected – Calval not coordinated (except of WS)

• Calibration of HYMAP– Pre-flight (however no visibility of calibration procedures)– Calval not coordinated– Validation Techniques at reference site Gilching



Hyperspectral Sensors

– Operations Boundary conditions • Operations of HYPERION/ CHRIS

– Dedicated data facilities (USGS/ESRIN)– Request via help desks / web

» FAST DATA DELIVERY!

• Operations of Airborne Sensors (Vito, DLR, INTA..)– Call for Requests (long preparation time)– Availability of sensor/aircraft (summer season)

» FEW months for data delivery

• Maintenance of (airborne) sensors– Methods (cleaning lenses?)– Techniques (spare part services)



Examples

Operational spaceborne sensors, with open calibration record and exemplary cal/val activities:– MODIS and SeaWiFS

• Best documented data descriptions and open data distribution policy (extraordinary funding resources are available).

– MERIS• Well documented data restricted to a selection of data products

due to funding limitations.



Examples

Operations of MIVIS:

The instrument was delivered as commercial off-the shelf solution, without visibility to the internal preprocessing.

Scientific usability is restricted due to:– Unknown radiometric calibration stability/accuracy– Undocumented on-board processing routines (and no

ability to switch off on-board processing).



Examples

Operations of AVIRIS:

for about 15 years, a team of ~10 people provided upgrades and calibration to the instrument. Calibration results were published in workshop proceedings.

High scientific value because of…

… very well known and accepted accuracy of the instrument. Open information and generous data policy.



DevelopmentsExample: APEX calibration methodology (SPIE paper*)

* Nieke, Kaiser, Schläpfer, Brazile, Itten, Strobl, Schaepman, Ulbrich, SPIE Vol. 5570 (2004)



DevelopmentsExample: APEX calibration methodology (SPIE paper*)

* Nieke, Kaiser, Schläpfer, Brazile, Itten, Strobl, Schaepman, Ulbrich, SPIE Vol. 5570 (2004)

APEX-IFC

APEX-CHB



Developments

Challenges: (1) meeting the accuracy requirements of the user community, (2) the lack of standard methodologies for calibration and validation

of hyperspectral methods and products, and(3) reliable (comparable) higher-level data products.

Needs:- The introduction of standard methods and processing schemes - Hyperspectral data with known performance and error propagation- More efforts on data pre-processing, including ortho-rectification,

atmospheric corrections and in-flight calibration.=> Standard methods and processing schemes will also allow to

compare higher-level data products in a better way.



Discussion Points

Open Qs:– What are the minimum calibration requirements of

end users?– Are the end users willing to pay more for better

knowledge of calibration issues?– Who is able to provide independent system

performance validation?– Is there a bigger market for cost-effective off-the shelf

instruments (with less calibration information) ?



Discussion Points

• Calibration of latest-generation hyperspectral sensors clearly requires new technological efforts: – Software: the complexity of data processing algorithms has

created the need for improved computing infrastructure, and implies stronger requirements on memory/storage issues as well as advanced downlink and data transmission strategies.

– Hardware: low-weight and low-power integrated components, along with calibration sources and fast electronics, are mandatory to reduce payload, data transmission overheads and satisfy other requirements in many planned and future Earth observing missions.

– Reliable CalVal requires operational data retrieval (CalVal sites, ground-truth data) and processing.



Discussion Points

• Operations & Services of latest-generation hyperspectral sensors clearly requires further efforts: – Fast delivery– User support– Additional data: quality flags, 3rd party data (ECMWF)– Further services: add-on modules, hotline– Automatic chain for standard products– Flexible exchange of research product codes



Discussion Points

• Maintenance of latest-generation hyperspectral sensors clearly requires further efforts: – On-board data processing capabilities and programmability,– Standardization of laboratory calibration procedures,– Streamlined cross-calibration procedures for validation,– Sensor stability between calibration.

SWOT and User Needs Workshop, DLR Oberpfaffenhofen, 5-6 July 2006 HYRESSA - HYperspectral REmote Sensing in Europe specific Support Actions Hyperspectral.

Documents

user needs workshop

dlr oberpfaffenhofen

inflight calibration

vicarious calibration

calibration results

open calibration record

recalibration activities

data preprocessing