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1Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
Jens Nieke and Klaus I. Itten
Remote Sensing LaboratoriesDepartment of Geography, University of Zurich
Winterthurerstrasse 190
8057 Zurich
[email protected], [email protected]
Hyperspectral Imagers
2Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
From Pinhole Camera to PushbroomSpectrometers
Sir Isaac Newton’s prism experiment, 1666-72
Camera obscuras,
Reinerus Gemma-Frisius, 1555
APEX experiment
2008
The Design Requirements:• High Data Rate• High Signal-to-Noise Ratio• High Performance Detectors• High Image Uniformity• High Calibration Accuracy
MOS experiment 1997
3Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
Imaging Unit (foreoptics)
Whiskbroom Pushbroom Staring
Scanning
approach
Advantages Disadvantages
Whiskbroom • simple over-all design • wide FOV • easy calibration
• mechanical scanner (moving parts in
vacuum) • post-processing required (spatial
incongruence) • constraints of high spectral and spatial
resolution requirements (low integration
time)
Pushbroom • no moving parts • congruence of spectral
images • longer integration time
for each ground pixel
• complex focal plane • narrow FOV • complex calibration • complex optics • spectral curvature
Staring • simple and compact
• post-processing required (spatial and
spectral incongruence) • constraints when many spectral bands
and high spatial resolution requirements
4Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
Objective Apertur
fixed mirrors
Interferometer
Collimator
Entrance SlitLens
Detector Area ArraySpatial Dimension y
Spe
ctra
l Dim
ensi
on
Filter MethodAbsorption / Interference Filter
Spectral Unit of Pushbroomers
Detector Area ArrayImager
Dispersing Element (Grating, Prism, Grism)
Collimator
Entrance Slit
Objective Aperture
y
Spatial D
imensio
n y
x
xy
x1
x n
x
1
n
x1
x n
Objective
Wedge Filter
Detector Area Array
Spa
tial D
imen
sion
y
Spectral and spatial Dimension ,x
Dispersion MethodGrating: Diffraction of LightPrisma: Refraction of Light
Fourier Transform Spectrometers (FTS)Time Domain FTS:
=> Michelson InterferometerSpatial Domain FTS
=> Sagnac Interferometer
5Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
CHRIS
Comparison of spectral selection systems
6Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
Design challenge: Data stream
• Data Rates of well-known systems:• Hyperion 220 x 12bit x 254pix x 233 Hz = 150 Mbit/sec = 18 MB/s• AVIRIS: 224 x 12bit x 614 pix x 12 Hz = 22 Mbit/sec = 2.8 MB/s
• APEX Data Rates:• High Spatial: (114+199) x 16bit x 1024 pix x 50 Hz = 256 Mbit/sec = 32 MB/s• High Spectral: (312+199) x 16bit x 1024 pix x 17 Hz = 140 Mbit/sec = 18 MB/s
AVIRIS 2.8 MB/s
Hyperion: 18 MB/s
APEX: 32 MB/s
MODIS: 1.35 MB/s
MERIS (FR): 6.25 MB/s
ASAR HR: 12.5 MB/s
7Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
Design challenge: Detector
• Requirements for “Scientific Detectors”• “Large Area” Detector• “Large” pixel size• Low read out noise• Dynamic range• High quantum efficiency• High fill factor• High radiation hardness (for space applications)• Low system power • Low system mass
• System volume• Low calibration complexity
• Constraints• The Detector Market is driven by consumer electronics needs• Only very few manufacturers (E2V, SOFRADIR, AIM) having developed
detectors for the niche of scientific imaging• Export restricted due to military or custom design• Certain fiscal restrictions
8Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
Design challenge: Image Uniformity
PSF in ideal position
PSF in real position
Dell Endice, et al. Appl. Opt. 2007
Schläpfer, et al. IEEE TGARS 2007
• Punctual defects,• Linear defects,• Areal defects,(spectral and spatial misregistration)
• Stability defects,• Discontinuity defects.
9Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
Design challenge: Calibration accuracy
• State-of-the-art are new generation of satellites, which deliver remotesensing data in unprecedented quantity and quality, such as SeaWiFS,ENVISAT, TERRA, AQUA and ADEOS-2.
• Driver applications:• Climatology• Ocean color
• Various methods were developed to improve the accuracy of remotesensing systems, such as
• Spectral calibration
• Geometric calibration• Radiometric calibration• Onboard calibration
• and vicarious calibration of the senor output (Level 1B data)• Validation of scientific algorithms (higher level output)
10Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
Airborne Hyperspectral Imager
1D whiskbroomgrating
65°2 mrad
30-12564-100
0.4-2.58-12
128 (VIS-SWIR); 30(TIR)
from2006
ARES (IntergratedSpectronics,AU/DLR, DE)
1D whiskbroom
grating
65°
2 mrad
30-1250.4-2.51281994HYMAP (IntergratedSpectronics, AU)
28°
0.5 mrad
40°1.5 mrad
70°
1.3 mrad
30°
1 mrad
3.7°2 mrad
FOV,/ IFOV(°, mrad)
2D pushbroom
prism
1000-2770.4-2.5313-500from2008
APEX (ESA /CH,BE)
2D pushbroomgrating
0.4-1.02881990CASI (ITRES, CA)
2D pushbroom
grating
200-3000.4-0.82881984FLI (Moniteq, Itres,CA)
1D whiskbroom
grating
40-2000.4 - 2.52241989AVIRIS (JPL, US)
1D whiskbroomgrating
80-2000.9-2.41281982AIS (JPL, US)
Imaging TechniqueSpectralResolution
( / )
SpectralRange(μm)
Numberof
SpectralBands
YearAirborne Hyper-IS
11Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
AISA Airborne Hyperspectral System
AISA EagleSpectral bands: 340Range: 400 - 970 nmFOV: 37.7 degCross-track pixels: 1024
AISA HawkSpectral bands: 255Range: 97 - 2450 nmFOV: 24 degCross-track pixels: 320
Prism-Grating-Prism (GRISM)Mass: 47.5 kgcompany: SPECIM
1024 pix 320 pix
12Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
AVIRIS Instrument
AVIRIS Technology Development•• Thermal control 1997 Thermal control 1997
•• Low Altitude 1998Low Altitude 1998
•• INU/GPS 1998INU/GPS 1998
•• Geo rectification 1998Geo rectification 1998
•• Onboard calibrator 1999Onboard calibrator 1999
•• Detector arrays 2000Detector arrays 2000
•• Digital signal chain 2001Digital signal chain 2001
•• Onboard data storage 2001Onboard data storage 2001
•• Scanner and fore optics 2003Scanner and fore optics 2003
Spectral bands: 224Range: 400 - 2500 nmFOV: 34 degCross-track pixels: 677four whiskbroom grating spectrometerwith four detectors (200 x 200 micron)Mass: 300 kgCompany: JPL/NASA
13Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
Hyperspectral Spaceborne Imaging Spectrometer
LEO, multi-viewing
Prism, pushbroom
13 km
25 - 50 m
1.25-11nm0.4-1.019-622001CHRIS (SIRA,PROBA, ESA)
LEO, 30deg tiling
grating, pushbroom
30 km
30 m
10nm0.43-2.52202011ENMAP (KeyserTrede, DLR)
Moon orbit, OffnerGrating, onChandrayaan-1(ISRO)
40 km
70 m
10 nm0.45-3.02612008Moon MineralogyMapper (JPL,NASA) on
15 km
50 m
7.5 km
30 m
15 km770 m
FOV,/ IFOV(km, m)
LEO
FTS, pushbroom
2-6 nm0.4-1.02562000AFRL MightySat II(Sindri) FTHSI
LEO
grating, pushbroom
10 nm0.4-2-52202000HYPERION (TRW,EO-1, NASA)
LEOgrating, pushbroom
15 nm0.4-1.02721996SPIMs (JohnHopkins University,MSX,DoD)
Imaging TechniqueSpectralResolution
SpectralRange(μm)
Numberof
SpectralBands
YearSpaceborne-IS(Producer,
Satellite, Agency)
14Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
EO-1, launched November 21, 2000Payload (90kg):•• Advanced Land Imager (ALI)Advanced Land Imager (ALI)
•• HYPERION HYPERION first high spatial resolution imaging spectrometerfirst high spatial resolution imaging spectrometer •• LEISA (Linear Etalon Imaging Spectral Array)LEISA (Linear Etalon Imaging Spectral Array)
•• AtmoAtmospheric Corrector (AC)spheric Corrector (AC)
Hyperion• 220 x 10nm bands in 400nm - 2500nm range• 6% absolute radiometric accuracy• Image swath width of 7.5 km• IFOV of 42.4 microradian• GSD of 30 m at 705 km altitude• 12-bit image data• Power: 51W orbit avg.,126W peak• Mass: 49kg• One year Life (2 year Goal)• Lewis Hyperspectral Imager (HSI) heritage• using JPL convex grating design• and Offner configuration
HYPERION on EO-1
HYPERION
15Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
Platform: PROBA*
• PROBA is the ESA Project for
On-Board Autonomy
• Launched: 22nd October 2001,
by Indian PSLV
• 100 kg, 100W,
• 800 x 600 x 600 mm3
Orbit: Sun-synchronous, polar, 553km
Platform agility:
Pitch range: ±55° -
Images at ±55°, ±36° and 0°
Roll range: ±25°
Pitch during imaging to increase integration time x 3
CHRIS on PROBA
* Prime: Verhaert Design and Development (BE)** SIRA (UK)*** OIP Systems (BE)**** Contraves (CH)
Payload:
CHRIS (Compact High Resolution Imaging Spectrometer)**:
Front baffle, carries solar calibration device
Telescope , images ground onto entrance slit
Prism dispersed image relayed to area-array CCD detector
LED and diffuser placed close to detector
Wide Angle Camera (WAC), High Resolution Camera (HRC)***
Standard Radiation Environment Monitor (SREM)****
Total costs US$ 14.5m (1996)
CHRIS SNR
16Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
Airborne Prism Experiment (APEX)
17Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
APEX Organization
Koen Meuleman
18Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
APEX Timeline
CDR = Critical Design ReviewATP = Acceptance To ProceedAR = Acceptance ReviewPM = Progress Meeting
OSU = Optical Sub-UnitTRR = Test Readiness ReviewMIP = Mechanical Interface Plate
AR (CHB)
FinalCDR/ATP
Calibration Home Base (CHB)
Institutes Phase C/D Phase E(5+5 years)
Industry Phase C/D
Delivery
Today
Construction
Integration
2007
Acceptance
2006 2008 2009
PM7 PM9 TRRPM10 PM11 AR TRR AR
Testing & Calibration
Calibration Test Master (CTM)
PM7 (Delivery of OBP): 15-Feb-2007PM9 (Delivery of MIP): 16-Mar-2007OSU TRR: 17-05-2007PM 10 (OSU tests): 11-Jul-2007PM 11 (OSU Assembly): 03-Dec-2007AR (OSU): 18-Feb-2008System TRR: 24-Mar-2008AR (APEX): 01-Jul-2008IFAR: 05-Nov-2008 PAF End to End Test
Data Format Testing Instr. Tests System Tests
First Light ofpreassembled
OSU
First Light offlight OSU
SW Concept & Development
Test A Test BConfig
19Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
APEX Team during Exploitation Phase E
SupportSupport
Standard ProductStandard Product(Custom/Research Product)(Custom/Research Product)
RequestRequest
ApplicationsApplicationsDevelopmentDevelopment(PAF, Algorithms (PAF, Algorithms ……))
Specialist,Specialist,DeveloperDeveloper User communityUser community
APEX science centerAPEX science center APEX operations centerAPEX operations center
AdviceAdvice
Science PolicyFoster the use of imaging spectrometer dataFoster the use of imaging spectrometer data Implementation of the science policy defined Implementation of the science policy defined
in the APEX science boardin the APEX science board Conception of the Level 2/3 product strategy Conception of the Level 2/3 product strategy Call for experiments, workshopsCall for experiments, workshops
New ApplicationsDevelopment of new scientific algorithmsDevelopment of new scientific algorithms Interaction with scientistsInteraction with scientists
Quality Control
APEX Operations Delivery of
Standard, Custom and ResearchStandard, Custom and Researchproductsproducts
Quality Control
wwwwwwinterfaceinterface
20Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
APEX Selected Specifications
21Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
Instrument Set-up in Aircraft
APEX Instrument
with Stabilizing Platform integrated in
Environmental Thermal Control Box
Aircraft I/F
Control and StorageUnit
Power DistributionUnit
Navigation SubSystem
Operator
Monitor
Flight ManagementSystem
Rack
22Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
Opto/Mechanical UnitOpto/Mechanical Unit(spectrometer hermetic sealed) with IFC*(spectrometer hermetic sealed) with IFC*
Optical Baseplate
(actively cooled)
* In-Flight/on-board Characterisation facility
QTH-Lamp, stabilized
Connectors
Baffle
23Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
Spectrometer - Design ConceptSpectrometer - Design Concept
24Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
Spectrometer - Optical Design ConceptSpectrometer - Optical Design Concept
25Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
CCD 55-30 from E2V Technologies (GB)• Frame transfer mode,• 1252 x 1152 pixel (used 1000 x 393)• Pixel pitch 22.5 x 22.5 μm2,• fill factor 100%,• Back illuminated,• Read out frequency 7 Mpix/s.
VNIRVNIR and SWIR - Detector Technology and SWIR - Detector Technology
0
20
40
60
80
100
380 400 500 650 750 900 1000
Wavelength [nm]
Qu
an
tum
Eff
icie
nc
y
[%] Dewar
Cooler
Sapphire Window
Transfer Line
Detector with Cryostat/Dewar Assembly
HgCdTe CMOS from SOFRADIR (F)*• hybridized on multiplexer,
• 1000 x 256 square pixel, 30 micron,
• addressable readout, fast operation,
• Integrated in cryostat cooler assembly,
• wavelength range: 0.94 – 2.50 micron,
• QE: > 70 % average, Top.: 150 K.
*under ESA-EOP contract
26Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
APEX Electronic: Data Streams Overview
27Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
Calibration Home Base (CHB)APEX-instrument
Rotary stage with foldingmirror, mounted on linearstage
Mirror-Collimatorsfor spectral andspatial calibration
Optical bench (granite)
28Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
Calibration Home Base (CHB)*
* Under ESA-EOP Contract* Under ESA-EOP ContractStatus: Acceptance review successfully in Jan 2007Status: Acceptance review successfully in Jan 2007
1.6 m Integrating Sphere
Optical bench (granite)
APEXCollimator
Monochromator
29Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
APEX PAF: The Processor Foundation
PAF Hardware: Linux,PAF Hardware: Linux,Archiving SystemArchiving System
PAF: PAF: IDL-emacsIDL-emacs, XML-tools,, XML-tools,CVS, CVS, TCL/webshTCL/websh
PAF Processor: PAF Processor: IDL, XML, CIDL, XML, C
APEX PAF
SearchAPEX
Archive
Server
Core
Web
Processor
Input
ToolsProcessing
ToolsCollaboration
ToolsBrowsing
Docs
Co-Developers
Users
Operators
CHB Data
Schläpfer et al. SPIE 2003Kaiser et al. SPIE 2003
30Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
Conclusions
APEX Instrument is in the manufacturing phase, PAF version 0.6 will be released in Dec-2007, Calibration Home Base CHB:
• Acceptance review was in Jan 2007
current activities:
• Establishment of the APEX Science Center (2006-2011)
• Preparation of the HALO “Earth Observation” Demo-Mission
• EU-FP6 Project HYPER-I-NET
• EU-FP6 Project HYRESSA
• JP-CH Scientific Seminar on “Remote Sensing of the Cryosphere” in 2007
• Support activity for ENMAP, TRAQ and other EO missions.
First data for the scientific user community shall be available in 2009!
31Advanced Imaging and Spectroscopy SSOM Engelberg Lectures 5.3.07
APEX Collaborations
HALO Earth Observation
Programme
DFGSCALAapplied
Special ApplicationsarmasuisseSpectralSignatures
ongoing
Science ApplicationsSNSFAlgorithmDevelopment
ongoing
Simulation and Calibration of GCOM-CJSPS/JAXAGCOM-C-simongoing
Infrastructure for hyperspectralresearch in Europe (10 partners)
EU FP-6HYRESSAongoing
Marie-Curie Hyperspectral NetworkingProgramme (15 partners)
EU FP-6HYPER-I-NETongoing
SubjectFounding SourceProject nameStatus