Multi-Spectral Vision Processing For the ExoMars 2018...
Transcript of Multi-Spectral Vision Processing For the ExoMars 2018...
ASTRA 12th – 14th April 2011 1
Multi-Spectral Vision Processing
For the ExoMars 2018 Mission
Dave Barnes, Martin Wilding, Matt Gunn, Stephen Pugh,
Laurence Tyler – Aberystwyth University, UK
Andrew Coates, Andrew Griffiths, Claire Cousins – UCL, UK
Nicole Schmitz – DLR, Gemany
Arnold Bauer, Gerhard Paar – Joanneum Research, Austria
UK Work Funded by UK Space Agency with contributions
from EU FP7 PRoVisG and PRoViScout projects
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ESA ExoMars
Rover:
Phase-B2X
Design
Launch 2018
(Credit ESA &
EADS Astrium)
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•The PanCam Calibration Target (PCT) is an essential component for
the science operations of the PanCam instrument.
•Its purpose is to allow both radiometric and geometric calibration
of the PanCam instrument whilst operating on the surface of Mars.
•Science target spectra can be generated (e.g. for rock mineralogy),
if the returned WAC images are radiometrically corrected. A key
element within this process involves measuring the reflectance of
the individual grey and coloured calibration targets on Mars, and
comparing these values with pre-flight laboratory measured data.
•The radiometrically corrected filtered images for those wavelengths
within the human visible light region can be used to create ‘true-
colour’ image products of the Martian surface; i.e. if a human stood
on the Martian surface, then they would perceive the same colours
as those exhibited by the generated PanCam image.
Why Do We Need A Calibration Target?
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Past and Current Mars Calibration Targets
NASA VL2 1976
NASA Pathfinder 1997 ESA Beagle 2 2003
NASA
Phoenix
Lander
2008
NASA
MER
2004
MER
FS
on
MSL
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PanCam Calibration Target (PCT) CAD Model
Width = 50 mm
Depth = 50 mm
Height =16 mm
4 × M3 Bolts
Stained glass
calibration targets
Good for Planetary
Protection
Will not ‘bleach’
under UV irradiation
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Red (Au
nano-particles)
Black
(Anodised Al)
Grey 30%(Fe + Co + Ni)
Grey 50%(Fe + Co + Ni)
Grey 70%(Fe + Co + Ni)
Yellow (Ag
nano-particles)
Blue
(CoO)
Green
(Cr2O3)
White 90%
(TiO2 + Fe )
Polished Al
Anodised Ti
Black
(Anodised Al)
All Greys and RGBY targets are made from stained,
radiation hard (Soda-Lime-Silica + Cerium) glass wafers
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Early Prototype Model and
Early Fabricated Glass Targets
Early PCT prototype with Macbeth
colour checker targets.
Note top retaining plate inverted.
Early version of top retaining plate with
test glass target wafers. Target
homogeneity under investigation.
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Calibration Target Radiometric Characterisation
AU BRDF GonioreflectometerAU Integrating Sphere, Spectrometers,
Uniform L.S., NIST Certified Calibration
Standards etc.
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Prototype Glass Target Relative Reflectance Data
(untreated sawn top surface used with ‘tin-foil’ against bottom surface!)
Stained Glass
Reflective Al coating
Glass layer
Bottom reflective surface
Top surface
Early results very encouraging
Scope for improvementBS(urface)S(cattering)RDF model required
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PCT Component Mass (g)
Shadow post × 3 (Al) 0.651
Retaining plate (Ti) 5.6
Calibration targets (glass) 5.958
Base plate (Ti) 11.797
Mounting pads (Al) 0.894
PCT TOTAL MASS (g) 24.9
Current design NOT mass optimised
Current PCT Mass Budget = 20 g + 20% contingency
Current PCT Mass Estimates:
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PCT and 3 × Fiducial Markers mounted on rover deck – Preferred Option
PCT
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PanCam Simulated Camera Views of the PCT
HRC Right WACLeft WAC
PCT Square Pixel Sample Areas Checked
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AU PanCam Emulator (AUPE)
Right WAC
Left WAC
HRC
Filter
wheel
Filter
wheel
Lightweight
optical bench
Mount
Pan/tilt
unit
Filter wheel detail
showing servo
Monochromatic
COTS Cameras
14
AUPE Filters
LEFT FILTER WHEEL
Filter Centre WidthCamera
nm nm sensitivity
1) Blue 460 ~100 ~0.85 █
2) Green 550 ~100 ~0.94 █
3) Red 660 ~100 ~0.62 █
4) Geol1 440 10 0.76 █
5) Geol2 470 10 0.89 █
6) Geol3 510 10 1.00 █
7) Geol4 560 10 0.92 █
8) Geol5 600 10 0.79 █
9) Geol6 660 10 0.62 █
RIGHT FILTER WHEEL
Filter Centre Width Camera
nm nm sensitivity
1) Blue 460 ~100 ~0.85 █
2) Green 550 ~100 ~0.94 █
3) Red 660 ~100 ~0.62 █
4) Geol7 720 10 0.49 █
5) Geol8 760 10 0.38 █
6) Geol9 830 10 0.26 █ IR
7) Geol10 880 10 0.16 █ IR
8) Geol11 950 10 0.08 █ IR
9) Geol12 1000 10 0.04 █ IR
PanCam will fly 11 × filters on each WAC
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AUPE and PCT Field Trial Equipment
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AUPE and PCT Field Trials – AMASE
Artic Mars Analog Svalbard Expedition
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Bridget the rover traversing northwards at Clarach Bay (July 2010)
AUPE and PCT Field Trials – Clarach Bay, UK
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Bridget traversing southwards spots an interesting target
AUPE and PCT Field Trials – Clarach Bay, UK
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Bridget on her way back to the ‘mission control centre’
AUPE and PCT Field Trials – Clarach Bay, UK
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Field Trials with the AU Idris Rover at Clarach and Ynyslas
AUPE and PCT Field Trials
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Baseline Radiometric Image Processing Pipeline Developed
raw image
data
compress
uncompressflat/dark
correction
camera
response
correction
relative
reflectanceCIE XYZ
CIE XYZ to
sRGB etcPanCam
image
PanCam
spectrumreflectance
ROI select
flats/darks
(temp,exp)
PCT
BRDF
data
ESA PSA
PDS format
R*
data
CIE
XYZ
data
SOC Operations
Surface Operations
camera radiometric correction
pixel → spectral radiance
(W∙sr-1∙m-2∙nm-1)
image radiometric and
colourimetric processing
ESA PSA
PDS format
Rover with
PanCam
and PCT
Mathcad
Java
LabVIEW
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Generating Rock Spectra AMASE 2009, BOCK01 Site
using PCT test target
BOCK01 'OUTCROP' SPECTRA
0
0.5
1
1.5
2
2.5
3
440 470 510 560 600 660 720 760 830 880 950 1000
Wavelength (nm)
Rela
tive R
efl
ecta
nce a
nd
SD
SULPHUR
FeB
VB
X
Mag
SiB
NBO
G
S
FeB
X
Mag
SulphurS
SiB
NBO VB
G
(Artic Mars Analogue Svalbard Expedition – AMASE)
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Baseline Radiometric Image Processing Pipeline Developed
raw image
data
compress
uncompressflat/dark
correction
camera
response
correction
relative
reflectanceCIE XYZ
CIE XYZ to
sRGB etcPanCam
image
PanCam
spectrumreflectance
ROI select
flats/darks
(temp,exp)
PCT
BRDF
data
ESA PSA
PDS format
R*
data
CIE
XYZ
data
SOC Operations
Surface Operations
camera radiometric correction
pixel → spectral radiance
(W∙sr-1∙m-2∙nm-1)
image radiometric and
colourimetric processing
ESA PSA
PDS format
Rover with
PanCam
and PCT
Dept. Research Presentation
9th March 201124
Left WAC Right WAC
Colour images generated from ‘raw’ uncorrected broadband (100 nm) RGB Filters
AMASE 2009, Bock01
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440 nm 560 nm
470 nm
510 nm
600 nm
660 nm
Narrow-band (10 nm) filtered input images
Image True Colour Correction
Output colour corrected image
in sRGB format
Svalbard, Bock01, 2009
Dept. Research Presentation
9th March 201126
Left WAC Right WAC
Clarach Bay, March 2010
Colour images generated from ‘raw’ uncorrected broadband (100 nm) RGB Filters
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440 nm 560 nm
470 nm
510 nm
600 nm
660 nm
Narrow-band (10 nm) filtered input images
Image True Colour Correction
Output colour corrected image
in sRGB format
Clarach Bay 2010
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• The PanCam Calibration Target (PCT) has been designed
• Early stained glass wafers manufactured
• Preliminary radiometric characterisation looks very encouraging
• Baseline radiometric and colourimetric image processing pipeline
developed in Mathcad and ported to Java and LabVIEW
• Early PCT field trials conducted at Clarach Bay and Ynyslas (UK)
and for AMASE
• STM PCT being fabricated for ΔPDR later this year
• Plan to perform preliminary thermal cycle and vibration tests
prior to ΔPDR
• Radiometric and colourimetric image processing pipeline will
continue to be developed
Conclusion