history of remote sensing in geological exploration · pdf filehistory of remote sensing in...

History of Remote Sensing in Geological Exploration

Dr Alan J Mauger

DMITRE

March 2014

AIG Remote Sensing and Interpretation Conference, Burswood on Swan Convention

Centre, 10 March 2014

Introduction

• “Remote Sensing”: a term that was coined in the 1950’s by Evelyn Pruitt, US Office of Naval Research

• History and development of remote sensing as applied to geology and mineral exploration

• Technology of acquisition

• Technology of analysis

• People and organisations



Remote Sensing The term "remote sensing," now commonly used to describe the science—and art—of

• identifying,

• observing, and

• measuring an object without coming into direct contact with it.

• This process involves the detection and measurement of radiation of different wavelengths reflected or emitted from distant objects or materials, by which they may be identified and categorized by class/type, substance, and spatial distribution.

• Satellite or aircraft platform, UV to radar wavelength, passive and active

• But generally NOT other forms of geophysics which might appear to fit the definition e.g. radioactivity, magnetics and gravity

• Consider the term “Spectral Geology” – both narrows the field and is more inclusive of proximal tools using same technology



Aerial Photography

• Having coined the term in 1950s aerial photography was retrospectively assimilated

• Balloon flight initiated in 1783

• First photograph from a balloon 1858

• World Wars saw great advances in photography from aeroplanes

• Geologists took advantage of the new technology

• Black and white stereo photography • Interpretation • Navigation • Cartography



Balloon Flight

• France, Montgolfier brothers, 1783

• Battle of Fleurus, 1794 used by French as observation post.



wikipedia

lÉntreprenant at the Battle of Fleurus 1794



wikipedia

Gaspar Felix Tournachon, 1858

Petit-Becectre, 1858, from a tethered hot air balloon. Image has not survived



wikipedia

Aerial photograph of Swedish landscape taken by rocket 1897

This aerial photograph of Karlskoga possibly used one of Captain W.T. Unge's rockets to carry one of Alfred Nobel cameras c. 1897.[2]



wikipedia

http://en.wikipedia.org/wiki/Karlskoga

http://en.wikipedia.org/wiki/Alfred_Nobel

http://en.wikipedia.org/wiki/Alfred_Nobel

http://en.wikipedia.org/wiki/Wilhelm_T._Unge

Pigeon with German miniature camera WW1



wikipedia

Space Race 1955-1972

• A race for supremacy in spaceflight between Cold War rivals – USA and USSR

• Oct 4th 1957 Soviet launch of the Sputnik

• Artificial satellites

• Unmanned probes – Moon, Venus and Mars

• Human spaceflight in low earth orbit

• Travel to the Moon

• July 20th 1969 Man walks on the Moon

• A new view of the Earth





http://lunarnetworks.blogspot.com.au/2010/04/new-lunar-globe-as-seen-by-chandrayaan.html

Earth Resource Technology Satellite - 1

• ERTS-1 Launched July 23rd 1972

• ERTS spacecraft represented the first step in merging space and remote-sensing technologies into a system for inventorying and managing the Earth 's resources

• Large areas (185 km x 185 km) under constant illumination

• Continental scale geological structures became visible

• Continental Drift and eventually Plate Tectonics were gaining currency in the geological fraternity

• The interrelationship between continental scaled and outcrop scaled geological structures required research

• Empirical relationships were observed – mostly photointerpretation



Digital Data

• With 4 bands of data from Landsat Multi-Spectral Scanner (MSS) digital enhancement and classification became possible

• Practical application of statistics

• Coping with band to band correlation

• Empirical relationships with geology

• Geological signal tantalisingly just out of reach

• Goal became to accurately, unambiguously and repeatedly map the earth’s surface geology



Development streams

• Increase the number of bands (channels)

• Add channels with geological applications

• Increase the sensitivity of the detectors

• Reduce the footprint of the pixel

• Increase the signal to noise

• Improve the geometry

• Model the transmission properties of the atmosphere

• Digitally filter out vegetation interference

• Develop radar imaging to penetrate cloud and penetrate the ground



Satellite vs Airborne

• These two platforms form an uneasy alliance

• Often satellite instruments are proved on an aircraft (which continues to offer a commercial service long after the satellite has been launched)

• Satellite data supply can be perceived to undermine the market share of the airborne operator reducing their potential profits

• Usually two separate markets

• They perform separate functions and have pros and cons for the users

AIG Remote Sensing and Interpretation

Conference, Burswood on Swan Convention Centre, 10 March 2014

Compared for the same technology installed on both platforms

Aircraft Satellite

Spatial Resolution Better and variable Set for life

Repeat observation Flies on demand Keeps recording – builds an archive

Atmosphere Less air column and user chooses best conditions to fly

No control of conditions but more stable

Signal to noise Can support many channels narrow band width - better

Requires larger pixel and broader band width to receive same energy

Cost End user pays more Huge capital costs covered by Government/Owner

Unique Tends to lead in technology Satellites tend to be conservative/proven



Platforms and Instruments .......................just a few

Satellite

• Landsat TM

• SPOT

• NOAA AVHRR

• Radarsat

• Hyperion

• ASTER

• ALOS (Pan, MSS, Radar)

• Orbview

• Quickbird

• Shuttle Radar DTM

Airborne

• Daedalus

• Collins GER

• MIRACO2LAS

• Geoscan

• AirSAR

• AVIRIS

• HyMap

• Specim

AIG Remote Sensing and Interpretation




Airphotos

ERTS-1 Landsat MSS - TM

SPOT

ASTER

Orbview/Quickbird

Collins GER profiler CO2 Laser Profiler

AMS De Beers HyMap AVIRIS

Hyperion

GER Handheld

AIS

TIMS SEBASS

ASD

PIMA

Terraspec Halo

NOAA

HyLogger

Corescan

AIRSAR

Radarsat

SLAR Shuttle Radar DTM

ARIES

Data processing ERMapper

Bureau services Meridian

ENVI

Geoscan

Specim

Drones

Specim

NEO - HySpex

HyspIRI EnMAP

DISIMP DIPIX

microBrian ERDAS ESRI ArcGIS

2017 2022

Itres

Approximate Technology Progression

Cerberus

1972

OARS

Extracting Geological Information from Remotely Sensed data

• The early Landsat series designed for agriculture

• Landsat 4 TM for the first time had Band 7 (2.08-2.35 um)

• Why was Band 7 so important to geologists? • Band 7 records the presence of clay, carbonate, chlorite, gypsum –

but not individually

• Combined with Band 1 which detected iron oxides there is potential to identify alteration which is an indicator towards mineralisation.

• Every pixel is a mixture. The mineral is only one component. How to extract the mineral component?



Sophisticated Processing

• Log Residuals – removing atmospheric and sun angle effects

• LSFit – predicting mineral component of Band 7

• Band ratios

• Directed PCs – defoliating ratios

• Decorrelation stretch

• 11 x 11 high pass filters and Pan sharpening with SPOT

• MNF transformation



ASTER – Band Ratio FCC

• Extracting mineral information from multispectral ASTER

• Quartz (y)

• Al(OH) (g)

• CO3 (r)



ASTER Mineral Maps



Thresholded band ratios based on spectral features

Specialised pre-processing to remove atmospheric effects and calibrated with Hyperion data

So what sort of geologically interesting things are found in imagery?

• Major faults and other geological structures

• Palaeodrainage systems in night time thermal data

• Alterations signatures – hydrothermal minerals

• Vegetation stress related to metals and hydrocarbon seepage

• Ocean oil seeps using radar

• Surface structural geology below jungle canopies

• Concealed structure beneath dry sand dunes

• Regolith materials

• Mineralogy 1981 Using Collins GER profiler proved that spectroscopy could be done from 10,000 ft (Mt Turner, Mt Isa, Mary Kathleen and Kambalda – (Gabel, Fraser, Huntington, CSIRO))



Night time NOAA TIR



Nullabor Plains, Eucla Basin, S Aust

From Bands to Spectra



Eucalypt spectrum as it should be defined by hundreds of points.

Landsat TM view based on just 6 data points

Chlorophyll & other pigment absorptions

Ref

lect

ance

Liquid water bands indicate species, stress and cell structural effects

More pigment & chemical absorptions

RVSI region

Red-edge inflexion Continuum as important

as absorption features

after J. Huntington

Break away from Bands

• The term “Hyperspectral” joins the lexicon circa 1998 • Usually means more than 100 channels • Closely approximating the analogue signal as a

spectrum • Every pixel is still a mixture of several pure substances • How to deconvolve the spectra in order to identify the

components? • “Hour Glass” approach – image dependant, signatures

not transferable • Alternatively pursue feature extraction using

polynomial interpolation, band differences, ratios and thresholds



Hyperspectral Data Cube

• A raw, un-geocoded hyperspectral data cube of 224 bands by 1024 pixels by 3340 lines

• The starting point to information extraction and then:

• Geo-coded product generation


Centre, 10 March 2014 after J. Huntington, 2000, 10ARSPC

HyMap – an airborne example


Centre, 10 March 2014 From HyVista publication

Alan Mauger Alice Springs 2000



HyMap data, Musgrave Ranges, South Australia, 2000


Centre, 10 March 2014 From HyVista publication

Panorama - HyMap Fluid Flow Model

Discharge zone Recharge zone

(after Cudahy et al, 2000)



Spectral Regions Relevant to Mineralogy

• Visible and near infrared (VNIR) • 400 - 1000 nm • Iron oxides (Haematite, Goethite, Jarosite) • REEs • Vegetation

• Shortwave Infrared (SWIR) • 1000 - 2500 nm • OH bearing minerals

• Clays, phyllosilicates, amphiboles, sulphates • Carbonates • Dry vegetation and lichens

• Mid or Thermal Infrared (MIR or TIR) • 6000 - 14000 nm • Silicates: Quartz, feldspars, garnets, pyroxenes • Carbonates and OH bearing minerals


Centre, 10 March 2014 after J. Huntington

Spectral Geology – ground truthing equipment • PFRS/ASD Field Spec Pro

• PIMA

• 1994-1997 AMIRA Project To develop field, visible and infrared, spectroscopic methods, for identifying minerals and lithologies indicative of ore-bearing environments

• 2002 AMIRA Project Develop prototype core logging instrument – HyLogger 0

• Specim sisuCHEMA and sisuROCK

• Corescan

• TerraSpec Halo

• 2011 Fully integrated VSWIR-TIR HyLogger 3

Alan Mauger 1999, GSSA Gibralter, Tarcoola, SAust



HyLogger 3-3 Technical details…

• Automated table

• VIS-SWIR Spectrometer • 400-2500 nm • ~ 1 cm pixels

• TIR 6000 - 14000 nm

• Camera 0.1 mm res.

• Laser profilometer

• 1 m per minute

• ~ 300 m / day sustained

• ~ 3 Gbytes / day



John Keeling, Glenside Core Library 2010

Mg-Chlorite

• 760nm

620nm

Muscovite 2232nm

1416nm

2345nm

Phengite

Muscovite

2204nm

2355nm

2220nm Cu Mineralzn 9800ppm

Fe-Chlorite

Fe2+

Spectra from HyLogger

Hyperion – Spectra from space

• First hyperspectral satellite launched by NASA as a technology demonstrator

• A research satellite – proof of concept – engineering prototype – queue jumper

• Some much potential

• So many issues

• Used to calibrate ASTER scenes for Australian Mineral Map



User Requirement

• Mineralogical mapping of silicate minerals beyond what is available with AVIRIS and HyMap

• How? • Hyperspectral Thermal

Infrared Sensing (8-14 m)

• SEBASS imaging results

• Thermal Infrared Profiling Spectrometer (TIPS)

• Technology now in HyLogger (6-14m)

SEBASS

after J. Huntington, 2000, 10ARSPC

g-ray spectrometry RGB = K, Th, U

Note high correlation between g -ray potassium (L) and muscovite, due to high potassium in mica crystal structure (M)

Muscovite abundance on Landsat backdrop

Cerberus profiler in SWIR and TIR (1998)

Quartz abundance on Landsat backdrop

TIPS

OARS


SEBASS – Liquid Helium cooled TIR


Centre, 10 March 2014 after J. Huntington, 2000, 10ARSPC

Passive vs Active Remote Sensing

AirSAR NASA/JPL is one of the most advanced radar systems

• Radar is an active sensor.

• A known signal is beamed at the ground and the reflection recorded.

• By modifying the frequency and polarisation of the signal can discriminate vegetation, soils and buried geology



The geology, landforms and topography of sub-Antarctic Macquarie Island, Australia, as revealed by AIRSAR Tapley, Dijkstra & Brolsma, 2004

• Enhancements of AIRSAR data are revealing an extraordinary amount of land-surface and geological information relevant to the island's genesis at a midocean ridge, ongoing uplift and subsequent shaping of the surface by extensive faulting, wave action and active processes including freeze/thawing, wind and rain.

• Overlaying these enhancements on the TOPSAR DEM enables this active landscape to be analyzed in three dimensions.

• The level of detail indicates that the radar signals are penetrating the snow cover and being backscattered by the underlying surface of rock, lag gravels and vegetation.

• Drainage patterns, dammed lakes, levels of incision, fault structures, raised beach deposits and terraces, and possible evidence of glacial action can all be recognized in various enhancements of the AIRSAR data.



Google Earth phenomena

• Google Earth has put remote sensing into the hands of everyone.

• The computer power and storage on people’s desktops and even their phones is now huge compared to 20 years ago

• What seemed difficult, complicated and expensive is now feasible and achievable by everyone with access to a PC and the Internet



Data Integration • Geometry and geolocation become critical issues when producing maps

from remote sensed data

• Landsat MSS with 80 m pixels represented a significant challenge for explorers

• Landsat TM – with specialist software could achieve 1:50,000 scale mapping accuracies

• Cartographic standard of 90% of features < 0.5mm of their true location at the scale of plotting. If 20 test points used – only one could be outside those limits

• New standard quotes horizontal and vertical accuracy at 95% confidence levels as an absolute property of the digital dataset

• With Orbview, Quickbird, HyMap etc user needs to specify accuracy required but the high resolution of the data combined with on board navigation systems and improved software makes this problem almost a historical footnote.

• Beware of GoogleEarth. All is not always as accurate as it seems. Look for mismatches at image boundaries.

• GPS can lull you into a false sense of security AIG Remote Sensing and Interpretation


User Requirement

HyVista Corporation HyMap with integrated Boeing C-MIGITS GPS/INS and SM2000 Zeiss gyro-stabilized platform for precise removal of 3D aircraft motions.

Uncorrected

Corrected

GIS-ready data


Players – a small sample of the many

Australia CSIRO

• Frank Honey

• Jon Huntington

• Andy Green

• Ian Tapley

• Tom Cudahy

• Mike Hornibrook

• Terry Cocks

• Peter Hausknecht

• Rob Hewson

• Alex Held

• Cindy Ong

• Mike Caccetta

• Peter Hick

• Andy Gabel

• Steve Fraser

• Carsten Laukamp

• Lew Whitbourn

USA • Phoebe Hauff

• Larry Rowan

• Joe Boardman

• Anne Kahl

• Fred Kruze

• Rob Lyon

• Jack Salisbury

• Alex Goetz

• Mike Abrams

• Robert Green

• Simon Hook

• Bill Collins

Industry

• Frank Honey

• Bob Agar

• Neil Goodey

• Kerry O’Sullivan

• Ian Tapley

• Mike Hussey

• Mike Hornibrook

• Terry Cocks

• John Douglas

• Max Bye

• Lyle Burgess

• Nick Locket

• Colin Nash

• Bob Walker

• Sylvia Michael

• Sasha Pontual

• Brian Bennett

• Maarten Haest

Academia

• Geoff Taylor

• John Richards

• Tony Milne

• Bruce Forster

• Gavin Hunt

• Steve Drury

• Rothery

• Nigel Press

• Stuart Marsh

• Dan Taranik

• Anthony Dennis

• Alistair Lamb

UK



Gov’t

• Geoscience Australia

• New South Wales

• Northern Territory

• Queensland

• South Australia

• Tasmania

• Victoria

• Western Australia

Apologies if your name is not on this slide. It is not meant to be definitive. The ordering is random.



Airphotos

ERTS-1 Landsat MSS - TM

SPOT

ASTER

Orbview/Quickbird

Collins GER profiler CO2 Laser Profiler

AMS De Beers HyMap AVIRIS

Hyperion

GER Handheld

AIS

TIMS SEBASS

ASD

PIMA

Terraspec Halo

NOAA

HyLogger

Corescan

AIRSAR

Radarsat

SLAR Shuttle Radar DTM

ARIES

Data processing ERMapper

Bureau services Meridian

ENVI

Geoscan

Specim

Drones

Specim

NEO - HySpex

HyspIRI EnMAP

DISIMP DIPIX

microBrian ERDAS ESRI ArcGIS

2017 2022

Itres

Approximate Technology Progression

Cerberus

1972

OARS

1995 Australia Prize (Remote Sensing) Andy Green, Jon Huntington and Ken McCracken • Acknowledgement of the Australian Remote Sensing

community • Developed software to analyse ERTS-1 data • World’s first image processing facilities to recover

information hidden by background ‘noise’ • Helped establish Alice Springs Landsat reception

facility • Constant challenge to detect very weakly expressed

characteristics of mineralisation that tend to be swamped by other more dominant features in the satellite image

• Developed world’s first airborne pulsed-laser profiling spectrometer



Summary

Archive datasets retain their value

• Landsat TM – good starting point, free data

• SPOT – very inexpensive data now coming out

• NOAA – coarse resolution but great if operational data needed quickly e.g. flood monitoring. Night-time thermal data still good for palaeodrainage

• Stereo colour aerial photography – worth revisiting – use in conjunction with orthophotography



Summary Technology today

• Satellite – • ASTER Archives best configured for geology. Requires sophisticated processing

to make mineral maps – but for Australia they have been done. • ALOS – no SWIR but MSS, Pan and Radar • Orbview/Quickbird

• Airborne – • VSWIR – AVIRIS & HyMap: superior signal to noise • TIR – SEBASS

• Handheld – Terraspec Halo

• Core Scanning – • HyLogger – Profiling VSWIR-TIR • Corescan – Imaging in VSWIR

• Spectral geology (remote sensing) should be part of the entire life cycle of a project not just picked up as an after thought. Use it as an adjunct to other methods and procedures.



Future

• Hyperspectral satellite - enMAP or HyspIRI

• Hyperspectral VSWIR-TIR airborne continuous spectra: - barrel sighted co-aligned instruments viewing the same spot on the ground with same resolution

• Full integration of underground mineralogy with surface spectroscopy using airborne and satellite data as well as high resolution DTM in 3D visualisation

• Augmented Reality – spectral goggles to view the world



history of remote sensing in geological exploration · pdf filehistory of remote sensing in...

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