#### Progress Report (02/07/2003): NASA Grant NCC5-495

####  Evaluation and Geologic Validation of EO-1 Hyperion 

**F. A. Kruse**[^1] **and J. W. Boardman**[^2]

**And**

**J. F. Huntington**[^3]

**Research Summary**

This is a summary of in-progress NASA-Funded research (NASA Grant
NCC5-495). Research is currently on a no-cost extension until 31 March
2003 at which time the final report will be delivered.

AIG, in cooperation with CSIRO, Sydney Australia has evaluated,
validated, and demonstrated Hyperion hyperspectral data for geologic
applications. Three test sites were originally proposed for analysis,
the northern Grapevine Mountains, Nevada; Oatman, Arizona; and Virginia
City, Nevada. Hyperion data analysis was conducted for these sites along
with additional sites added to the study based on data availability. The
additional sites are the Los Menucos area, Argentina and Cuprite,
Nevada. Cumulatively, these test sites provide geologically diverse
terrains allowing validation of Hyperion data across a variety of
geologic environments. Airborne Visible/Infrared Imaging Spectrometer
(AVIRIS) data served as the baseline for comparative determination of
Hyperion data characteristics and performance. Previous field and
airborne mapping and spectral characterization allowed AIG/CSIRO to
assess Hyperion suitability and performance for geologic mapping and
mineral resource appraisal. Results over sites with established ground
truth and years of airborne hyperspectral data show that Hyperion data
from the short-wave-infrared (SWIR) spectrometer can be used to produce
useful geologic (mineralogical) information. Minerals mapped include
carbonates, chlorite, epidote, kaolinite, alunite, buddingtonite,
muscovite, hydrothermal silica, and zeolite. Hyperion data collected
under optimum conditions (summer season, bright targets, well-exposed
geology) indicate that Hyperion data meet pre-launch specifications and
allow subtle distinctions such as determining the difference between
calcite and dolomite and mapping solid solution differences in micas
caused by substitution in octahedral molecular sites. Comparison of
airborne hyperspectral data (AVIRIS) to the Hyperion data establishes
that Hyperion provides similar basic mineralogical information, with the
principal limitation being limited mapping of fine spectral detail under
less-than-optimum acquisition conditions (winter season, dark targets)
based on lower signal-to-noise ratios (SNR). The case histories
demonstrate the analysis methodologies and level of information
available from the Hyperion data. They also show the viability of
Hyperion as a means of extending hyperspectral mineral mapping to areas
not accessible to aircraft sensors. The analysis results demonstrate
that spaceborne hyperspectral sensors can produce useful mineralogical
information, but also indicate that SNR improvements are required of
future spaceborne sensors to allow the same level of mapping that is
currently possible from airborne sensors such as AVIRIS. Results from
this research provide valuable information about hyperspectral sensing
from space that can be used to help bootstrap future hyperspectral
satellite missions.

# Research Results

The following presents the key results from the main EO-1 Hyperion
geologic study sites used for this analysis/research.

-   Los Menucos Argentina: represents a case where Hyperion data
    collected during the winter season (low sun angle) lack sufficient
    SNR (\<40:1 VNIR, \<15:1 SWIR) for accurate mineral mapping.

-   Cuprite, NV: an "Early" Hyperion acquisition for the northern
    hemisphere (a winter scene). SWIR SNR is approximately 25:1.
    Hyperion analysis and comparison to known geology derived from
    AVIRIS data and ancillary ground measurements validate Hyperion
    basic mineral mapping. Some confusion occurs between similar
    minerals.

-   Virginia City, NV: General mineral mapping using Hyperion possible,
    however, some minerals missed, and similar minerals confused. SWIR
    SNR is particularly low (approximately 20:1) principally because of
    lower albedo, vegetated, heterogeneous, mountainous, mixed terrain.
    Limited separation of cation-substituted micas is possible.
    Particular problems mapping 2.3 mm minerals such as chlorite,
    epidote, amphiboles, carbonates.

-   Oatman, AZ: Hyperion successfully maps basic mineral groups
    (kaolinite, alunite, chlorite and muscovites) and detects and maps
    subspecies (cation substitution) of muscovites. Hyperion was unable
    to fully separate calcite from chlorite and did not detect dolomite
    or dickite (probable SNR issues).

-   N. Grapevine Mtns, NV is a "best case" Hyperion acquisition from
    the N. Hemisphere Summer (July 2001). SWIR SNR is approximately
    60:1. The higher SNR allows improved mineral identification and
    within-species variability mapping compared to Hyperion data sets
    with lower SNR.

Other key results of this research include:

-   Validation of methods developed for analysis of airborne
    hyperspectral data for analysis of spaceborne HSI data ("hands-off"
    analysis using model-based atmospheric correction and n-Dimensional
    scatterplot approach)

-   Demonstration and validation of HSI mineral mapping from space for a
    variety of geologic environments

    i.  Basic Mineral Mapping performed for minerals with high spectral
        contrast @ \>90% Accuracy for pixels mapped as specific mineral

    ii. Basic Mineral Mapping for similar minerals (eg: MgOH vs
        Carbonate minerals) but some problems at lower SNR

    iii. Within-Species variability (cation-substitution), but lower
         accuracy dependent on spectral feature similarity and SNR

         -   Establishment of effective Hyperion SWIR SNR as \~60:1 for
             mid-latitude, summer Hyperion scenes and as low as \~15:1
             for similar winter scenes. Results illustrate requirement
             for higher SNR for future spaceborne systems

# Research Significance

The AIG/CSIRO proposal was for evaluation, validation, and demonstration
of Hyperion's capabilities for geologic mapping and mineral resource
assessment, offering a low-cost, high-experience, high-leverage
approach. The effort drew heavily on previous work and outside funding
sources to maximize the cost-effectiveness for the Hyperion evaluation
and validation. Examining Hyperion data collected over well-understood
geological sites resulted in practical and important demonstrations of
Hyperion data for geological mapping and mineral resource assessment.
Validation of the spatial, spectral and radiometric performance of
Hyperion was achieved using real-world applications as the defining
metric. Additionally, analysis methods originally developed for airborne
hyperspectral data were validated for use with satellite-based sensors.
The following points illustrate the significance of this research:

-   These Hyperion geologic case histories demonstrate the analysis
    methodologies and level of information available from Hyperion for
    mineral mapping

-   AIG's/CSIRO's hyperspectral data processing methods applied to
    Hyperion data lead to definition of specific key minerals and
    mineral assemblages

-   Hyperion analysis and comparison to known geology derived from
    AVIRIS data and ancillary ground measurements generally validate
    on-orbit mineral mapping and Hyperion performance

-   Hyperion's lower SWIR SNR compared to AVIRIS results in lower data
    dimensionality, thus fewer endmembers can be identified and mapped
    than with AVIRIS

-   Relatively low Hyperion SWIR SNR limits effectiveness for many
    datasets, placing them at the margin of operational utility (Some
    minerals mapped, others missed)

-   Hyperion often confuses similar minerals that are separable using
    AVIRIS

-   "Success" evident in "summer" (high-sun-angle) data for near-100%
    exposed, high-albedo areas with little mixing and little vegetation

-   Results from AIG/CSIRO's primary test sites demonstrate that more
    detailed within-species mineral identification and mapping is
    possible in some cases under optimum acquisition conditions

-   Even with the SNR problems noted, Hyperion is a success as a
    technology demonstration. It performs well under most circumstances
    for basic mineral identification/mapping

-   Hyperion has acted as a valuable learning experience for the future
    of spaceborne hyperspectral imaging. Our (and others) Hyperion
    analyses illustrate that improved performance (principally SNR) is
    required for typical geologic applications. Future satellite systems
    will need to be enhanced to improve overall mapping performance, the
    capability to make detailed mineralogical distinctions, and
    "all-season" mapping capabilities

## Kruse et al., EO-1 Hyperion Publications

Kruse, F. A., Boardman, J. W., Huntington, J. F., Mason, P., and
Quigley, M.A., 2003, Evaluation and Validation of EO-1 Hyperion for
Geologic Mapping: in Special Issue, TGARSS, IEEE (Accepted for
Publication 01/27/2003).

Kruse, F. A., Boardman, J. W., Huntington, J. F., Mason, P., and
Quigley, M.A., 2002, Evaluation and Validation of EO-1 Hyperion for
Geologic Mapping: in Proceedings, IGARSS 2002, 24 -- 28 June 2002,
Toronto, Canada , Published on CD ROM -- Paper 02_06_17:00, ISBN:
0-7803-7537-8. Also in hardcopy, v. I, p. 593-595, IEEE Operations
Center, Piscataway, NJ.

Kruse, F. A., Comparison of AVIRIS and Hyperion for Hyperspectral
Mineral Mapping, 2002, In proceedings 11^th^ JPL Airborne Geoscience
Workshop, Jet Propulsion Laboratory, 4-8 March 2002 (in press).

Kruse F. A., Perry, S. L., and Caballero, A., 2002, Integrated
Multispectral and Hyperspectral Mineral Mapping, Los Menucos, Rio Negro,
Argentina, Part I: Landsat TM Reconnaissance and AVIRIS Prospect
Mapping: In proceedings 11^th^ JPL Airborne Geoscience Workshop, Jet
Propulsion Laboratory, 4-8 March 2002 (in press).

Kruse F. A., Perry, S. L., and Caballero, A., 2002, Integrated
Multispectral and Hyperspectral Mineral Mapping, Los Menucos, Rio Negro,
Argentina, Part II: EO-1 Hyperion/AVIRIS Comparisons and Landsat
TM/ASTER Extensions: In proceedings 11^th^ JPL Airborne Geoscience
Workshop, Jet Propulsion Laboratory, 4-8 March 2002 (in press).

Kruse, F. A., Boardman, J. W., and Huntington, J. F., 2002, Comparison
of Airborne and Satellite Hyperspectral Data for Geologic Mapping: in
Proceedings, SPIE International Symposium on AeroSense, 1-5 April 2002,
Orlando, FL, v. 4725, p. 128-139.

Kruse, F. A., Boardman, J. W., and Huntington, J. F., 2002, Comparison
of EO-1 Hyperion and Airborne Hyperspectral Remote Sensing Data for
Geologic Applications: in Proceedings, IEEE Aerospace Conference, 9-16
March 2002, Big Sky, Montana , published on CD-ROM, IEEE Catalog Number
02TH8593C, Paper #6.0102, 12 p.

Kruse, F. A., Boardman, J. W., and Huntington, J. F., 2001, Progress
Report: Geologic Validation of EO-1 Hyperion: in Proceedings of the
10^th^ JPL Airborne Earth Science Workshop: Jet Propulsion Laboratory
Publication 02-1, p. 253 -- 265.

[^1]: ^1^ Analytical Imaging and Geophysics LLC (AIG), 4450 Arapahoe
    Ave, Suite 100, Boulder, Colorado 80303, (e-mail: kruse@aigllc.com)

[^2]: ^1^ Analytical Imaging and Geophysics LLC (AIG), 4450 Arapahoe
    Ave, Suite 100, Boulder, Colorado 80303, (e-mail: kruse@aigllc.com)

[^3]: ^2^ Commonwealth Scientific & Industrial Research Organisation
    (CSIRO), Division of Exploration and Mining, North Ryde, NSW,
    Australia, 2113