Hyperspectral Imaging

All objects reflect, absorb, or emit electromagnetic radiation based on their composition. A hyperspectral sensor, using reflected solar radiation, captures the unique spectra, or 'spectral signature', of an object, which can then be used to identify the material of which it is composed. The electromagnetic spectrum is shown in Figure 1.

Figure 1: Typical Hyperspectral Frequency Bands

Figure 1: Typical Hyperspectral Frequency Bands
Vis = Visible
NIR = Near infrared
SWIR = Short wavelength infrared
MWIR = Medium wavelength infrared
LWIR = Long wavelength infrared (Economic and Market Analysis Centre, United States Air Force)

Hyperspectral imagers typically sample between 50 and 300+ bands or channels in the electromagnetic spectrum. They produce vast quantities of data because of the number of bands simultaneously imaged, creating a 3-dimensional image cube (see Figure 2).

Figure 2: Hyperspectral Imaging

Click to enlarge

The spectral signature of an object is compared with an existing 'spectral library' to determine its composition and identity. Collection of the spectral library typically involves in-situ sampling and analysis.

Hyperspectral Uses

Mineral Exploration

• Lithologic mapping
• Geobotanical mapping

Agriculture

• Crop stress mitigation
• Yield prediction
• Soil quality
• Agro-environmental health

Marine and Coastal Waters

• Impacts of land use and river runoff
• Eutrophication and harmful algae
• Fisheries applications/productivity
• Coastal zone change detection

Forestry

• Forest inventory
• Forest chemistry
• Kyoto products

The Environment

• Wetlands
• Mine waste management/rehabilitation
• Land degradation and soils mapping
• Climate Change

The Military

• Terrain mapping
• Detection of soil disturbance
• Near-shore bathymetry
• Target detection

The Benefits of Spaceborne Hyperspectral Imaging

A spaceborne hyperspectral imager will provide significant advantages over existing multispectral satellite sensors. And while there will always be a need for airborne hyperspectral imagers where very high spatial resolutions (1-4 m) are called for, or for short-term time-critical events that may not coincide with satellite overpasses, a spcaebone hyperspectral instrument presents a number of advantages:

1. Hyperspectral data will provide unique capabilities to discern physical and chemical properties of Earth surface features not possible using current broadband multispectral sensors.
2. A spaceborne hyperspectral instrument will acquire data anywhere globally and at low cost to the end user.
3. The spaceborne sensor will have a well-defined sun-synchronous orbit, ensuring consistent illumination characteristics.
4. A spaceborne hyperspectral sensor will provide year-round monitoring capability for applications requiring temporal information.

Lithological Mapping

Socio-Economic Benefits

Socio-economic benefits will accrue from:

• Satellite construction
• Satellite operations
• Data analysis
• Data Use

Resulting in:

• Productivity improvements
• Environmental benefits
• Sovereignty and security benefits
• Health and safety benefits
• Improved technological capacity

Mine Waste Management

The Canadian Hyperspectral Mission

The CSA is currently conducting mission concept studies in preparation for launch of a hyperspectral earth observation satellite. The mission will build on Canadian industry's experience and expertise in remote sensing, and make new capabilities available for a wide variety of users that will provide economic, social, and environmental benefits to Canada and the world.

More information can be obtained from:

SPACECRAFT PAYLOADS
6767 route de l'Aéroport
Saint-Hubert, Quebec
Canada
J3Y 8Y9
Telephone: (450) 926-4616

Wetlands Mapping