Collection of pushbroom sensor imagery from a mobile platform requires correction of the platform motions using inertial measurement units (IMU’s) as well as DGPS in order to create useable imagery for environmental monitoring and surveillance of shorelines in freshwater, littoral or harbour areas. This paper will present a suite of imaging systems used during collection of hyperspectral imagery during recent northern Gulf of Mexico airborne missions to detect weathered oil in coastal littoral zones. Underlying concepts of pushbroom imagery, the needed corrections for directional changes using DGPS and corrections for platform yaw, pitch, and roll using IMU data is described as well as the development and application of optimal band and spectral region selection for developing remote sensing algorithms. Pushbroom sensor and frame camera data collected in response to the recent Gulf of Mexico oil spill disaster will be presented as the scenario documenting the environmental monitoring and surveillance techniques using mobile sensing platforms. Data was acquired during the months of February, March, April and May of 2011. The low altitude airborne systems include a cooled hyperspectral imaging system with 1024 spectral channels and 1375 spatial pixels flown at 3,000 to 4,000 feet. The hyperspectral imaging system is collocated with a full resolution high definition video recorder for simultaneous HD video imagery, a 12.3 megapixel digital images for multispectral "sharpening" the hyperspectral imagery, a large frame 9 inch film mapping camera that yields scanned aerial imagery with approximately 2200 by 2200 pixel multispectral imagery (255 megapixel RGB images. Two high spectral (252 channels) and radiometric sensitivity solid state spectrographs are used for collecting upwelling radiance (sub-meter pixels) and a downwelling irradiance using a fiber optic irradiance sensor. These sensors are utilized for cross calibration and independent acquisition of ground or water reflectance signatures and for calculation of the bi-directional reflectance distribution function (BRDF). Methods are demonstrated for selecting optimal spectral regions and bands for discrimination, detection and characterization of weathered oil in the Northern Gulf of Mexico in response to the Deepwater Horizon oil spill disaster.

The imagery presented and described allow for modern research in the use of sun and sky glint regions in imagery to identify water surface wave field characteristics as well as oil slicks. The systems described provide unique data sets of for modern airborne or satellite remote sensing algorithm development and future testing of radiative transfer models useful in studying the environment at small spatial scales.

Partally Funded by : BP Florida Institute of Oceanography Deepwater Horizon Research Funds Remote Sensing Project