Canadian Forest Service Publications
Mission planning for operational data acquisition campaigns with the casi. 1996. Wulder, M.A.; Mah, S.; Trudeau, D. Pages 53-62 (Vol. 1) in Technology, Measurement, and Analysis, Proceedings: Second International Airborne Remote Sensing Conference and Exhibition. June 24-27, 1996, San Francisco, CA. Environmental Research Institute of Michigan (ERIM), Ann Arbor, MI.
Issued by: Pacific Forestry Centre
Catalog ID: 25062
Availability: PDF (download)
The compact airborne spectrographic imager (casi) is a “pushbroom” style airborne remote sensing instrument which has been used for a variety of applications suited to its high performance, portability, flexibility in choice of spectral bands and imaging combinations, image geocoding capabilities, low-cost data acquisition, and relative ease of use and processing. Accordingly, the casi offers a versatile tool to the environmental monitoring specialist. As the casi may be configured to operate in either spatial or spectral mode the user decides which is most appropriate for the needs of a particular study. Spatial mode is appropriate for identifying and mapping attributes spatially using a priori spectral knowledge whereas spectral mode is well suited to identifying detailed spectral characteristics of a feature. The hyperspectral acquisition mode is a combination of both spatial and spectral operations, where contiguous spatial and spectral information are collected. The array of imaging possibilities provided by the casi requires the user to make many decisions. Yet, the options provided by the casi are not the only issues that need to be addressed pre-flight. Other considerations are flight azimuth, positioning of flight lines, sun angle, differential correction of airborne GPS data, and possible collection of pseudo-invariant features (PIFs) with a spectroradiometer. The above issues need to be addressed to reduce sun “hot spots”, sun glint, minimize bidirectional effects, and improve image mosaicking. Data may be acquired to optimize use of a downwelling irradiance sensor, real-time attitude sensing using either a vertical gyroscope or Inertial Navigation System, and differential GPS measurements. The goal of this paper is to provide a general “guide” for airborne casi remote sensing mission planning that will facilitate the acquisition of quality imagery for forestry, water, environmental, and mapping applications.