The Advanced Land Image Assessment Systems (ALIAS) supports radiometric and geometric image processing for the Advanced Land Imager (ALI) instrument on board NASA’s Earth Observing-1 (EO-1) satellite. ALIAS consists of two processing subsystems for radiometric and geometric processing of the ALI’s multispectral imagery. The radiometric processing subsystem characterizes and corrects, where possible, radiometric qualities including: detector operability; gain; bias; coherent, impulse and random noise; signal-to-noise ratios (SNR); saturation levels; striping and banding; and the stability of detector performance. The geometric processing subsystem and analysis capabilities support sensor alignment calibrations; sensor chip assembly (SCA)-to-SCA alignments and related issues; geodetic accuracy assessments; modulation transfer function (MTF) characterizations; and perform image-to-image characterizations. The ALIAS also characterizes and corrects band-to-band registration, and performs systematic, precision and terrain correction of ALI images. The ALIAS can geometrically correct and automatically mosaic the SCA image strips into a seamless, map-projected image. The ALIAS was developed through collaboration between NASA and the U.S. Geological Survey (USGS).
The primary technical goal of the ALIAS development was to generate an Image Assessment System prototype based on the algorithms and software used for EO-1 ALI and Landsat 7 ETM+ analyses.
These goals are listed below.
The key design an functional attributes of ALIAS include:· Demonstrate the technical feasibility of trending radiometric performance data on a detector-by-detector basis (Bulk Trending)· Develop and exercise a very large IAS database (>5TB)· Develop a system architecture to support a virtual IAS concept· Port the radiometric and geometric algorithms to a common platform· Maintain a modular/reusable architecture· Develop Calibration Parameter File (CPF) information in a logical database (still supports a CPF delivery)
If an ALI-like instrument is flown on a future spacecraft, it is possible that the ALIAS software could be adapted to perform processing of image data from such an instrument.
Usability Goals:The primary use for ALIAS is in the scientific processing of image data from the NASA EO-1 Advanced Land Imager instrument. NASA and USGS will also use ALIAS to further advance the analyst body of knowledge on push broom sensor calibration and validation.