Remote Sensing Technology and Applications

Abstract

A long anticipated new era in remote sensing has begunwith data now being acquired by commercially-ownedsatellites and airplanes as well as ~as in the past!government-owned satellites. The advent of this era ismarked by new imaging sensors and platforms includingthe first commercial high-resolution satellites. These pro-vide better than 1 meter ground sample distance. Thereare several commercial systems, including IKONOS,Quickbird and EROS, providing an unprecedented qualityand quantity of earth observation data in a very short timeafter acquisition! In addition, data can be readily pur-chased commercially from many other systems. Thetimely availability of this data opens up exciting new ap-plication areas including disaster management, urbanplanning and many others. For the first time in the historyof remote sensing, there are systems and data currently inthe commercial marketplace which, previously, were un-available or available only to governments. The industryis maturing and this Remote Sensing special section ofOptical Engineering includes papers addressing many as-pects of the current state of remote sensing.This special section begins with an overview of theglobal emergence of commercial earth observation satel-lites and their impact on current and future availability ofdigital remote sensing imagery data. This impact is syn-ergistic with the rapidly expanding field of geospatial in-formation systems ~GIS! applications. Subsequent papersfocus on: 1! image collection, 2! image processing tools,and 3! applications using both aerial and satellite collec-tion platforms.In their overview paper, Baker, O’Connor, and Venzorprovide observations from their unique position at RANDon the emergence of commercially-operated high-resolution imaging satellites. Although capable of provid-ing continuous earth coverage of great information valueto GIS analysts, the high initial cost of satellites and com-petition with government-sponsored systems present chal-lenges for the private investor. Chief among these chal-lenges are the policies of world governments that permitfree public access to commercial imagery, as well as clearrules governing competition from government-sponsoredcompetitors. The chief benefit of a financially healthy in-ternational commercial remote sensing satellite industry isnothing less than a significant increase in global transpar-ency, with attendant benefits of timely environmentalmonitoring and common datasets accessible to all govern-ments, non-government organizations ~NGOs!, and aca-demic and commercial value-added services groups.The group of papers on image collection includes Mar-tin’s paper describing the image collection optimizationprocess. This optimization is crucial to maximize use ofexpensive remote sensing satellites. Gorin and Sharp eachpresent important enabling techniques for hyperspectralimaging ~HSI!, an exciting remote sensing image datasetthat promises significant increase in information content.Gorin’s paper deals with the optimization, for object de-tection and recognition, of atmospheric correction of hy-perspectral data in the thermal wave bands. His techniqueuses a new image assessment measure, the spectral simi-larity scale, to quantify the ‘‘goodness of fit’’ for spectralemissivity output from atmospheric correction. Sharp de-scribes a data compression technique to greatly reduce thevast amounts of data to be stored and transmitted fromHSI sensors having 2001 sensor bands recorded in eachimage pixel. She demonstrates the technique’s effective-ness on datasets from a number of operational HSI sen-sors.The image processing papers describe automated ap-proaches to extract information from imagery data and atechnique to protect the intellectual property rights of adigital image by embedding a digital watermark. Chengand Toutin describe an automated process of extracting