Remote sensing is the science of measuring characteristics of interest from a distance. Our focus in this chapter is the remote sensing of Earth from instruments flown on aircraft or spacecraft. Imaging from remote sensors has had a long history, starting early in the twentieth century with photographs from balloons and aircraft. In recent years, there has been a proliferation of aerial and space-borne sensors that image the Earth at various resolutions. | Image Databases Search and Retrieval of Digital Imagery Edited by Vittorio Castelli Lawrence D. Bergman Copyright 2002 John Wiley Sons Inc. ISBNs 0-471-32116-8 Hardback 0-471-22463-4 Electronic 3 Satellite Imagery in Earth Science Applications . RAMAPRIYAN NASA Goddard Space Flight Center Greenbelt Maryland INTRODUCTION Remote sensing is the science of measuring characteristics of interest from a distance. Our focus in this chapter is the remote sensing of Earth from instruments flown on aircraft or spacecraft. Imaging from remote sensors has had a long history starting early in the twentieth century with photographs from balloons and aircraft. In recent years there has been a proliferation of aerial and space-borne sensors that image the Earth at various resolutions. There is considerable international interest in remote sensing both in the public and in the private sectors. The data from remote sensors come in many forms such as images profiles and so on. However images tend to dominate the archives of remotely sensed data both in volume and in variety. The applications of remote sensing are numerous in both civilian and military arenas. Examples of civilian applications include daily weather forecasting long-term climate studies monitoring atmospheric ozone forecasting crops and helping farmers with precision agriculture. A variety of data collection systems exist today to obtain image and nonimage data using remote sensing. Instruments that obtain image data are in general referred to as imagers. Measurements such as surface height obtained by altimeters and reflected radiance from the Earth at various wavelengths obtained by radiometers spectrometers or spectroradiometers are represented as images. The number of wavelength ranges spectral bands used by imaging instruments can vary from one panchromatic to hundreds hyperspectral . A variety of mechanisms are used in sensing including across-track and along-track scanning Section resulting in the .
