CHAPTER I - Introduction and Objectives

Abstract

This chapter describes electro-optical sensors as a very powerful tool, which has a wide range of applications in various fieldssuch as military, industries, and scientific field. In the chapter, emphasis is given to the radiometer and the spectrometer. Spatial scanners, imaging systems, and polarimeters are also described. Radiometry or spectroscopy is concerned with the transfer of optical radiation between a target source and its associated background, through the intervening medium, to a receiver or detector of optical radiant energy. The chapter highlights the calibration of the spatial response, or field of view of a sensor, as a problem of spatial purity. It further explains the general objective of the calibration of electro-optical instrumentation, which is to obtain a functional relationship between the incident flux and the instrument output. The functional relationship is generally expressed as a mathematical equation that gives the magnitude of the radiant entity of interest as a function of the instrument output. Calibration of an instrument should make the measurement independent of the instrument and be conducted under conditions that reproduce the conditions under which the measurements are to be made. The calibration of the instrument requires a functional set of data concerning the spectral, spatial, temporal, and polarization characteristics of the instrument for which the linearity and background noise level in the instrument need to be investigated.