IMAGING SPECTROMETER BASED ON AN ACOUSTOOPTIC TUNABLE FILTER

This article describes an imaging spectrometer developed for remote se nsing applications. The instrument consists of an acousto-optic tunabl e filter (AOTF), a high sensitive charged coupled device camera and op tic lens. The selected AOTF was designed to have a large entrance aper ture and to diffract light between 600 and 900 nm with a high spectral resolution. The signal was digitized by the camera and acquired with a developed WINDOWS executable software which drives the instrument. T he spectrometer has been operated in a classical mode and in an imagin g mode for its evaluation: In the imaging mode, images including diffe rent types of targets were acquired in reflection and transmission mod e and were used to investigate image homogeneity, spatial resolution, chromatic and geometric aberrations, sensitivity and reliability. Spec tra have been extracted from images and were successfully compared wit h spectra from the same sample area obtained with classical nonimaging spectrometers. This confirms the ability of this instrument to clear up many problems in surface analysis, particularly in the case of labo ratory and field measurements used in remote sensing studies. (C) 1998 American Institute of Physics.