THE SIGNAL-TO-NOISE RATIO (SNR) REQUIRED FOR THE ESTIMATION OF FOLIARBIOCHEMICAL CONCENTRATIONS

This paper compares estimates of the signal-to-noise ratio (SNR) requi red by imaging spectrometers for the estimation of foliar biochemical concentrations and the SNR currently achieved by the Airborne Visible/ Infrared Imaging Spectrometer (AVIRIS). The work was comprised of thre e sections. Section 1: the SNR required by imaging spectrometers was e stimated by modelling three data sets, each of which more closely appr oximated the data recorded by the AVIRIS. The remaining stages were co ncerned with estimating the SNR currently achieved by the AVIRIS. Sect ion 2: SNR estimates made as part of instrument calibration were scale d to those that would be expected when viewing vegetation, and section 3: SNR was estimated directly from AVIRIS imagery. The results of the se three sections were then compared to assess the SNR performance of the AVIRIS and its utility for the estimation of foliar biochemical co ncentrations. The SNR of the AVIRIS is planned to double between 1994- 5 and while this sensor was barely adequate for the estimation of foli ar biochemical concentrations in 1992-3 it should be more than adequat e from 1995 onwards.