<title>Estimation of spatial resolution characteristics for the AVNIR sensor</title>

Abstract

As part of the ADEOS CAL/VAL program, the authors have studied how to accurately estimate the system spatial resolution characteristics of the Advanced Visible and Near-Infrared Radiometer (AVNIR) in Earth orbit. This report summarizes our study effort for estimating system PSF/MTF characteristics of the AVNIR sensor after launch. Scene structures of a sharp knife-edge with step targets were used with estimation experiments to predict the resolution of the AVNIR sensor. Finding optimal candidate target sites from a display of profiles for the gray level from Earth observation images taken by the AVNIR sensor is very difficult, error-prone and tedious work. Using a newly developed automatic target detection method, we looked for many near-optimal sharp knife edges with step targets in AVNIR operational images. In the data analysis experiments, two estimation methods, the frequency domain method (Fourier transform techniques) and the spatial domain method (spatial convolution techniques), were applied to subscenes of the AVNIR imagery from target sites selected above. The effect of atmospheric degradation was also investigated using atmospheric corrected observation data of the same target sites. The computational results of these methods agree relatively well. AVNIR's estimated spatial resolution for the atmospheric compensation data cases seemed reasonable with respect to design and prelaunch parameters.