Gram-Schmidt orthogonalization technique for atmospheric and sun glint correction of Landsat imagery

A technique for correcting for haze and sunglint in Landsat Thematic Mapper imagery in coastal regions has been developed and demonstrated using Gram-Schmidt orthogonalization of the band covariance matrix. This procedure is an adaptation of Wiener filtering and noise cancellation stochastic signal processing. Using a covariance matrix constructed from an over water portion of the image containing haze and sunglint pixels, a transfer function between infrared (IR) bands (e.g. TM 5) and visible bands (e.g. TM 2) is derived. This transfer function is then applied to the entire image and the visible band contribution predicted by the IR is subtracted from the measured visible signal, pixel by pixel. A comparison between images with and without haze of the same scene indicates that the procedure allows the observation of underwater features not previously visible.