Restoration of Turbulence-Degraded Images*

Turbulence-degraded images have been processed to obtain an improvement of their visual image quality. The initial objects were photographed through laboratory-generated turbulence. The resulting transparencies of the degraded images were digitized by a photoelectric scanner and processed on a digital computer. The processing consisted of applying corrections to the amplitude and phase coefficients of the two-dimensional Fourier series representing the degraded images. The correction factors were obtained from the optical transfer function of the turbulence measured at the time the images were photographed. The experiment was done for 5-msec and 1-min exposure times. The processed data were used to generate photographs. The processed images were found to have significantly more visual detail than the original degraded images; the 5-msec-exposure restorations were superior to the 1-min-exposure restorations.