title: Imaging performance of annular apertures. 3:Apodization and modulation transfer functions.
abstract: Apodization functions with decreasing transmission and their opposite, functions with increasing transmission, are investigated for various central obstruction ratios. The resultant modulation transfer functions are presented for various transmission functions and central obstruction ratios. Conclusions applicable to the improvement of imaging performance are discussed.
authors.forename: H F
authors.initials: HF
authors.lastname: Tschunko