Modulation–spectral analysis of an image transmitted across a distorting medium

The task of simultaneous determination of the structure and characteristics of a two-dimensional amplitude – phase signal and a two-dimensional complex transfer or instrumental function is considered. The solution is based on determination of four independent intensity distributions of spectral representations of the signal I_sr(ω_x, ω_y) subjected to the action of the transfer function, of the signal I_smr(ω_x, ω_y) which has experienced additional modulation applied in a certain manner and the action of the transfer function, of the signal I_srn(ω_x, ω_y) representing the signal I_sr(ω_x, ω_y) with certain additional modulation at the output, and of the signal I_smrn(ω_x, ω_y) which is the signal I_smr(ω_x, ω_y) with certain additional modulation at the output. These intensity distributions make it possible to calculate the amplitude and phase components of the image being analysed and of the transfer function. Additional modulations should in some way ensure visualisation of the phase information. A specific type of additional spatial modulation, in the form of linear amplitude, is discussed.