Abstract: A method of performing a complex Fourier transform of an input function including amplitude and phase information, including decomposing the input function into a plurality of sub-functions, wherein the Fourier transform of each sub-function includes an amplitude function and a phase function in which the phase is constrained to a plurality of possible phase values. The phase function of the Fourier transform of each sub-function is determined with an optical system that measures the amplitude function of an optical Fourier transform of the sub-function and changes in the amplitude function of the optical Fourier transform caused by applying a perturbation function to the sub-function. The determined phase functions and the measured amplitude functions are combined for each of the sub-functions to form the complex Fourier transform of the input function.

Abstract: An optical processing system comprises at least one spatial light modulator, SLM, configured to simultaneously display a first input data pattern (a) and at least one data focusing pattern which is a Fourier domain representation (B) of a second input data pattern (b), the optical processing system further comprising a detector for detecting light that has been successively optically processed by said input data patterns and focusing data patterns, thereby producing an optical convolution of the first and second input data patterns, the optical convolution for use in a neural network.

Abstract: A method of performing a complex Fourier transform of an input function including amplitude and phase information, including decomposing the input function into a plurality of sub-functions, wherein the Fourier transform of each sub-function includes an amplitude function and a phase function in which the phase is constrained to a plurality of possible phase values. The phase function of the Fourier transform of each sub-function is determined with an optical system that measures the amplitude function of an optical Fourier transform of the sub-function and changes in the amplitude function of the optical Fourier transform caused by applying a perturbation function to the sub-function. The determined phase functions and the measured amplitude functions are combined for each of the sub-functions to form the complex Fourier transform of the input function.