1. A method of utilizing an optical image processing system, the method comprising: (a) providing a measured magnitude of the Fourier transform of a complex transmission function of an object or optical image; (b) providing an estimated phase term of the Fourier transform of the complex transmission function; (c) multiplying the measured magnitude and the estimated phase term to generate an estimated Fourier transform of the complex transmission function; (d) calculating an inverse Fourier transform of the estimated Fourier transform, wherein the inverse Fourier transform is a spatial function; and (e) calculating an estimated complex transmission function by applying at least one constraint to the inverse Fourier transform.