The redistribution of light energy in the receiving plane of the diffraction pattern by means of concurrent suppression of side-lobes and the amplification of the central disc by applying rotating phase masks at the exit pupil has been investigated. The magnitude of the suppression of side-lobes depends on the degree of the phase mask at the edge zones of the pupil. The mask is applied to achieve the side-lobe suppression on one side of the PSF. By applying a rotated mask, side-lobe suppression will occur on the other side of the PSF. The resolution of the object or signal under the optimum masking conditions is analysed by employing the standard characteristic parameters of the diffraction
