Research Projects

Double random phase encoding (DRPE) is one of the well-known and successful classical optical image encryption technique proposed by Refregier and Javidi. In DRPE, aim is to encode the plain image by converting it into stationary white noise called cipher image by applying statistically independent two random phase diffusers (masks), one in input plane and another in Fourier plane in system. The basic principle of DRPE is based on 4-f optical system for encrypting the plaintext into stationary white noise. Basic principle of DRPE is, the primary image I is immediately followed by first random phase mask R1, then both are placed in input plane of first lens. Further in the Fourier plane of the first lens, the product of I×R1 is Fourier transformed (FT). The output of this product is further multiplied by second random phase mask R2, and then converted to spatial domain by the second lens; subsequently inverse Fourier transformed (FT-1). In this scheme, the phase masks R1 and R2 are independent and generated randomly distributed in [0, 1], and it play as the secret key of DRPE. Traditional random phase masks (RPMs) were replaced with structured phase masks (SPMs), which are derived from devil’s vortex Fresnel lens (DVFL), devil’s vortex Toroidal Lens (DVTL), Hybrid structured phase masks (HSPMs), deterministic phase masks (DPMs), and Chaotic structured phase masks (CSPMs) etc. The purpose of using these phase keys are to enhance the security of algorithms by increasing the key space. Such SPMs have multiple storing keys in a single-phase mask. They are diffractive optical elements (DOEs) and are difficult to replace them. These provides extra security parameters which make system more secure and reliable. The main objective is present proposal is to design and study optically of following phase masks Structure Phase Masks (SPMs), Generation of optical vortex phase masks (OV), Chaotic Structured Phase Masks (CSPM), Generation of hybrid structure phase mask (HSPM), Generation of Deterministic Phase Mask (DPM), DVFL Phase Mask, DVTL based phase mask.