Multiple-image authentication based on the single-pixel correlated imaging and multiple-level wavelet transform

Abstract

Single-pixel correlated imaging has been developed as one of the most promising techniques in the past decades. In this paper, a new mechanism of single-pixel correlated imaging is designed for multiple-image authentication. The object wave is sequentially modulated by a series of phase-only mask pairs embedded into two cascaded spatial light modulators. The modulated wave passes through the input image located in the object plane, and its intensity is recorded as one of the ciphertext values by using a single-pixel bucket detector without spatial resolution. The sparse data of plaintext images are obtained with the multiple-level wavelet transform and used to construct an interim image with the help of binary amplitude masks. The interim image with a smaller size than that of plaintext images is considered as the input of single-pixel correlated imaging, which can guarantee the number of measurements reduced. Simultaneously, the phase-only mask pairs are retrieved from the 2D patterns formed with the row vectors of the spatially orthogonal Hadamard matrix by using an efficient iterative phase retrieval algorithm. Because the redundancy between speckle patterns generated with these phase-only mask pairs is greatly restrained, the number of measurements can be further reduced. Moreover, the related binary amplitude masks are employed as the secret keys so that the security level is also extensively enhanced. Given the above, the proposed method can significantly achieve the goal of multiple-image verification and provide a different research approach for optical authentication based on single-pixel correlated imaging.