A security-enhanced multiple-image encryption method is proposed based on modified iterative phase retrieval algorithm with structured phase mask in Fresnel domain in this paper, where each plaintext is encoded to onl...
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A security-enhanced multiple-image encryption method is proposed based on modified iterative phase retrieval algorithm with structured phase mask in Fresnel domain in this paper, where each plaintext is encoded to only one independent phase-only mask with the help of the used struc-tured phase mask, and a group of phase-only masks retrieved by multiple plaintexts are integrated into the ciphertext with the noise-like distribution by using the phase mask multiplexing tech-nique. In the proposed method, the Fresnel diffraction distances and the wavelength of light as well as the optical parameters of the structured phase mask such as focal length, topological charge number are all used as digital keys to expand the key space. Most importantly, the sen-sitivities of the digital keys are substantially improved by mapping the digital keys with the initial values of chaotic system thanks to the nonlinear, pseudo-random, high sensitivity of initial value of special phase generated by chaotic system, contributing to an extremely high security of multiple-image encryption method. Moreover, computational simulations are performed to demonstrate the feasibility of the proposed security-enhanced multiple-image encryption method, and the simulation results confirm that the proposed method exhibits high effectiveness and strong robustness.
Direct detection imaging in complex, inhomogeneous media is a difficult challenge due to the existence of multiple scattering. One way used to extract the information of the object from the speckle pattern is to use s...
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ISBN:
(纸本)9781510623330
Direct detection imaging in complex, inhomogeneous media is a difficult challenge due to the existence of multiple scattering. One way used to extract the information of the object from the speckle pattern is to use speckle correlation based on the memory effect, and the object is recovered by an iterative phase retrieval algorithm. Here we report a new iterative phase retrieval algorithm that is referred to as the absolute output (AO) Gerchberg-Saxton algorithm and can single-shot ultra-fast reconstruct the object image. Different from the error reduction (ER) algorithm and hybrid input-output (HIO) algorithm, this algorithm does not need to satisfy the non-negative constraints. We experimentally demonstrate that the reconstructed image achieved by our algorithm is faster, more reliable, and more consistent. Our method has strong anti-interference ability, which has great potential in imaging through turbid medium such as fog and biological tissue.
We previously implemented a conical CT system as X-ray CT system for industrial inspection. But there is the problem, "missing cone" problem, which conical data is missed in fourier space, and vertical accur...
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ISBN:
(纸本)9784907764401
We previously implemented a conical CT system as X-ray CT system for industrial inspection. But there is the problem, "missing cone" problem, which conical data is missed in fourier space, and vertical accuracy was comparatively low. We intend to improve the vertical accuracy by iterative phase retrieval algorithm. The overall reconstruction algorithm is based on Filtered back projection algorithm and iterative phase retrieval algorithm. We implemented this simulation with the Shepp-Logan phantom, which is often used for CT simulation. Through the study it was revealed that the proposed method can recovery missing data of low frequency.
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 authenti...
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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.
We previously implemented a conical CT system as X-ray CT system for industrial inspection. But there is the problem, "missing cone" problem, which conical data is missed in fourier space, and vertical accur...
详细信息
ISBN:
(纸本)9784907764401
We previously implemented a conical CT system as X-ray CT system for industrial inspection. But there is the problem, "missing cone" problem, which conical data is missed in fourier space, and vertical accuracy was comparatively low. We intend to improve the vertical accuracy by iterative phase retrieval algorithm. The overall reconstruction algorithm is based on Filtered back projection algorithm and iterative phase retrieval algorithm. We implemented this simulation with the Shepp-Logan phantom, which is often used for CT simulation. Through the study it was revealed that the proposed method can recovery missing data of low frequency.
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