Showing papers by "Guohai Situ published in 2007"
TL;DR: To avoid additive cross-talk among multiple images, they are separated from each other and even from the host image in the hiding and the extraction process by locating them independently in the Fresnel domain with computer-generated double phase-only masks.
Abstract: To avoid additive cross-talk among multiple images, they are separated from each other and even from the host image in the hiding and the extraction process by locating them independently in the Fresnel domain with computer-generated double phase-only masks. Gray images and white-ground and black-ground binary images can be hidden in the system at the same time. The hiding capacity of the system as to these three types of multiple image has also been investigated using a cascaded iterative algorithm. The security and the multiplexing parameters of the system are analyzed as well.
110 citations
TL;DR: An iterative phase-retrieval algorithm based on multiple intensity measurements to heuristically estimate the phase key in the Fourier domain by several plaintext-cyphertext pairs is introduced and it is demonstrated that this algorithm can be used to attack the double random phase encoding technique.
Abstract: The security of the encryption and verification techniques with significant output images is examined by a known-plaintext attack. We introduce an iterative phase-retrieval algorithm based on multiple intensity measurements to heuristically estimate the phase key in the Fourier domain by several plaintext-cyphertext pairs. We obtain correlation output images with very low error by correlating the estimated key with corresponding random phase masks. Our studies show that the convergence behavior of this algorithm sensitively depends on the starting point. We also demonstrate that this algorithm can be used to attack the double random phase encoding technique.
85 citations
TL;DR: It is shown that in the case of in-line holography, the reconstruction can be regarded as phase tomography, which provides a unified picture for the formulation of both noninterferometric and interferometric phase-retrieval techniques.
Abstract: The formation of holograms is interpreted as the consequence of the bilinearity of the ambiguity function. Reconstruction can then be regarded as the manipulation of the ambiguity function. Specifically, we show that in the case of in-line holography, the reconstruction can be regarded as phase tomography. In this way we provide a unified picture for the formulation of both noninterferometric and interferometric phase-retrieval techniques.
34 citations
17 Jun 2007
TL;DR: In this article, a reconstruction algorithm for the case where the object wave is weaker than the reference by virtue of an approximation in reconstruction is proposed and an in-line hologram recording set-up is described.
Abstract: Summary form only given. A reconstruction algorithm which is not only suitable for the case where the object wave is weaker than the reference by virtue of an approximation in reconstruction is proposed. An in-line hologram recording set-up is described.
1 citations