Estimation of optimized timely system matrix with improved image quality in iterative reconstruction algorithm: A simulation study

Abstract

The system matrix (SM) being a main part of statistical image reconstruction algorithms establishes relationship between the object and projection space. The aim was to determine it in a short duration time, towards obtaining the best quality of contrast images. In this study, a new analytical method based on Cavalieri's principle as subdividing common regions has been proposed in which the precision of the amounts of estimated areas was improved by increasing the number of divisions (NOD), and consequently the total SM's time was increased. An important issue is the tradeoff between the NODs and computational time. For this purpose, a Monte Carlo simulated Jaszczak phantom study was performed by the Monte Carlo N-Particle transport code version 5 (MCNP5) in which the tomographic images of resolution and contrast phantoms were reconstructed by maximum likelihood expectation maximization (MLEM) algorithm, and the influence of NODs variations was investigated. The results show that the lowest and best quality have been obtained at the NODs of 0 and 8, respectively and in the optimum case, the SM's total time at NOD of 8 was 925 s, which was much lower than those of the conventional Monte Carlo simulations and experimental test.

An optical multiple-image authentication based on computational ghost imaging and total-variation minimization

“…In order to enhance the ability to resist some common attacks, DRPE has been applied in various domains, including Gyrator domain [ [5] , [6] , [7] ], Fresnel domain [ 8 , 9 ], fractional Fourier domain [ [10] , [11] , [12] ], and so on. Furthermore, various methods based on different kinds of optical theories and technologies, such as fractional Mellin transform [ 13 ], interference [ 14 , 15 ], transport of intensity equation [ 16 ], hologram [ 17 , 18 ], data container [ 19 ], iterative algorithm [ 20 , 21 ], photon-counting [ 22 ], monocular depth rendering [ 23 ], holography [ 24 ], image denoising [ 25 ], single-pixel imaging [ 26 ], and binary tree-sliced pattern [ 27 ], have been reported in recent years. Because a lot of optical parameters are used as secret keys, these methods has high security.…”