scholarly journals A thorough study on genetic algorithms in feedback-based wavefront shaping

2019 ◽  
Vol 12 (04) ◽  
pp. 1942004 ◽  
Author(s):  
Daixuan Wu ◽  
Jiawei Luo ◽  
Zhaohui Li ◽  
Yuecheng Shen
Keyword(s):  
Genetic Algorithms ◽  
Natural Selection ◽  
Optimization Algorithms ◽  
Superior Performance ◽  
Noisy Environment ◽  
Scattering Media ◽  
Phase Map ◽  
Numerical Tools ◽  
Wavefront Shaping ◽  
Phase Optimization

Feedback-based wavefront shaping focuses light through scattering media by employing phase optimization algorithms. Genetic algorithms (GAs), inspired by the process of natural selection, are well suited for phase optimization in wavefront shaping problems. In 2012, Conkey et al. first introduced a GA into feedback-based wavefront shaping to find the optimum phase map. Since then, due to its superior performance in noisy environment, the GA has been widely adopted by lots of implementations. However, there have been limited studies discussing and optimizing the detailed procedures of the GA. To fill this blank, in this study, we performed a thorough study on the performance of the GA for focusing light through scattering media. Using numerical tools, we evaluated certain procedures that can be potentially improved and provided guidance on how to choose certain parameters appropriately. This study is beneficial in improving the performance of wavefront shaping systems with GAs.

scholarly journals A comparative study of optimization algorithms for wavefront shaping

2019 ◽  
Vol 12 (04) ◽  
pp. 1942002 ◽  
Author(s):  
Zahra Fayyaz ◽  
Nafiseh Mohammadian ◽  
M. Reza Rahimi Tabar ◽  
Rayyan Manwar ◽  
Kamran Avanaki
Keyword(s):  
Comparative Study ◽  
Spatial Light Modulator ◽  
Scattered Light ◽  
Optimization Algorithms ◽  
Estimation Method ◽  
Noise Levels ◽  
Light Modulator ◽  
Matrix Estimation ◽  
Phase Map ◽  
Wavefront Shaping

By manipulating the phase map of a wavefront of light using a spatial light modulator, the scattered light can be sharply focused on a specific target. Several iterative optimization algorithms for obtaining the optimum phase map have been explored. However, there has not been a comparative study on the performance of these algorithms. In this paper, six optimization algorithms for wavefront shaping including continuous sequential, partitioning algorithm, transmission matrix estimation method, particle swarm optimization, genetic algorithm (GA), and simulated annealing (SA) are discussed and compared based on their efficiency when introduced with various measurement noise levels.

scholarly journals Focusing light into scattering media with ultrasound-induced field perturbation

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Zhongtao Cheng ◽  
Lihong V. Wang
Keyword(s):  
High Speed ◽  
Superior Performance ◽  
Single Shot ◽  
Scattering Media ◽  
Zeroth Order ◽  
Field Perturbation ◽  
Induced Field ◽  
Wavefront Shaping ◽  
Flexible Mechanism ◽  
Optical Focusing

AbstractFocusing light into scattering media, although challenging, is highly desirable in many realms. With the invention of time-reversed ultrasonically encoded (TRUE) optical focusing, acousto-optic modulation was demonstrated as a promising guidestar mechanism for achieving noninvasive and addressable optical focusing into scattering media. Here, we report a new ultrasound-assisted technique, ultrasound-induced field perturbation optical focusing, abbreviated as UFP. Unlike in conventional TRUE optical focusing, where only the weak frequency-shifted first-order diffracted photons due to acousto-optic modulation are useful, here UFP leverages the brighter zeroth-order photons diffracted by an ultrasonic guidestar as information carriers to guide optical focusing. We find that the zeroth-order diffracted photons, although not frequency-shifted, do have a field perturbation caused by the existence of the ultrasonic guidestar. By detecting and time-reversing the differential field of the frequency-unshifted photons when the ultrasound is alternately ON and OFF, we can focus light to the position where the field perturbation occurs inside the scattering medium. We demonstrate here that UFP optical focusing has superior performance to conventional TRUE optical focusing, which benefits from the more intense zeroth-order photons. We further show that UFP optical focusing can be easily and flexibly developed into double-shot realization or even single-shot realization, which is desirable for high-speed wavefront shaping. This new method upsets conventional thinking on the utility of an ultrasonic guidestar and broadens the horizon of light control in scattering media. We hope that it provides a more efficient and flexible mechanism for implementing ultrasound-guided wavefront shaping.

scholarly journals Numerical simulation of the two-locus Wright-Fisher stochastic differential equation with application to approximating transition probability densities

2020 ◽  
Author(s):  
Zhangyi He ◽  
Mark Beaumont ◽  
Feng Yu
Keyword(s):  
Differential Equation ◽  
Natural Selection ◽  
Probability Density Function ◽  
Stochastic Differential Equation ◽  
Probability Density ◽  
Density Function ◽  
Genetic Recombination ◽  
Transition Probability ◽  
Superior Performance ◽  
Transition Probability Density

AbstractOver the past decade there has been an increasing focus on the application of the Wright-Fisher diffusion to the inference of natural selection from genetic time series. A key ingredient for modelling the trajectory of gene frequencies through the Wright-Fisher diffusion is its transition probability density function. Recent advances in DNA sequencing techniques have made it possible to monitor genomes in great detail over time, which presents opportunities for investigating natural selection while accounting for genetic recombination and local linkage. However, most existing methods for computing the transition probability density function of the Wright-Fisher diffusion are only applicable to one-locus problems. To address two-locus problems, in this work we propose a novel numerical scheme for the Wright-Fisher stochastic differential equation of population dynamics under natural selection at two linked loci. Our key innovation is that we reformulate the stochastic differential equation in a closed form that is amenable to simulation, which enables us to avoid boundary issues and reduce computational costs. We also propose an adaptive importance sampling approach based on the proposal introduced by Fearnhead (2008) for computing the transition probability density of the Wright-Fisher diffusion between any two observed states. We show through extensive simulation studies that our approach can achieve comparable performance to the method of Fearnhead (2008) but can avoid manually tuning the parameter ρ to deliver superior performance for different observed states.

Application of Genetic Algorithms in Inventory Control

2016 ◽  
pp. 1087-1098
Author(s):  
Vinod Kumar Mishra
Keyword(s):  
Genetic Algorithm ◽  
Genetic Algorithms ◽  
Natural Selection ◽  
Inventory Control ◽  
Future Trend ◽  
Production Engineering ◽  
Mathematical Sciences ◽  
Adaptive Heuristic ◽  
Definition Of ◽  
Key Terms

The genetic algorithm (GA) is an adaptive heuristic search procedures based on the mechanics of natural selection and natural genetics. Inventory control is widely used in the area of mathematical sciences, management sciences; system science, industrial engineering, production engineering etc. but they have wide differences in mathematical and computation maturity. This chapter enables the reader to understand the basic theory of genetic algorithm and how to apply the genetic algorithms for optimizing the parameters in inventory control The current and future trend of the research with the definition of key terms of genetic algorithm has also incorporated in this chapter.

scholarly journals High-speed single-shot optical focusing through dynamic scattering media with full-phase wavefront shaping

2017 ◽  
Vol 111 (22) ◽  
pp. 221109 ◽  
Author(s):  
Ashton S. Hemphill ◽  
Yuecheng Shen ◽  
Yan Liu ◽  
Lihong V. Wang
Keyword(s):  
High Speed ◽  
Single Shot ◽  
Scattering Media ◽  
Wavefront Shaping ◽  
Optical Focusing ◽  
Dynamic Scattering
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