scholarly journals Enhancing the Quality of Sampled Phase-Only Hologram (SPOH) Based on Time-Division Comb Filtering

2020 ◽  
Vol 10 (8) ◽  
pp. 2732
Author(s):  
Peter W. M. Tsang ◽  
Jung-Ping Liu ◽  
Hoson Lam ◽  
Ting-Chung Poon
Keyword(s):  
Digital Holography ◽  
Low Complexity ◽  
Research Area ◽  
Reconstructed Image ◽  
Display System ◽  
Holographic Display ◽  
Image Prior ◽  
Important Research Area ◽  
Time Division

Generation of digital phase-only Fresnel holograms is an important research area in digital holography, as it leads to a substantial simplification of a holographic display system. However, the quality of the reconstructed image of a hologram without the magnitude component is heavily degraded. The problem can be reduced by down-sampling the intensity of an image prior to generating the hologram. The method, referred to as “sampled phase-only hologram” (SPOH) generation, results in reconstructed images that are masked with the pattern of the down-sampling lattice. This paper reports a novel, low complexity method to alleviate this problem through the concept of comb filtering. Results reveal prominent enhancement on the reconstructed image of a SPOH.

A survey on metrics for the evaluation of user simulations

2012 ◽  
Vol 28 (1) ◽  
pp. 59-73 ◽  
Author(s):  
Olivier Pietquin ◽  
Helen Hastie
Keyword(s):  
Management Strategies ◽  
Research Area ◽  
Dialogue Systems ◽  
Spoken Dialogue Systems ◽  
Machine Learning Methods ◽  
User Simulation ◽  
Open Issue ◽  
Important Research Area ◽  
Assessment Metrics

AbstractUser simulation is an important research area in the field of spoken dialogue systems (SDSs) because collecting and annotating real human–machine interactions is often expensive and time-consuming. However, such data are generally required for designing, training and assessing dialogue systems. User simulations are especially needed when using machine learning methods for optimizing dialogue management strategies such as Reinforcement Learning, where the amount of data necessary for training is larger than existing corpora. The quality of the user simulation is therefore of crucial importance because it dramatically influences the results in terms of SDS performance analysis and the learnt strategy. Assessment of the quality of simulated dialogues and user simulation methods is an open issue and, although assessment metrics are required, there is no commonly adopted metric. In this paper, we give a survey of User Simulations Metrics in the literature, propose some extensions and discuss these metrics in terms of a list of desired features.

scholarly journals Time-Division Color Holographic Projection in Large Size Using a Digital Micromirror Device

2021 ◽  
Vol 11 (14) ◽  
pp. 6277
Author(s):  
Takayuki Takahashi ◽  
Tomoyoshi Shimobaba ◽  
Takashi Kakue ◽  
Tomoyoshi Ito
Keyword(s):  
Image Quality ◽  
High Speed ◽  
Reconstructed Image ◽  
Digital Micromirror Device ◽  
Full Color ◽  
Large Size ◽  
Reconstruction Image ◽  
Reduction Methods ◽  
Time Division

Holographic projection is a simple projection as it enlarges or reduces reconstructed images without using a zoom lens. However, one major problem associated with this projection is the deterioration of image quality as the reconstructed image enlarges. In this paper, we propose a time-division holographic projection, in which the original image is divided into blocks and the holograms of each block are calculated. Using a digital micromirror device (DMD), the holograms were projected at high speed to obtain the entire reconstructed image. However, the holograms on the DMD need to be binarized, thereby causing uneven brightness between the divided blocks. We correct this by controlling the displaying time of each hologram. Additionally, combining both the proposed and noise reduction methods, the image quality of the reconstructed image was improved. Results from the simulation and optical reconstructions show we obtained a full-color reconstruction image with reduced noise and uneven brightness.

scholarly journals Full color holographic display system based on intensity matching of reconstructed image

2019 ◽  
Vol 27 (12) ◽  
pp. 16599 ◽  
Author(s):  
Di Wang ◽  
Chao Liu ◽  
Fan Chu ◽  
Qiong-Hua Wang
Keyword(s):  
Reconstructed Image ◽  
Display System ◽  
Holographic Display ◽  
Full Color

Two-Step Phase-Shifting Iterative Algorithm of Improving Quality of Reconstructed Image in Digital Holography

2008 ◽  
Vol 28 (12) ◽  
pp. 2292-2295
Author(s):  
吴友朋 Wu Youpeng ◽  
刘祥萱 Liu Xiangxuan ◽  
王红霞 Wang Hongxia
Keyword(s):  
Iterative Algorithm ◽  
Digital Holography ◽  
Phase Shifting ◽  
Reconstructed Image

scholarly journals Time-division Color Holographic Projection in Large Size Using a Digital Micromirror Device

2021 ◽  
Author(s):  
Takayuki Takahashi ◽  
Tomoyoshi Shimobaba ◽  
Takashi Kakue ◽  
Tomoyoshi Ito
Keyword(s):  
Image Quality ◽  
High Speed ◽  
Reconstructed Image ◽  
Digital Micromirror Device ◽  
Full Color ◽  
Large Size ◽  
Reconstruction Image ◽  
Reduction Methods ◽  
Time Division

Holographic projection is a simple projection because it enlarges or reduces reconstructed images without using a zoom lens. However, one major problem associated with this projection is the deterioration of image quality as the reconstructed image enlarges. In this paper, we propose a time-division holographic projection, in which the original image is divided into blocks and the holograms of each block are calculated. Using a digital micromirror device (DMD), the holograms were projected at high speed to obtain the entire reconstructed image. However, the holograms on the DMD need to be binarized, thereby causing uneven brightness between the divided blocks. We correct this by controlling the displaying time of each hologram. Additionally, combining both the proposed and noise reduction methods, the image quality of the reconstructed image was improved. Results from the simulation and optical reconstructions show we obtained a full-color reconstruction image with reduced noise and uneven brightness.

scholarly journals Holographic Display System to Suppress Speckle Noise Based on Beam Shaping

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 204
Author(s):  
Di Wang ◽  
Yi-Wei Zheng ◽  
Nan-Nan Li ◽  
Qiong-Hua Wang
Keyword(s):  
Optical Element ◽  
Speckle Noise ◽  
Beam Shaping ◽  
Diffractive Optical Element ◽  
The Other ◽  
Spatial Light Modulators ◽  
Viewing Angle ◽  
Display System ◽  
Holographic Display ◽  
Light Modulators

In this paper, a holographic system to suppress the speckle noise is proposed. Two spatial light modulators (SLMs) are used in the system, one of which is used for beam shaping, and the other is used for reproducing the image. By calculating the effective viewing angle of the reconstructed image, the effective hologram and the effective region of the SLM are calculated accordingly. Then, the size of the diffractive optical element (DOE) is calculated accordingly. The dynamic DOEs and effective hologram are loaded on the effective regions of the two SLMs, respectively, while the wasted areas of the two SLMs are performed with zero-padded operations. When the laser passes through the first SLM, the light can be modulated by the effective DOEs. When the modulated beam illuminates the second SLM which is loaded with the effective hologram, the image is reconstructed with better quality and lower speckle noise. Moreover, the calculation time of the hologram is reduced. Experiments indicate the validity of the proposed system.

scholarly journals Joint optimization of computing ratio and access points’ density for mixed mobile edge/cloud computing

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Tianqi Jing ◽  
Shiwen He ◽  
Fei Yu ◽  
Yongming Huang ◽  
Luxi Yang ◽  
...  
Keyword(s):  
Cloud Computing ◽  
Coverage Probability ◽  
Optimization Problem ◽  
Mobile Cloud Computing ◽  
Low Complexity ◽  
Mixed Integer ◽  
Joint Optimization ◽  
Mobile Cloud ◽  
Convex Problem

AbstractCooperation between the mobile edge computing (MEC) and the mobile cloud computing (MCC) in offloading computing could improve quality of service (QoS) of user equipments (UEs) with computation-intensive tasks. In this paper, in order to minimize the expect charge, we focus on the problem of how to offload the computation-intensive task from the resource-scarce UE to access point’s (AP) and the cloud, and the density allocation of APs’ at mobile edge. We consider three offloading computing modes and focus on the coverage probability of each mode and corresponding ergodic rates. The resulting optimization problem is a mixed-integer and non-convex problem in the objective function and constraints. We propose a low-complexity suboptimal algorithm called Iteration of Convex Optimization and Nonlinear Programming (ICONP) to solve it. Numerical results verify the better performance of our proposed algorithm. Optimal computing ratios and APs’ density allocation contribute to the charge saving.

Research Commentary: Analysis of Curriculum Standards: An Important Research Area

2016 ◽  
Vol 47 (2) ◽  
pp. 118-133 ◽  
Author(s):  
Dung Tran ◽  
Barbara J. Reys ◽  
Dawn Teuscher ◽  
Shannon Dingman ◽  
Lisa Kasmer
Keyword(s):  
Mathematics Education ◽  
Education Reform ◽  
Careful Analysis ◽  
Research Area ◽  
State Standards ◽  
Content Standards ◽  
Curriculum Standards ◽  
Education Professionals ◽  
Important Research Area ◽  
Improving Student Learning

This commentary highlights the contribution that careful and systematic analyses of curriculum or content standards can make to questions and issues important in the mathematics education field. We note the increased role that curriculum standards have played as part of a standards-based education reform strategy. We also review different methods used by researchers to compare and analyze the Common Core State Standards for Mathematics, each method designed for a particular purpose. Finally, we call upon mathematics education researchers to engage in careful analysis of curriculum standards and to share their findings in ways that can inform public debate as well as support education professionals in improving student learning opportunities.

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