Dr. Honggang Wang Profile

Dr. Honggang Wang

at Ludong Univ

SPIE Involvement:

Author

Publications (7)

SPIE Journal Paper | 10 March 2023

Photoluminescence detection method for silicon photovoltaic modules at high light level

Meicheng Dong, Yunsheng Qian, Honggang Wang, Yizheng Lang

OE, Vol. 62, Issue 03, 033102, (March 2023) https://doi.org/10.1117/12.10.1117/1.OE.62.3.033102

KEYWORDS: Solar cells, Modulation, Photoluminescence, Silicon solar cells, Image processing, Light sources and illumination, Cameras, Optical engineering, Field programmable gate arrays, Light sources

Read Abstract +

SPIE Journal Paper | 28 May 2020

Objective evaluation of the resolution of low-light-level image intensifiers based on fast Fourier transform

Luzi Wang, Yunsheng Qian, Honggang Wang

OE, Vol. 59, Issue 05, 054106, (May 2020) https://doi.org/10.1117/12.10.1117/1.OE.59.5.054106

KEYWORDS: Image resolution, Image intensifiers, Cameras, Imaging systems, Fourier transforms, Optical engineering, Microscopes, Image analysis, Eye, Image processing

Read Abstract +

Resolution is an important index for evaluating the performance of a low-light-level image intensifier. The traditional method of image tube resolution measurement is to observe the resolution target on the image intensifier through a microscope and give a subjective judgment. The disadvantage is that the difference in the visual acuity between testers will lead to variability in measurement results. In addition, the process of focusing the resolution image is very time-consuming and eye-consuming. To solve these problems, an objective evaluation system of image tube resolution based on fast Fourier transform (FFT) that provides an efficient and feasible objective evaluation scheme for the estimation of image tube resolution is proposed. In this system, the resolution target is first focused on the cathode surface of the image tube through an optical system, and then the image is taken by a high-resolution camera. The region of interest of the collected image shows that the gray-scale sequence along the direction of the stripe change reflects the frequency of the stripe. When the gray-scale sequence is transformed to the frequency domain using FFT, the clarity and resolution of the stripe will be correlated with some quantities in the frequency domain. We extract the clarity-resolution values from the frequency domain of all stripe elements and use the generated clarity threshold combined with the linear fitting strategy to achieve the resolution value. The experimental results show that, in terms of accuracy, the test results of the system are consistent with the subjective evaluation results. For the tubes with resolutions between 61.37 and 66.49 lp / mm, the accuracy of our system is higher than that of human judgment. For repeatability, the measurement results of the system are in good agreement with the subjective evaluation results of the tubes with resolutions between 50 and 62 lp / mm. Therefore, our system can be regarded as a reasonable alternative to the subjective evaluation method, which will greatly reduce the variability caused by different testers.

Proceedings Article | 18 December 2019 Paper

First principles calculations of the electronic structure of GaAs in (001), (011) and (111) electric field directions

Ya Li, Junju Zhang, Yong Wang, Honggang Wang

Proceedings Volume 11336, 1133604 (2019) https://doi.org/10.1117/12.2540358

KEYWORDS: Gallium arsenide, Chemical species, Electrons, Gallium, Semiconductors, Optimization (mathematics), Physics, Semiconductor materials, Lithium, Electronics engineering

Read Abstract +

SPIE Journal Paper | 15 February 2018

Finite element analysis-based study of fiber Bragg grating sensor for cracks detection in reinforced concrete

Lili Wang, Xiangjun Xin, Jun Song, Honggang Wang, Yaozhang Sai

OE, Vol. 57, Issue 02, 027103, (February 2018) https://doi.org/10.1117/12.10.1117/1.OE.57.2.027103

KEYWORDS: Iron, Refractive index, Fiber Bragg gratings, Reflectivity, Sensors, Finite element methods, Fiber optics sensors, Optical fibers, 3D modeling, Optical engineering

Read Abstract +

Proceedings Article | 16 August 2013 Paper

Comparison of resolution characteristics between exponential-doping and uniform-doping GaN photocathodes

Hong-gang Wang, Yun-sheng Qian, Liu-bing Lu, Hong-chang Cheng, Ben-kang Chang

Proceedings Volume 8912, 89121D (2013) https://doi.org/10.1117/12.2034701

KEYWORDS: Modulation transfer functions, Gallium nitride, Diffusion, Quantum efficiency, Image resolution, Image intensifiers, Fourier transforms, Spatial frequencies, Tellurium, Spatial resolution

Read Abstract +

The studies of quantum efficiency, electronic energy distribution and stability are highly concerned in the application of Negative electron affinity (NEA) gallium nitride (GaN) photocathodes while the resolution of photocathodes are concerned rarely. The resolutions of some image intensifiers are smaller than computational value partly because of ignoring the resolution of photocathodes. To a certain extent, the resolutions of image intensifiers are influenced by photocathodes. Electronic transverse diffusion is the main cause of decreasing the resolution of photocathodes whereas the exponential-doping structure can reduce its influence. In this paper, the resolution characteristics of photocathodes have been studied by using the modulation transfer function (MTF) method. The MTF expressions of transmission-mode exponential-doping photocathodes have been obtained by solving the two-dimensional continuity equations. According to the MTF expressions, the resolution characteristics between exponential-doping and uniform-doping GaN photocathodes are calculated theoretically and analyzed comparatively. At the same time, the relationships between resolution and thickness of the emission layer T_e, electron diffusion length L_D are researched in detail. The calculated results show that, compared with the uniform-doping photocathode, the exponential-doping structure can increase the resolution of photocathode evidently. The resolution of exponential-doping GaN photocathode is improved distinctly when the spatial frequency varies from 400 to 800 lp/mm. The MTF characteristics approach gradually when f increases or decreases. Let f =600 lp/mm, the resolution increases by 20%-48% approximately. The constant built-in electric field for exponential-doping GaN photocathode can increase the resolution of photocathode. The improvement of resolution is different from decreasing T_e, L_D or increasing the recombination velocity of back-interface which are at the cost of reducing the quantum efficiency of photocathode. Therefore, the MTF expressions of transmission-mode exponential-doping photocathode play a positive role in improving the resolution of ultraviolet detector and optimizing the structural design of GaN photocathode.

Proceedings Article | 4 March 2013 Paper

Halo performance on low light level image intensifiers

Dongxu Cui, Ling Ren, Benkang Chang, Feng Shi, Jifang Shi, Yunsheng Qian, Honggang Wang, Junju Zhang

Proceedings Volume 8761, 876108 (2013) https://doi.org/10.1117/12.2019621

KEYWORDS: Image intensifiers, Charge-coupled devices, Microchannel plates, Integrating spheres, Light sources, Scattering, Image resolution, Image processing, Optical filters, Sensors

Read Abstract +

Proceedings Article | 27 November 2012 Paper

Variable doping narrow-band response GaAlAs photocathode the preparation method of the research

Yuan Xu, XinLong Chen, Jing Zhao, Honggang Wang, BenKang Chang

Proceedings Volume 8555, 85551I (2012) https://doi.org/10.1117/12.2001207

KEYWORDS: Doping, Quantum efficiency, Gallium arsenide, Aluminum, Cesium, Structural design, Control systems, Ocean optics, Interfaces, Absorption

Read Abstract +

Showing 5 of 7 publications

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years