检索结果-内蒙古大学图书馆

Phase-stepped fringe projection by rotation about the camera's perspective center

OPTICS EXPRESS 2011年第19期19卷 18458-18469页

作者： Huddart, Y. R. Valera, J. D. Weston, N. J. Featherstone, T. C. Moore, A. J. Renishaw Plc Edinburgh EH14 4AP Midlothian Scotland Heriot Watt Univ Sch Engn & Phys Sci Edinburgh EH14 4AS Midlothian Scotland

A technique to produce phase steps in a fringe projection system for shape measurement is presented. Phase steps are produced by introducing relative rotation between the object and the fringe projection probe ( comprising a projector and camera) about the camera's perspective center. Relative motion of the object in the camera image can be compensated, because it is independent of the distance of the object from the camera, whilst the phase of the projected fringes is stepped due to the motion of the projector with respect to the object. The technique was validated with a static fringe projection system by moving an object on a coordinate measuring machine (CMM). The alternative approach, of rotating a lightweight and robust CMM-mounted fringe projection probe, is discussed. An experimental accuracy of approximately 1.5% of the projected fringe pitch was achieved, limited by the standard phase-stepping algorithms used rather than by the accuracy of the phase steps produced by the new technique. (C) 2011 Optical Society of America

关键词： Fringe projection image processing algorithms Optical measurement Phase measurement Precision metrology Speckle noise

来源：评论

学校读者我要写书评

暂无评论

Demonstration of 136 dB dynamic range capability for a simultaneous dual optical band CAOS camera

引用

OPTICS EXPRESS 2016年第26期24卷 29427-29443页

作者： Riza, Nabeel A. La Torre, J. Pablo Univ Coll Cork Sch Engn Coll Rd Cork Ireland

For the first time, proposed and demonstrated is a simultaneous dual optical band coded access optical sensor (CAOS) camera design suited for extreme contrast multispectral bright target scenarios. Deploying a digital micromirror devices (DMDs)-based time-frequency agile pixels CAOS-mode within a two point detector spatially and spectrally isolating framework, this imager simultaneously and independently detects pixel selective image information for two different broad spectral bands that further undergo independent spectral image data extraction via finer-tuned wavelength filtering using all-optical or CAOSmode electronic filters. A proof-of-concept visible-near infrared band CAOS imager is successfully demonstrated using a target scene containing LEDs and engaging narrowband optical filters. In addition, using the CAOS-mode, demonstrated is the RF domain simultaneous color content monitoring of a white light LED image pixel. Also proposed is the use of a higher bit count analog-to-digital converter (ADC) with both range and sampling duration parameter control along with a larger data set electronic DSP to extract higher DSP gain and realize additional noise suppression. Using a 16-bit ADC and 2,097,152 point fast Fourier transform (FFT) digital signal processing (DSP) for a 633 nm laser engaged test target scene that is subject to nearly 7 decades (10(7)) of gradual optical attenuation, the experimental camera demonstrates an agile pixel extreme dynamic range of 136 dB, which is a 56 dB improvement over the previous CAOS-imaging demonstrations. (C) 2016 Optical Society of America

关键词： Digital micromirror devices image processing image processing algorithms Multispectral imaging Optical wireless communication Variable optical attenuators

来源：评论

学校读者我要写书评

暂无评论

Deep learning for precise axial localization of trapped microspheres in reflective optical systems

引用

OPTICS EXPRESS 2023年第8期31卷 12397-12409页

作者： Guo, Mengdi Lin, Zuzeng Zhai, Cong Chen, Yulu Zhou, Xiaowei Chai, Zhongyan Guo, Tong Hu, Chunguang Tianjin Univ State Key Lab Precis Measuring Technol & Instrumen Tianjin 300072 Peoples R China

High-precision axial localization measurement is an important part of micro-nanometer optical measurement, but there have been issues such as low calibration efficiency, poor accuracy, and cumbersome measurement, especially in reflected light illumination systems, where the lack of clarity of imaging details leads to the low accuracy of commonly used methods. Herein, we develop a trained residual neural network coupled with a convenient data acquisition strategy to address this challenge. Our method improves the axial localization precision of microspheres in both reflective illumination systems and transmission illumination systems. Using this new localization method, the reference position of the trapped microsphere can be extracted from the identification results, namely the "positioning point" among the experimental groups. This point relies on the unique signal characteristics of each sample measurement, eliminates systematic repeatability errors when performing identification across samples, and improves the localization precision of different samples. This method has been verified on both transmission and reflected illumination optical tweezers platforms. We will bring greater convenience to measurements in solution environments and will provide higher-order guarantees for force spectroscopy measurements in scenarios such as microsphere-based super-resolution microscopy and the surface mechanical properties of adherent flexible materials and cells.(c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

关键词： image processing image processing algorithms Optical measurement Optical systems Optical tweezers Super resolution microscopy

来源：评论

学校读者我要写书评

暂无评论

Axial nanodisplacement measurement based on astigmatism effect of crossed cylindrical lenses

引用

APPLIED OPTICS 2012年第13期51卷 2379-2387页

作者： Li, Long Kuang, Cuifang Luo, Ding Liu, Xu Zhejiang Univ State Key Lab Modern Opt Instrumentat Hangzhou 310027 Peoples R China

Spot distortion caused by astigmatism effect in orthogonal cylindrical lenses is utilized to measure axial displacement with 30 nm resolution, strong noise immunity, and compact experiment setup. Axial displacement of the sample surface is determined by four-quadrant difference processing of distorted laser spots' energy distribution images received by CCD. Four-quadrant difference processing results indicate an applicable measuring range of 5.6 mu m (cubic fitting r = 0.9988) with a highly linear range of 1.2 mu m (linear fitting r = 0.9996). Factors affecting measuring range and sensitivity are analyzed by theoretical deduction and numerical simulation. This technique has potential applications in drifting sample tracking and measurement in advanced microscopy. (c) 2012 Optical Society of America

关键词： Cylindrical lenses image processing algorithms Laser beam shaping Laser beams Laser materials processing Optical components

来源：评论

学校读者我要写书评

暂无评论

Ballistic imaging through an intense scattering medium using a supercontinuum with a roundabout spatial gate

引用

OPTICS EXPRESS 2017年第17期25卷 20431-20436页

作者： Zheng, Yipeng Tan, Wenjiang Liu, Xiaojing Tong, Junyi Xi An Jiao Tong Univ Key Lab Phys Elect & Devices Sch Elect & Informat Engn Minist EducShannxi Key Lab InformatPhoton Tech Xianning Xilu 28 Xian 710049 Shaanxi Peoples R China Xian Univ Technol Dept Appl Phys Xian 710048 Shaanxi Peoples R China

We propose a new ballistic imaging method that is capable of imaging an object through an intense scattering medium. In this method, a femtosecond supercontinuum and a roundabout spatial gate were used to suppress speckles and filter background noise, respectively. The roundabout spatial gate extracts ballistic light and avoids low- pass spatial filtering to ensure the high resolution of images. The experimental results showed that even when the optical depth of the scattering medium reached 17, the images extracted by the method had improved identifiability and contrast. (C) 2017 Optical Society of America

关键词： Digital image processing image processing algorithms image quality Imaging systems Spatial frequency Speckle patterns

来源：评论

学校读者我要写书评

暂无评论

Characterizing and correcting camera noise in back-illuminated sCMOS cameras

引用

OPTICS EXPRESS 2021年第5期29卷 6668-6690页

作者： Zhang, Zhaoning Wang, Yujie Piestun, Rafael Huang, Zhen-li Huazhong Univ Sci & Technol Britton Chance Ctr Biomed Photon Wuhan Natl Lab Optoelect Wuhan 430074 Hubei Peoples R China Huazhong Univ Sci & Technol Sch Engn Sci MoE Key Lab Biomed Photon Wuhan 430074 Hubei Peoples R China Univ Colorado Dept Elect Comp & Energy Engn Boulder CO 80309 USA Hainan Univ Sch Biomed Engn Haikou 570228 Hainan Peoples R China

With promising properties of fast imaging speed, large field-of-view, relative low cost and many others, back-illuminated sCMOS cameras have been receiving intensive attention for low light level imaging in the past several years. However, due to the pixel-to-pixel difference of camera noise (called noise non-uniformity) in sCMOS cameras, researchers may hesitate to use them in some application fields, and sometimes wonder whether they should optimize the noise non-uniformity of their sCMOS cameras before using them in a specific application scenario. In this paper, we systematically characterize the impact of different types of sCMOS noise on image quality and perform corrections to these types of sCMOS noise using three representative algorithms (PURE, NCS and MLEsCMOS). We verify that it is possible to use appropriate correction methods to push the non-uniformity of major types of camera noise, including readout noise, offset, and photon response, to a satisfactory level for conventional microscopy and single molecule localization microscopy. We further find out that, after these corrections, global read noise becomes a major concern that limits the imaging performance of back-illuminated sCMOS cameras. We believe this study provides new insights into the understanding of camera noise in back-illuminated sCMOS cameras, and also provides useful information for future development of this promising camera technology. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： Charge coupled devices Complementary metal oxide semiconductors High speed photography image processing algorithms image quality Low light levels

来源：评论

学校读者我要写书评

暂无评论

Reducing the light scattering impact in liquid-crystal-based imaging systems

引用

APPLIED OPTICS 2020年第16期59卷 4780-4789页

作者： Pusenkova, Anastasiia Galstian, Tigran Univ Laval Dept Phys Engn Phys & Opt Ctr Opt Photon & Lasers 2325 Rue Terrasse Quebec City PQ G1V 0A6 Canada LensVector Inc 6203 San Ignacio AveSuite 110 San Jose CA 95119 USA

We show an experimental method of quantifying the effect of light scattering by liquid crystals (LCs) and then apply rather simple image processing algorithms (Wiener deconvolution and contrast-limited adaptive histogram equalization) to improve the quality of obtained images when using electrically tunable LC lenses (TLCLs). Better contrast and color reproduction have been achieved. We think that this approach will allow the use of thicker LC cells and thus increase the maximum achievable optical power of the TLCL without a noticeable reduction of image quality. This eliminates one of the key limitations for their use in various adaptive imaging applications requiring larger apertures. (C) 2020 Optical Society of America

关键词： Effective refractive index image processing algorithms image quality Imaging systems Liquid crystals Tunable lenses

来源：评论

学校读者我要写书评

暂无评论

A real-time noise filtering strategy for photon counting 3D imaging lidar

引用

OPTICS EXPRESS 2013年第8期21卷 9247-9254页

作者： Zhang, Zijing Zhao, Yuan Zhang, Yong Wu, Long Su, Jianzhong Harbin Inst Technol Dept Phys Harbin 150001 Peoples R China Tianjin Jinhang Inst Technol Phys Tianjin 300192 Peoples R China

For a direct-detection 3D imaging lidar, the use of Geiger mode avalanche photodiode (Gm-APD) could greatly enhance the detection sensitivity of the lidar system since each range measurement requires a single detected photon. Furthermore, Gm-APD offers significant advantages in reducing the size, mass, power and complexity of the system. However the inevitable noise, including the background noise, the dark count noise and so on, remains a significant challenge to obtain a clear 3D image of the target of interest. This paper presents a smart strategy, which can filter out false alarms in the stage of acquisition of raw time of flight (TOF) data and obtain a clear 3D image in real time. As a result, a clear 3D image is taken from the experimental system despite the background noise of the sunny day. (C) 2013 Optical Society of America

关键词： Avalanche photodiodes Geiger modes image processing image processing algorithms Photon counting Three dimensional imaging

来源：评论

学校读者我要写书评

暂无评论

Optical-image communication through random-phase propagation channels using phase-shifting coding

引用

APPLIED OPTICS 2021年第11期60卷 3162-3169页

作者： Servin, Manuel Padilla, Moises Ctr Invest Opt AC Loma Bosque 115 Guanajuato 37150 Mexico

We propose an optical-image communication system robust to random-phase propagation using phase-shifting (PS) image coding. That is, this optical-image communication system is based on digital PS interferometry principles. Each pixel of the parallel transmitted image is coded as the phase of a sequence of N phase-shifted fringe patterns. The temporal fringe patterns may be displayed on a TV screen (or a multimedia projector) for transmission through the random-phase channel. At the receiver, the PS fringe patterns are digitized with a telescopic digital camera. The received fringes are phase-demodulated using an N-steps least-squares PS algorithm (LS-PSA). We show that the received, phase-demodulated images are less blurred and have better contrast than any received image without PS coding. We propose and analyze a mathematical model for the received PS fringes degraded by random-phase propagation. This PS communication system can also be used for robust optical communications through random refractive media such as underwater, air-water, or random-thickness textured glass. In particular, we show experiments for LS-PSA imaging through textured-glass, obtaining sharper images. As far as we know, this is the first time that PS interferometry has been used for parallel optical-image communication through random-phase channels. (C) 2021 Optical Society of America

关键词： Atmospheric turbulence Free space optics image processing image processing algorithms Optical imaging Underwater imaging

来源：评论

学校读者我要写书评

暂无评论

Correction for color artifacts using the RGB intersection and the weighted bilinear interpolation

引用

APPLIED OPTICS 2019年第29期58卷 8083-8091页

作者： Wang, Xiuhua Jia, Xinyue Zhou, Wei Qin, Xiaoyun Guo, Hanming Univ Shanghai ForSci & Technol Engn Res Ctr Opt Instrument & Syst Shanghai Key Lab Modern Opt Syst Minist EducSch Opt Elect & Comp Engn 516 Jungong Rd Shanghai 200093 Peoples R China

Due to the defects of optical systems, image sensors, and imperfect algorithms for image acquisition, compression, and restoration, color artifacts often appear in images obtained by imaging devices such as digital cameras and scanners. Moreover, color artifacts are difficult to eliminate because of technical limitations, even in some mature commercial cameras. On the basis of red, green, and blue (RGB) intersection (RGBI), a correction method for color artifacts is proposed in this paper, where the RGB intersection-based method can effectively detect various types of color artifacts. Also, by combining the object information with weighted bilinear interpolation, the continuity of the image is kept while restoring the real color. Experiments demonstrate that the RGBI method, which is applicable to all color images, can eliminate various types of color artifacts with accurate detection and less artifact residue, even if the image has severe color distortion or the areas of the color artifacts are small and discrete. (C) 2019 Optical Society of America

关键词： Color difference Color spaces Digital imaging image processing algorithms image quality image sensors

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：