检索结果-内蒙古大学图书馆

All-day thin-lens computational imaging with scene-specific learning recovery

APPLIED OPTICS 2022年第4期61卷 1097-1105页

作者： Qi, Bingyun Chen, Wei Dun, Xiong Hao, Xiang Wang, Rui Liu, Xu Li, Haifeng Peng, Yifan Zhejiang Univ Coll Opt Sci & Engn Hangzhou 310027 Peoples R China Tongji Univ Sch Phys Sci & Engn Inst Precis Opt Engn Shanghai 200092 Peoples R China Zhejiang Univ Coll Comp Sci & Technol Hangzhou 310058 Peoples R China Stanford Univ Elect Engn Dept Stanford CA 94305 USA

Modern imaging optics ensures high-quality photography at the cost of a complex optical form factor that deviates from the portability. The drastic development of image processing algorithms, especially advanced neural networks, shows great promise to use thin optics but still faces the challenges of residual artifacts and chromatic aberration. In this work, we investigate photorealistic thin-lens imaging that paves the way to actual applications by exploring several fine-tunes. Notably, to meet all-day photography demands, we develop a scene-specific generative-adversarial-network-based learning strategy and develop an integral automatic acquisition and processing pipeline. Color fringe artifacts are reduced by implementing a chromatic aberration pre-correction trick. Our method outperforms existing thin-lens imaging work with better visual perception and excels in both normal-light and low-light scenarios. (C) 2022 Optica Publishing Group

关键词： Diffractive optical elements image processing image processing algorithms image quality Imaging systems Imaging techniques

来源：评论

学校读者我要写书评

暂无评论

Improving reconstruction of speckle correlation imaging by using a modified phase retrieval algorithm with the number of nonzero-pixels constraint

引用

APPLIED OPTICS 2019年第2期58卷 473-478页

作者： Liao, Meihua Lu, Dajiang He, Wenqi Pedrini, Giancarlo Osten, Wolfgang Peng, Xiang Shenzhen Univ Coll Optoelect Engn Key Lab Optoelect Devices & Syst Educ Minist China Shenzhen Peoples R China Univ Stuttgart Inst Tech Opt Pfaffenwaldring 9 D-70569 Stuttgart Germany

Speckle correlation imaging (SCI) has been considered one of the most promising techniques for computational imaging through a scattering medium. However, the image quality is not always acceptable in conventional SCI, especially when a complex object is involved. In this work, a modified phase retrieval algorithm is introduced to significantly improve the imaging quality of SCI. In the proposed scheme, nonzero-pixel constraints, rather than the real and nonnegative constraints, are employed as the object domain constraints of the iterative algorithm in the image reconstruction process. Experimental results are presented to show the performance enhancement of this scheme, inclusive of less iterations, better image quality, and higher reliability, in comparison with the conventional SCI method. (C) 2019 Optical Society of America

关键词： image processing algorithms image quality Phase retrieval Scattering media Speckle patterns Zernike polynomials

来源：评论

学校读者我要写书评

暂无评论

THz imaging technique for nondestructive analysis of debonding defects in ceramic matrix composites based on multiple echoes and feature fusion

引用

OPTICS EXPRESS 2020年第14期28卷 19901-19915页

作者： Zhang, Ji-Yang Ren, Jiao-Jiao Li, Li-Juan Gu, Jian Zhang, Dan-Dan Changchun Univ Sci & Technol Changchun 130000 Peoples R China Minist Educ Key Lab Optoelect Measurement & Opt Informat Tran Beijing Peoples R China

We propose a THz nondestructive analysis method based on multiple echoes and feature fusion. Conventionally, it is difficult to identify the debonding defects of the glue layer (II) due to the thin adhesive layer. To this end, a THz propagation model is established, and a quantitative method for determining the thickness of debonding defects based on multiple echoes is presented. The measurement error for preset defect thickness of 500 mu m was 4%. Further, for determining the area of debonding defects, a feature fusion imaging algorithm is proposed to realize the lateral recognition of defects and quantitative analysis is used to improve the recognition ability of defects. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： Analytical techniques Computed tomography image processing algorithms Imaging techniques Terahertz imaging Three dimensional imaging

来源：评论

学校读者我要写书评

暂无评论

Two-photon images reveal unique texture features for label-free identification of ovarian cancer peritoneal metastases

引用

BIOMEDICAL OPTICS EXPRESS 2019年第9期10卷 4479-4488页

作者： Pouli, Dimitra Genega, Elizabeth M. Sullivan, Travis B. Rieger-Christ, Kimberly M. Wright, Valena Georgakoudi, Irene Schnelldorfer, Thomas Tufts Univ Dept Biomed Engn Medford MA 02155 USA Tufts Med Ctr Dept Pathol & Lab Med Boston MA 02111 USA Lahey Hosp & Med Ctr Dept Translat Res Burlington MA 01805 USA Lahey Hosp & Med Ctr Dept Surg Burlington MA 01805 USA Beth Israel Deaconess Med Ctr Dept Pathol Boston MA 02215 USA Harvard Univ Harvard Med Sch Boston MA 02115 USA

For cancer patients, treatment selection fundamentally relies on staging, with "understaging" considered a common problem. Imaging modalities that can complement conventional white-light laparoscopy are needed to detect more accurately small metastatic lesions in patients undergoing operative cancer care. Biopsies from healthy parietal peritoneum and ovarian peritoneal metastases obtained from 8 patients were imaged employing a two-photon laser scanning microscope to generate collagen-second harmonic generation (SHG) and fluorescence images at 755 nm and 900 nm excitation and 460 +/- 20 nm and 525 +/- 25 nm emission. Forty-one images were analyzed by automated image processing algorithms and statistical textural analysis techniques, namely gray level co-occurrence matrices. Two textural features (contrast and correlation) were employed to describe the spatial intensity variations within the captured images and outcomes were used for discriminant analysis. We found that healthy tissues displayed large variations in contrast and correlation features as a function of distance, corresponding to repetitive, increased local intensity fluctuations. Metastatic tissue images exhibited decreased contrast and correlation related values, representing more uniform intensity patterns and smaller fibers, indicating the destruction of the healthy stroma by the cancerous infiltration. The textural outcomes resulted in high classification accuracy as evaluated quantitatively by discriminant analysis. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： Harmonic generation image processing algorithms Imaging systems Laser scanning Scanning microscopy White light

来源：评论

学校读者我要写书评

暂无评论

Real-time display camera communication system based on LED displays and smartphones

引用

OPTICS EXPRESS 2021年第15期29卷 23558-23568页

作者： Bao, Xingyu Pan, Junxing Cai, Zetao Li, Jingwen Huang, Xia Chen, Renzhang Fang, Junbin Jinan Univ Guangzhou 510632 Peoples R China Cyberspace Secur Res Ctr Peng Cheng Lab Shenzhen 518055 Peoples R China Guangdong Prov Engn Technol Res Ctr Visible Light Guangzhou 510632 Peoples R China Guangzhou Municipal Key Lab Engn Technol Visible Guangzhou 510632 Peoples R China

Visible light communication based on display and camera can simultaneously provide the functionalities of display and invisible intbrmation transmission. There are widely potential applications in information broadcasting, stealth advertising, etc. In this paper, a real-time display camera communication system based on LED displays and smartphones is proposed. To solve the rate mismatch problem and the symbol unsynchronization problem between the LED display panel with a relatively high frame rate and the smartphones' camera with a relatively low frame rate, we propose an Alternate Bit-flipping Repeat Coding scheme for adjustable frame rate matching and symbol synchronization with the advantage of eliminating flickers perceivable to human eyes. Fast image processing algorithms are also designed to decrease the computational complexity of extracting information from the captured video frames in real-time. An experimental system was implemented on a 16x16 points LED display panel with a refresh rate of 150 fps and a commercial Android smartphone with an 8 megapixels camera working at 30 fps and a self-developed Android APP. The experimental results show that the real-time LED display camera communication system can achieve a data transmission rate of 30 bps for one LED display point and a maximum distance of 80 cm, and the computational time on the Android smartphone for data receiving is only 11.827 ms. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： CCD cameras CMOS cameras image processing algorithms image sensors LED displays Visible light communications

来源：评论

学校读者我要写书评

暂无评论

Polarization-based smoke removal method for surgical images

引用

BIOMEDICAL OPTICS EXPRESS 2022年第4期13卷 2364-2379页

作者： WANG, D. A. Q. I. A. N. QI, J. I. HUANG, B. A. O. R. U. NOBLE, E. L. I. Z. A. B. E. T. H. STOYANOV, D. A. N. A. I. L. GAO, J. U. N. ELSON, D. A. N. I. E. L. S. Hefei Univ Technol Sch Comp & Informat Hefei 230601 Peoples R China Imperial Coll London Hamlyn Ctr Robot Surg London SW7 2AZ England Imperial Coll London Dept Surg & Canc London SW7 2AZ England Zhejiang Lab Res Ctr Intelligent Sensing Hangzhou 311100 Peoples R China UCL Dept Comp Sci London WC1E 6BT England

Smoke generated during surgery affects tissue visibility and degrades image quality, affecting surgical decisions and limiting further image processing and analysis. Polarization is a fundamental property of light and polarization-resolved imaging has been studied and applied to general visibility restoration scenarios such as for smog or mist removal or in underwater environments. However, there is no related research or application for surgical smoke removal. Due to differences between surgical smoke and general haze scenarios, we propose an alternative imaging degradation model by redefining the form of the transmission parameters. The analysis of the propagation of polarized light interacting with the mixed medium of smoke and tissue is proposed to realize polarization-based smoke removal (visibility restoration). Theoretical analysis and observation of experimental data shows that the cross-polarized channel data generated by multiple scattering is less affected by smoke compared to the co-polarized channel. The polarization difference calculation for different color channels can estimate the model transmission parameters and reconstruct the image with restored visibility. Qualitative and quantitative comparison with alternative methods show that the polarization-based image smoke removal method can effectively reduce the degradation of biomedical images caused by surgical smoke and partially restore the original degree of polarization of the samples. Published by Optica Publishing Group under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

关键词： image processing algorithms image quality Imaging techniques Light properties Medical image processing Medical imaging

来源：评论

学校读者我要写书评

暂无评论

Fast, closed-loop iterative system-on-chip of deflection efficiency enhancement for a liquid crystal optical phased array

引用

APPLIED OPTICS 2022年第6期61卷 1583-1592页

作者： Huang, Yanwei Wang, Kangzhe He, Xiaoxian Yan, Qianying Wang, Yifan Liang, Zhiqing Zhuo, Rusheng Tan, Qinggui Hu, Junxiang Wang, Xiangru Gao, Shihan Univ Elect Sci & Technol China Sch Optoelect Sci & Engn Chengdu 610054 Peoples R China Natl Key Lab Sci & Technol Space Microwave Xian 710100 Peoples R China Res Inst Guangzhou Haige Commun Guangzhou 510663 Peoples R China

To implement a liquid crystal optical phased array (LC-OPA) on a practical free-space laser communication terminal, there are two essential parameters: insertion loss and the dosed-loop bandwidth required to meet the dynamic linking condition of the acquisition-tracking-pointing sub-system. Real-time hardware platforms and deflection efficiency optimization algorithms have been suggested since the invention of LC-OPA. In this paper, the so-called ZYNQ platform, a field-programmable-gate-array-based heterogeneous system-on-chip (SoC), is utilized to keep real-time response and accelerate data generation, such as beam steering, beamforming, beam enhancement, etc. In addition, a novel, to the best of our knowledge, optimization algorithm is proposed on the concept of dimension reduction of the number of objective variables. After deploying on this heterogeneous SoC platform, numerical simulations and experimental results both verify that, compared to the conventional PC-based system, the integrated SoC platform offers 15.8 times faster iterative speed., a rapid convergence rate, and excellent robustness, yet with less usage of power, physical size, and monetary cost. The efficiency enhancement process costs only a few seconds at any angle, laying the foundation for practical in-line applications. (C) 2022 Optica Publishing Group

关键词： Beam steering Free space optics image processing algorithms Laser communications Numerical simulation Phased arrays

来源：评论

学校读者我要写书评

暂无评论

Interferometric laser imaging for droplet-size measurement in spray

引用

APPLIED OPTICS 2022年第18期61卷 5496-5506页

作者： Ma, Yarui Cui, Jiwen Tan, Jiubin Harbin Inst Technol Ctr Ultraprecis Optoelect Instrument Engn Harbin 150080 Peoples R China Harbin Inst Technol Key Lab Ultraprecis Intelligent Instrumentat Minist Ind & Informat Technol Harbin 150080 Peoples R China

An upgraded droplet-size measurement method, based on laser interference particle imaging (IPI) technology, is applied to accomplish high-precision measurement of particle size and spatial distribution of gas-liquid two-phase flow in the atomization field. In this study, an improved morphological-Hough transform interference fringe location algorithm is applied to IPI measurement. The particle size of the standard particle field with a diameter of 24 mu m is measured by the upgraded IPI measurement experimentally, whose absolute error and relative error are 0.14 mu m and 0.58%, respectively. The atomization field of the 400 mu m centrifugal nozzle under different pressures is demonstrated by direct imaging and IPI technology, where the assessment results are evaluated by SMD value and particle size distribution, and the results exhibit good agreement. (C) 2022 Optica Publishing Group

关键词： Fourier transforms image processing image processing algorithms Laser induced fluorescence Laser velocimetry Spatial frequency

来源：评论

学校读者我要写书评

暂无评论

3D second harmonic generation imaging tomography by multi-view excitation

引用

OPTICA 2017年第10期4卷 1171-1179页

作者： Campbell, Kirby R. Wen, Bruce Shelton, Emily M. Swader, Robert Cox, Benjamin L. Eliceiri, Kevin Campagnola, Paul J. Univ Wisconsin Dept Biomed Engn Lab Opt & Computat Instrumentat 1550 Engn Dr Madison WI 53706 USA Morgridge Inst Res 330 N Orchard St Madison WI 53715 USA

Biological tissues have complex 3D collagen fiber architecture that cannot be fully visualized by conventional second harmonic generation (SHG) microscopy due to electric dipole considerations. We have developed a multi-view SHG imaging platform that successfully visualizes all orientations of collagen fibers. This is achieved by rotating tissues relative to the excitation laser plane of incidence, where the complete fibrillar structure is then visualized following registration and reconstruction. We evaluated high frequency and Gaussian weighted fusion reconstruction algorithms, and found the former approach performs better in terms of the resulting resolution. The new approach is a first step toward SHG tomography. (C) 2017 Optical Society of America

关键词： image processing image processing algorithms image quality Light sheet microscopy Reconstruction algorithms Ti:sapphire lasers

来源：评论

学校读者我要写书评

暂无评论

In vivo SS-OCT imaging of crystalline lens sutures

引用

BIOMEDICAL OPTICS EXPRESS 2020年第10期11卷 5388-5400页

作者： Gupta, Ashish Ruminski, Daniel Villar, Alfonso Jimenez Toledo, Raul Duarte Manzanera, Silvestre Panezai, Spozmai Mompean, Juan Artal, Pablo Grulkowski, Ireneusz Nicolaus Copernicus Univ Fac Phys Astron & Informat Ul Grudziadzka 5 PL-87100 Torun Poland Univ Murcia Lab Opt Inst Univ Invest Opt & Nanofis Campus Espinardo E-30100 Murcia Spain

We demonstrate in vivo three-dimensional (3-D) visualization of crystalline lens sutures in healthy eyes using swept source optical coherence tomography (SS-OCT). Volumetric data sets of the crystalline lenses were acquired and processed to obtain enhanced contrast projection images and to extract suture patterns in both anterior and posterior lens. The results presented different types of the sutures including Y-sutures, simple and complex star sutures. Age-related changes in suture arrangement were characterized quantitatively. Crystalline lens suture imaging with SS-OCT might be a useful tool in fundamental studies on development and ageing of human lens. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： Crystalline lens image processing algorithms image quality In vivo imaging Swept sources Visual accommodation

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：