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Aberration-robust monocular passive depth sensing using a meta-imaging camera

Light(Science & Applications) 2024年第11期13卷 2556-2565页

作者： Zhexuan Cao Ning Li Laiyu Zhu Jiamin Wu Qionghai Dai Hui Qiao Department of Automation Tsinghua UniversityBeijing 100084China Institute for Brain and Cognitive Sciences Tsinghua UniversityBeijing 100084China Beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China

Depth sensing plays a crucial role in various applications,including robotics,augmented reality,and autonomous *** passive depth sensing techniques have come into their own for the cost-effectiveness and compact design,offering an alternative to the expensive and bulky active depth sensors and stereo vision *** the light-field camera can address the defocus ambiguity inherent in 2D cameras and achieve unambiguous depth perception,it compromises the spatial resolution and usually struggles with the effect of optical *** contrast,our previously proposed meta-imaging sensor1 has overcome such hurdles by reconciling the spatial-angular resolution trade-off and achieving the multi-site aberration correction for high-resolution ***,we present a compact meta-imaging camera and an analytical framework for the quantification of monocular depth sensing precision by calculating the Cramér–Rao lower bound of depth *** evaluations reveal that the meta-imaging camera exhibits not only higher precision over a broader depth range than the light-field camera but also superior robustness against changes in signal-background ***,both the simulation and experimental results demonstrate that the meta-imaging camera maintains the capability of providing precise depth information even in the presence of *** the promising compatibility with other point-spread-function engineering methods,we anticipate that the meta-imaging camera may facilitate the advancement of monocular passive depth sensing in various applications.

关键词： passive camera offering

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A modular hierarchical array camera

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Light(Science & Applications) 2021年第4期10卷 542-550页

作者： Xiaoyun Yuan Mengqi Ji Jiamin Wu David JBrady Qionghai Dai Lu Fang Departm ent of Electronic Engineering Tsinghua UniversityBeijing 100084China Department of Automation Tsinghua UniversityBeijing 100084China College of Optical Sciences University of ArizonaTucsonAZ 85721USA lnstitute of Brain and Cognitive Science Tsinghua UniversityBeijing 100084China Beijing National Research Center for Information Science and Technology Beijing 100084China

Array cameras removed the optical limitations of a single camera and paved the way for high-performance imaging via the combination of micro-cameras and computation to fuse multiple aperture ***,existing solutions use dense arrays of cameras that require laborious calibration and lack flexibility and *** by the cognition function principle of the human brain,we develop an unstructured array camera system that adopts a hierarchical modular design with multiscale hybrid cameras composing different *** computations are designed to collaboratively operate along both intra-and intermodule *** system can adaptively allocate imagery resources to dramatically reduce the hardware cost and possesses unprecedented flexibility,robustness,and *** scenes of real-world data were acquired to perform human-centric studies for the assessment of human behaviours at the individual level and crowd behaviours at the population level requiring highresolution long-term monitoring of dynamic wide-area scenes.

关键词： camera system removed

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Investigation and optimization of sampling characteristics of light field camera for flame temperature measurement

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Chinese Physics B 2019年第3期28卷 202-217页

作者： Yudong Liu Md.Moinul Hossain Jun Sun Biao Zhang Chuanlong Xu Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education School of Energy and EnvironmentSoutheast UniversityNanjing 210096China School of Engineering and Digital Arts University of KentCanterburyKentCT27NTUK Sunny Central Research Institute Hangzhou 310052China

It is essential to investigate the light field camera parameters for the accurate flame temperature measurement because the sampling characteristics of the flame radiation can be varied with them. In this study, novel indices of the light field camera were proposed to investigate the directional and spatial sampling characteristics of the flame radiation. Effects of light field camera parameters such as focal length and magnification of the main lens, focal length and magnification of the microlens were investigated. It was observed that the sampling characteristics of the flame are varied with the different parameters of the light field camera. The optimized parameters of the light field camera were then proposed for the flame radiation sampling. The larger sampling angle(23 times larger) is achieved by the optimized parameters compared to the commercial light field camera parameters. A non-negative least square(NNLS) algorithm was used to reconstruct the flame temperature. The reconstruction accuracy was also evaluated by the optimized parameters. The results suggested that the optimized parameters can provide higher reconstruction accuracy for axisymmetric and non-symmetric flame conditions in comparison to the commercial light field camera.

关键词： light field camera flame radiation sampling parameter optimization temperature reconstruction

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Neutronic analysis of ITER radial x-ray camera

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Plasma Science and Technology 2019年第2期21卷 105-112页

作者： Luying NIU Hongrui CAO Kun XU Liqun HU Institute of Plasma Physics Chinese Academy of Sciences

The radial x-ray camera(RXC) is designed to measure the poloidal profile of plasma x-ray emission with high spatial and temporal resolution. The RXC diagnostic system consists of internal camera module and external camera module that view the core region and outer region through the vertical slots of the diagnostic first wall and diagnostics shield module of the equatorial port plug. To ensure the normal performance of the silicon photodiode array detectors of the cameras in the hard neutron irradiation environment in ITER tokamak, it is necessary to calculate neutron flux, radiation damage and the nuclear heating of the silicon photodiode array detectors and simulate the radiation maps of the range of RXC. This work estimated the nuclear environment of RXC based on Monte Carlo N-particle transport code, plasma scenarios of ITER tokamak and the RXC-integrated ITER CLITE model. The neutron flux of silicon photodiode array detectors and the lifetime of the silicon photodiode detector in the camera were calculated. The neutronic analysis results show that the shielding design has achieved the effect as expected and is able to guarantee the normal work of the detector during the ITER deuterium–deuterium phase without replacement, three detectors of the external camera can be operated during the whole deuterium–tritium phase without replacement.

关键词： tokamak radial x-ray camera neutronic

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Robust RGB-D camera and IMU Fusion-based Cooperative and Relative Close-range Localization for Multiple Turtle-inspired Amphibious Spherical Robots

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Journal of Bionic Engineering 2019年第3期16卷 442-454页

作者： Huiming Xing Liwei Shi Kun Tang Shuxiang Guo Xihuan Hou Yu Liu Huikang Liu Yao Hu Key Laboratory of Convergence Medical Engineering System and Healthcare Technology the Ministry of Industry and Information Technology School of Life Science Beijing Institute of Technology Beijing 100081 China Key Laboratory of Biomimetic Robots and Systems Ministry of Education Beijing Institute of Technology Beijing 100081 China Faculty of Engineering Kagawa University 2217-20 Hayashicho Takamatsu Kagawa 761-0396 Japan

In the narrow, submarine, unstructured environment, the present localization approaches, such as GPS measurement, dead?rcckoning, acoustic positioning, artificial landmarks-based method, are hard to be used for multiple small-scale underwater robots. Therefore, this paper proposes a novel RGB-D camera and Inertial Measurement Unit (IMU) fusion-based cooperative and relative close-range localization approach for special environments, such as underwater caves. Owing to the rotation movement with zero-radius, the cooperative localization of Multiple Turtle-inspired Amphibious Spherical Robot (MTASRs) is realized. Firstly, we present an efficient Histogram of Oriented Gradient (HOG) and Color Names (CNs) fusion feature extracted from color images ofTASRs. Then, by training Support Vector Machine (SVM) classifier with this fusion feature, an automatic recognition method of TASRs is developed. Secondly, RGB-D camerabased measurement model is obtained by the depth map In order to realize the cooperative and relative close-range localization of MTASRs, the MTASRs model is established with RGB-D camera and IMU. Finally, the depth measurement in water is corrected and the efficiency of RGB-D camera for underwater application is validated. Then experiments of our proposed localization method with three robots were conducted and the results verified the feasibility of the proposed method for MTASRs.

关键词： vision localization bio-inspired robots RGB-D camera histogram of oriented gradient and color names fusion feature Co operative and Relative Localization (CRL)

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Xenos peckii vision inspires an ultrathin digital camera

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Light(Science & Applications) 2018年第1期7卷 272-278页

作者： Dongmin Keum Kyung-Won Jang Daniel S.Jeon Charles S.H.Hwang Elke K.Buschbeck Min H.Kim Ki-Hun Jeong Department of Bio and Brain Engineering Korea Advanced Institute of Science and Technology(KAIST)291 Daehak-roYuseong-guDaejeon 34141Korea School of Computing Korea Advanced Institute of Science and Technology(KAIST)291 Daehak-roYuseong-guDaejeon 34141Korea Department of Biological Sciences University of CincinnatiCincinnatiOH 45221-0006USA

Increased demand for compact devices leads to rapid development of miniaturized digital ***,conventional camera modules contain multiple lenses along the optical axis to compensate for optical aberrations that introduce technical challenges in reducing the total thickness of the camera ***,we report an ultrathin digital camera inspired by the vision principle of Xenos peckii,an endoparasite of paper *** male Xenos peckii has an unusual visual system that exhibits distinct benefits for high resolution and high sensitivity,unlike the compound eyes found in most insects and some *** biologically inspired camera features a sandwiched configuration of concave microprisms,microlenses,and pinhole arrays on a flat image *** camera shows a field-of-view(FOV)of 68 degrees with a diameter of 3.4mm and a total track length of *** biologically inspired camera offers a new opportunity for developing ultrathin cameras in medical,industrial,and military fields.

关键词： camera sandwich digital

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Radiometric cross-calibration of the CBERS-02 CCD camera with the TERRA MODIS

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Science China(Technological Sciences) 2005年第S2期48卷 44-60页

作者： LI Xiaoying1,2,3, GU Xingfa1,3,4, MIN Xiangjun5, YU Tao1,3, FU Qiaoyan5, ZHANG Yong1,2,3 & LI Xiaowen1,3 1. State Key Laboratory of Remote Sensing Science, Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101, China 2. Graduate University of Chinese Academy of Sciences, Beijing 100039, China 3. The Center for National Spaceborne Demonstration, Beijing 100101, China 4. Institut National de la Recherche Agronomique, Climat Sol Environnement, 84914 Avignon, France 5. China Center for Resource Satellite Data and Application, Beijing 100830, China 1. State Key Laboratory of Remote Sensing Science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University 100101 Beijing China 2. Graduate University of Chinese Academy of Sciences 100039 Beijing China 3. The Center for National Spaceborne Demonstration 100101 Beijing China 4. Institut National de la Recherche Agronomique Climat Sol Environnement 84914 Avignon France 5. China Center for Resource Satellite Data and Application 100830 Beijing China

For the application of the CCD camera, the most important payload on CBERS-02, the key is to provide long-term stable radiometric calibration coefficients. Although the vicarious calibration had been proved successful, it had its limitations such as test site requirement and unsuitable for historical data. Cross-calibration is one of the alternative methods, but it needs synchro surface spectrum to achieve spectral band matching factors. Our effort is to probe the influences on these factors. Simulations with a lot of surface spectrum showed that the factors changed with the viewing geometry, atmospheric condition and surface targets. However, simulating with the same viewing geometry and atmospheric condition, the spectral band matching factors of the same or similar surface targets’ spectrum acquired from different dates and different places would like to be consistent to each other within 1%―5%. Thus, the synchro measurement data can be substituted by the same or similar target from other source. Based on this method, using the MODIS as the reference, the cross-calibration was performed for CCD camera. The research demonstrated that the traditional method with single calibration site was inappropriate for CCD camera, since the offsets for its four spectral bands were not zeros. With four calibration sites, these offsets were obtained. And the camera was detected to degrade with dates based on four times of cross-calibrations.

关键词： CBERS-02 CCD camera cross-calibration the spectral band matching factors.

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Improved plasma position detection method in EAST Tokamak using fast CCD camera

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Nuclear Science and Techniques 2019年第2期30卷 71-80页

作者： Shuang-Bao Shu Chuan-Mu Yu Chao Liu Mei-Wen Chen Yu-Zhong Zhang Xin Li School of Instrument Science and Opto-electronics Engineering Hefei University of Technology China Institute of Plasma Physics Chinese Academy of Sciences

To control the steady-state operation of Tokamak plasma, it is crucial to accurately obtain its shape and position. This paper presents a method for use in rapidly detecting plasma configuration during discharge of the Experimental Advanced Superconducting Tokamak device. First, a visible/infrared integrated endoscopy diagnostic system with a large field of view is introduced,and the ***5.5 camera in this system is used to acquire a plasma discharge image. Based on the analysis of various traditional edge detection algorithms, an improved wavelet edge detection algorithm is then introduced to identify the edge of the plasma. In this method, the local maximum of the modulus of wavelet transform is searched along four gradient directions, and the adaptive threshold is adopted. Finally, the detected boundary is fitted using the least square iterative method to accurately obtain the position of the plasma. Experimental results obtained using the EAST device show that the method presented in this paper can realize expected goals and produce ideal effects;this method thus has significant potential for application in further feedback control of plasma.

关键词： Experimental Advanced Superconducting Tokamak (EAST) Plasma CCD camera Edge detection

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Design of a control system with high stability for a streak camera using isolated ADC

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Nuclear Science and Techniques 2018年第2期29卷 57-67页

作者： Yu-Man Fang Xiang-Yan Xu Jin-Shou Tian Cheng-Quan Pei Key Laboratory of Ultra-Fast Photoelectric Diagnostics Technology Xi’an Institute of Optics and Precision MechanicsXi’an 710119ShaanxiChina University of Chinese Academy of Sciences Beijing 100049China Xi'an Jiaotong University Xi’an 710049ShaanxiChina

The streak camera is an ultra-fast diagnostic instrument with high sensitivity, and a high temporal and spatial resolution. It is primarily employed in various scientific research, such as inertial confinement fusion(ICF),synchrotron light sources, and electron–positron *** automatic control system for an X-ray streak camera is presented in this paper. The output terminal of an analogto-digital converter was isolated from its input terminal, to reduce interference from high-voltage electrodes. Compared with traditional methods, this scheme also improved the internal electromagnetic interface immunity. Therefore,the system stability was enhanced. With this optimized control system, some characterizations of the streak camera were measured. Static and dynamic spatial resolutions of 25 and 20 lp/mm(CTF = 20%), respectively, were obtained. In addition, a dynamic range of 552:1 and a temporal resolution of 7.3 ps were achieved. The results confirmed that these characterizations are sufficient for the specifications derived from the diagnostic requirements of ICF.

关键词： ICF Distributed control Streak camera Isolated ADC X-ray detector

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Biologically inspired ultrathin arrayed camera for high-contrast and high-resolution imaging

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Light(Science & Applications) 2020年第1期9卷 1742-1748页

作者： Kisoo Kim Kyung-Won Jang Jae-Kwan Ryu Ki-Hun Jeong Department of Bio and Brain Engineering Korea Advanced Institute of Science and Technology(KAIST)291 Daehak-roYuseong-guDaejeon 34141Republic of Korea KAIST Institute for Health Science and Technology KAISTDaejeon 34141Republic of Korea Unmanned/Robotic Systems Lab. LIG Nex1 Co.LtdSeongnam 13488Republic of Korea

Compound eyes found in insects provide intriguing sources of biological inspiration for miniaturised imaging ***,we report an ultrathin arrayed camera inspired by insect eye structures for high-contrast and super-resolution *** ultrathin camera features micro-optical elements(MOEs),i.e.,inverted microlenses,multilayered pinhole arrays,and gap spacers on an image *** MOE was fabricated by using repeated photolithography and thermal *** fully packaged camera shows a total track length of 740μm and a field-of-view(FOV)of 73°.The experimental results demonstrate that the multilayered pinhole of the MOE allows high-contrast imaging by eliminating the optical crosstalk between *** integral image reconstructed from array images clearly increases the modulation transfer function(MTF)by~1.57 times compared to that of a single channel image in the ultrathin *** ultrathin arrayed camera provides a novel and practical direction for diverse mobile,surveillance or medical applications.

关键词： resolution high camera

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