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...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.展开更多
Film buffs are regarding 2018 as a golden year for both Chinese cinema and Sino-African film cooperation. Released during the Spring Festival in 201& the Chinese antiterrorism action movie Operation Red Sea has gr...Film buffs are regarding 2018 as a golden year for both Chinese cinema and Sino-African film cooperation. Released during the Spring Festival in 201& the Chinese antiterrorism action movie Operation Red Sea has grossed more than $3.65 billion at the box office, becoming one of the most profitable Chinese films in histoiy. Many cinema goers don't know that most of the footage of the overseas evacuation sequence was filmed in Morocco. According to Dante Lam, Director of tlie film, the Moroccan army provided considerable support for the shooting of the film, supplying tanks, armored vehicles and helicopters to his team, with even the elite gendarmerie of the Royal Guard participating.展开更多
African film industry needs to reinvent itself and focus on indigenous culture to drive story lines IN June each year Cameroon’s capital Yaounde opens its arms to Africa’s movie elite,with the Ecrans Noirs(Black Scr...African film industry needs to reinvent itself and focus on indigenous culture to drive story lines IN June each year Cameroon’s capital Yaounde opens its arms to Africa’s movie elite,with the Ecrans Noirs(Black Screens),an international festival of film.The theme for 2011 was "African Cinema and Its Actors" and the event brought together a large number of film professionals, critics and other industry insiders.展开更多
We present the Fourier lightfield multiview stereoscope(FiLM-Scope).This imaging device combines concepts from Fourier lightfield microscopy and multiview stereo imaging to capture high-resolution 3D videos over large...We present the Fourier lightfield multiview stereoscope(FiLM-Scope).This imaging device combines concepts from Fourier lightfield microscopy and multiview stereo imaging to capture high-resolution 3D videos over large fields of view.The FiLM-Scope optical hardware consists of a multicamera array,with 48 individual microcameras,placed behind a high-throughput primary lens.This allows the FiLM-Scope to simultaneously capture 48 unique 12.8 megapixel images of a 28×37 mm field-of-view,from unique angular perspectives over a 21 deg×29 deg range,with down to 22μm lateral resolution.We also describe a self-supervised algorithm to reconstruct 3D height maps from these images.Our approach demonstrates height accuracy down to 11μm.To showcase the utility of our system,we perform tool tracking over the surface of an ex vivo rat skull and visualize the 3D deformation in stretching human skin,with videos captured at up to 100 frames per second.The FiLM-Scope has the potential to improve 3D visualization in a range of microsurgical settings.展开更多
A real-time arc welding robot visual control system based on a local network with a multi-level hierarchy is developed in this paper. It consists of an intelligence and human-machine interface level, a motion planning...A real-time arc welding robot visual control system based on a local network with a multi-level hierarchy is developed in this paper. It consists of an intelligence and human-machine interface level, a motion planning level, a motion control level and a servo control level. The last three levels form a local real-time open robot controller, which realizes motion planning and motion control of a robot. A camera calibration method based on the relative movement of the end-effector connected to a robot is proposed and a method for tracking weld seam based on the structured light stereovision is provided. Combining the parameters of the cameras and laser plane, three groups of position values in Cartesian space are obtained for each feature point in a stripe projected on the weld seam. The accurate three-dimensional position of the edge points in the weld seam can be calculated from the obtained parameters with an information fusion algorithm. By calculating the weld seam parameter from position and image data, the movement parameters of the robot used for tracking can be determined. A swing welding experiment of type V groove weld is successfully conducted, the results of which show that the system has high resolution seam tracking in real-time, and works stably and efficiently.展开更多
The different reflection characteristics of the surface of tin steel strips and the different speeds of the tinning line demand an adaptive illumination light source for online machine vision inspection. This light so...The different reflection characteristics of the surface of tin steel strips and the different speeds of the tinning line demand an adaptive illumination light source for online machine vision inspection. This light source can be integrated with a time delay integration charge-coupled device （TDI CCD ） to capture the images of moving objects and facilitate inspection of the surface quality of tin steel strips. On-site application show the effectiveness of the TDI camera with the adaptive illumination light source in detecting the surface defects on tin steel strips of three different materials and with different tin coating weights.展开更多
For a portable structured light system,it must be easy to use and fiexible.So the inconvenient and expensive equipment for calibration such as two or three orthogonal planes or extra fixed equipment should not be cons...For a portable structured light system,it must be easy to use and fiexible.So the inconvenient and expensive equipment for calibration such as two or three orthogonal planes or extra fixed equipment should not be considered.For the purpose of fast 3D acquisition,the projection matrices of a portable structured light system should be estimated.This paper proposes a flexible calibration method to meet the requirements of the portable structured light system through a surface plane.A calibration board is attached to the surface plane,and a reference pattern is also projected by an LCD projector onto the surface plane.The camera observes the surface plane at a few different positions.Then,the world-to-image point pairs for the camera and projector are obtained based on the cross ratio and epipolar geometry,and the system is thus calibrated.The experiments conducted for the proposed calibration method demonstrate its accuracy and robustness.展开更多
To address the challenges of high-precision optical surface defect detection,we propose a novel design for a wide-field and broadband light field camera in this work.The proposed system can achieve a 50°field of ...To address the challenges of high-precision optical surface defect detection,we propose a novel design for a wide-field and broadband light field camera in this work.The proposed system can achieve a 50°field of view and operates at both visible and near-infrared wavelengths.Using the principles of light field imaging,the proposed design enables 3D reconstruction of optical surfaces,thus enabling vertical surface height measurements with enhanced accuracy.Using Zemax-based simulations,we evaluate the system’s modulation transfer function,its optical aberrations,and its tolerance to shape variations through Zernike coefficient adjustments.The results demonstrate that this camera can achieve the required spatial resolution while also maintaining high imaging quality and thus offers a promising solution for advanced optical surface defect inspection.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.51676044 and 51327803)the Social Development Project of Jiangsu Province,China(Grant No.BE20187053)+1 种基金the Postgraduate Research and Practice Innovation Program of Jiangsu Province,China(Grant No.KYCX170081)China Scholarship Council
文摘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.
文摘Film buffs are regarding 2018 as a golden year for both Chinese cinema and Sino-African film cooperation. Released during the Spring Festival in 201& the Chinese antiterrorism action movie Operation Red Sea has grossed more than $3.65 billion at the box office, becoming one of the most profitable Chinese films in histoiy. Many cinema goers don't know that most of the footage of the overseas evacuation sequence was filmed in Morocco. According to Dante Lam, Director of tlie film, the Moroccan army provided considerable support for the shooting of the film, supplying tanks, armored vehicles and helicopters to his team, with even the elite gendarmerie of the Royal Guard participating.
文摘African film industry needs to reinvent itself and focus on indigenous culture to drive story lines IN June each year Cameroon’s capital Yaounde opens its arms to Africa’s movie elite,with the Ecrans Noirs(Black Screens),an international festival of film.The theme for 2011 was "African Cinema and Its Actors" and the event brought together a large number of film professionals, critics and other industry insiders.
基金supported by the National Cancer Institute(NCI)of the National Institutes of Health(Grant No.R44CA250877)the Office of Research Infrastructure Programs(ORIP),Office of the Director,National Institutes of Health,and the National Institute of Environmental Health Sciences(NIEHS)of the National Institutes of Health(Grant No.R44OD024879)+2 种基金the National Institute of Biomedical Imaging and Bioengineering(NIBIB)of the National Institutes of Health(Grant No.R43EB030979)the National Science Foundation(Grant Nos.2036439 and 2238845)the Duke Coulter Translational Part-nership Award,the Fitzpatrick Institute at the Duke University.
文摘We present the Fourier lightfield multiview stereoscope(FiLM-Scope).This imaging device combines concepts from Fourier lightfield microscopy and multiview stereo imaging to capture high-resolution 3D videos over large fields of view.The FiLM-Scope optical hardware consists of a multicamera array,with 48 individual microcameras,placed behind a high-throughput primary lens.This allows the FiLM-Scope to simultaneously capture 48 unique 12.8 megapixel images of a 28×37 mm field-of-view,from unique angular perspectives over a 21 deg×29 deg range,with down to 22μm lateral resolution.We also describe a self-supervised algorithm to reconstruct 3D height maps from these images.Our approach demonstrates height accuracy down to 11μm.To showcase the utility of our system,we perform tool tracking over the surface of an ex vivo rat skull and visualize the 3D deformation in stretching human skin,with videos captured at up to 100 frames per second.The FiLM-Scope has the potential to improve 3D visualization in a range of microsurgical settings.
基金This work was supported by the National High Technology Research and Development Program of China under Grant 2002AA422160 by the National Key Fundamental Research and the Devel-opment Project of China (973) under Grant 2002CB312200.
文摘A real-time arc welding robot visual control system based on a local network with a multi-level hierarchy is developed in this paper. It consists of an intelligence and human-machine interface level, a motion planning level, a motion control level and a servo control level. The last three levels form a local real-time open robot controller, which realizes motion planning and motion control of a robot. A camera calibration method based on the relative movement of the end-effector connected to a robot is proposed and a method for tracking weld seam based on the structured light stereovision is provided. Combining the parameters of the cameras and laser plane, three groups of position values in Cartesian space are obtained for each feature point in a stripe projected on the weld seam. The accurate three-dimensional position of the edge points in the weld seam can be calculated from the obtained parameters with an information fusion algorithm. By calculating the weld seam parameter from position and image data, the movement parameters of the robot used for tracking can be determined. A swing welding experiment of type V groove weld is successfully conducted, the results of which show that the system has high resolution seam tracking in real-time, and works stably and efficiently.
文摘The different reflection characteristics of the surface of tin steel strips and the different speeds of the tinning line demand an adaptive illumination light source for online machine vision inspection. This light source can be integrated with a time delay integration charge-coupled device （TDI CCD ） to capture the images of moving objects and facilitate inspection of the surface quality of tin steel strips. On-site application show the effectiveness of the TDI camera with the adaptive illumination light source in detecting the surface defects on tin steel strips of three different materials and with different tin coating weights.
基金Supported by National Key Technology Research and Development Program of China(2006BAK31B04)National High Technology Research and Development Program of China(863 Program)(2007AA01Z341)
文摘For a portable structured light system,it must be easy to use and fiexible.So the inconvenient and expensive equipment for calibration such as two or three orthogonal planes or extra fixed equipment should not be considered.For the purpose of fast 3D acquisition,the projection matrices of a portable structured light system should be estimated.This paper proposes a flexible calibration method to meet the requirements of the portable structured light system through a surface plane.A calibration board is attached to the surface plane,and a reference pattern is also projected by an LCD projector onto the surface plane.The camera observes the surface plane at a few different positions.Then,the world-to-image point pairs for the camera and projector are obtained based on the cross ratio and epipolar geometry,and the system is thus calibrated.The experiments conducted for the proposed calibration method demonstrate its accuracy and robustness.
基金supported by the Jilin Science and Technology Development Plan (20240101029JJ) for the following study:synchronized high-speed detection of surface shape and defects in the grinding stage of complex surfaces (KLMSZZ202305)for the high-precision wide dynamic large aperture optical inspection system for fine astronomical observation by the National Major Research Instrument Development Project (62127901)+2 种基金for ultrasmooth manufacturing technology of large diameter complex curved surface by the National Key R&D Program(2022YFB3403405)for research on the key technology of rapid synchronous detection of surface shape and subsurface defects in the grinding stage of large diameter complex surfaces by the International Cooperation Project(2025010157)The Key Laboratory of Optical System Advanced Manufacturing Technology,Chinese Academy of Sciences (2022KLOMT02-04) also supported this study
文摘To address the challenges of high-precision optical surface defect detection,we propose a novel design for a wide-field and broadband light field camera in this work.The proposed system can achieve a 50°field of view and operates at both visible and near-infrared wavelengths.Using the principles of light field imaging,the proposed design enables 3D reconstruction of optical surfaces,thus enabling vertical surface height measurements with enhanced accuracy.Using Zemax-based simulations,we evaluate the system’s modulation transfer function,its optical aberrations,and its tolerance to shape variations through Zernike coefficient adjustments.The results demonstrate that this camera can achieve the required spatial resolution while also maintaining high imaging quality and thus offers a promising solution for advanced optical surface defect inspection.
