The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Stanley T. Birchfield - One of the best experts on this subject based on the ideXlab platform.
-
automated traffic surveillance system with Aerial Camera arrays imagery macroscopic data collection with vehicle tracking
Journal of Computing in Civil Engineering, 2017Co-Authors: Xi Zhao, Douglas Dawson, Wayne A Sarasua, Stanley T. BirchfieldAbstract:AbstractThe paper presents a novel computer vision-based traffic surveillance system capable of processing Aerial imagery to track vehicles and their movements. The system uses a preprocessed 1-Hz ...
-
An Automated Traffic Surveillance System with Aerial Camera Arrays: Data Collection with Vehicle Tracking
2016Co-Authors: Xi Zhao, Douglas Dawson, Wayne A Sarasua, Stanley T. BirchfieldAbstract:The paper presents a novel computer vision-based traffic surveillance system capable of processing Aerial imagery to track vehicles and their movements. The system uses a preprocessed 1-Hertz image sequence with a coverage of 25 square miles from an Aerial Camera array mounted on an airplane. The unique characteristics of the input data make this work challenging. Several heuristic and machine learning approaches are proposed and evaluated to track vehicles for the purpose of collecting traffic data. The system is capable of collecting speed, density, and volume data for uninterrupted flow corridors which is useful for “big data” monitoring of traffic parameters over an entire 25 square mile area with a single sensor. The deep learning and SURF-based approach is able to achieve over 93% accuracy throughout 50 seconds on density estimates when compared with manually collected ground truth. It has 100% accuracy when level of service (LOS) was measured for the uninterrupted facilities tested. These evaluations were conducted for facilities of different levels of congestion as indicated by the different levels of service. With further research, improved preprocessing, and a higher frame rate, the accuracy of tracking vehicles can be improved which will allow for other potential applications such as identification of erratic drivers and origin-destination studies.
Mei Zhao - One of the best experts on this subject based on the ideXlab platform.
-
Two Methods of Improving the Focus Survey Precision Based on CCD Camera
Advanced Materials Research, 2013Co-Authors: Mei Zhao, Fei Guo, Yu Fang Sha, Ying Zhao, Jun Xie, Wei HanAbstract:The principium of measuring focus of Aerial Camera and the location of the actual image plane with CCD Camera are introduced, and the methods to improve survey precision are described. The image is received by area CCD Camera. The accuracy of orientation of the imaging central line is improved by means of fit the curve method or by center of gravity method. Therefore, the distance between imaging central lines is refinedly calculated. The experimented turn out that the two methods on measuring focus of Aerial Camera have high precision, and the survey errors are in accordance with the theoretical ones (0.12%). The two methods on deterministic result of the location of the actual image plane are identical, with their precision reaching 100%.
-
Study on Locating of Focus Surface Position for Aerial Cameras
Applied Mechanics and Materials, 2013Co-Authors: Mai Yu Zhou, Mei Zhao, Fei Guo, Ming Quan Yang, Wei HanAbstract:A system for locating the focus surface position of Aerial Cameras is designed, and the working principle, hardware composition and software design of the system are described. In the system, a collimator is used for producing locating information, and CCD Camera is used as a photoelectric converter for receiving the images. The data is processed by center of gravity method, and the converter controls the translation of the Camera in axial direction precisely. The focus surface was determined by size of the collected images. Defocusing or not is judged based on the distance between the actual image location and focal plane. Tests to a couple of Aerial Cameras show that the defocusing judgment result is the same as the flight test result. Therefore, the system can be used to judge whether the Aerial Camera is defocusing, and thus to judge whether it can work normally or not.
-
A Measuring System of Focus Surface Message to Aerial Cameras Using CCD Camera
Advanced Materials Research, 2012Co-Authors: Mei Zhao, Fei Guo, Yu Fang Sha, Ming Quan YangAbstract:A measuring system of the focus surface message of bigger aperture Aerial Camera was described. The image is received by the collimator of long focus and area CCD Camera. The location and size of the optimum image were measured effectively by using dynamic scanning and least square method. Therefore, the accurate measurements of the focus of Aerial Camera lens and the location of the actual imaging surface can be realized in the relative accuracies of 0.1% and 100% respectively.
-
Precision Focal Measuring System Based on CCD Aerial Cameras
Advanced Materials Research, 2012Co-Authors: Mei Zhao, Fei Guo, Yu Fang Sha, Ming Quan YangAbstract:In view of bigger error (0.24%) of conventional measuring method, this paper focuses on a bigger aperture Aerial Camera focus measuring system and discusses measuring principle and structure of the system. The image in this system is received by the collimator of long focus and area CCD (Charge Coupled Devices) Camera. Using dynamic scanning and center of gravity method, the system measures effectively the location and size of the optimum image. The image resolution of CCD can be up to one tenth of the size of the photosensitive sensor and the precision of 0.1percent of focus measuring can be obtained. The problem of the larger error of conventional measuring method is salved fundamentally. The accurate, real-time and on-line measurement of the focus of Aerial Camera lens can be realized and the exact determination of the position of the surface can be determined.
-
An Automatic Examining-Focus System to Aerial Cameras with CCD
Advanced Materials Research, 2012Co-Authors: Mei Zhao, Fei Guo, Ming Quan Yang, Yu Fang ShaAbstract:A system is put forward which can automatically measure focus and estimate whether the Aerial Camera is off-focus and the situation of the factual image plane is in the focus depth range or not. The principle, the hardware composition and the software design are discussed in detail. The system acquires examining-focus information with the optical collimate system, receives images information with CCD Camera which can be regarded as optoelectric conversion apparatus, processes data with the center of gravity method, and realizes the axial flow of the CCD Camera translation with the grating displacement sensor and the digital readout together. Then, the optimum image situation and the image size can be fixed on. The optimum image situation can be used to judge whether the Camera is off-focus, and the image size can be used to calculate the focus. The accurate rate of examining focus can reach almost99.87% and the estimation of off-focus or not accords with experiment result of flight. Use this system, the focus of the lens and the situation of the actual image plane can be judged to accord with the technical standards or not, so that image of high quality can be get with Aerial Camera.
Xi Zhao - One of the best experts on this subject based on the ideXlab platform.
-
automated traffic surveillance system with Aerial Camera arrays imagery macroscopic data collection with vehicle tracking
Journal of Computing in Civil Engineering, 2017Co-Authors: Xi Zhao, Douglas Dawson, Wayne A Sarasua, Stanley T. BirchfieldAbstract:AbstractThe paper presents a novel computer vision-based traffic surveillance system capable of processing Aerial imagery to track vehicles and their movements. The system uses a preprocessed 1-Hz ...
-
An Automated Traffic Surveillance System with Aerial Camera Arrays: Data Collection with Vehicle Tracking
2016Co-Authors: Xi Zhao, Douglas Dawson, Wayne A Sarasua, Stanley T. BirchfieldAbstract:The paper presents a novel computer vision-based traffic surveillance system capable of processing Aerial imagery to track vehicles and their movements. The system uses a preprocessed 1-Hertz image sequence with a coverage of 25 square miles from an Aerial Camera array mounted on an airplane. The unique characteristics of the input data make this work challenging. Several heuristic and machine learning approaches are proposed and evaluated to track vehicles for the purpose of collecting traffic data. The system is capable of collecting speed, density, and volume data for uninterrupted flow corridors which is useful for “big data” monitoring of traffic parameters over an entire 25 square mile area with a single sensor. The deep learning and SURF-based approach is able to achieve over 93% accuracy throughout 50 seconds on density estimates when compared with manually collected ground truth. It has 100% accuracy when level of service (LOS) was measured for the uninterrupted facilities tested. These evaluations were conducted for facilities of different levels of congestion as indicated by the different levels of service. With further research, improved preprocessing, and a higher frame rate, the accuracy of tracking vehicles can be improved which will allow for other potential applications such as identification of erratic drivers and origin-destination studies.
Ming Quan Yang - One of the best experts on this subject based on the ideXlab platform.
-
Study on Locating of Focus Surface Position for Aerial Cameras
Applied Mechanics and Materials, 2013Co-Authors: Mai Yu Zhou, Mei Zhao, Fei Guo, Ming Quan Yang, Wei HanAbstract:A system for locating the focus surface position of Aerial Cameras is designed, and the working principle, hardware composition and software design of the system are described. In the system, a collimator is used for producing locating information, and CCD Camera is used as a photoelectric converter for receiving the images. The data is processed by center of gravity method, and the converter controls the translation of the Camera in axial direction precisely. The focus surface was determined by size of the collected images. Defocusing or not is judged based on the distance between the actual image location and focal plane. Tests to a couple of Aerial Cameras show that the defocusing judgment result is the same as the flight test result. Therefore, the system can be used to judge whether the Aerial Camera is defocusing, and thus to judge whether it can work normally or not.
-
A Measuring System of Focus Surface Message to Aerial Cameras Using CCD Camera
Advanced Materials Research, 2012Co-Authors: Mei Zhao, Fei Guo, Yu Fang Sha, Ming Quan YangAbstract:A measuring system of the focus surface message of bigger aperture Aerial Camera was described. The image is received by the collimator of long focus and area CCD Camera. The location and size of the optimum image were measured effectively by using dynamic scanning and least square method. Therefore, the accurate measurements of the focus of Aerial Camera lens and the location of the actual imaging surface can be realized in the relative accuracies of 0.1% and 100% respectively.
-
Precision Focal Measuring System Based on CCD Aerial Cameras
Advanced Materials Research, 2012Co-Authors: Mei Zhao, Fei Guo, Yu Fang Sha, Ming Quan YangAbstract:In view of bigger error (0.24%) of conventional measuring method, this paper focuses on a bigger aperture Aerial Camera focus measuring system and discusses measuring principle and structure of the system. The image in this system is received by the collimator of long focus and area CCD (Charge Coupled Devices) Camera. Using dynamic scanning and center of gravity method, the system measures effectively the location and size of the optimum image. The image resolution of CCD can be up to one tenth of the size of the photosensitive sensor and the precision of 0.1percent of focus measuring can be obtained. The problem of the larger error of conventional measuring method is salved fundamentally. The accurate, real-time and on-line measurement of the focus of Aerial Camera lens can be realized and the exact determination of the position of the surface can be determined.
-
An Automatic Examining-Focus System to Aerial Cameras with CCD
Advanced Materials Research, 2012Co-Authors: Mei Zhao, Fei Guo, Ming Quan Yang, Yu Fang ShaAbstract:A system is put forward which can automatically measure focus and estimate whether the Aerial Camera is off-focus and the situation of the factual image plane is in the focus depth range or not. The principle, the hardware composition and the software design are discussed in detail. The system acquires examining-focus information with the optical collimate system, receives images information with CCD Camera which can be regarded as optoelectric conversion apparatus, processes data with the center of gravity method, and realizes the axial flow of the CCD Camera translation with the grating displacement sensor and the digital readout together. Then, the optimum image situation and the image size can be fixed on. The optimum image situation can be used to judge whether the Camera is off-focus, and the image size can be used to calculate the focus. The accurate rate of examining focus can reach almost99.87% and the estimation of off-focus or not accords with experiment result of flight. Use this system, the focus of the lens and the situation of the actual image plane can be judged to accord with the technical standards or not, so that image of high quality can be get with Aerial Camera.
Jieqiong Lin - One of the best experts on this subject based on the ideXlab platform.
-
Modeling and optimization of the integrated TDICCD Aerial Camera pointing error.
Applied optics, 2020Co-Authors: Xiaoqin Zhou, Liu Hao, Qiang Liu, Jieqiong LinAbstract:Aerial Cameras are widely used in a number of fields. Various mechanical errors cannot be ignored with the improvement of imaging quality requirements. This paper introduces an integrated time delay integration charge coupled device (TDICCD) Aerial Camera. Compared with traditional Aerial Cameras, it can significantly improve shooting efficiency and imaging quality under similar load conditions. This paper first analyzes mechanical errors of the integrated TDICCD Aerial Camera and establishes a pointing error model based on ray tracing, then performs model parameter identification using a genetic algorithm, and completes error compensation. Finally, test results demonstrate that the compensation of the pointing error can effectively improve pointing accuracy of the optical axis. The mean of comprehensive errors was reduced by an order of magnitude, and the variance of comprehensive errors was reduced from 1.0075(mm)2 to 0.0543(mm)2.
-
design analysis and preliminary tests of a linear array ccd Aerial Camera for ground simulation
Optik, 2020Co-Authors: Jieqiong Lin, Haitao Wang, Junqiang Wang, Zhen YangAbstract:Abstract Demand for high quality images and simple structures is a trend in Aerial Camera lens design, however, Aerial Camera lens structures are complicated if there are complex optical systems. In this paper, to improve the imaging quality and reduce the weight of Aerial Camera lens, an aspherical surface is introduced to the optical system and an Aerial Camera is designed for ground simulation. As a result, the modulation transfer function (MTF) of the optical system is higher than 34% @ 91 lp/mm in all fields. Then, the modal and static properties of the developed Aerial Camera are verified by using finite element analysis, which satisfies the Camera structural design requirements. The imaging test results indicate that the imaging performance satisfy design requirements of the Aerial Camera.
-
Development of an Aspherical Aerial Camera Optical System
IEEE Photonics Journal, 2019Co-Authors: Jieqiong Lin, Jiang Chenping, Minghui Gao, Guo QingAbstract:The Aerial Camera lens largely determines the performance of the Camera. It is necessary to further optimize the lens to satisfy the requirements of small-scale and lightweight aircraft Camera systems. The optical system design is the primary prerequisite. Therefore, considering the image quality and working environment of the Aerial Camera, an aspherical Aerial Camera optical system is developed by studying the Aerial Camera optical system. The work presented in this paper decreases the overall weight of the Aerial Camera by using an aspherical lens instead of a spherical lens, which reduces the number of lenses and improves the image quality. The athermalization of the optical system ensures that the Camera has good temperature adaptability in the temperature range of −60 °C∼60 °C. The definition of the aspherical surface shape is detected by a ZYGO digital interferometer. The root mean square (RMS) of the system is 0.0403λ(λ = 632 nm), and the peak value (PV) is 0.354λ, which ensures the image quality of the Camera. The research results verify that the aspherical lens can be well applied to the Camera optical system, improving the image quality of the system and reducing the weight of the Camera.
