The trend towards automation and intelligence in aircraft final assembly testing has led to a new demand for autonomous perception of unknown cockpit operation scenes in robotic collaborative airborne system testing.T...The trend towards automation and intelligence in aircraft final assembly testing has led to a new demand for autonomous perception of unknown cockpit operation scenes in robotic collaborative airborne system testing.To address this demand,a robotic automated 3D reconstruction cell which enables to autonomously plan the robot end-camera’s trajectory is developed for image acquisition and 3D modeling of the cockpit operation scene.A continuous viewpoint path planning algorithm is proposed that incorporates both 3D reconstruction quality and robot path quality into optimization process.Smoothness metrics for viewpoint position paths and orientation paths are introduced together for the first time in 3D reconstruction.To ensure safe and effective movement,two spatial constraints,Domain of View Admissible Position(DVAP)and Domain of View Admissible Orientation(DVAO),are implemented to account for robot reachability and collision avoidance.By using diffeomorphism mapping,the orientation path is transformed into 3D,consistent with the position path.Both orientation and position paths can be optimized in a unified framework to maximize the gain of reconstruction quality and path smoothness within DVAP and DVAO.The reconstruction cell is capable of automatic data acquisition and fine scene modeling,using the generated robot C-space trajectory.Simulation and physical scene experiments have confirmed the effectiveness of the proposed method to achieve highprecision 3D reconstruction while optimizing robot motion quality.展开更多
The main payload on CBERS-01/02 of China-Brazil Earth Resources Satellite(CBERS)is a push-broom CCD camera with moderate spatial and radiant resolution.Because at lab the data for calibration at satellite assembly sta...The main payload on CBERS-01/02 of China-Brazil Earth Resources Satellite(CBERS)is a push-broom CCD camera with moderate spatial and radiant resolution.Because at lab the data for calibration at satellite assembly stage were unable to be collected,and also because the onboard calibrator after launch was in a different state from imaging,the calibration of CCD image got a series of difficulties involved.In practice,two methods are used in the processing on the ground station:One is extracting calibration data by statistics from the image itself,and the other is the method of histogram match.It was proved that the latter can calibrate the image much better,because it can remove the effect of unstable response of the camera largely and also can overcome the nonlinearity of the camera basically by using Look-Up Table(LUT)calculated from histogram statistics of different temporal images.Considering the problems of CBERS-01,a lot of calibration tests were done before the launch of CBERS-02,in which a set of lab coefficients for relative calibration was formulated after the data collection by using integration-hemisphere in the stage of satellite assembly test.During the on-orbit test,it was found that the calibration result from such coefficients was not satisfying,especially there being response difference between 3 detector arrays,which was attributed to the unstable dark currents of the CCD camera.This paper comes up with a statistic method to remove such response difference.In this method the middle detector array was used as reference to find the response differences of adjacent similar features between these arrays and it was proved to have a broad adaptability.展开更多
基金supported by the National Key Research and Development Program of China(2019YFB1707505)the National Natural Science Foundation of China(Grant No.52005436)。
文摘The trend towards automation and intelligence in aircraft final assembly testing has led to a new demand for autonomous perception of unknown cockpit operation scenes in robotic collaborative airborne system testing.To address this demand,a robotic automated 3D reconstruction cell which enables to autonomously plan the robot end-camera’s trajectory is developed for image acquisition and 3D modeling of the cockpit operation scene.A continuous viewpoint path planning algorithm is proposed that incorporates both 3D reconstruction quality and robot path quality into optimization process.Smoothness metrics for viewpoint position paths and orientation paths are introduced together for the first time in 3D reconstruction.To ensure safe and effective movement,two spatial constraints,Domain of View Admissible Position(DVAP)and Domain of View Admissible Orientation(DVAO),are implemented to account for robot reachability and collision avoidance.By using diffeomorphism mapping,the orientation path is transformed into 3D,consistent with the position path.Both orientation and position paths can be optimized in a unified framework to maximize the gain of reconstruction quality and path smoothness within DVAP and DVAO.The reconstruction cell is capable of automatic data acquisition and fine scene modeling,using the generated robot C-space trajectory.Simulation and physical scene experiments have confirmed the effectiveness of the proposed method to achieve highprecision 3D reconstruction while optimizing robot motion quality.
基金supported by a program from Commission of Science Technology and Industry for National Defense(Grant No.[2001]891).
文摘The main payload on CBERS-01/02 of China-Brazil Earth Resources Satellite(CBERS)is a push-broom CCD camera with moderate spatial and radiant resolution.Because at lab the data for calibration at satellite assembly stage were unable to be collected,and also because the onboard calibrator after launch was in a different state from imaging,the calibration of CCD image got a series of difficulties involved.In practice,two methods are used in the processing on the ground station:One is extracting calibration data by statistics from the image itself,and the other is the method of histogram match.It was proved that the latter can calibrate the image much better,because it can remove the effect of unstable response of the camera largely and also can overcome the nonlinearity of the camera basically by using Look-Up Table(LUT)calculated from histogram statistics of different temporal images.Considering the problems of CBERS-01,a lot of calibration tests were done before the launch of CBERS-02,in which a set of lab coefficients for relative calibration was formulated after the data collection by using integration-hemisphere in the stage of satellite assembly test.During the on-orbit test,it was found that the calibration result from such coefficients was not satisfying,especially there being response difference between 3 detector arrays,which was attributed to the unstable dark currents of the CCD camera.This paper comes up with a statistic method to remove such response difference.In this method the middle detector array was used as reference to find the response differences of adjacent similar features between these arrays and it was proved to have a broad adaptability.
