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| 1 | New method for camera pose estimation based on line correspondence显示文摘The key technology of the measuring method of pose shaking of unstable platform based on CCD lies in the camera pose estimation.A new method for camera pose estimation based on line correspondence is put forward in this paper.First,two appropriate lines are selected in the space to establish a local coordinate system,the remaining lines form three-line sets with these two lines respectively and then the angle depth of the lines of the local coordinate system can be obtained by using the linearity of interpretation plane;then the invariance of included angle between spatial coordinate system and camera coordinate system during rigid transformation is used to establish a constraint equation set of angle depth of three lines similar to traditional P3P,and the corresponding angle depth of the third line in the set can be obtained linearly by variable substitution;finally,the rotation matrix can be expressed with quaternion and the pose parameters of camera in the space can be calculated by singular value decomposition(SVD).The static experiment and dynamic experiment verify the accuracy and stability of the algorithm and that the camera pose shocking is within 1°and the 3σ error is superior to 0.3′.The method in this paper can be directly used in the micro-vibration measurement of experimental platform and robot navigation and other fields and is of important theoretical significance and engineering application prospect. | LIU JinBo ZHANG XiaoHu LIU HaiBo YUAN Yun ZHU ZhaoKun YU QiFeng | 2013 | Science China(Technological Sciences)2013，56，11： | 11 |
| 2 | Monocular trajectory intersection method for 3D motion measurement of a point target显示文摘This article proposes a monocular trajectory intersection method,a videometrics measurement with a mature theoretical system to solve the 3D motion parameters of a point target.It determines the target’s motion parameters including its 3D trajectory and velocity by intersecting the parametric trajectory of a motion target and series of sight-rays by which a motion camera observes the target,in contrast with the regular intersection method for 3D measurement by which the sight-rays intersect at one point.The method offers an approach to overcome the technical failure of traditional monocular measurements for the 3D motion of a point target and thus extends the application fields of photogrammetry and computer vision.Wide application is expected in passive observations of motion targets on various mobile beds. | YU QiFeng SHANG Yang ZHOU Jian ZHANG XiaoHu LI LiChun | 2009 | Science China(Technological Sciences)2009，52，12： | 10 |
| 3 | Vision navigation for aircrafts based on 3D reconstruction from real-time image sequences显示文摘In this paper,we propose a novel vision navigation method based on three-dimensional(3D)reconstruction from real-time image sequences.It adapts 3D reconstruction and terrain matching to establish the correspondence between image points and3D space points and the terrain reference(by using a digital elevation map(DEM)).An adaptive weighted orthogonal iterative pose estimation method is employed to calculate the position and attitude angle of the aircraft.Synthesized and real experiments show that the proposed method is capable of providing accurate navigation parameters for a long-endurance flight without using a global positioning system or an inertial navigation system(INS).Moreover,it can be combined with an INS to achieve an improved navigation result. | ZHU ZunShang SU Ang LIU HaiBo SHANG Yang YU QiFeng | 2015 | Science China(Technological Sciences)2015，58，7： | 8 |
| 4 | Research on 3D Target Pose Tracking and Modeling显示文摘This paper tackles pose tracking and model refinement, one of the fundamental work for 3D photogrammetry. The researches belong to the videometrics, an interdisciplinewhich combines computer vision, digital image processing, photogrammetry and optical measurement. Related works are summarized briefly in this paper. This paper studies the problem of pose tracking for target with 3D model. For the target with accurate 3D model, line model based pose tracking methods are proposed for target which is rich in line features. Experimental results indicate that the proposed methods track the target pose accurately. Normal distance iterative reweighted least squares and distance image iterative least squares methods are proposed to process more general targets. This paper adopts bundle adjustment to tackle pose tracking in image sequence for target with inaccurate 3D line model. The proposed method optimizes the model line parameters and the pose parameters simultaneously. The model line orientation, position and mean angle error, mean position error of the pose are 0.3°,3.5 mm and 0.12°,20.1 mm in simulation experiments of satellite pose tracking. Line features are used to track target pose with unknown 3D model through image sequence. The model line parameters and pose parameters are optimized under the framework of SFM. In simulation experiments, the reconstructed line orientation, position error and mean angle error, mean position error of pose are 0.4°,7.5 mm and 0.16°,23.5 mm. | Yang SHANG Xiaoliang SUN Yueqiang ZHANG You LI Qifeng YU | 2019 | Journal of Geodesy and Geoinformation Science2019，2，2： | 7 |
| 5 | An area-based position and attitude estimation for unmanned aerial vehicle navigation显示文摘The paper aims to challenge non-GPS navigation problems by using visual sensors and geo-referenced images. An area-based method is proposed to estimate full navigation parameters(FNPs), including attitude, altitude and horizontal position, for unmanned aerial vehicle(UAV) navigation. Our method is composed of three main modules: geometric transfer function, local normalized sobel energy image(LNSEI) based objective function and simplex-simulated annealing(SSA) based optimization algorithm. The adoption of relatively rich scene information and LNSEI, makes it possible to yield a solution robustly even in the presence of very noisy cases, such as multi-modal and/or multi-temporal images that differ in the type of visual sensor, season, illumination, weather, and so on, and also to handle the sparsely textured regions where features are barely detected or matched. Simulation experiments using many synthetic images clearly support noise resistance and estimation accuracy, and experimental results using 2367 real images show the maximum estimation error of 5.16(meter) for horizontal position, 9.72(meter) for altitude and 0.82(degree) for attitude. | LIU XiaoChun WANG Hou FU Dan YU QiFeng GUO PengYu LEI ZhiHui SHANG Yang | 2015 | Science China(Technological Sciences)2015，58，5： | 7 |
| 6 | Pose-relay videometrics based ship deformation measurement system and sea trials显示文摘The measurement of ship deformation has been a difficult problem for the global ship building industry and navigation field research.So far,an effective and proven method for measuring 3D position and attitude deformation remains unavailable.This article proposes an innovative pose-relay videometrics measurement system for ship deformation on the basis of primary research and experimental validation.The system offers solutions to the important technical problems such as infrared marker manufacture,high-precision detection and multi-camera synchronization and control.Sea trials were carried out,and reasonable,long-term,and continuous 3D data of position and attitude deformations between a given deck point and the ship reference,and between the ship's head and the stern were acquired for the first time.The experiments have highlighted the considerable applicability of the proposed method of deformation measurement and long-term monitoring of ships and similar large structures. | JIANG GuangWen FU SiHua CHAO ZhiChao YU QiFeng | 2011 | Chinese Science Bulletin2011，56，1： | 6 |
| 7 | Videometric research on deformation measurement of large-scale wind turbine blades显示文摘Utilization of wind energy is a promising way to generate power,and wind turbine blades play a key role in collecting the wind energy effectively.This paper attempts to measure the deformation parameter of wind turbine blades in mechanics experiments using a videometric method. In view that the blades experience small buckling deformation and large integral deformation simultaneously, we proposed a parallel network measurement(PNM) method including the key techniques such as camera network construction,c... | Xiangyi Sun,Yun Yuan,~(a))Zhaokun Zhu,Xiaohu Zhang,and Qifeng Yu College of Aerospace and Materials Engineering,National University of Defense Technology,Changsha 410073, Hunan,China | 2011 | Theoretical & Applied Mechanics Letters2011，1，1： | 5 |
| 8 | Correction method for non-landing measuring of vehicle-mounted theodolite based on static datum conversion显示文摘During the non-landing measuring of vehicle mounted theodolite, especially under high-speed tracking measurement, the misalignment of theodolite's center of mass and spindle etc. will cause high-frequency vibration of theodolite platform, increase the observation error of targets and even unbelievable results. In this paper, a correction method of non-landing measuring of theodolite based on static datum conversion is presented, which can effectively improve the observation accuracy of theodolite. The CCD camera is fixed to the theodolite platform to calculate the gesture shaking quantity of theodolite platform in geodetic coordinate system through the real time imaging of static datum. The observation results of theodolite are corrected by using such shaking quantity. The experiment shows that the correction accuracy exceeds 10 s of arc. The intrinsic parameter calibration technology of camera based on stellar angular distance and absolute conic put forward in this paper can prevent the estimated error of extrinsic parameters influencing the intrinsic parameter calibration and improve the intrinsic parameter calibration accuracy; the static datum conversion technology can reduce the influence of installation error of camera and theodolite platform on gesture measuring of the platform. The simulation experiment shows that when the shaking range of the platform is less than 30 min of arc, the influence of the three-axis installation error of camera within 3deg on the accuracy of correction results is less than 8 s of arc. The method in this paper can be extended to and used in the field of gesture shaking measuring and micro-structure deformation of various unstable platforms, therefore it is of important theoretical research significance and has wide engineering application prospect. | LIU JinBo ZHANG XiaoHu LIU HaiBo YUAN Yun ZHU ZhaoKun YU QiFeng | 2013 | Science China(Technological Sciences)2013，56，9： | 5 |
| 9 | A method for weighing broiler chickens using improved amplitude-limiting filtering algorithm and BP neural networks显示文摘Broiler chickens are traditionally weighed by steelyard or platform scale,which is timeconsuming and labor-intensive.Broiler chickens usually exhibit stress-related behavior during weighing.The 3D camera-based weighing system for broiler chickens can only weigh the broiler chicken in the monitoring area.Usually,it makes poor weight prediction due to poor segmentation especially when the broiler chicken is flapping its wings.To solve these issues,we developed one simple and low-cost weighing system with high stability and accuracy.A validity value extraction method from dynamic weighing was proposed.Then,an improved amplitude-limiting filtering algorithm and a BP neural networks model were developed to avoid accidental interference.The BP neural networks model used daily weight gain,day-age,average velocity,and the weight data after filtering algorithm as the input layer.The weighing system was tested in a commercial Beijing Fatty Chickens house with Beijing Fatty Chickens.We tested thirteen groups of Beijing Fatty Chickens of different weights,from 500 g to 1800 g in intervals of 100 g,using the three different methods:no filtering algorithm or BP neural networks,only the improved amplitude-limiting filtering algorithm and a hybrid of the improved amplitude-limiting filtering algorithm and BP neural networks.The results showed that the hybrid algorithm had a better performance in minimizing the error,lowering from the original 6%down to 3%.The accurate weight data was transmitted to the remote service platform for further decision-making,such as activity analysis,feeding management,and health alerts. | Weihong Ma Qifeng Li Jiawei Li Luyu Ding Qinyang Yu | 2021 | Information Processing in Agriculture2021，8，2： | 5 |
| 10 | A displacement-relay videometric method for surface subsidence surveillance in unstable areas显示文摘When measuring the surface subsidence of unstable areas such as railroad beds and large construction fields, it is not practical to always find stable positions to install measurement instruments. Yet installing those instruments in unstable positions will cause measurement errors or even the complete failure of long-term subsidence surveillance. In this paper, the innovative concept and its method of 'displacement-relay videometrics' are proposed. With the method, a double-headed camera is designed, and two constraints, the 'fixation constraint' and the 'homologous constraint', are established to construct the displacement-relay measurement equations, which can concurrently give the subsidence of the points to be measured and the positions where the cameras are fixed. The method and its measurement system are thus capable of automatically measuring the surface subsidence under the condition that the cameras are mounted on unstable locations over long durations. Therefore, the method has the broad prospect of undertaking automatic, long-term and continuous measurement for surface subsidence in engineering projects such as railroad beds, bridges and the ground beds of tall buildings. The proposed method opens a new area that cameras can be mounted on unstable platform to make high accuracy measurements, which is of great significance for applications. | YU QiFeng JIANG GuangWen SHANG Yang XU Yong LIU XiaoLin FU SiHua GUAN BangLei ZHU XianWei | 2015 | Science China(Technological Sciences)2015，58，6： | 5 |
| 11 | Relay camera videometrics based conversion method for unstable platform to static reference显示文摘This article proposes a relay camera videometrics based method to convert an unstable measuring platform to a static reference to solve the problems of large error or invalidation caused by measuring platform instability in photogrammetric and videometric measurements.The method installs a relay camera on the unstable platform and captures images of a reference marker fixed on a static reference or vice versa to resolve the 3D movement of the unstable platform relative to the static reference,based on which it corrects the error of the measured results and thus eliminating the influence of the platform movement.It finds new and important applications for videometrics by making high-precision dynamic measurement possible on unstable platforms.Verification experiments and numerical simulations have proven its validity and practicability. | YU QiFeng SUN XiangYi JIANG GuangWen LIU XiaoLin ZHANG XiaoHu ZHOU Jian SHANG Yang | 2011 | Science China(Technological Sciences)2011，54，4： | 4 |
| 12 | Pose optimization based on integral of the distance between line segments显示文摘In this paper, new solutions for the problem of pose estimation from correspondences between 3D model lines and 2D image lines are proposed. Traditional line-based pose estimation methods rely on the assumption that the noises(perpendicular to the line) for the two endpoints are statistically independent. However, these two noises are in fact negatively correlated when the image line segment is fitted using the least-squares technique. Therefore, we design a new error function expressed by the average integral of the distance between line segments. Three least-squares techniques that optimize both the rotation and translation simultaneously are proposed in which the new error function is exploited. In addition, Lie group formalism is utilized to describe the pose parameters, and then, the optimization problem can be solved by means of a simple iterative least squares method. To enhance the robustness to outliers existing in the match data, an M-estimation method is developed to convert the pose optimization problem into an iterative reweighted least squares problem. The proposed methods are validated through experiments using both synthetic and real-world data. The experimental results show that the proposed methods yield a clearly higher precision than the traditional methods. | ZHANG YueQiang LI Xin LIU HaiBo SHANG Yang YU QiFeng | 2016 | Science China(Technological Sciences)2016，59，1： | 3 |
| 13 | HGF percutaneous endocardial injection induces cardiomyocyte proliferation and rescues cardiac function in pigs显示文摘Objective:To investigate the effect of cardiomyocyte proliferation induced by human hepatocyte growth factor(HGF)in pigs with chronic myocardial infarction(CMI).Methods:A steerable,deflectable 7F catheter incorporating a 27-guage needle was advanced percutaneously to the left ventricular myocardium of 18 pigs with CMI.Pigs were randomized(1:1:1)to receive adenoviral vector HGF(total dose,1×1010 genome copies),which was administered as five injections into the infarcted myocardium(total,1.0 mL),or saline,or Ad-null(control groups).Injections were guided by Ensite NavX left ventricular electroanatomical mapping.HGF and cyclin proteins were detected by western blot and immunoprecipitation analysis.Histological and immunohistochemical analysis determined proliferating cardiomyocytes.Myocardial perfusion and cardiac function were estimated by Gated-Single Photon Emission Computed Tomography(G-SPECT).Results:Western blot analyses showed that HGF were predominantly expressed in the infarct core and border in the myocardium of the infarcted heart.G-SPECT analysis indicated that the HGF group had better cardiac function and myocardial perfusion four weeks after the injection of Ad-HGF than before the injection of Ad-HGF.After treatment there were more proliferating cardiomyocytes in the HGF group compared to either of the control groups.Furthermore,the HGF group myocardial samples expressed higher levels of p-Akt,cyclin A,cyclin E,cyclin D1,cdk2,cdk4 than those in the control groups.Conclusion:The over-expression of HGF activates pro-survival pathways,induces cardiomyocyte proliferation,and improves the perfusion and function of the porcine CMI heart. | Zhengxian Tao Bo Chen Yingming Zhao Hongwu Chen Liansheng Wang Yonghong Yong Kejiang Cao Qifeng Yu Danian Ke` Hua Wang Zuze Wu Zhijian Yang | 2010 | The Journal of Biomedical Research2010，24，3： | 3 |
| 14 | Precise monocular vision-based pose measurement system for lunar surface sampling manipulator显示文摘Space manipulator has been playing an increasingly important role in space exploration due to its flexibility and versatility. This paper is to design a vision-based pose measurement system for a four-degree-of-freedom(4-DOF) lunar surface sampling manipulator relying on a monitoring camera and several fiducial markers. The system first employs double plateaus histogram equalization for the markers to improve the robustness to varying noise and illumination. The markers are then accurately extracted in sub-pixel based on template matching and curved surface fitting. Finally, given the camera parameters and 3D reference points, the pose of the manipulator end-effector is solved from the 3D-to-2D point correspondences by combining a plane-based pose estimation method with rigid-body transformation. Experiment results show that the system achieves highprecision positioning and orientation performance. The measurement error is within 3 mm in position, and 0.2° in orientation,meeting the requirements for space manipulator operations. | WANG Gang SHI ZhongChen SHANG Yang SUN XiaoLiang ZHANG WenLong YU QiFeng | 2019 | Science China(Technological Sciences)2019，62，10： | 3 |
| 15 | Full-parameter vision navigation based on scene matching for aircrafts显示文摘Vision navigation based on scene matching between real-time images and a reference image has many advantages over the commonly used inertial navigation system(INS),such as no cumulative measurement errors for long-endurance flight.Recent developments in vision navigation are mainly used for partial navigation parameters measurements,such as the position and the relative velocity,which cannot meet the requirements of completely autonomous navigation.We present the concept,principle and method of full-parameter vision navigation(FPVN)based on scene matching.The proposed method can obtain the three-dimensional(3D)position and attitude angles of an aircraft by the scene matching for multiple feature points instead of a single point in existing vision navigations.Thus,FPVN can achieve the geodetic position coordinates and attitude angles of the aircraft and then the velocity vector,attitude angular velocity and acceleration can be derived by the time differentials,which provide a full set of navigation parameters for aircrafts and unmanned aerial vehicles(UAVs).The method can be combined with the INS and the cumulative errors of the INS can be corrected using the measurements of FPVN rather than satellite navigation systems.The approach provides a completely autonomous and accurate navigation method for long-endurance flight without the help of satellites. | YU QiFeng SHANG Yang LIU XiaoChun LEI ZhiHui LI Xiang ZHU XianWei LIU XiaoLin YANG Xia SU Ang ZHANG XiaoHu ZHANG HongLiang | 2014 | Science China(Information Sciences)2014，57，5： | 3 |
| 16 | Super-resolution reconstruction and higher-degree function deformation model based matching for Chang’E-1 lunar images显示文摘This article intends to solve the matching problem of 2C level lunar images by Chang’E-1(CE-1)lunar probe satellite.A line-scanner image matching method is proposed which represents deformation by the quadric function along the camera motion direction and bases on the deformation model for a relief terrain’s imaging on sensors of the satellite borne three-line scanner camera.A precise matching is carried out for the normal view,the frontward view,and the backward view images of the CE-1 by combining the proposed method with the standard correlation method.A super-resolution(SR)reconstruction algorithm based on the wavelet interpolation of non-uniformly sampled data is also adopted to realize SR reconstruction of CE-1 lunar images,which adds the recognizable targets and explores CE-1 lunar images to the full. | LI LiChun YU QiFeng YUAN Yun SHANG Yang LU HongWei SUN XiangYi | 2009 | Science China(Technological Sciences)2009，52，12： | 3 |
| 17 | Numerical investigation on effects of side curtain opening behavior on indoor climate of naturally ventilated dairy buildings显示文摘The side-curtain is popular in cattle buildings to regulate indoor climates and ventilation rates by adjusting the opening ratio.It normally had three different adjusting strategies relate to the position of rollers,i.e.central roller(S1),top roller(S2)and bottom roller(S3),which result in different opening behaviors to generate the same opening ratio but different opening positions in the side wall for a full-curtain house.Numerical simulations were conducted using computational fluid dynamics(CFD)to investigate the effects of the eight potential opening behaviors of side curtains on the indoor climates and airflow rates in winter for a typical naturally ventilated dairy house in China when the opening ratio were 8.5%and 17%.Airflow patterns,wind chilled temperature(WCT)and age of air were analyzed in the animal occupied zone(AOZ)by taking reference planes.Openings at the very bottom of side walls had more efficient ventilation due to the younger air age,more effective air disturbing,more uniformly distributed indicators in AOZ.However,it will result in a lower WCT in AOZ although a lower ventilation rate was observed in this case.Openings on the very top of side wall would generate a better thermal comfort in AOZ but with very poor air quality and nonuniformly distributed airflows in the dairy house.S1 was not recommended to the practical application due to the poor indoor climate and the higher cost of the mechanical structure.Based on the comprehensive evaluations of the analytic hierarchy process,the most satisfaction opening positions were at the bottom of the side curtains and the optimized adjusting strategy is S2. | Qifeng Li Chuanxia Yao Luyu Ding Ligen Yu Weihong Ma Ronghua Gao Wengang Zheng | 2020 | International Journal of Agricultural and Biological Engineering2020，13，5： | 2 |
| 18 | SETD8 induces stemness and epithelial–mesenchymal transition of pancreatic cancer cells by regulating ROR1 expression显示文摘Pancreatic cancer(PC)is one of the most deadly diseases,and its incidence is increasing year by year.The methyltransferase SETD8 has been demonstrated to play an important role in tumor cell proliferation and metastasis.However,little is known about whether SETD8 could affect the invasion and metastasis of PC and the mechanism underlying the regulation.Based on our previous report,here,we further found that SETD8 could promote the invasion and migration of PC cells by inducing the expression of receptor tyrosine kinase-like orphan receptor 1(ROR1).ROR1 was predominantly upregulated in PC tissues and was correlated with lymph node metastasis and worse prognosis.Mechanistically,SETD8 mediated ROR1 activity and regulated PC cells invasion and migration,although promoting the expression of stemness and epithelial–mesenchymal transition-related molecules.This promotion effect disappeared when the catalytically inactive mutant SETD8 was overexpressed,which could be counteracted by the SETD8-specific methyltransferase inhibitor UNC0379.Collectively,our results demonstrate that SETD8 may be a novel prognostic factor and a therapeutic target of PC. | Mengqi Liu Yihua Shi Qiangsheng Hu Yi Qin Shunrong Ji Wensheng Liu Qifeng Zhuo Guixiong Fan Zeng Ye Changfeng Song Xianjun Yu Xiaowu Xu Wenyan Xu | 2021 | Acta Biochimica et Biophysica Sinica2021，53，12： | 2 |
| 19 | Hull deformation measurement for spacecraft TT&C ship by Photogrammetry显示文摘When voyaging,ships are subject to inevitable hull deformations caused by the changes in the environmental temperature and external stress.These are a crucial source of errors when measuring data using a spacecraft tracking,telemetry,and control(TT&C) ship.A prototype system based on photogrammetry was developed for the real-time measurement of a spacecraft TT&C ship's hull deformation.This system has high accuracy,a simple structure,and convenient maintenance,and requires few changes to the ship's structures.To improve its performance,an estimation approach is proposed for hull deformation angles.With the proposed approach,the central positions of cross spots in successive frames can be predicted based on the prediction of the camera's attitude,and their extract locations can be found by defining a series of small windows around each predictive location.Then,the optimal estimate of the camera's attitude is updated by the designed extended Kalman filter using the extracted cross spots and their corresponding local coordinates,with which the hull deformation angles can be found.To verify the proposed measurement approach,its performance was tested during the normal sailing,floating,and rocking on the sea of a spacecraft TT&C ship.The experimental testing results demonstrated that the proposed approach performs well in terms of accuracy and robustness.It can satisfy the hull deformation measurement requirement for a spacecraft TT&C ship in real time. | LIU HaiBo SUN Cong ZHANG YueQiang LIU XinMing LIU JinBo ZHANG XiaoHu YU QiFeng | 2015 | Science China(Technological Sciences)2015，58，8： | 2 |
| 20 | Non-contact optical dynamic measurements at different ranges:a review显示文摘Optical dynamic measurements are widely used for non-contact vibration,continuous deformation,or moving objects.Various measurement techniques were developed for different deformation amplitudes.This paper reviews three types of technique for different measurement ranges:interferometric techniques for deformation or vibration(nanometer to submillimeter amplitude)whose measurement accuracies rely on phase extraction of interferometric signal;imaging based techniques for deformation or vibration(micrometer to centimeter amplitude)with the aid of moire,structured light,and man-made speckles,whose sensitivities is from 1/100 to 1/10 pixel;and videometrics for large deformation or movement detection(greater than centimeter amplitude).Many research groups have improved measurement capabilities for these three techniques to meet particular industrial application requirements. | Yu Fu Yang Shang Wenxin Hu Bin Li Qifeng Yu | 2021 | Acta Mechanica Sinica2021，37，4： | 2 |
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