AIM To design a miniature magnetically anchored and controlled camera system to reduce the number of trocars which are required for laparoscopy.METHODS The system consists of a miniature magnetically anchored camera w...AIM To design a miniature magnetically anchored and controlled camera system to reduce the number of trocars which are required for laparoscopy.METHODS The system consists of a miniature magnetically anchored camera with a 30° downward angle, an external magnetically anchored unit, and a vision output device. The camera weighs 12 g, measures Φ10.5 mm × 55 mm and has two magnets, a vision model, a light source, and a metal hexagonal nut. To test the prototype, the camera was inserted through a 12-mm conventional trocar in an ex vivo real liver laparoscopic training system. A trocar-less laparoscopic cholecystectomy was performed 6 times using a 12-mm and a 5-mm conventional trocar. In addition, the same procedure was performed in four canine models.RESULTS Both procedures were successfully performed using only two conventional laparoscopic trocars. The cholecystectomy was completed without any major complication in 42 min(38-45 min) in vitro and in 50 min(45-53 min) using an animal model. This camera was anchored and controlled by an external unit magnetically anchored on the abdominal wall. The camera could generate excellent image. with no instrument collisions.CONCLUSION The camera system we designed provides excellent optics and can be easily maneuvered. The number of conventional trocars is reduced without adding technical difficulties.展开更多
Divertor heat patterns induced by Lower Hybrid Current Drive （LHCD） L-mode plasmas are investigated using an infra-red （IR） camera system on an Experimental Advanced Superconducting Tokamak （EAST）. A two-dimensi...Divertor heat patterns induced by Lower Hybrid Current Drive （LHCD） L-mode plasmas are investigated using an infra-red （IR） camera system on an Experimental Advanced Superconducting Tokamak （EAST）. A two-dimensional finite element analysis code DFlux is used to compute heat flux along the poloidal divertor target and corresponding quantities. Outside the Origin Strike Zone （OSZ）, a Second Peak Heat Flux （SPHF） zone, where the heat flux is even stronger than that at the OSZ, appears on the lower-outer （LO） divertor plates with LHCD and disappears immediately after switching off the LHCD. The main heat-flux shifts from the SPHF zone towards the OSZ when the divertor configuration converts from double null to lower single null, indicating that the growth of the SPHF zone is apparently affected by a plasma magnetic configuration. The heat patterns on the LO divertor plates are observed to be different from that on the lower-inner （LI） targets as the SPHF zone appears only on the LO divertor target. It is also found that the heat flux at the SPHF zone was obviously enhanced after the Supersonic Molecule Beam Injection （SMBI） pulse.展开更多
A control model of binocular vergence eye movements is presented. The control model can reduce blind areas caused by the double cameras in motion platform. In order to validate the model performance, an experimental p...A control model of binocular vergence eye movements is presented. The control model can reduce blind areas caused by the double cameras in motion platform. In order to validate the model performance, an experimental platform and its control system based on TMS320LF2407 are designed. The control system has its compacted configuration and high reliability. The simulation and experimental results show that the control system can realize binocular vergence movements. Compared with the conventional moving double cameras system, this new system can considerably reduce blind areas.展开更多
This paper designs and implements a single-camera 360°panoramic imaging system based on motor-driven fisheye rotation.The system utilizes a stepper motor for precise angular control,enabling the camera to rotate ...This paper designs and implements a single-camera 360°panoramic imaging system based on motor-driven fisheye rotation.The system utilizes a stepper motor for precise angular control,enabling the camera to rotate around its optical center to capture multi-view images,thereby avoiding the parallax and geometric mismatch problems inherent in traditional multi-camera configurations.To address the strong distortion characteristics of fisheye images,an equidistant projection model is adopted for distortion correction.On this basis,a brightness normalization method combining global linear brightness correction and local illumination compensation is proposed to enhance stitching consistency.By establishing a geometry model constrained by camera rotation and integrating cylindrical projection with cosine-weighted blending,the system achieves high-precision panoramic stitching and seamless visual transitions.展开更多
Closed thoracic drainage can be performed using a steel-needle-guided chest tube to treat pleural effusion or pneumothorax in clinics.However,the puncture procedure during surgery is invisible,increasing the risk of s...Closed thoracic drainage can be performed using a steel-needle-guided chest tube to treat pleural effusion or pneumothorax in clinics.However,the puncture procedure during surgery is invisible,increasing the risk of surgical failure.Therefore,it is necessary to design a visualization system for closed thoracic drainage.Augmented reality(AR)technology can assist in visualizing the internal anatomical structure and determining the insertion point on the body surface.The structure of the currently used steel-needle-guided chest tube was modified by integrating it with an ultrafine diameter camera to provide real-time visualization of the puncture process.After simulation experiments,the overall registration error of the AR method was measured to be within(3.59±0.53)mm,indicating its potential for clinical application.The ultrafine diameter camera module and improved steel-needle-guided chest tube can timely reflect the position of the needle tip in the human body.A comparative experiment showed that video guidance could improve the safety of the puncture process compared to the traditional method.Finally,a qualitative evaluation of the usability of the system was conducted through a questionnaire.This system facilitates the visualization of closed thoracic drainage puncture procedure and pro-vides an implementation scheme to enhance the accuracy and safety of the operative step,which is conducive to reducing the learning curve and improving the proficiency of the doctors.展开更多
In this paper, a new CCD camera system used in the OTR beam measurement is presented, the basic principle of OTR beam measurement and the application of CCD chips-ICX208CL and AD9929 in camera system design are introd...In this paper, a new CCD camera system used in the OTR beam measurement is presented, the basic principle of OTR beam measurement and the application of CCD chips-ICX208CL and AD9929 in camera system design are introduced in detail.展开更多
This study introduces the new results of a novel low-cost digital zenith camera system operated in Turkey that uses astronomical and geodetic instrumentation.Currently,it is possible to determine deflections of the ve...This study introduces the new results of a novel low-cost digital zenith camera system operated in Turkey that uses astronomical and geodetic instrumentation.Currently,it is possible to determine deflections of the vertical(DoV)components by using a vast amount of information gathered from geo-referenced star images,tilt measurements,and Global Navigation Satellite System technology.This new design of an astro-geodetic camera system is used for calculating DoV components with 12 independent solutions on a test station in Istanbul,and additional observations were performed to investigate the external accuracy of the system on a test network.A specific leveling method is developed to align system toward the zenithal direction.The final results of the observations on a test station located in Istanbul indicate that the accuracy of the system is about±0.19 arc-seconds in latitude and±0.28 arc-seconds in longitude determination.The system has been further tested on a network with 4 control points that have averagely 20 km baselines.At the test network,the root mean square of the average value of the vertical deflections is calculated as±0.36 arc-seconds.Furthermore,DoV components are compared with the values that are calculated using global geopotential models.展开更多
This paper seeks to determine how the overlap of several infrared beams affects the tracked position of the user, depending on the angle of incidence of light, distance to the target, distance between sensors, and the...This paper seeks to determine how the overlap of several infrared beams affects the tracked position of the user, depending on the angle of incidence of light, distance to the target, distance between sensors, and the number of capture devices used. We also try to show that under ideal conditions using several Kinect sensors increases the precision of the data collected. The results obtained can be used in the design of telerehabilitation environments in which several RGB-D cameras are needed to improve precision or increase the tracking range. A numerical analysis of the results is included and comparisons are made with the results of other studies. Finally, we describe a system that implements intelligent methods for the rehabilitation of patients based on the results of the tests carried out.展开更多
During the discharging of Tokamak devices, interactions between the core plasma and plasma-facing components (PFCs) may cause exorbitant heat deposition in the latter. This poses a grave threat to the lifetimes of PFC...During the discharging of Tokamak devices, interactions between the core plasma and plasma-facing components (PFCs) may cause exorbitant heat deposition in the latter. This poses a grave threat to the lifetimes of PFCs materials. An infrared (IR) diagnostic system consisting of an IR camera and an endoscope was installed on an Experimental Advanced Superconducting Tokamak (EAST) to monitor the surface temperature of the lower divertor target plate (LDTP) and to calculate the corresponding heat flux based on its surface temperature and physical structure, via the finite element method. First, the temperature obtained by the IR camera was calibrated against the temperature measured by the built-in thermocouple of EAST under baking conditions to determine the true temperature of the LDTP. Next, based on the finite element method, a target plate model was built and a discretization of the modeling domain was carried out. Then, a heat conduction equation and boundary conditions were determined. Finally, the heat flux was calculated. The new numerical tool provided results similar to those for DFLUX;this is important for future work on related physical processes and heat flux control.展开更多
We develop and build a new type of inspection car.A beam that is not rigidly connected to the train axle boxes and can absorb the vibration and impact caused by the high speed train is used,and a laser-camera measurem...We develop and build a new type of inspection car.A beam that is not rigidly connected to the train axle boxes and can absorb the vibration and impact caused by the high speed train is used,and a laser-camera measurement system based on the machine vision method is adopted.This method projects structural light onto the track and measures gauge and longitudinal irregularity.The measurement principle and model are discussed.Through numerous practical experiments,the rebuilt car is found to considerably eliminate the measurement errors caused by vibration and impact,thereby increasing measurement stability under high speeds.This new kind of inspection cars have been used in several Chinese administration bureaus.展开更多
Camera calibration is a critical process in photogrammetry and a necessary step to acquire 3D information from a 2D image. In this paper, a flexible approach for CCD camera calibration using 2D direct linear transform...Camera calibration is a critical process in photogrammetry and a necessary step to acquire 3D information from a 2D image. In this paper, a flexible approach for CCD camera calibration using 2D direct linear transformation （DLT） and bundle adjustment is proposed. The proposed approach assumes that the camera interior orientation elements are known, and addresses a new closed form solution in planar object space based on homogenous coordinate representation and matrix factorization. Homogeneous coordinate representation offers a direct matrix correspondence between the parameters of the 2D DLT and the collinearity equation. The matrix factorization starts by recovering the elements of the rotation matrix and then solving for the camera position with the collinearity equation. Camera calibration with high precision is addressed by bundle adjustment using the initial values of the camera orientation elements. The results show that the calibration precision of principal point and focal length is about 0.2 and 0.3 pixels respectivelv, which can meet the requirements of close-range photogrammetry with high accuracy.展开更多
Quality control of Gamma Camera with SPECT System is highly valuable for assurance performance characteristic. We report the performance characteristic of gamma camera by intrinsic calibration and verification measure...Quality control of Gamma Camera with SPECT System is highly valuable for assurance performance characteristic. We report the performance characteristic of gamma camera by intrinsic calibration and verification measurement. The study has been done using the data from Siemens Symbia S Series gamma camera by using a point source 99mTc at the Institute of Nuclear Medicine & Allied Sciences (INMAS), Khulna, Bangladesh. From intrinsic calibration and verification flood series, the integral uniformity for the central field of view (CFOV) has been found in between 4.01% and 2.88% and for the useful field of view (UFOV) has been in between 4.77% and 4.30%. The differential uniformity for the CFOV has been in between 1.53% and 2.04% and for the UFOV has been in between 2.32% and 2.77%. According to Operating Instruction Symbia System S Series manual, uniformity can compensate for values exceeding 10%, however while integral uniformity exceed 7%, have to contract Siemens customer service representative. In conclusion, these results show that the intrinsic uniformity of the gamma camera under this condition is within an acceptable range;thus the gamma camera working in INMAS is performed well.展开更多
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(...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 colliders.An 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.展开更多
Inspired by box jellyfish that has distributed and complementary perceptive system,we seek to equip manipulator with a camera and an Inertial Measurement Unit(IMU)to perceive ego motion and surrounding unstructured en...Inspired by box jellyfish that has distributed and complementary perceptive system,we seek to equip manipulator with a camera and an Inertial Measurement Unit(IMU)to perceive ego motion and surrounding unstructured environment.Before robot perception,a reliable and high-precision calibration between camera,IMU and manipulator is a critical prerequisite.This paper introduces a novel calibration system.First,we seek to correlate the spatial relationship between the sensing units and manipulator in a joint framework.Second,the manipulator moving trajectory is elaborately designed in a spiral pattern that enables full excitations on yaw-pitch-roll rotations and x-y-z translations in a repeatable and consistent manner.The calibration has been evaluated on our collected visual inertial-manipulator dataset.The systematic comparisons and analysis indicate the consistency,precision and effectiveness of our proposed calibration method.展开更多
A tangential fast visible camera has been set up in EAST tokamak for the study of edge MHD instabilities such as ELM. To determine the 3-D information from CCD images, Tsai＇s two-stage technique was utilized to calib...A tangential fast visible camera has been set up in EAST tokamak for the study of edge MHD instabilities such as ELM. To determine the 3-D information from CCD images, Tsai＇s two-stage technique was utilized to calibrate the high-speed camera imaging system for ELM study. By applying tiles of the passive stabilizers in the tokamak device as the calibration pattern, transformation parameters for transforming from a 3-D world coordinate system to a 2-D image coordinate system were obtained, including the rotation matrix, the translation vector, the focal length and the lens distortion. The calibration errors were estimated and the results indicate the reliability of the method used for the camera imaging system. Through the calibration, some information about ELM filaments, such as positions and velocities were obtained from images of H-mode CCD videos.展开更多
The performance of decoding algorithm is one of the important influential factors to determine the communication quality of optical camera communication(OCC) system. In this paper, we first propose a decoding algorith...The performance of decoding algorithm is one of the important influential factors to determine the communication quality of optical camera communication(OCC) system. In this paper, we first propose a decoding algorithm with adaptive thresholding based on the captured pixel values under an ideal environment, and then we further propose a decoding algorithm with multiple features, which is more suitable under the existence of the interference of light sources. The algorithm firstly determines the light-emitting diode(LED) array profile information by removing the interfering light sources through geometric features, and then identifies the LED state by calculating two grayscale features, the average gray ratio(AGR) and the gradient radial inwardness(GRI) of the LEDs, and finally obtains the LED state matrix. The experimental results show that the bit error ratio(BER) of the decoding algorithm with multiple features decreases from 1×10^(-2) to 5×10^(-4) at 80 m.展开更多
Accurate vehicle localization is a key technology for autonomous driving tasks in indoor parking lots,such as automated valet parking.Additionally,infrastructure-based cooperative driving systems have become a means t...Accurate vehicle localization is a key technology for autonomous driving tasks in indoor parking lots,such as automated valet parking.Additionally,infrastructure-based cooperative driving systems have become a means to realizing intelligent driving.In this paper,we propose a novel and practical vehicle localization system using infrastructure-based RGB-D cameras for indoor parking lots.In the proposed system,we design a depth data preprocessing method with both simplicity and efficiency to reduce the computational burden resulting from a large amount of data.Meanwhile,the hardware synchronization for all cameras in the sensor network is not implemented owing to the disadvantage that it is extremely cumbersome and would significantly reduce the scalability of our system in mass deployments.Hence,to address the problem of data distortion accompanying vehicle motion,we propose a vehicle localization method by performing template point cloud registration in distributed depth data.Finally,a complete hardware system was built to verify the feasibility of our solution in a real-world environment.Experiments in an indoor parking lot demonstrated the effectiveness and accuracy of the proposed vehicle localization system,with a maximum root mean squared error of 5 cm at 15Hz compared with the ground truth.展开更多
A Projector-camera （Procam） system is an inexpensive, household, controllable system that can be used to eliminate inter-reflection existing in the measurement. We propose an estimation method for spectral reflectan...A Projector-camera （Procam） system is an inexpensive, household, controllable system that can be used to eliminate inter-reflection existing in the measurement. We propose an estimation method for spectral reflectance that uses the Procam system. The method recovers reflectance from the training set constructed by a known reflectance and the corresponding 9D color-mixing matrix. Experiment results show that our method performs well with 9D response, and the local weighted training set based on Mahalanobis metric can enhance the accuracy of result efficiently.展开更多
Instead of traditionally using a 3D physical model with many control points on it, a calibration plate with printed chess grid and movable along its normal direction is implemented to provide large area 3D control poi...Instead of traditionally using a 3D physical model with many control points on it, a calibration plate with printed chess grid and movable along its normal direction is implemented to provide large area 3D control points with variable Z values. Experiments show that the approach presented is effective for reconstructing 3D color objects in computer vision system.展开更多
With many advantages such as non-invasive,safe and quick effect,focused ultrasound lipolysis stands out among many fat-removing methods.However,during the whole process,the doctor needs to hold the ultrasound transduc...With many advantages such as non-invasive,safe and quick effect,focused ultrasound lipolysis stands out among many fat-removing methods.However,during the whole process,the doctor needs to hold the ultrasound transducer and press it on the patient’s skin with a large pressure for a long time;thus the probability of muscle and bone damage for doctors is greatly increased.To reduce the occurrence of doctors’occupational diseases,a depth camera-based ultrasonic lipolysis robot system is proposed to realize robot-assisted automatic ultrasonic lipolysis operation.The system is composed of RealSense depth camera,KUKA LBR Med seven-axis robotic arm,PC host,and ultrasonic lipolysis instrument.The whole operation includes two parts:preoperative planning and intraoperative operation.In preoperative planning,the treatment area is selected in the camera image by the doctor;then the system automatically plans uniformly distributed treatment points in the treatment area.At the same time,the skin normal vector is calculated to determine the end posture of the robot,so that the ultrasound transducer can be pressed down in the normal direction of skin.During the intraoperative operation,the robot is controlled to arrive at the treatment point in turn.Meanwhile,the patient’s movement can be detected by the depth camera,and the path of robot is adjusted in real time so that the robot can track the movement of patient,thereby ensuring the accuracy of the ultrasonic lipolysis operation.Finally,the human body model experiment is conducted.The results show that the maximum error of the robot operation is within 5mm,average error is 3.1mm,and the treatment points of the robot operation are more uniform than those of manual operation.Therefore,the system can replace the doctor and achieve autonomous ultrasonic lipolysis to reduce the doctor’s labor intensity.展开更多
基金Supported by National Natural Science Foundation of China(Major Instrumental Program)No.81127005the Science and Technology Innovation Project of Shaanxi Province,China,No.S2016TNGY0119
文摘AIM To design a miniature magnetically anchored and controlled camera system to reduce the number of trocars which are required for laparoscopy.METHODS The system consists of a miniature magnetically anchored camera with a 30° downward angle, an external magnetically anchored unit, and a vision output device. The camera weighs 12 g, measures Φ10.5 mm × 55 mm and has two magnets, a vision model, a light source, and a metal hexagonal nut. To test the prototype, the camera was inserted through a 12-mm conventional trocar in an ex vivo real liver laparoscopic training system. A trocar-less laparoscopic cholecystectomy was performed 6 times using a 12-mm and a 5-mm conventional trocar. In addition, the same procedure was performed in four canine models.RESULTS Both procedures were successfully performed using only two conventional laparoscopic trocars. The cholecystectomy was completed without any major complication in 42 min(38-45 min) in vitro and in 50 min(45-53 min) using an animal model. This camera was anchored and controlled by an external unit magnetically anchored on the abdominal wall. The camera could generate excellent image. with no instrument collisions.CONCLUSION The camera system we designed provides excellent optics and can be easily maneuvered. The number of conventional trocars is reduced without adding technical difficulties.
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2014GB101001 and 2014GB101002)
文摘Divertor heat patterns induced by Lower Hybrid Current Drive （LHCD） L-mode plasmas are investigated using an infra-red （IR） camera system on an Experimental Advanced Superconducting Tokamak （EAST）. A two-dimensional finite element analysis code DFlux is used to compute heat flux along the poloidal divertor target and corresponding quantities. Outside the Origin Strike Zone （OSZ）, a Second Peak Heat Flux （SPHF） zone, where the heat flux is even stronger than that at the OSZ, appears on the lower-outer （LO） divertor plates with LHCD and disappears immediately after switching off the LHCD. The main heat-flux shifts from the SPHF zone towards the OSZ when the divertor configuration converts from double null to lower single null, indicating that the growth of the SPHF zone is apparently affected by a plasma magnetic configuration. The heat patterns on the LO divertor plates are observed to be different from that on the lower-inner （LI） targets as the SPHF zone appears only on the LO divertor target. It is also found that the heat flux at the SPHF zone was obviously enhanced after the Supersonic Molecule Beam Injection （SMBI） pulse.
基金supported by the National Natural Science Foundation of China (Grant Nos.60605028, 50975168)National Hi-tech Research and Development Program of China (Grant Nos.2007AA04Z225, 2009AA04Z211)+1 种基金Program for Excellent Young Teachers of Shanghai (Grant Nos.07Q14024,07QH14006)Shuguang Program of Shanghai (Grant No.07SG47)
文摘A control model of binocular vergence eye movements is presented. The control model can reduce blind areas caused by the double cameras in motion platform. In order to validate the model performance, an experimental platform and its control system based on TMS320LF2407 are designed. The control system has its compacted configuration and high reliability. The simulation and experimental results show that the control system can realize binocular vergence movements. Compared with the conventional moving double cameras system, this new system can considerably reduce blind areas.
基金Graduate Innovation Ability Training Program of the Hebei Provincial Department of Education,2025(Project No.:CXZZSS2025095)。
文摘This paper designs and implements a single-camera 360°panoramic imaging system based on motor-driven fisheye rotation.The system utilizes a stepper motor for precise angular control,enabling the camera to rotate around its optical center to capture multi-view images,thereby avoiding the parallax and geometric mismatch problems inherent in traditional multi-camera configurations.To address the strong distortion characteristics of fisheye images,an equidistant projection model is adopted for distortion correction.On this basis,a brightness normalization method combining global linear brightness correction and local illumination compensation is proposed to enhance stitching consistency.By establishing a geometry model constrained by camera rotation and integrating cylindrical projection with cosine-weighted blending,the system achieves high-precision panoramic stitching and seamless visual transitions.
基金the Shanghai Municipal Education Commission-Gaofeng Clinical Medicine Grant(No.20172005)。
文摘Closed thoracic drainage can be performed using a steel-needle-guided chest tube to treat pleural effusion or pneumothorax in clinics.However,the puncture procedure during surgery is invisible,increasing the risk of surgical failure.Therefore,it is necessary to design a visualization system for closed thoracic drainage.Augmented reality(AR)technology can assist in visualizing the internal anatomical structure and determining the insertion point on the body surface.The structure of the currently used steel-needle-guided chest tube was modified by integrating it with an ultrafine diameter camera to provide real-time visualization of the puncture process.After simulation experiments,the overall registration error of the AR method was measured to be within(3.59±0.53)mm,indicating its potential for clinical application.The ultrafine diameter camera module and improved steel-needle-guided chest tube can timely reflect the position of the needle tip in the human body.A comparative experiment showed that video guidance could improve the safety of the puncture process compared to the traditional method.Finally,a qualitative evaluation of the usability of the system was conducted through a questionnaire.This system facilitates the visualization of closed thoracic drainage puncture procedure and pro-vides an implementation scheme to enhance the accuracy and safety of the operative step,which is conducive to reducing the learning curve and improving the proficiency of the doctors.
基金Supported by Major State Basic Besearch Development Program(2002CB713606)
文摘In this paper, a new CCD camera system used in the OTR beam measurement is presented, the basic principle of OTR beam measurement and the application of CCD chips-ICX208CL and AD9929 in camera system design are introduced in detail.
基金This project is supported by The Scientific and Technological Research Council of Turkey(TUBITAK)[grant number 111Y125].
文摘This study introduces the new results of a novel low-cost digital zenith camera system operated in Turkey that uses astronomical and geodetic instrumentation.Currently,it is possible to determine deflections of the vertical(DoV)components by using a vast amount of information gathered from geo-referenced star images,tilt measurements,and Global Navigation Satellite System technology.This new design of an astro-geodetic camera system is used for calculating DoV components with 12 independent solutions on a test station in Istanbul,and additional observations were performed to investigate the external accuracy of the system on a test network.A specific leveling method is developed to align system toward the zenithal direction.The final results of the observations on a test station located in Istanbul indicate that the accuracy of the system is about±0.19 arc-seconds in latitude and±0.28 arc-seconds in longitude determination.The system has been further tested on a network with 4 control points that have averagely 20 km baselines.At the test network,the root mean square of the average value of the vertical deflections is calculated as±0.36 arc-seconds.Furthermore,DoV components are compared with the values that are calculated using global geopotential models.
基金partially supported by Spanish Ministerio de Economía y Competitividad/FEDER(Nos.TIN2012-34003 and TIN2013-47074-C2-1-R)FPU Scholarship(FPU13/03141)from the Spanish Government
文摘This paper seeks to determine how the overlap of several infrared beams affects the tracked position of the user, depending on the angle of incidence of light, distance to the target, distance between sensors, and the number of capture devices used. We also try to show that under ideal conditions using several Kinect sensors increases the precision of the data collected. The results obtained can be used in the design of telerehabilitation environments in which several RGB-D cameras are needed to improve precision or increase the tracking range. A numerical analysis of the results is included and comparisons are made with the results of other studies. Finally, we describe a system that implements intelligent methods for the rehabilitation of patients based on the results of the tests carried out.
基金supported by the National Natural Science Foundation of China(Nos.51505120 and 11105028)the National Magnetic Confinement Fusion Science Program of China(No.2015GB102004)
文摘During the discharging of Tokamak devices, interactions between the core plasma and plasma-facing components (PFCs) may cause exorbitant heat deposition in the latter. This poses a grave threat to the lifetimes of PFCs materials. An infrared (IR) diagnostic system consisting of an IR camera and an endoscope was installed on an Experimental Advanced Superconducting Tokamak (EAST) to monitor the surface temperature of the lower divertor target plate (LDTP) and to calculate the corresponding heat flux based on its surface temperature and physical structure, via the finite element method. First, the temperature obtained by the IR camera was calibrated against the temperature measured by the built-in thermocouple of EAST under baking conditions to determine the true temperature of the LDTP. Next, based on the finite element method, a target plate model was built and a discretization of the modeling domain was carried out. Then, a heat conduction equation and boundary conditions were determined. Finally, the heat flux was calculated. The new numerical tool provided results similar to those for DFLUX;this is important for future work on related physical processes and heat flux control.
基金supported by the National "863" Program of China under Grant No.2009AA11Z102-1
文摘We develop and build a new type of inspection car.A beam that is not rigidly connected to the train axle boxes and can absorb the vibration and impact caused by the high speed train is used,and a laser-camera measurement system based on the machine vision method is adopted.This method projects structural light onto the track and measures gauge and longitudinal irregularity.The measurement principle and model are discussed.Through numerous practical experiments,the rebuilt car is found to considerably eliminate the measurement errors caused by vibration and impact,thereby increasing measurement stability under high speeds.This new kind of inspection cars have been used in several Chinese administration bureaus.
基金Project 2005A030 supported by the Youth Science and Research Foundation from China University of Mining & Technology
文摘Camera calibration is a critical process in photogrammetry and a necessary step to acquire 3D information from a 2D image. In this paper, a flexible approach for CCD camera calibration using 2D direct linear transformation （DLT） and bundle adjustment is proposed. The proposed approach assumes that the camera interior orientation elements are known, and addresses a new closed form solution in planar object space based on homogenous coordinate representation and matrix factorization. Homogeneous coordinate representation offers a direct matrix correspondence between the parameters of the 2D DLT and the collinearity equation. The matrix factorization starts by recovering the elements of the rotation matrix and then solving for the camera position with the collinearity equation. Camera calibration with high precision is addressed by bundle adjustment using the initial values of the camera orientation elements. The results show that the calibration precision of principal point and focal length is about 0.2 and 0.3 pixels respectivelv, which can meet the requirements of close-range photogrammetry with high accuracy.
文摘Quality control of Gamma Camera with SPECT System is highly valuable for assurance performance characteristic. We report the performance characteristic of gamma camera by intrinsic calibration and verification measurement. The study has been done using the data from Siemens Symbia S Series gamma camera by using a point source 99mTc at the Institute of Nuclear Medicine & Allied Sciences (INMAS), Khulna, Bangladesh. From intrinsic calibration and verification flood series, the integral uniformity for the central field of view (CFOV) has been found in between 4.01% and 2.88% and for the useful field of view (UFOV) has been in between 4.77% and 4.30%. The differential uniformity for the CFOV has been in between 1.53% and 2.04% and for the UFOV has been in between 2.32% and 2.77%. According to Operating Instruction Symbia System S Series manual, uniformity can compensate for values exceeding 10%, however while integral uniformity exceed 7%, have to contract Siemens customer service representative. In conclusion, these results show that the intrinsic uniformity of the gamma camera under this condition is within an acceptable range;thus the gamma camera working in INMAS is performed well.
文摘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 colliders.An 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.
基金supported by the National Natural Science Foundation of China(61903357,61902299,62022088)the International Partnership Program of Chinese Academy of Sciences(173321KYSB20200002)+2 种基金Liaoning Provincial Natural Science Foundation of China(2020-MS-032,2021JH6/10500114,2020JH2/10500002)Guangzhou Science and Technology Planning Project(202102021300)China Postdoctoral Science Foundation(2019TQ0239,2019M663636).
文摘Inspired by box jellyfish that has distributed and complementary perceptive system,we seek to equip manipulator with a camera and an Inertial Measurement Unit(IMU)to perceive ego motion and surrounding unstructured environment.Before robot perception,a reliable and high-precision calibration between camera,IMU and manipulator is a critical prerequisite.This paper introduces a novel calibration system.First,we seek to correlate the spatial relationship between the sensing units and manipulator in a joint framework.Second,the manipulator moving trajectory is elaborately designed in a spiral pattern that enables full excitations on yaw-pitch-roll rotations and x-y-z translations in a repeatable and consistent manner.The calibration has been evaluated on our collected visual inertial-manipulator dataset.The systematic comparisons and analysis indicate the consistency,precision and effectiveness of our proposed calibration method.
基金supported by National Natural Science Foundation of China(No.11275047)the National Magnetic Confinement Fusion Science Program of China(No.2013GB102000)
文摘A tangential fast visible camera has been set up in EAST tokamak for the study of edge MHD instabilities such as ELM. To determine the 3-D information from CCD images, Tsai＇s two-stage technique was utilized to calibrate the high-speed camera imaging system for ELM study. By applying tiles of the passive stabilizers in the tokamak device as the calibration pattern, transformation parameters for transforming from a 3-D world coordinate system to a 2-D image coordinate system were obtained, including the rotation matrix, the translation vector, the focal length and the lens distortion. The calibration errors were estimated and the results indicate the reliability of the method used for the camera imaging system. Through the calibration, some information about ELM filaments, such as positions and velocities were obtained from images of H-mode CCD videos.
基金supported by the Department of Science and Technology of Jilin Province (No.20200401122GX)。
文摘The performance of decoding algorithm is one of the important influential factors to determine the communication quality of optical camera communication(OCC) system. In this paper, we first propose a decoding algorithm with adaptive thresholding based on the captured pixel values under an ideal environment, and then we further propose a decoding algorithm with multiple features, which is more suitable under the existence of the interference of light sources. The algorithm firstly determines the light-emitting diode(LED) array profile information by removing the interfering light sources through geometric features, and then identifies the LED state by calculating two grayscale features, the average gray ratio(AGR) and the gradient radial inwardness(GRI) of the LEDs, and finally obtains the LED state matrix. The experimental results show that the bit error ratio(BER) of the decoding algorithm with multiple features decreases from 1×10^(-2) to 5×10^(-4) at 80 m.
基金the National Natural Science Foundation of China(No.62173228)。
文摘Accurate vehicle localization is a key technology for autonomous driving tasks in indoor parking lots,such as automated valet parking.Additionally,infrastructure-based cooperative driving systems have become a means to realizing intelligent driving.In this paper,we propose a novel and practical vehicle localization system using infrastructure-based RGB-D cameras for indoor parking lots.In the proposed system,we design a depth data preprocessing method with both simplicity and efficiency to reduce the computational burden resulting from a large amount of data.Meanwhile,the hardware synchronization for all cameras in the sensor network is not implemented owing to the disadvantage that it is extremely cumbersome and would significantly reduce the scalability of our system in mass deployments.Hence,to address the problem of data distortion accompanying vehicle motion,we propose a vehicle localization method by performing template point cloud registration in distributed depth data.Finally,a complete hardware system was built to verify the feasibility of our solution in a real-world environment.Experiments in an indoor parking lot demonstrated the effectiveness and accuracy of the proposed vehicle localization system,with a maximum root mean squared error of 5 cm at 15Hz compared with the ground truth.
基金supported by the National Basic Research Program of China(No.2012CB725305)the National Natural Science Foundation of China(No.61003146)
文摘A Projector-camera （Procam） system is an inexpensive, household, controllable system that can be used to eliminate inter-reflection existing in the measurement. We propose an estimation method for spectral reflectance that uses the Procam system. The method recovers reflectance from the training set constructed by a known reflectance and the corresponding 9D color-mixing matrix. Experiment results show that our method performs well with 9D response, and the local weighted training set based on Mahalanobis metric can enhance the accuracy of result efficiently.
基金Supported by the Natural Science Foundation of China (69775022)the State High-Technology Development program of China(863 306ZT04 06 3)
文摘Instead of traditionally using a 3D physical model with many control points on it, a calibration plate with printed chess grid and movable along its normal direction is implemented to provide large area 3D control points with variable Z values. Experiments show that the approach presented is effective for reconstructing 3D color objects in computer vision system.
基金the National Natural Science Foundation of China(Nos.61973211,51911540479 and M-0221)the Research Project of Institute of Medical Robotics of Shanghai Jiao Tong Universitythe Project of Science and Technology Commission of Shanghai Municipality(No.20DZ2220400)。
文摘With many advantages such as non-invasive,safe and quick effect,focused ultrasound lipolysis stands out among many fat-removing methods.However,during the whole process,the doctor needs to hold the ultrasound transducer and press it on the patient’s skin with a large pressure for a long time;thus the probability of muscle and bone damage for doctors is greatly increased.To reduce the occurrence of doctors’occupational diseases,a depth camera-based ultrasonic lipolysis robot system is proposed to realize robot-assisted automatic ultrasonic lipolysis operation.The system is composed of RealSense depth camera,KUKA LBR Med seven-axis robotic arm,PC host,and ultrasonic lipolysis instrument.The whole operation includes two parts:preoperative planning and intraoperative operation.In preoperative planning,the treatment area is selected in the camera image by the doctor;then the system automatically plans uniformly distributed treatment points in the treatment area.At the same time,the skin normal vector is calculated to determine the end posture of the robot,so that the ultrasound transducer can be pressed down in the normal direction of skin.During the intraoperative operation,the robot is controlled to arrive at the treatment point in turn.Meanwhile,the patient’s movement can be detected by the depth camera,and the path of robot is adjusted in real time so that the robot can track the movement of patient,thereby ensuring the accuracy of the ultrasonic lipolysis operation.Finally,the human body model experiment is conducted.The results show that the maximum error of the robot operation is within 5mm,average error is 3.1mm,and the treatment points of the robot operation are more uniform than those of manual operation.Therefore,the system can replace the doctor and achieve autonomous ultrasonic lipolysis to reduce the doctor’s labor intensity.
