In this study,we concluded the Hamiltonian equations on(M3,φ,ξ,η,g𝑔),being a model.Finally introduce,some geometrical and physical results on the related mechanic systems have been discussed.
An automatic three-dimensional(3D) reconstruction method based on four-view stereo vision using checkerboard pattern is presented. Mismatches easily exist in traditional binocular stereo matching due to the repeatable...An automatic three-dimensional(3D) reconstruction method based on four-view stereo vision using checkerboard pattern is presented. Mismatches easily exist in traditional binocular stereo matching due to the repeatable or similar features of binocular images. In order to reduce the probability of mismatching and improve the measure precision, a four-camera measurement system which can add extra matching constraints and offer multiple measurements is applied in this work. Moreover, a series of different checkerboard patterns are projected onto the object to obtain dense feature points and remove mismatched points. Finally, the 3D model is generated by performing Delaunay triangulation and texture mapping on the point cloud obtained by four-view matching. This method was tested on the 3D reconstruction of a terracotta soldier sculpture and the Buddhas in the Mogao Grottoes. Their point clouds without mismatched points were obtained and less processing time was consumed in most cases relative to binocular matching. These good reconstructed models show the effectiveness of the method.展开更多
This paper describes specific constraints of vision systems that are dedicated to be embedded in mobile robots. If PC-based hardware architecture is convenient in this field because of its versatility, flexibility, pe...This paper describes specific constraints of vision systems that are dedicated to be embedded in mobile robots. If PC-based hardware architecture is convenient in this field because of its versatility, flexibility, performance, and cost, current real-time operating systems are not completely adapted to long processing with varying duration, and it is often necessary to oversize the system to guarantee fail-safe functioning. Also, interactions with other robotic tasks having more priority are difficult to handle. To answer this problem, we have developed a dynamically reconfigurable vision processing system, based on the innovative features of Cleopatre real-time applicative layer concerning scheduling and fault tolerance. This framework allows to define emergency and optional tasks to ensure a minimal quality of service for the other subsystems of the robot, while allowing to adapt dynamically vision processing chain to an exceptional overlasting vision process or processor overload. Thus, it allows a better cohabitation of several subsystems in a single hardware, and to develop less expensive but safe systems, as they will be designed for the regular case and not rare exceptional ones. Finally, it brings a new way to think and develop vision systems, with pairs of complementary operators.展开更多
Stereoscopic three-dimensional echocardiography（S-3DE） is a novel displaying technol-ogy based on real-time 3-dimensional echocardiography （RT-3DE）. Our study was to evaluate the feasibility and efficiency of S-3D...Stereoscopic three-dimensional echocardiography（S-3DE） is a novel displaying technol-ogy based on real-time 3-dimensional echocardiography （RT-3DE）. Our study was to evaluate the feasibility and efficiency of S-3DE in the diagnosis of atrial septal defect （ASD） and its use in the guidance for transcatheter ASD occlusion. Twelve patients with secundum ASD underwent RT-3DE examination and 9 of the 12 were subjected to transcatheter closure of ASD. Stereoscopic vision was generated with a high-performance volume renderer with red-green stereoscopic glasses. S-3DE was compared with standard RT-3D display for the assessment of the shape, size, and the surrounding tis-sues of ASD and for the guidance of ASD occlusion. The appearance rate of coronary sinus and the mean formation time of the IVC, SVC were compared. Our results showed that S-3DE could measure the diameter of ASD accurately and there was no significant difference in the measurements between S-3DE and standard 3D display （2.89±0.73 cm vs 2.85±0.72 cm, P〉0.05; r=0.96, P〈0.05）. The appearance of coronary sinus for S-3DE was higher as compared with the standard 3D display （93.3% vs 100%）. The mean time of the IVC, SVC for S-3DE monitor was slightly shorter than that of the standard 3D display （11.0±3.8 s vs 10.3±3.6 s, P〉0.05）. The mean completion time of interven-tional procedure was shortened with S-3DE display as compared with standard 3D display （17.3±3.1 min vs 23.0±3.9 min, P〈0.05）. Stereoscopic three-dimensional echocardiography could improve the visualization of three-dimensional echocardiography, facilitate the identification of the adjacent structures, decrease the time required for interventional manipulation. It may be a feasible, safe, and efficient tool for guiding transcatheter septal occlusion or the surgical interventions.展开更多
Multi-sensor vision system plays an important role in the 3D measurement of large objects.However,due to the widely distribution of sensors,the problem of lacking common fields of view（FOV） arises frequently,which m...Multi-sensor vision system plays an important role in the 3D measurement of large objects.However,due to the widely distribution of sensors,the problem of lacking common fields of view（FOV） arises frequently,which makes the global calibration of the vision system quite difficult.The primary existing solution relies on large-scale surveying equipments,which is ponderous and inconvenient for field calibrations.In this paper,a global calibration method of multi-sensor vision system is proposed and investigated.The proposed method utilizes pairs of skew laser lines,which are generated by a group of laser pointers,as the calibration objects.Each pair of skew laser lines provides a unique coordinate system in space which can be reconstructed in certain vision sensor＇s coordinates by using a planar pattern.Then the geometries of sensors are computed under rigid transformation constrains by taking coordinates of each skew lines pair as the intermediary.The method is applied on both visual cameras with synthetic data and a real two-camera vision system;results show the validity and good performance.The prime contribution of this paper is taking skew laser lines as the global calibration objects,which makes the method simple and flexible.The method need no expensive equipments and can be used in large-scale calibration.展开更多
Based on the characteristics of line structured light sensor, a speedy method for the calibration was established. With the coplanar reference target, the spacial pose between camera and optical plane can be calibrate...Based on the characteristics of line structured light sensor, a speedy method for the calibration was established. With the coplanar reference target, the spacial pose between camera and optical plane can be calibrated by using of the camera’s projective center and the light’s information in the camera’s image surface. Without striction to the movement of the coplanar reference target and assistant adjustment equipment, this calibration method can be implemented. This method has been used and decreased the cost of calibration equipment, simplified the calibration procedure, improved calibration efficiency. Using experiment, the sensor can attain relative accuracy about 0.5%, which indicates the rationality and effectivity of this method.展开更多
To assess functional outcomes of optical low vision aids(LVAs) for pediatric visual impairment due to central nervous system(CNS) tumors. A prospective case study was conducted on 15 children with history of CNS tumor...To assess functional outcomes of optical low vision aids(LVAs) for pediatric visual impairment due to central nervous system(CNS) tumors. A prospective case study was conducted on 15 children with history of CNS tumors with mean age of 10.47±1.85 y. Lighthouse distance, near visual acuity tests, cycloplegic refraction, reading speed measurement and visual field examination were done. Prescription of far and near LVAs followed by training sessions. LVPrasad-functional vision questionnaire was done to evaluate performance. Visual impairment was moderate(13.3%), severe(73.3%), profound(6.7%) and near blindness in 6.7%. Telescopes prescribed in 33.4%, video magnifier in 46.7%. Questionnaire scores were significantly improved for distant rather than near tasks(P≤0.05) after training. LVAs rehabilitation is an effective method of improving vision in pediatric visual defects secondary to CNS tumors.展开更多
The fast paced nature of robotic soccer necessitates real time sensing coupled with quick behaving and decision making. In the field with real robots, it is important to well perceive the location of ball, team robots...The fast paced nature of robotic soccer necessitates real time sensing coupled with quick behaving and decision making. In the field with real robots, it is important to well perceive the location of ball, team robots and opponent robots through the vision system in real time. In this paper the architecture of global vision system of our small size robotic team and the process of object recognition is described. According to the study on color distribution in different color space and quantitative investigation, a method which uses H (Hue) thresholds as the major thresholds to feature exact and recognize object in real time is presented.展开更多
This paper establishes two theorems for two time-delayed （chaotic） discrete systems to achieve timedelayed generalized synchronization （TDGS）. These two theorems uncover the genera/forms of two TDGS systems via a ...This paper establishes two theorems for two time-delayed （chaotic） discrete systems to achieve timedelayed generalized synchronization （TDGS）. These two theorems uncover the genera/forms of two TDGS systems via a prescribed transformation. As examples, we convert the Lorenz three-dimensional chaotic map to an equal time-delayed system as the driving system, and construct the TDGS driven systems according to the Theorems 1 and 2. Numerical simulations demonstrate the effectiveness of the proposed theorems.展开更多
Building fences to manage the cattle grazing can be very expensive;cost inefficient. These do not provide dynamic control over the area in which the cattle are grazing. Existing virtual fencing techniques for the cont...Building fences to manage the cattle grazing can be very expensive;cost inefficient. These do not provide dynamic control over the area in which the cattle are grazing. Existing virtual fencing techniques for the control of herds of cattle, based on polygon coordinate definition of boundaries is limited in the area of land mass coverage and dynamism. This work seeks to develop a more robust and an improved monocular vision based boundary avoidance for non-invasive stray control system for cattle, with a view to increase land mass coverage in virtual fencing techniques and dynamism. The monocular vision based depth estimation will be modeled using concept of global Fourier Transform (FT) and local Wavelet Transform (WT) of image structure of scenes (boundaries). The magnitude of the global Fourier Transform gives the dominant orientations and textual patterns of the image;while the local Wavelet Transform gives the dominant spectral features of the image and their spatial distribution. Each scene picture or image is defined by features v, which contain the set of global (FT) and local (WT) statistics of the image. Scenes or boundaries distances are given by estimating the depth D by means of the image features v. Sound cues of intensity equivalent to the magnitude of the depth D are applied to the animal ears as stimuli. This brings about the desired control as animals tend to move away from uncomfortable sounds.展开更多
Through the study of mutual process between groundwater systems and eco-environmental water demand, the eco-environmental water demand is brought into groundwater systems model as the important water consumption item ...Through the study of mutual process between groundwater systems and eco-environmental water demand, the eco-environmental water demand is brought into groundwater systems model as the important water consumption item and unification of groundwater抯 economic, environmental and ecological functions were taken into account. Based on eco-environmental water demand at Da抋n in Jilin province, a three-dimensional simulation and optimized management model of groundwater systems was established. All water balance components of groundwater systems in 1998 and 1999 were simulated with this model and the best optimal exploitation scheme of groundwater systems in 2000 was determined, so that groundwater resource was efficiently utilized and good economic, ecologic and social benefits were obtained.展开更多
A three-dimensional stabilization problem for underactuated autonomous underwater vehicles(AUVs)is addressed in this paper.A novel coordinate transformation form consisting of state modifications and input transformat...A three-dimensional stabilization problem for underactuated autonomous underwater vehicles(AUVs)is addressed in this paper.A novel coordinate transformation form consisting of state modifications and input transformations is introduced such that the whole system is divided into two decoupled one-order subsystems.Some switching functions are presented to further decouple the underactuated dynamics and to produce persistently exciting(PE)signals for those underactuated states.Based on the aforementioned results,a quite simple control law is designed to achieve global three-dimensional asymptotic convergence of all states of underactuated AUVs.Comparative simulations are carried out to validate the effectiveness and performance of the proposed control scheme.展开更多
In order to satisfy the requirements of UAV’s aerial safety monitoring and surveillance of sensitive areas,a robust vision system for the rotor UAV is designed and implemented,which includes visual airborne subsystem...In order to satisfy the requirements of UAV’s aerial safety monitoring and surveillance of sensitive areas,a robust vision system for the rotor UAV is designed and implemented,which includes visual airborne subsystem,ground station subsystem and wireless communication subsystem.Complete sky-ground and human-computer interaction loops are constructed.Based on the developed UAV vision platform,a real-time target tracking algorithm under the mean shift tracking framework is developed.The joint color-texture histogram is used to represent the target robustly.With the help of moment information,the scale and the orientation of the tracked target is estimated adaptively during the tracking process.A model updating scheme for the target and the background is introduced to reduce the interferences from background and the locating biases.Numerical simulation and real flight tracking experiments demonstrate that the overall visual tracking system is effective and has superior performance against several state-of-the-art algorithms.展开更多
Archaeological excavation involves disintegration, removal, and reassembly of the archaeological record;as such it is considered by many to be an unrepeatable, destructive activity. This perception has contributed to ...Archaeological excavation involves disintegration, removal, and reassembly of the archaeological record;as such it is considered by many to be an unrepeatable, destructive activity. This perception has contributed to an advancement in archaeological practice, namely, the development of computerized recording systems that digitally record archaeological excavations spatially and volumetrically during fieldwork. This paper is concerned with those archaeological sites where digital field recording has not been done. These sites, recorded by traditional methods, should not be excluded from attempts to restructure the spatial, volumetric, and stratigraphic archaeological data. A thorough methodology for the conversion of traditional records into digitized data is presented, including the detailed procedures required for three-dimensional plotting of recorded data—both the excavated material and the drawn site maps and cross-sections. Finally, the use of these methods is demonstrated on a complex Early to Middle Pleistocene site, illustrating the benefits of digitization and three-dimensional reconstruction in resolving stratigraphic and spatial questions.展开更多
EyeScreen is a vision-based interaction system which provides a natural gesture interface for humancomputer interaction （HCI） by tracking human fingers and recognizing gestures. Multi-view video images are captured ...EyeScreen is a vision-based interaction system which provides a natural gesture interface for humancomputer interaction （HCI） by tracking human fingers and recognizing gestures. Multi-view video images are captured by two cameras facing a computer screen, which can be used to detect clicking actions of a fingertip and improve the recognition rate. The system enables users to directly interact with rendered objects on the screen. Robustness of the system has been verified by extensive experiments with different user scenarios. EyeScreen can be used in many applications such as intelligent interaction and digital entertainment.展开更多
Cold Workability limits of Brass were studied as a function of friction, aspect ratio and specimen geometry. Five standard shapes of the axis symmetric specimens of cylindrical with aspect ratios 1.0 and 1.5, ring, ta...Cold Workability limits of Brass were studied as a function of friction, aspect ratio and specimen geometry. Five standard shapes of the axis symmetric specimens of cylindrical with aspect ratios 1.0 and 1.5, ring, tapered and flanged were selected for the present investigation. Specimens were deformed in compression between two flat platens to predict the metal flow at room temperature. The longitudinal and oblique cracks were obtained as the two major modes of surface fractures. Cylindrical and ring specimen shows the oblique surface crack while the tapered and flanged shows the longitudinal crack. Machine Vision system using PC based video recording with a CCD camera was used to analyze the deformation of 4 X 4 mm square grid marked at mid plane of the specimen. The strain paths obtained from different specimens exhibited nonlinearity from the beginning to the end of the strain path. The circumferential stress component Os increasingly becomes tensile with continued deformation. On the other hand the axial stress Oz , increased in the very initial stages of deformation but started becoming less compressive immediately as barreling develops. The nature of hydrostatic stress on the rim of the flanged specimen was found to be tensile. Finite element software ANSYS has been applied for the analysis of the upset forming process. When the stress values obtained from finite element analysis were compared to the measurements of grids using Machine Vision system it was found that they were in close proximity.展开更多
Pixel-parallel PE and SIMD architectures are widely used in high-speed image processing to enhance computing power. With fully exploiting the data level parallelism of low- and middle-level image processing, SIMD arch...Pixel-parallel PE and SIMD architectures are widely used in high-speed image processing to enhance computing power. With fully exploiting the data level parallelism of low- and middle-level image processing, SIMD architecture is able to finish great amount of computation with much less instruction cycle thus satisfy the high-speed system requirement. The main computation parts in those SIMD image processing hardware is known as PE (processing element) and it is responsible for transferring, storing and processing the image data. This paper describes a high-speed vision system with superscalar PE to enhance system performance and its dedicated parallel computing language specifically devel-oped for this vision system. The vision system can achieve motion detection at more than 2000fps and face detection at more than 100 fps which overwhelms some general serial CPUs in the same applications.展开更多
目的 探讨基于Vision-LSTM的人工智能(artificial intelligence,AI)技术对甲状腺影像报告与数据系统4b (Thyroid Imaging Reporting and Data System Category 4b,TI-RADS 4b)类甲状腺结节的超声诊断准确性,评估其辅助临床决策的可行性...目的 探讨基于Vision-LSTM的人工智能(artificial intelligence,AI)技术对甲状腺影像报告与数据系统4b (Thyroid Imaging Reporting and Data System Category 4b,TI-RADS 4b)类甲状腺结节的超声诊断准确性,评估其辅助临床决策的可行性。方法 收集我院401例TI-RADS 4b类甲状腺结节的超声影像数据,并利用这些数据对Vision-LSTM模型进行训练和验证。将AI模型的诊断结果与初级医生及高级医生的诊断结果进行对比,评估其在诊断准确性、稳定性等方面的表现;采用曲线下面积(area under the curve,AUC)、精确率-召回率(precision-recall,PR)曲线等指标对模型性能进行量化分析。结果 在独立验证中,Vision-LSTM模型的AUC(0.88)与准确率(89.4%)均显著高于初级医生(AUC:0.624),并达到与高级医生(AUC:0.787)相当的水平,证明了其辅助诊断的应用潜力。AI模型能够准确识别超声影像中的复杂特征,稳定输出一致的诊断结果,展现出较高的准确性和可靠性。结论 基于Vision-LSTM模型的AI技术可显著提升TI-RADS 4b类甲状腺结节的诊断效率与准确性,为医生提供有效辅助,减轻工作负担。展开更多
Recent advancements in autonomous vehicle technologies are transforming intelligent transportation systems.Artificial intelligence enables real-time sensing,decision-making,and control on embedded platforms with impro...Recent advancements in autonomous vehicle technologies are transforming intelligent transportation systems.Artificial intelligence enables real-time sensing,decision-making,and control on embedded platforms with improved efficiency.This study presents the design and implementation of an autonomous radio-controlled(RC)vehicle prototype capable of lane line detection,obstacle avoidance,and navigation through dynamic path planning.The system integrates image processing and ultrasonic sensing,utilizing Raspberry Pi for vision-based tasks and ArduinoNano for real-time control.Lane line detection is achieved through conventional image processing techniques,providing the basis for local path generation,while traffic sign classification employs a You Only Look Once(YOLO)model optimized with TensorFlow Lite to support navigation decisions.Images captured by the onboard camera are processed on the Raspberry Pi to extract lane geometry and calculate steering angles,enabling the vehicle to follow the planned path.In addition,ultrasonic sensors placed in three directions at the front of the vehicle detect obstacles and allow real-time path adjustment for safe navigation.Experimental results demonstrate stable performance under controlled conditions,highlighting the system’s potential for scalable autonomous driving applications.This work confirms that deep learning methods can be efficiently deployed on low-power embedded systems,offering a practical framework for navigation,path planning,and intelligent transportation research.展开更多
文摘In this study,we concluded the Hamiltonian equations on(M3,φ,ξ,η,g𝑔),being a model.Finally introduce,some geometrical and physical results on the related mechanic systems have been discussed.
基金Project(2012CB725301)supported by the National Basic Research Program of ChinaProject(201412015)supported by the National Special Fund for Surveying and Mapping Geographic Information Scientific Research in the Public Welfare of ChinaProject(212000168)supported by the Basic Survey-Mapping Program of National Administration of Surveying,Mapping and Geoinformation of China
文摘An automatic three-dimensional(3D) reconstruction method based on four-view stereo vision using checkerboard pattern is presented. Mismatches easily exist in traditional binocular stereo matching due to the repeatable or similar features of binocular images. In order to reduce the probability of mismatching and improve the measure precision, a four-camera measurement system which can add extra matching constraints and offer multiple measurements is applied in this work. Moreover, a series of different checkerboard patterns are projected onto the object to obtain dense feature points and remove mismatched points. Finally, the 3D model is generated by performing Delaunay triangulation and texture mapping on the point cloud obtained by four-view matching. This method was tested on the 3D reconstruction of a terracotta soldier sculpture and the Buddhas in the Mogao Grottoes. Their point clouds without mismatched points were obtained and less processing time was consumed in most cases relative to binocular matching. These good reconstructed models show the effectiveness of the method.
基金This work was supported by the French research office(No.01 K 0742)under the Cléopatre project.
文摘This paper describes specific constraints of vision systems that are dedicated to be embedded in mobile robots. If PC-based hardware architecture is convenient in this field because of its versatility, flexibility, performance, and cost, current real-time operating systems are not completely adapted to long processing with varying duration, and it is often necessary to oversize the system to guarantee fail-safe functioning. Also, interactions with other robotic tasks having more priority are difficult to handle. To answer this problem, we have developed a dynamically reconfigurable vision processing system, based on the innovative features of Cleopatre real-time applicative layer concerning scheduling and fault tolerance. This framework allows to define emergency and optional tasks to ensure a minimal quality of service for the other subsystems of the robot, while allowing to adapt dynamically vision processing chain to an exceptional overlasting vision process or processor overload. Thus, it allows a better cohabitation of several subsystems in a single hardware, and to develop less expensive but safe systems, as they will be designed for the regular case and not rare exceptional ones. Finally, it brings a new way to think and develop vision systems, with pairs of complementary operators.
文摘Stereoscopic three-dimensional echocardiography（S-3DE） is a novel displaying technol-ogy based on real-time 3-dimensional echocardiography （RT-3DE）. Our study was to evaluate the feasibility and efficiency of S-3DE in the diagnosis of atrial septal defect （ASD） and its use in the guidance for transcatheter ASD occlusion. Twelve patients with secundum ASD underwent RT-3DE examination and 9 of the 12 were subjected to transcatheter closure of ASD. Stereoscopic vision was generated with a high-performance volume renderer with red-green stereoscopic glasses. S-3DE was compared with standard RT-3D display for the assessment of the shape, size, and the surrounding tis-sues of ASD and for the guidance of ASD occlusion. The appearance rate of coronary sinus and the mean formation time of the IVC, SVC were compared. Our results showed that S-3DE could measure the diameter of ASD accurately and there was no significant difference in the measurements between S-3DE and standard 3D display （2.89±0.73 cm vs 2.85±0.72 cm, P〉0.05; r=0.96, P〈0.05）. The appearance of coronary sinus for S-3DE was higher as compared with the standard 3D display （93.3% vs 100%）. The mean time of the IVC, SVC for S-3DE monitor was slightly shorter than that of the standard 3D display （11.0±3.8 s vs 10.3±3.6 s, P〉0.05）. The mean completion time of interven-tional procedure was shortened with S-3DE display as compared with standard 3D display （17.3±3.1 min vs 23.0±3.9 min, P〈0.05）. Stereoscopic three-dimensional echocardiography could improve the visualization of three-dimensional echocardiography, facilitate the identification of the adjacent structures, decrease the time required for interventional manipulation. It may be a feasible, safe, and efficient tool for guiding transcatheter septal occlusion or the surgical interventions.
基金supported by National Natural Science Foundation of China (Grant No. 60804060)Research Fund for the Doctoral Program of Higher Education of China (Grant No. 200800061003)
文摘Multi-sensor vision system plays an important role in the 3D measurement of large objects.However,due to the widely distribution of sensors,the problem of lacking common fields of view（FOV） arises frequently,which makes the global calibration of the vision system quite difficult.The primary existing solution relies on large-scale surveying equipments,which is ponderous and inconvenient for field calibrations.In this paper,a global calibration method of multi-sensor vision system is proposed and investigated.The proposed method utilizes pairs of skew laser lines,which are generated by a group of laser pointers,as the calibration objects.Each pair of skew laser lines provides a unique coordinate system in space which can be reconstructed in certain vision sensor＇s coordinates by using a planar pattern.Then the geometries of sensors are computed under rigid transformation constrains by taking coordinates of each skew lines pair as the intermediary.The method is applied on both visual cameras with synthetic data and a real two-camera vision system;results show the validity and good performance.The prime contribution of this paper is taking skew laser lines as the global calibration objects,which makes the method simple and flexible.The method need no expensive equipments and can be used in large-scale calibration.
文摘Based on the characteristics of line structured light sensor, a speedy method for the calibration was established. With the coplanar reference target, the spacial pose between camera and optical plane can be calibrated by using of the camera’s projective center and the light’s information in the camera’s image surface. Without striction to the movement of the coplanar reference target and assistant adjustment equipment, this calibration method can be implemented. This method has been used and decreased the cost of calibration equipment, simplified the calibration procedure, improved calibration efficiency. Using experiment, the sensor can attain relative accuracy about 0.5%, which indicates the rationality and effectivity of this method.
文摘To assess functional outcomes of optical low vision aids(LVAs) for pediatric visual impairment due to central nervous system(CNS) tumors. A prospective case study was conducted on 15 children with history of CNS tumors with mean age of 10.47±1.85 y. Lighthouse distance, near visual acuity tests, cycloplegic refraction, reading speed measurement and visual field examination were done. Prescription of far and near LVAs followed by training sessions. LVPrasad-functional vision questionnaire was done to evaluate performance. Visual impairment was moderate(13.3%), severe(73.3%), profound(6.7%) and near blindness in 6.7%. Telescopes prescribed in 33.4%, video magnifier in 46.7%. Questionnaire scores were significantly improved for distant rather than near tasks(P≤0.05) after training. LVAs rehabilitation is an effective method of improving vision in pediatric visual defects secondary to CNS tumors.
文摘The fast paced nature of robotic soccer necessitates real time sensing coupled with quick behaving and decision making. In the field with real robots, it is important to well perceive the location of ball, team robots and opponent robots through the vision system in real time. In this paper the architecture of global vision system of our small size robotic team and the process of object recognition is described. According to the study on color distribution in different color space and quantitative investigation, a method which uses H (Hue) thresholds as the major thresholds to feature exact and recognize object in real time is presented.
基金Supported by the National Natural Science Foundation of China under Grant No. 60674059
文摘This paper establishes two theorems for two time-delayed （chaotic） discrete systems to achieve timedelayed generalized synchronization （TDGS）. These two theorems uncover the genera/forms of two TDGS systems via a prescribed transformation. As examples, we convert the Lorenz three-dimensional chaotic map to an equal time-delayed system as the driving system, and construct the TDGS driven systems according to the Theorems 1 and 2. Numerical simulations demonstrate the effectiveness of the proposed theorems.
文摘Building fences to manage the cattle grazing can be very expensive;cost inefficient. These do not provide dynamic control over the area in which the cattle are grazing. Existing virtual fencing techniques for the control of herds of cattle, based on polygon coordinate definition of boundaries is limited in the area of land mass coverage and dynamism. This work seeks to develop a more robust and an improved monocular vision based boundary avoidance for non-invasive stray control system for cattle, with a view to increase land mass coverage in virtual fencing techniques and dynamism. The monocular vision based depth estimation will be modeled using concept of global Fourier Transform (FT) and local Wavelet Transform (WT) of image structure of scenes (boundaries). The magnitude of the global Fourier Transform gives the dominant orientations and textual patterns of the image;while the local Wavelet Transform gives the dominant spectral features of the image and their spatial distribution. Each scene picture or image is defined by features v, which contain the set of global (FT) and local (WT) statistics of the image. Scenes or boundaries distances are given by estimating the depth D by means of the image features v. Sound cues of intensity equivalent to the magnitude of the depth D are applied to the animal ears as stimuli. This brings about the desired control as animals tend to move away from uncomfortable sounds.
基金The Key Project of the National Ninth-Five-Year Plan No. 96-004-02-09The 48Project of Ministry of Water Resources No. 985106The Project of Chinese Academy of Sciences
文摘Through the study of mutual process between groundwater systems and eco-environmental water demand, the eco-environmental water demand is brought into groundwater systems model as the important water consumption item and unification of groundwater抯 economic, environmental and ecological functions were taken into account. Based on eco-environmental water demand at Da抋n in Jilin province, a three-dimensional simulation and optimized management model of groundwater systems was established. All water balance components of groundwater systems in 1998 and 1999 were simulated with this model and the best optimal exploitation scheme of groundwater systems in 2000 was determined, so that groundwater resource was efficiently utilized and good economic, ecologic and social benefits were obtained.
文摘A three-dimensional stabilization problem for underactuated autonomous underwater vehicles(AUVs)is addressed in this paper.A novel coordinate transformation form consisting of state modifications and input transformations is introduced such that the whole system is divided into two decoupled one-order subsystems.Some switching functions are presented to further decouple the underactuated dynamics and to produce persistently exciting(PE)signals for those underactuated states.Based on the aforementioned results,a quite simple control law is designed to achieve global three-dimensional asymptotic convergence of all states of underactuated AUVs.Comparative simulations are carried out to validate the effectiveness and performance of the proposed control scheme.
基金National Natural Science Foundation of China(6120327)
文摘In order to satisfy the requirements of UAV’s aerial safety monitoring and surveillance of sensitive areas,a robust vision system for the rotor UAV is designed and implemented,which includes visual airborne subsystem,ground station subsystem and wireless communication subsystem.Complete sky-ground and human-computer interaction loops are constructed.Based on the developed UAV vision platform,a real-time target tracking algorithm under the mean shift tracking framework is developed.The joint color-texture histogram is used to represent the target robustly.With the help of moment information,the scale and the orientation of the tracked target is estimated adaptively during the tracking process.A model updating scheme for the target and the background is introduced to reduce the interferences from background and the locating biases.Numerical simulation and real flight tracking experiments demonstrate that the overall visual tracking system is effective and has superior performance against several state-of-the-art algorithms.
文摘Archaeological excavation involves disintegration, removal, and reassembly of the archaeological record;as such it is considered by many to be an unrepeatable, destructive activity. This perception has contributed to an advancement in archaeological practice, namely, the development of computerized recording systems that digitally record archaeological excavations spatially and volumetrically during fieldwork. This paper is concerned with those archaeological sites where digital field recording has not been done. These sites, recorded by traditional methods, should not be excluded from attempts to restructure the spatial, volumetric, and stratigraphic archaeological data. A thorough methodology for the conversion of traditional records into digitized data is presented, including the detailed procedures required for three-dimensional plotting of recorded data—both the excavated material and the drawn site maps and cross-sections. Finally, the use of these methods is demonstrated on a complex Early to Middle Pleistocene site, illustrating the benefits of digitization and three-dimensional reconstruction in resolving stratigraphic and spatial questions.
基金Sponsored by the National Natural Science Foundation of China(60473049)the National Hi-Tech R&D programof China(2006AA01Z120)
文摘EyeScreen is a vision-based interaction system which provides a natural gesture interface for humancomputer interaction （HCI） by tracking human fingers and recognizing gestures. Multi-view video images are captured by two cameras facing a computer screen, which can be used to detect clicking actions of a fingertip and improve the recognition rate. The system enables users to directly interact with rendered objects on the screen. Robustness of the system has been verified by extensive experiments with different user scenarios. EyeScreen can be used in many applications such as intelligent interaction and digital entertainment.
文摘Cold Workability limits of Brass were studied as a function of friction, aspect ratio and specimen geometry. Five standard shapes of the axis symmetric specimens of cylindrical with aspect ratios 1.0 and 1.5, ring, tapered and flanged were selected for the present investigation. Specimens were deformed in compression between two flat platens to predict the metal flow at room temperature. The longitudinal and oblique cracks were obtained as the two major modes of surface fractures. Cylindrical and ring specimen shows the oblique surface crack while the tapered and flanged shows the longitudinal crack. Machine Vision system using PC based video recording with a CCD camera was used to analyze the deformation of 4 X 4 mm square grid marked at mid plane of the specimen. The strain paths obtained from different specimens exhibited nonlinearity from the beginning to the end of the strain path. The circumferential stress component Os increasingly becomes tensile with continued deformation. On the other hand the axial stress Oz , increased in the very initial stages of deformation but started becoming less compressive immediately as barreling develops. The nature of hydrostatic stress on the rim of the flanged specimen was found to be tensile. Finite element software ANSYS has been applied for the analysis of the upset forming process. When the stress values obtained from finite element analysis were compared to the measurements of grids using Machine Vision system it was found that they were in close proximity.
文摘Pixel-parallel PE and SIMD architectures are widely used in high-speed image processing to enhance computing power. With fully exploiting the data level parallelism of low- and middle-level image processing, SIMD architecture is able to finish great amount of computation with much less instruction cycle thus satisfy the high-speed system requirement. The main computation parts in those SIMD image processing hardware is known as PE (processing element) and it is responsible for transferring, storing and processing the image data. This paper describes a high-speed vision system with superscalar PE to enhance system performance and its dedicated parallel computing language specifically devel-oped for this vision system. The vision system can achieve motion detection at more than 2000fps and face detection at more than 100 fps which overwhelms some general serial CPUs in the same applications.
文摘目的 探讨基于Vision-LSTM的人工智能(artificial intelligence,AI)技术对甲状腺影像报告与数据系统4b (Thyroid Imaging Reporting and Data System Category 4b,TI-RADS 4b)类甲状腺结节的超声诊断准确性,评估其辅助临床决策的可行性。方法 收集我院401例TI-RADS 4b类甲状腺结节的超声影像数据,并利用这些数据对Vision-LSTM模型进行训练和验证。将AI模型的诊断结果与初级医生及高级医生的诊断结果进行对比,评估其在诊断准确性、稳定性等方面的表现;采用曲线下面积(area under the curve,AUC)、精确率-召回率(precision-recall,PR)曲线等指标对模型性能进行量化分析。结果 在独立验证中,Vision-LSTM模型的AUC(0.88)与准确率(89.4%)均显著高于初级医生(AUC:0.624),并达到与高级医生(AUC:0.787)相当的水平,证明了其辅助诊断的应用潜力。AI模型能够准确识别超声影像中的复杂特征,稳定输出一致的诊断结果,展现出较高的准确性和可靠性。结论 基于Vision-LSTM模型的AI技术可显著提升TI-RADS 4b类甲状腺结节的诊断效率与准确性,为医生提供有效辅助,减轻工作负担。
文摘Recent advancements in autonomous vehicle technologies are transforming intelligent transportation systems.Artificial intelligence enables real-time sensing,decision-making,and control on embedded platforms with improved efficiency.This study presents the design and implementation of an autonomous radio-controlled(RC)vehicle prototype capable of lane line detection,obstacle avoidance,and navigation through dynamic path planning.The system integrates image processing and ultrasonic sensing,utilizing Raspberry Pi for vision-based tasks and ArduinoNano for real-time control.Lane line detection is achieved through conventional image processing techniques,providing the basis for local path generation,while traffic sign classification employs a You Only Look Once(YOLO)model optimized with TensorFlow Lite to support navigation decisions.Images captured by the onboard camera are processed on the Raspberry Pi to extract lane geometry and calculate steering angles,enabling the vehicle to follow the planned path.In addition,ultrasonic sensors placed in three directions at the front of the vehicle detect obstacles and allow real-time path adjustment for safe navigation.Experimental results demonstrate stable performance under controlled conditions,highlighting the system’s potential for scalable autonomous driving applications.This work confirms that deep learning methods can be efficiently deployed on low-power embedded systems,offering a practical framework for navigation,path planning,and intelligent transportation research.
