Existing stereo matching methods cannot guarantee both the computational accuracy and efficiency for ihe disparity estimation of large-scale or multi-view images.Hybrid tree method can obtain a disparity estimation fa...Existing stereo matching methods cannot guarantee both the computational accuracy and efficiency for ihe disparity estimation of large-scale or multi-view images.Hybrid tree method can obtain a disparity estimation fast with relatively low accuracy,while PatchMatch can give high-precision disparity value with relatively high computational cost.In this work,we propose the Hybrid Tree Guided PatchMatch which can calculate the disparity fast and accurate.Firstly,an initial disparity map is estimated by employing hybrid tree cost aggregation,which is used to constrain the label searching range of the PatchMatch.Furthermore,a reliable normal searching range for each current normal vector defined on the initial disparity map is calculated to refine the PatchMatch.Finally,an effective quantizing acceleration strategy is designed to decrease the matching computational cost of continuous disparity.Experimental results demonstrate that the disparity estimation based on our algorithm is better in binocular image benchmarks such as Middlebury and KITTI.We also provide the disparity estimation results for multi-view stereo in real scenes.展开更多
To balance the accuracy and efficiency in multiple-view triangulation with sequential images, a high-efficiency propagationbased incremental triangulation(INT) method, carving three-dimensional(3 D) scene points by up...To balance the accuracy and efficiency in multiple-view triangulation with sequential images, a high-efficiency propagationbased incremental triangulation(INT) method, carving three-dimensional(3 D) scene points by updating the incoming feature track one by one without iterations, is proposed. Based on the INT method, a more accurate iteration-limited INT method is also established with few iterations to bound the propagated errors, ensuring the accuracy of subsequent3 D reconstruction. Finally, experimental results demonstrate that the proposed methods can balance the efficiency and accuracy in different multiple-view INT situations.展开更多
Since the early 20th century,China has gradually established a clinical,educational,and research system centered around modern scientific medicine,which has now become the dominant force in China's medical and hea...Since the early 20th century,China has gradually established a clinical,educational,and research system centered around modern scientific medicine,which has now become the dominant force in China's medical and health system and services,with the construction and development of the Chinese Academy of Medical Sciences and Peking Union Medical College as the most prominent symbol.The scientific medicine in the new era requires close cooperation across multiple disciplines and fields to build a high-quality and efficient medical and health service system.It also involves combining the excellent traditional Chinese culture with Western medicine to explore a unique path of modern scientific medicine with Chinese characteristics.展开更多
Three-dimensional(3-D) free-form shape measurement,a challenging task pursued by computer vision,is mainly characterized with single view acquisition and multiple view registration.Most of the conventional scanning ...Three-dimensional(3-D) free-form shape measurement,a challenging task pursued by computer vision,is mainly characterized with single view acquisition and multiple view registration.Most of the conventional scanning systems are less flexibility and difficult to realize engineering applications for employing sequential registration tactic.To develop portable scanning system and engineering registration method overcoming problems of error accumulation and propagation is the research direction.In this paper,one 3-D free-form shape measuring system using unconstrained range sensor is designed.A quasi-active stereo binocular visual sensor embedded within a scanning mechanism is used as the range sensor.Error compensation is performed by residual amendment according to camera calibration lattice.Artificial control points are designed and adhered on object and one camera is introduced to shot these control points from different positions and orientations.Then ray bundle adjustment(BA) method is used to calculate the space coordinates of all the control points,so as to set up a global control net work.Registration can be completed by mapping at least 3 control points observed by range sensor in single view acquisition into the global control network.In this system,no calibration for laser plane is required and the motion of range sensor is completely free.The overlapping of neighboring region is unessential for registration.Therefore,the working range of the system can be easily extended.The measuring precision mainly depends on the quality of global control network.The sequential distances of coding control points are observed by electronic theodolites and then compared with those obtained according to BA result.Experimental results show that relative distance error of control points is no more than 0.2%.The proposed measuring system is portable,provides good capacity for global error control,and contributes to the engineering application of 3-D free-form shape measurement.展开更多
This paper is to illustrate that form develops meaning in Maxine Hong Kingston's The Woman Warrior (1989). Her writing is permeated with the dual forces stretching to diverse directions, and equips readers with the...This paper is to illustrate that form develops meaning in Maxine Hong Kingston's The Woman Warrior (1989). Her writing is permeated with the dual forces stretching to diverse directions, and equips readers with the mimic world to be pushed and pulled to experience all the paradoxes in narrator's life. This enigmatic writing style is the mimesis of the push-pull dynamics existent in the mother-daughter relationship in the book, and also through this kind of writing does the writer finally succeed in breaking away from the suffocating mother-daughter relationship and in claiming her own unique identity.展开更多
This paper presents a survey on automatic or semi-automatic recommendation systems that help users create dashboards.It starts by showing the important role that dashboards play in data science,and gives an informal d...This paper presents a survey on automatic or semi-automatic recommendation systems that help users create dashboards.It starts by showing the important role that dashboards play in data science,and gives an informal definition of dashboards,i.e.,a set of visualizations possibly with linkage,a screen layout and user feedback.We are mainly interested in systems that use a fully or partially automatic mechanism to recommend dashboards to users.This automation includes the suggestion of data and visualizations,the optimization of the layout and the use of user feedback.We position our work with respect to existing surveys.Starting from a set of over 1000 papers,we have selected and analyzed 19 papers/systems along several dimensions.The main dimensions were the set of considered visualizations,the suggestion method,the utility/objective functions,the layout,and the user interface.We conclude by highlighting the main achievements in this domain and by proposing perspectives.展开更多
In most conventional algorithms of registering multiple range images, the pose parameters are estimated by using the distance sum between closest point pairs as the objective function. These algorithms have the proble...In most conventional algorithms of registering multiple range images, the pose parameters are estimated by using the distance sum between closest point pairs as the objective function. These algorithms have the problems of inexact point correspondence, registration accuracy, and sensitivity to initial registration parameters. Due to the scanner settings, scanner distance, and surface slopes, two or more 3D data sets are unlikely to be acquired such that the 3D data points exactly correspond, and also each point in the data set may represent different surface areas. This paper proposes a novel registration algorithm based on a distance metric of surface-to-surface. The algorithm uses triangle meshes to represent the surfaces. Based on surface sampling and the point-to-surface distances, the integration calculation of the mean distance between surfaces is derived and reduced to a simple formula. The method was tested on synthetic and real range images.展开更多
In this paper, we investigate the problem of determining regions in 3D scene visible to some given viewpoints when obstacles are present in the scene. We assume that the obstacles are composed of some opaque objects w...In this paper, we investigate the problem of determining regions in 3D scene visible to some given viewpoints when obstacles are present in the scene. We assume that the obstacles are composed of some opaque objects with closed surfaces. The problem is formulated in an implicit framework where the obstacles are represented by a level set function. The visible and invisible regions of the given viewpoints are determined through an efficient implicit ray tracing technique. As an extension of our approach, we apply the multiview visibility estimation to an image-based modeling technique. The unknown scene geometry and multiview visibility information are incorporated into a variational energy functional. By minimizing the energy functional, the true scene geometry as well as the accurate visibility information of the multiple views can be recovered from a number of scene images. This makes it feasible to handle the visibility problem of multiple views by our approach when the true scene geometry is unknown.展开更多
文摘Existing stereo matching methods cannot guarantee both the computational accuracy and efficiency for ihe disparity estimation of large-scale or multi-view images.Hybrid tree method can obtain a disparity estimation fast with relatively low accuracy,while PatchMatch can give high-precision disparity value with relatively high computational cost.In this work,we propose the Hybrid Tree Guided PatchMatch which can calculate the disparity fast and accurate.Firstly,an initial disparity map is estimated by employing hybrid tree cost aggregation,which is used to constrain the label searching range of the PatchMatch.Furthermore,a reliable normal searching range for each current normal vector defined on the initial disparity map is calculated to refine the PatchMatch.Finally,an effective quantizing acceleration strategy is designed to decrease the matching computational cost of continuous disparity.Experimental results demonstrate that the disparity estimation based on our algorithm is better in binocular image benchmarks such as Middlebury and KITTI.We also provide the disparity estimation results for multi-view stereo in real scenes.
基金partially supported by the National Key Research and Development Program of China(No.2019YFC0119200)the Beijing Natural Science Foundation(No.3204050)+1 种基金the Open Project Program of State Key Laboratory of Virtual Reality Technology and Systems(No.VRLAB2020B05)the Fundamental Research Funds for the Central Universities(Nos.2019RC26 and 2019RC28)。
文摘To balance the accuracy and efficiency in multiple-view triangulation with sequential images, a high-efficiency propagationbased incremental triangulation(INT) method, carving three-dimensional(3 D) scene points by updating the incoming feature track one by one without iterations, is proposed. Based on the INT method, a more accurate iteration-limited INT method is also established with few iterations to bound the propagated errors, ensuring the accuracy of subsequent3 D reconstruction. Finally, experimental results demonstrate that the proposed methods can balance the efficiency and accuracy in different multiple-view INT situations.
基金Supported by the Study on Chen Zhiqian's Public Health Thought Theory and Practice in Urban and Rural Areas(No.:3332022175).
文摘Since the early 20th century,China has gradually established a clinical,educational,and research system centered around modern scientific medicine,which has now become the dominant force in China's medical and health system and services,with the construction and development of the Chinese Academy of Medical Sciences and Peking Union Medical College as the most prominent symbol.The scientific medicine in the new era requires close cooperation across multiple disciplines and fields to build a high-quality and efficient medical and health service system.It also involves combining the excellent traditional Chinese culture with Western medicine to explore a unique path of modern scientific medicine with Chinese characteristics.
基金supported by Fujian Provincial Natural Science Foundation for the Youth of China (Grant No. 2009J05136)Key Program of National Natural Science Foundation of China (Grant No.50735003)
文摘Three-dimensional(3-D) free-form shape measurement,a challenging task pursued by computer vision,is mainly characterized with single view acquisition and multiple view registration.Most of the conventional scanning systems are less flexibility and difficult to realize engineering applications for employing sequential registration tactic.To develop portable scanning system and engineering registration method overcoming problems of error accumulation and propagation is the research direction.In this paper,one 3-D free-form shape measuring system using unconstrained range sensor is designed.A quasi-active stereo binocular visual sensor embedded within a scanning mechanism is used as the range sensor.Error compensation is performed by residual amendment according to camera calibration lattice.Artificial control points are designed and adhered on object and one camera is introduced to shot these control points from different positions and orientations.Then ray bundle adjustment(BA) method is used to calculate the space coordinates of all the control points,so as to set up a global control net work.Registration can be completed by mapping at least 3 control points observed by range sensor in single view acquisition into the global control network.In this system,no calibration for laser plane is required and the motion of range sensor is completely free.The overlapping of neighboring region is unessential for registration.Therefore,the working range of the system can be easily extended.The measuring precision mainly depends on the quality of global control network.The sequential distances of coding control points are observed by electronic theodolites and then compared with those obtained according to BA result.Experimental results show that relative distance error of control points is no more than 0.2%.The proposed measuring system is portable,provides good capacity for global error control,and contributes to the engineering application of 3-D free-form shape measurement.
文摘This paper is to illustrate that form develops meaning in Maxine Hong Kingston's The Woman Warrior (1989). Her writing is permeated with the dual forces stretching to diverse directions, and equips readers with the mimic world to be pushed and pulled to experience all the paradoxes in narrator's life. This enigmatic writing style is the mimesis of the push-pull dynamics existent in the mother-daughter relationship in the book, and also through this kind of writing does the writer finally succeed in breaking away from the suffocating mother-daughter relationship and in claiming her own unique identity.
文摘This paper presents a survey on automatic or semi-automatic recommendation systems that help users create dashboards.It starts by showing the important role that dashboards play in data science,and gives an informal definition of dashboards,i.e.,a set of visualizations possibly with linkage,a screen layout and user feedback.We are mainly interested in systems that use a fully or partially automatic mechanism to recommend dashboards to users.This automation includes the suggestion of data and visualizations,the optimization of the layout and the use of user feedback.We position our work with respect to existing surveys.Starting from a set of over 1000 papers,we have selected and analyzed 19 papers/systems along several dimensions.The main dimensions were the set of considered visualizations,the suggestion method,the utility/objective functions,the layout,and the user interface.We conclude by highlighting the main achievements in this domain and by proposing perspectives.
基金This work was supported by the National Natural Science Foundation of China(Grant No.60275001).
文摘In most conventional algorithms of registering multiple range images, the pose parameters are estimated by using the distance sum between closest point pairs as the objective function. These algorithms have the problems of inexact point correspondence, registration accuracy, and sensitivity to initial registration parameters. Due to the scanner settings, scanner distance, and surface slopes, two or more 3D data sets are unlikely to be acquired such that the 3D data points exactly correspond, and also each point in the data set may represent different surface areas. This paper proposes a novel registration algorithm based on a distance metric of surface-to-surface. The algorithm uses triangle meshes to represent the surfaces. Based on surface sampling and the point-to-surface distances, the integration calculation of the mean distance between surfaces is derived and reduced to a simple formula. The method was tested on synthetic and real range images.
基金supported by the National Natural Science Foundation of China under Grant No.90920009the National High-Tech Research and Development 863 Program of China under Grant No.2009AA01Z323
文摘In this paper, we investigate the problem of determining regions in 3D scene visible to some given viewpoints when obstacles are present in the scene. We assume that the obstacles are composed of some opaque objects with closed surfaces. The problem is formulated in an implicit framework where the obstacles are represented by a level set function. The visible and invisible regions of the given viewpoints are determined through an efficient implicit ray tracing technique. As an extension of our approach, we apply the multiview visibility estimation to an image-based modeling technique. The unknown scene geometry and multiview visibility information are incorporated into a variational energy functional. By minimizing the energy functional, the true scene geometry as well as the accurate visibility information of the multiple views can be recovered from a number of scene images. This makes it feasible to handle the visibility problem of multiple views by our approach when the true scene geometry is unknown.