The international journal of medical robotics + computer assisted surgery : MRCAS, Jan 30, 2018
Skull reconstruction is an important and challenging task in craniofacial surgery planning, foren... more Skull reconstruction is an important and challenging task in craniofacial surgery planning, forensic investigation and anthropological studies. Existing methods typically reconstruct approximating surfaces that regard corresponding points on the target skull as soft constraints, thus incurring non-zero error even for non-defective parts and high overall reconstruction error. This paper proposes a novel geometric reconstruction method that non-rigidly registers an interpolating reference surface that regards corresponding target points as hard constraints, thus achieving low reconstruction error. To overcome the shortcoming of interpolating a surface, a flip-avoiding method is used to detect and exclude conflicting hard constraints that would otherwise cause surface patches to flip and self-intersect. Comprehensive test results show that our method is more accurate and robust than existing skull reconstruction methods. By incorporating symmetry constraints, it can produce more symmet...
... increasing number of robots and sensing range. References [Low et al., 2002] KH Low, WK Leow,... more ... increasing number of robots and sensing range. References [Low et al., 2002] KH Low, WK Leow, and MH Ang Jr. A hybrid mobile robot architecture with integrated plan-ning and control. In Proc. AAMAS, pages 219226, 2002.
IEEE International Conference on Image Processing 2005, 2005
Accurate human body posture refinement from single or multiple images is essential in many applic... more Accurate human body posture refinement from single or multiple images is essential in many applications, such as vision-based sport coaching and physical rehabilitation. Two main causes of difficulty to solve the refinement problem are high degree freedom of human body and self-occlusion. One of the most recent algorithms is nonparametric belief propagation (NBP) that solves the problem in a lower dimensional state space. However, it is difficult to handle self-occlusion. This paper presents an NBP-based algorithm that can refine body posture even in self-occlusion case, which has been shown by experimental results. The experimental results also show that our algorithm can accurately refine body posture even if the initial posture has large difference from the true posture.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2009
Histopathological examination is a powerful method for prognosis of major diseases such as breast... more Histopathological examination is a powerful method for prognosis of major diseases such as breast cancer. Analysis of medical images largely remains the work of human experts. Current virtual microscope systems are mainly an emulation of real microscopes with annotation and some image analysis capabilities. However, the lack of effective knowledge management prevents such systems from being computer-aided prognosis platforms. The cognitive virtual microscopic framework, through an extended modeling and use of medical knowledge, has the capacity to analyse histopathological images and to perform grading of breast cancer, providing pathologists with a robust and traceable second opinion.
Abstract Scoring the nuclear pleomorphism in histopathological images is a standard clinical prac... more Abstract Scoring the nuclear pleomorphism in histopathological images is a standard clinical practice for the diagnosis and prognosis of breast cancer. It relies highly on the experience of the pathologists. In a large hospital, one pathologist may have to evaluate more than a ...
Reconstruction of surface discontinuities from unorganized 3D points is a difficult problem. Both... more Reconstruction of surface discontinuities from unorganized 3D points is a difficult problem. Both the polygonization and surface fitting approaches to surface reconstruction face the same chicken-and-egg problem: to correctly reconstruct surface discontinuities, the points that lie on the same side of the discontinuities should be used to reconstruct the surfaces to form the discontinuities. However, to know whether the points lie on the same or different sides, the algorithm needs to know the locations and orientations of edge discontinuities, which are not directly available in the unorganized point set.
Studies in Health Technology and Informatics, Feb 1, 2009
This paper proposes a hybrid approach for modeling torsion of blood vessels that undergo deformat... more This paper proposes a hybrid approach for modeling torsion of blood vessels that undergo deformation and joining. The proposed model takes 3D mesh of the blood vessel as input. It first fits a generalized cylinder to extract the blood vessel's medial axis. Then, it uses rotation minimizing frame as a reference to model and measure the torsion of blood vessel after deformation. In general, the proposed approach can incorporate any kind of deformation algorithms. In our experiments, differential geometry method is used as an example. The test results show that our algorithm can correctly and effectively evaluate the amount of torsion caused by blood vessel deformation. In addition, it can also determine the configuration of the blood vessel with minimum torsion.
Using object recognition in simple scenes as the task, two fundamental problems in neural network... more Using object recognition in simple scenes as the task, two fundamental problems in neural network systems are addressed: (1) processing large amounts of input with limited resources, and (2) the representation and use of structured knowledge. The solution to the first problem is to process a small amount of the input in parallel, and successively focus on other parts of
Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association, Jan 22, 2016
Internal carotid artery (ICA) occlusions are poorly responsive to intravenous thrombolysis with t... more Internal carotid artery (ICA) occlusions are poorly responsive to intravenous thrombolysis with tissue plasminogen activator (IV-tPA) in acute ischemic stroke (AIS). Most study populations have combined intracranial and extracranial ICA occlusions for analysis; few have studied purely cervical ICA occlusions. We evaluated AIS patients with acute cervical ICA occlusion treated with IV-tPA to identify predictors of outcomes. We studied 550 consecutive patients with AIS who received IV-tPA and identified 100 with pure acute cervical ICA occlusion. We evaluated the associations of vascular risk factors, National Institutes of Health Stroke Scale (NIHSS) score, and leptomeningeal collateral vessel status via 3 different grading systems, with functional recovery at 90 days, mortality, recanalization of the primary occlusion, and symptomatic intracranial hemorrhage (SICH). Modified Rankin Scale score 0-1 was defined as an excellent outcome. The 100 patients had mean age of 67.8 (range 32-9...
. Texture segmentation aims at dividing an image into perceptuallyuniform regions each containing... more . Texture segmentation aims at dividing an image into perceptuallyuniform regions each containing a distinct texture. In imagesof natural scene, texture in a region can change gradually in scale andorientation due to perspective distortion. A naive segmentation methodmay erroneously group image patches with the same texture but slowlyvarying scales and orientations into distinct regions. This paper describesa novel segmentation method which takes into account the rate of changeof texture ...
2004 International Conference on Image Processing 2004 Icip 04, Nov 24, 2004
In this paper, we present a novel approach to vectorize elliptic arcs for 3D pie chart recognitio... more In this paper, we present a novel approach to vectorize elliptic arcs for 3D pie chart recognition and data extraction. As a preprocessing step, a set of straight line segments are obtained first. By estimating the parameters based on the line segments, we are able to generate elliptic arc candidates. Curve fitting is then performed to reject false positives and
Proceedings of the Eighth International Conference on Document Analysis and Recognition, 2005
This paper presents our recent work that aims at associating the recognition results of textual a... more This paper presents our recent work that aims at associating the recognition results of textual and graphical information contained in the scientific chart images. Text components are first located in the input image and then recognized using OCR. On the other hand, the graphical objects are segmented and form high level symbols. Both logical and semantic correspondence between text and graphical symbols are identified. The association of text and graphics allows us to capture the semantic meaning carried by scientific chart images in a more complete way. The result of scientific chart image understanding is presented using XML documents.
The international journal of medical robotics + computer assisted surgery : MRCAS, Jan 30, 2018
Skull reconstruction is an important and challenging task in craniofacial surgery planning, foren... more Skull reconstruction is an important and challenging task in craniofacial surgery planning, forensic investigation and anthropological studies. Existing methods typically reconstruct approximating surfaces that regard corresponding points on the target skull as soft constraints, thus incurring non-zero error even for non-defective parts and high overall reconstruction error. This paper proposes a novel geometric reconstruction method that non-rigidly registers an interpolating reference surface that regards corresponding target points as hard constraints, thus achieving low reconstruction error. To overcome the shortcoming of interpolating a surface, a flip-avoiding method is used to detect and exclude conflicting hard constraints that would otherwise cause surface patches to flip and self-intersect. Comprehensive test results show that our method is more accurate and robust than existing skull reconstruction methods. By incorporating symmetry constraints, it can produce more symmet...
... increasing number of robots and sensing range. References [Low et al., 2002] KH Low, WK Leow,... more ... increasing number of robots and sensing range. References [Low et al., 2002] KH Low, WK Leow, and MH Ang Jr. A hybrid mobile robot architecture with integrated plan-ning and control. In Proc. AAMAS, pages 219226, 2002.
IEEE International Conference on Image Processing 2005, 2005
Accurate human body posture refinement from single or multiple images is essential in many applic... more Accurate human body posture refinement from single or multiple images is essential in many applications, such as vision-based sport coaching and physical rehabilitation. Two main causes of difficulty to solve the refinement problem are high degree freedom of human body and self-occlusion. One of the most recent algorithms is nonparametric belief propagation (NBP) that solves the problem in a lower dimensional state space. However, it is difficult to handle self-occlusion. This paper presents an NBP-based algorithm that can refine body posture even in self-occlusion case, which has been shown by experimental results. The experimental results also show that our algorithm can accurately refine body posture even if the initial posture has large difference from the true posture.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2009
Histopathological examination is a powerful method for prognosis of major diseases such as breast... more Histopathological examination is a powerful method for prognosis of major diseases such as breast cancer. Analysis of medical images largely remains the work of human experts. Current virtual microscope systems are mainly an emulation of real microscopes with annotation and some image analysis capabilities. However, the lack of effective knowledge management prevents such systems from being computer-aided prognosis platforms. The cognitive virtual microscopic framework, through an extended modeling and use of medical knowledge, has the capacity to analyse histopathological images and to perform grading of breast cancer, providing pathologists with a robust and traceable second opinion.
Abstract Scoring the nuclear pleomorphism in histopathological images is a standard clinical prac... more Abstract Scoring the nuclear pleomorphism in histopathological images is a standard clinical practice for the diagnosis and prognosis of breast cancer. It relies highly on the experience of the pathologists. In a large hospital, one pathologist may have to evaluate more than a ...
Reconstruction of surface discontinuities from unorganized 3D points is a difficult problem. Both... more Reconstruction of surface discontinuities from unorganized 3D points is a difficult problem. Both the polygonization and surface fitting approaches to surface reconstruction face the same chicken-and-egg problem: to correctly reconstruct surface discontinuities, the points that lie on the same side of the discontinuities should be used to reconstruct the surfaces to form the discontinuities. However, to know whether the points lie on the same or different sides, the algorithm needs to know the locations and orientations of edge discontinuities, which are not directly available in the unorganized point set.
Studies in Health Technology and Informatics, Feb 1, 2009
This paper proposes a hybrid approach for modeling torsion of blood vessels that undergo deformat... more This paper proposes a hybrid approach for modeling torsion of blood vessels that undergo deformation and joining. The proposed model takes 3D mesh of the blood vessel as input. It first fits a generalized cylinder to extract the blood vessel's medial axis. Then, it uses rotation minimizing frame as a reference to model and measure the torsion of blood vessel after deformation. In general, the proposed approach can incorporate any kind of deformation algorithms. In our experiments, differential geometry method is used as an example. The test results show that our algorithm can correctly and effectively evaluate the amount of torsion caused by blood vessel deformation. In addition, it can also determine the configuration of the blood vessel with minimum torsion.
Using object recognition in simple scenes as the task, two fundamental problems in neural network... more Using object recognition in simple scenes as the task, two fundamental problems in neural network systems are addressed: (1) processing large amounts of input with limited resources, and (2) the representation and use of structured knowledge. The solution to the first problem is to process a small amount of the input in parallel, and successively focus on other parts of
Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association, Jan 22, 2016
Internal carotid artery (ICA) occlusions are poorly responsive to intravenous thrombolysis with t... more Internal carotid artery (ICA) occlusions are poorly responsive to intravenous thrombolysis with tissue plasminogen activator (IV-tPA) in acute ischemic stroke (AIS). Most study populations have combined intracranial and extracranial ICA occlusions for analysis; few have studied purely cervical ICA occlusions. We evaluated AIS patients with acute cervical ICA occlusion treated with IV-tPA to identify predictors of outcomes. We studied 550 consecutive patients with AIS who received IV-tPA and identified 100 with pure acute cervical ICA occlusion. We evaluated the associations of vascular risk factors, National Institutes of Health Stroke Scale (NIHSS) score, and leptomeningeal collateral vessel status via 3 different grading systems, with functional recovery at 90 days, mortality, recanalization of the primary occlusion, and symptomatic intracranial hemorrhage (SICH). Modified Rankin Scale score 0-1 was defined as an excellent outcome. The 100 patients had mean age of 67.8 (range 32-9...
. Texture segmentation aims at dividing an image into perceptuallyuniform regions each containing... more . Texture segmentation aims at dividing an image into perceptuallyuniform regions each containing a distinct texture. In imagesof natural scene, texture in a region can change gradually in scale andorientation due to perspective distortion. A naive segmentation methodmay erroneously group image patches with the same texture but slowlyvarying scales and orientations into distinct regions. This paper describesa novel segmentation method which takes into account the rate of changeof texture ...
2004 International Conference on Image Processing 2004 Icip 04, Nov 24, 2004
In this paper, we present a novel approach to vectorize elliptic arcs for 3D pie chart recognitio... more In this paper, we present a novel approach to vectorize elliptic arcs for 3D pie chart recognition and data extraction. As a preprocessing step, a set of straight line segments are obtained first. By estimating the parameters based on the line segments, we are able to generate elliptic arc candidates. Curve fitting is then performed to reject false positives and
Proceedings of the Eighth International Conference on Document Analysis and Recognition, 2005
This paper presents our recent work that aims at associating the recognition results of textual a... more This paper presents our recent work that aims at associating the recognition results of textual and graphical information contained in the scientific chart images. Text components are first located in the input image and then recognized using OCR. On the other hand, the graphical objects are segmented and form high level symbols. Both logical and semantic correspondence between text and graphical symbols are identified. The association of text and graphics allows us to capture the semantic meaning carried by scientific chart images in a more complete way. The result of scientific chart image understanding is presented using XML documents.
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