Haiyan Guan - Profile on Academia.edu (original) (raw)
Papers by Haiyan Guan
Geometric validation of a mobile laser scanning system for urban applications
2nd ISPRS International Conference on Computer Vision in Remote Sensing (CVRS 2015), 2016
Endocrinology, Jul 1, 2013
The placental 11-hydroxysteroid dehydrogenase type 2 (11-HSD2; encoded by the HSD11B2 gene) has... more The placental 11-hydroxysteroid dehydrogenase type 2 (11-HSD2; encoded by the HSD11B2 gene) has emerged as a key player in controlling fetal development, but its regulation is incompletely understood. Here we identified p38 MAPK as an important regulator of placental 11-HSD2. We showed that inhibition of p38 MAPK with the pharmacological inhibitor SB202190 led to an approximately 50% reduction in 11-HSD2 activity, protein, and mRNA in primary human placental trophoblast cells. Furthermore, the effect of SB202190 was confirmed by the use of two additional p38 inhibitors, SB203580 and SB220025. In addition, SB202190 decreased the half-life of 11-HSD2 mRNA without altering the HSD11B2 promoter activity, indicating that p38 MAPK regulates placental 11-HSD2 expression through modulation of 11-HSD2 mRNA stability. Importantly, small interfering RNA-mediated knockdown of p38␣ caused a 50% reduction in 11-HSD2 activity, suggesting that p38␣ is the primary p38 isoform involved. Taken together, these findings suggest a novel pathway controlling placental 11-HSD2 expression resulting from the activation of p38 MAPK. Given that p38␣ is abundantly expressed in the human placenta in which its function is largely unknown, our present study also reveals 11-HSD2 as an important target through which p38␣ may regulate human placental function and consequently fetal growth and development.
Cadmium reduces 11 β-hydroxysteroid dehydrogenase type 2 activity and expression in human placental trophoblast cells
American Journal of Physiology Endocrinology and Metabolism, 2006
... Kaiping Yang, Laura Julan, Fran Rubio, Anju Sharma, and Haiyan Guan. ... Birth Defects Res C ... more ... Kaiping Yang, Laura Julan, Fran Rubio, Anju Sharma, and Haiyan Guan. ... Birth Defects Res C Embryo Today 72: 361370, 2004.[CrossRef][Medline]; McTernan CL, Draper N, Nicholson H, Chalder SM, Driver P, Hewison M, Kilby MD, and Stewart PM. ...
Building detection from LIDAR and images in urban areas
Proceedings of Spie the International Society For Optical Engineering, Nov 1, 2007
Rapid texture mapping of buildings is a key aspect for reconstruction of 3D city landscapes. An e... more Rapid texture mapping of buildings is a key aspect for reconstruction of 3D city landscapes. An effective approach by the way of coarse-to-fine 3D building model generation by integration of LIDAR and multiple overlap images is proposed. Classification and segmentation can be processed by combined multi-spectral information which is provided by color aerial image and geometric information from multi-return laser scanned data. A connected graph of the segment label image has to be created to derive the neighborhood relation of the planar segments. A line segment matching, based on geometry and chromatic constraint, is applied for automatically getting the corresponding line features in multi target images. Hypotheses for polyhedral surfaces are selected using topological relations and verified using geometry.
2013 Fifth International Conference on Geo Information Technologies For Natural Disaster Management, Oct 1, 2013
Road surface markings are used on paved roadways to provide guidance and information to drivers a... more Road surface markings are used on paved roadways to provide guidance and information to drivers and pedestrians, which are a critical feature in the traffic management systems. This paper presents an automated approach to detection and extraction of road markings from mobile laser scanning (MLS) point clouds by taking advantages of multiple data features. To improve computational efficiency, the raw MLS point cloud data are first converted to geo-referenced images, based on elevation, intensity and point density, using inverse distance weighted interpolation, respectively. Afterwards, three filters are designed to extract road markings step -bystep:
Amer J Physiol Endocrinol Met, 2005
Cadmium, a common environmental pollutant and a major constituent of tobacco smoke, has been iden... more Cadmium, a common environmental pollutant and a major constituent of tobacco smoke, has been identified as a new class of endocrine disruptors with a wide range of detrimental effects on mammalian reproduction. During human pregnancy maternal cadmium exposure, via the environment and/or cigarette smoking, leads to fetal growth restriction (FGR), but the underlying mechanisms are unknown. Although a substantial amount of evidence suggests that cadmium may affect fetal growth indirectly via the placenta, the molecular targets remain to be identified. Given that reduced placental 11 -hydroxysteroid dehydrogenase type 2 (11 -HSD2; encoded by HSD11B2 gene) is causally linked to FGR, the present study was undertaken to examine the hypothesis that cadmium induces FGR in part by targeting placental HSD11B2.
Cortisol Induces Aromatase Expression in Human Placental Syncytiotrophoblasts Through the cAMP/Sp1 Pathway
Endocrinology, Feb 7, 2012
One of the dominant effects of glucocorticoids in triggering parturition in certain animal specie... more One of the dominant effects of glucocorticoids in triggering parturition in certain animal species is to drive the placental conversion of progesterone to estrogen. However, in the human placenta, estrogen is formed using dehydroepiandrosterone from the fetal adrenal glands rather than progesterone as precursor. Although aromatization of dehydroepiandrosterone is crucial in estrogen synthesis in human placenta, it is not known whether glucocorticoids affect aromatase expression. Human term placental syncytiotrophoblasts were used to examine the effect of cortisol on aromatase expression. The signaling pathway and transcription factors involved were identified in this study. Results showed that cortisol induced aromatase expression in a concentration-dependent manner, which was mediated indirectly by glucocorticoid receptor and required the participation of other proteins. The induction of aromatase by cortisol could be blocked by either specificity protein 1 (Sp1) antagonist mithramycin or knockdown of Sp1 expression. The induction of aromatase and Sp1 by cortisol could be prevented by inhibitors of the cAMP pathway, whereas activators of the cAMP pathway induced Sp1 and aromatase expression as well as Sp1 binding to aromatase promoter. Concomitantly, cortisol treatment and activation of the cAMP pathway led to increased acetylation and decreased methylation of histone 3 at the aromatase promoter. In conclusion, cortisol stimulates aromatase expression through the cAMP/Sp1 pathway in human placental syncytiotrophoblasts. These findings reveal a novel role of cortisol in increasing the local level of estrogen within the placenta that would help transform the myometrium to a contractile state, thereby contributing to a cascade of events leading to human parturition.
Endocrinology, 2009
The placental 11-hydroxysteroid dehydrogenase type 2 (11-HSD2; encoded by the HSD11B2 gene) has... more The placental 11-hydroxysteroid dehydrogenase type 2 (11-HSD2; encoded by the HSD11B2 gene) has emerged as a key player in controlling fetal development, but its regulation is incompletely understood. Here we identified p38 MAPK as an important regulator of placental 11-HSD2. We showed that inhibition of p38 MAPK with the pharmacological inhibitor SB202190 led to an approximately 50% reduction in 11-HSD2 activity, protein, and mRNA in primary human placental trophoblast cells. Furthermore, the effect of SB202190 was confirmed by the use of two additional p38 inhibitors, SB203580 and SB220025. In addition, SB202190 decreased the half-life of 11-HSD2 mRNA without altering the HSD11B2 promoter activity, indicating that p38 MAPK regulates placental 11-HSD2 expression through modulation of 11-HSD2 mRNA stability. Importantly, small interfering RNA-mediated knockdown of p38␣ caused a 50% reduction in 11-HSD2 activity, suggesting that p38␣ is the primary p38 isoform involved. Taken together, these findings suggest a novel pathway controlling placental 11-HSD2 expression resulting from the activation of p38 MAPK. Given that p38␣ is abundantly expressed in the human placenta in which its function is largely unknown, our present study also reveals 11-HSD2 as an important target through which p38␣ may regulate human placental function and consequently fetal growth and development.
3D Reconstruction of Small-sized Cultural Relics Based on Laser Scanning and Close-range Photogrammetry
International Journal of Digital Content Technology and its Applications, 2012
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2015
This paper presents a novel method for automated extraction of road markings directly from three ... more This paper presents a novel method for automated extraction of road markings directly from three dimensional (3-D) point clouds acquired by a mobile light detection and ranging (LiDAR) system. First, road surface points are segmented from a raw point cloud using a curb-based approach. Then, road markings are directly extracted from road surface points through multisegment thresholding and spatial density filtering. Finally, seven specific types of road markings are further accurately delineated through a combination of Euclidean distance clustering, voxel-based normalized cut segmentation, large-size marking classification based on trajectory and curb-lines, and small-size marking classification based on deep learning, and principal component analysis (PCA). Quantitative evaluations indicate that the proposed method achieves an average completeness, correctness, and F-measure of 0.93, 0.92, and 0.93, respectively. Comparative studies also demonstrate that the proposed method achieves better performance and accuracy than those of the two existing methods.
IEEE Geoscience and Remote Sensing Letters, 2015
This letter presents a 3-D object matching framework to support information extraction directly f... more This letter presents a 3-D object matching framework to support information extraction directly from 3-D point clouds. The problem of 3-D object matching is to match a template, represented by a group of 3-D points, to a point cloud scene containing an instance of that object. A locally affine-invariant geometric constraint is proposed to effectively handle affine transformations, occlusions, incompleteness, and scales in 3-D point clouds. The 3-D object matching framework is integrated into 3-D correspondence computation, 3-D object detection, and point cloud object classification in mobile laser scanning (MLS) point clouds. Experimental results obtained using the 3-D point clouds acquired by a RIEGL VMX-450 system showed that completeness, correctness, and quality of over 0.96, 0.94, and 0.91 are achieved, respectively, with the proposed framework in 3-D object detection. Comparative studies demonstrate that the proposed method outperforms the two existing methods for detecting 3-D objects directly from large-volume MLS point clouds.
IEEE Transactions on Geoscience and Remote Sensing, 2015
This paper proposes a novel algorithm for extracting street light poles from vehicleborne mobile ... more This paper proposes a novel algorithm for extracting street light poles from vehicleborne mobile light detection and ranging (LiDAR) point-clouds. First, the algorithm rapidly detects curb-lines and segments a point-cloud into road and nonroad surface points based on trajectory data recorded by the integrated position and orientation system onboard the vehicle. Second, the algorithm accurately extracts street light poles from the segmented nonroad surface points using a novel pairwise 3-D shape context. The proposed algorithm is tested on a set of point-clouds acquired by a RIEGL VMX-450 mobile LiDAR system. The results show that road surfaces are correctly segmented, and street light poles are robustly extracted with a completeness exceeding 99%, a correctness exceeding 97%, and a quality exceeding 96%, thereby demonstrating the efficiency and feasibility of the proposed algorithm to segment road surfaces and extract street light poles from huge volumes of mobile LiDAR point-clouds.
IEEE Transactions on Intelligent Transportation Systems, 2015
This paper presents a survey of literature about road feature extraction, giving a detailed descr... more This paper presents a survey of literature about road feature extraction, giving a detailed description of a Mobile Laser Scanning (MLS) system (RIEGL VMX-450) for transportationrelated applications. This paper describes the development of automated algorithms for extracting road features (road surfaces, road markings, and pavement cracks) from MLS point cloud data. The proposed road surface extraction algorithm detects road curbs from a set of profiles that are sliced along vehicle trajectory data. Based on segmented road surface points, we create Geo-Referenced Feature (GRF) images and develop two algorithms, respectively, for extracting the following: 1) road markings with high retroreflectivity and 2) cracks containing low contrast with their surroundings, low signal-to-noise ratio, and poor continuity. A comprehensive comparison illustrates satisfactory performance of the proposed algorithms and concludes that MLS is a reliable and cost-effective alternative for rapid road inspection.
IEEE Transactions on Intelligent Transportation Systems, 2015
Updating road markings is one of the routine tasks of transportation agencies. Compared with trad... more Updating road markings is one of the routine tasks of transportation agencies. Compared with traditional road inventory mapping techniques, vehicle-borne mobile light detection and ranging (LiDAR) systems can undertake the job safely and efficiently. However, current hurdles include software and computing challenges when handling huge volumes of highly dense and irregularly distributed 3-D mobile LiDAR point clouds. This paper presents the development and implementation aspects of an automated object extraction strategy for rapid and accurate road marking inventory. The proposed road marking extraction method is based on 2-D georeferenced feature (GRF) images, which are interpolated from 3-D road surface points through a modified inverse distance weighted (IDW) interpolation. Weighted neighboring difference histogram (WNDH)-based dynamic thresholding and multiscale tensor voting (MSTV) are proposed to segment and extract road markings from the noisy corrupted GRF images. The results obtained using 3-D point clouds acquired by a RIEGL VMX-450 mobile LiDAR system in a subtropical urban environment are encouraging.
Automated Extraction of Urban Road Facilities Using Mobile Laser Scanning Data
IEEE Transactions on Intelligent Transportation Systems, 2015
2013 Fifth International Conference on Geo-Information Technologies for Natural Disaster Management, 2013
Road surface markings are used on paved roadways to provide guidance and information to drivers a... more Road surface markings are used on paved roadways to provide guidance and information to drivers and pedestrians, which are a critical feature in the traffic management systems. This paper presents an automated approach to detection and extraction of road markings from mobile laser scanning (MLS) point clouds by taking advantages of multiple data features. To improve computational efficiency, the raw MLS point cloud data are first converted to geo-referenced images, based on elevation, intensity and point density, using inverse distance weighted interpolation, respectively. Afterwards, three filters are designed to extract road markings step -bystep:
MIPPR 2007: Pattern Recognition and Computer Vision, 2007
Rapid texture mapping of buildings is a key aspect for reconstruction of 3D city landscapes. An e... more Rapid texture mapping of buildings is a key aspect for reconstruction of 3D city landscapes. An effective approach by the way of coarse-to-fine 3D building model generation by integration of LIDAR and multiple overlap images is proposed. Classification and segmentation can be processed by combined multi-spectral information which is provided by color aerial image and geometric information from multi-return laser
Prenatal Exposure to Bisphenol A Disrupts Mouse Fetal Liver Maturation in a Sex-Specific Manner
Journal of Cellular Biochemistry, 2015
Bisphenol A (BPA) is one of the most prevalent endocrine disrupting chemicals in the environment.... more Bisphenol A (BPA) is one of the most prevalent endocrine disrupting chemicals in the environment. Developmental exposure to BPA is known to be associated with liver dysfunction and diseases, such as hepatic steatosis, liver tumors, metabolic syndrome, and altered hepatic gene expression, and DNA methylation profiles. However, the effects of BPA on rodent liver development are unknown. The present study was undertaken to address this important question using the mouse as an experimental model. Pregnant mice were exposed to BPA via diet from embryonic day 7.5 (E7.5) to E18.5. At E18.5, fetal livers were collected, and analyzed for changes in the expression of key hepatocyte maturation markers. We found the following significant alterations in BPA-exposed female but not male fetal livers: (a) levels of the mature hepatocyte markers, albumin and glycogen synthase proteins, were decreased (-65% and -40%, respectively); (b) levels of the immature hepatocyte marker, α-fetoprotein, were increased (+43%); (c) the level of C/EBP-α protein, the master transcription factor essential for hepatocyte maturation, was down-regulated (-50%); and (d) the level of PCNA protein (marker of proliferation) was elevated (+40%), while that of caspase-3 protein and activity (markers of apoptosis) was reduced (-40% and -55%, respectively), suggestive of a perturbed balance between cell proliferation and apoptosis in BPA-exposed female fetuses. Taken together, these findings demonstrate that prenatal exposure to BPA disrupts the mouse fetal liver maturation in a sex-specific manner, and suggest a fetal origin for BPA-induced hepatic dysfunction and diseases.
Vehicle Detection in High-Resolution Aerial Images via Sparse Representation and Superpixels
IEEE Transactions on Geoscience and Remote Sensing, 2015
2014 IEEE Geoscience and Remote Sensing Symposium, 2014
This paper presents a stepwise algorithm for extracting power-lines from mobile laser scanning (M... more This paper presents a stepwise algorithm for extracting power-lines from mobile laser scanning (MLS) data. This algorithm first extracts non-road points from MLS data by estimating road ranges with regard to scanning mechanism and applying elevation-difference and slope criteria to the road ranges scan-line by scan-line. Then, three filters, in terms of height, spatial density, and size-and-shape, are proposed to extract power-line points in the identified nonroad points, followed by Hough transform and Euclidean distance clustering. Finally, a 3D power line is modelled as a horizontal line in X-Y plane and a vertical catenary curve defined by a hyperbolic cosine function in X-Z plane. The proposed algorithm has been tested on a sample of point clouds acquired by a RIEGL VMX-450 MLS system. The results demonstrate the applicability of the proposed algorithm in extracting power transmission lines.
Geometric validation of a mobile laser scanning system for urban applications
2nd ISPRS International Conference on Computer Vision in Remote Sensing (CVRS 2015), 2016
Endocrinology, Jul 1, 2013
The placental 11-hydroxysteroid dehydrogenase type 2 (11-HSD2; encoded by the HSD11B2 gene) has... more The placental 11-hydroxysteroid dehydrogenase type 2 (11-HSD2; encoded by the HSD11B2 gene) has emerged as a key player in controlling fetal development, but its regulation is incompletely understood. Here we identified p38 MAPK as an important regulator of placental 11-HSD2. We showed that inhibition of p38 MAPK with the pharmacological inhibitor SB202190 led to an approximately 50% reduction in 11-HSD2 activity, protein, and mRNA in primary human placental trophoblast cells. Furthermore, the effect of SB202190 was confirmed by the use of two additional p38 inhibitors, SB203580 and SB220025. In addition, SB202190 decreased the half-life of 11-HSD2 mRNA without altering the HSD11B2 promoter activity, indicating that p38 MAPK regulates placental 11-HSD2 expression through modulation of 11-HSD2 mRNA stability. Importantly, small interfering RNA-mediated knockdown of p38␣ caused a 50% reduction in 11-HSD2 activity, suggesting that p38␣ is the primary p38 isoform involved. Taken together, these findings suggest a novel pathway controlling placental 11-HSD2 expression resulting from the activation of p38 MAPK. Given that p38␣ is abundantly expressed in the human placenta in which its function is largely unknown, our present study also reveals 11-HSD2 as an important target through which p38␣ may regulate human placental function and consequently fetal growth and development.
Cadmium reduces 11 β-hydroxysteroid dehydrogenase type 2 activity and expression in human placental trophoblast cells
American Journal of Physiology Endocrinology and Metabolism, 2006
... Kaiping Yang, Laura Julan, Fran Rubio, Anju Sharma, and Haiyan Guan. ... Birth Defects Res C ... more ... Kaiping Yang, Laura Julan, Fran Rubio, Anju Sharma, and Haiyan Guan. ... Birth Defects Res C Embryo Today 72: 361370, 2004.[CrossRef][Medline]; McTernan CL, Draper N, Nicholson H, Chalder SM, Driver P, Hewison M, Kilby MD, and Stewart PM. ...
Building detection from LIDAR and images in urban areas
Proceedings of Spie the International Society For Optical Engineering, Nov 1, 2007
Rapid texture mapping of buildings is a key aspect for reconstruction of 3D city landscapes. An e... more Rapid texture mapping of buildings is a key aspect for reconstruction of 3D city landscapes. An effective approach by the way of coarse-to-fine 3D building model generation by integration of LIDAR and multiple overlap images is proposed. Classification and segmentation can be processed by combined multi-spectral information which is provided by color aerial image and geometric information from multi-return laser scanned data. A connected graph of the segment label image has to be created to derive the neighborhood relation of the planar segments. A line segment matching, based on geometry and chromatic constraint, is applied for automatically getting the corresponding line features in multi target images. Hypotheses for polyhedral surfaces are selected using topological relations and verified using geometry.
2013 Fifth International Conference on Geo Information Technologies For Natural Disaster Management, Oct 1, 2013
Road surface markings are used on paved roadways to provide guidance and information to drivers a... more Road surface markings are used on paved roadways to provide guidance and information to drivers and pedestrians, which are a critical feature in the traffic management systems. This paper presents an automated approach to detection and extraction of road markings from mobile laser scanning (MLS) point clouds by taking advantages of multiple data features. To improve computational efficiency, the raw MLS point cloud data are first converted to geo-referenced images, based on elevation, intensity and point density, using inverse distance weighted interpolation, respectively. Afterwards, three filters are designed to extract road markings step -bystep:
Amer J Physiol Endocrinol Met, 2005
Cadmium, a common environmental pollutant and a major constituent of tobacco smoke, has been iden... more Cadmium, a common environmental pollutant and a major constituent of tobacco smoke, has been identified as a new class of endocrine disruptors with a wide range of detrimental effects on mammalian reproduction. During human pregnancy maternal cadmium exposure, via the environment and/or cigarette smoking, leads to fetal growth restriction (FGR), but the underlying mechanisms are unknown. Although a substantial amount of evidence suggests that cadmium may affect fetal growth indirectly via the placenta, the molecular targets remain to be identified. Given that reduced placental 11 -hydroxysteroid dehydrogenase type 2 (11 -HSD2; encoded by HSD11B2 gene) is causally linked to FGR, the present study was undertaken to examine the hypothesis that cadmium induces FGR in part by targeting placental HSD11B2.
Cortisol Induces Aromatase Expression in Human Placental Syncytiotrophoblasts Through the cAMP/Sp1 Pathway
Endocrinology, Feb 7, 2012
One of the dominant effects of glucocorticoids in triggering parturition in certain animal specie... more One of the dominant effects of glucocorticoids in triggering parturition in certain animal species is to drive the placental conversion of progesterone to estrogen. However, in the human placenta, estrogen is formed using dehydroepiandrosterone from the fetal adrenal glands rather than progesterone as precursor. Although aromatization of dehydroepiandrosterone is crucial in estrogen synthesis in human placenta, it is not known whether glucocorticoids affect aromatase expression. Human term placental syncytiotrophoblasts were used to examine the effect of cortisol on aromatase expression. The signaling pathway and transcription factors involved were identified in this study. Results showed that cortisol induced aromatase expression in a concentration-dependent manner, which was mediated indirectly by glucocorticoid receptor and required the participation of other proteins. The induction of aromatase by cortisol could be blocked by either specificity protein 1 (Sp1) antagonist mithramycin or knockdown of Sp1 expression. The induction of aromatase and Sp1 by cortisol could be prevented by inhibitors of the cAMP pathway, whereas activators of the cAMP pathway induced Sp1 and aromatase expression as well as Sp1 binding to aromatase promoter. Concomitantly, cortisol treatment and activation of the cAMP pathway led to increased acetylation and decreased methylation of histone 3 at the aromatase promoter. In conclusion, cortisol stimulates aromatase expression through the cAMP/Sp1 pathway in human placental syncytiotrophoblasts. These findings reveal a novel role of cortisol in increasing the local level of estrogen within the placenta that would help transform the myometrium to a contractile state, thereby contributing to a cascade of events leading to human parturition.
Endocrinology, 2009
The placental 11-hydroxysteroid dehydrogenase type 2 (11-HSD2; encoded by the HSD11B2 gene) has... more The placental 11-hydroxysteroid dehydrogenase type 2 (11-HSD2; encoded by the HSD11B2 gene) has emerged as a key player in controlling fetal development, but its regulation is incompletely understood. Here we identified p38 MAPK as an important regulator of placental 11-HSD2. We showed that inhibition of p38 MAPK with the pharmacological inhibitor SB202190 led to an approximately 50% reduction in 11-HSD2 activity, protein, and mRNA in primary human placental trophoblast cells. Furthermore, the effect of SB202190 was confirmed by the use of two additional p38 inhibitors, SB203580 and SB220025. In addition, SB202190 decreased the half-life of 11-HSD2 mRNA without altering the HSD11B2 promoter activity, indicating that p38 MAPK regulates placental 11-HSD2 expression through modulation of 11-HSD2 mRNA stability. Importantly, small interfering RNA-mediated knockdown of p38␣ caused a 50% reduction in 11-HSD2 activity, suggesting that p38␣ is the primary p38 isoform involved. Taken together, these findings suggest a novel pathway controlling placental 11-HSD2 expression resulting from the activation of p38 MAPK. Given that p38␣ is abundantly expressed in the human placenta in which its function is largely unknown, our present study also reveals 11-HSD2 as an important target through which p38␣ may regulate human placental function and consequently fetal growth and development.
3D Reconstruction of Small-sized Cultural Relics Based on Laser Scanning and Close-range Photogrammetry
International Journal of Digital Content Technology and its Applications, 2012
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2015
This paper presents a novel method for automated extraction of road markings directly from three ... more This paper presents a novel method for automated extraction of road markings directly from three dimensional (3-D) point clouds acquired by a mobile light detection and ranging (LiDAR) system. First, road surface points are segmented from a raw point cloud using a curb-based approach. Then, road markings are directly extracted from road surface points through multisegment thresholding and spatial density filtering. Finally, seven specific types of road markings are further accurately delineated through a combination of Euclidean distance clustering, voxel-based normalized cut segmentation, large-size marking classification based on trajectory and curb-lines, and small-size marking classification based on deep learning, and principal component analysis (PCA). Quantitative evaluations indicate that the proposed method achieves an average completeness, correctness, and F-measure of 0.93, 0.92, and 0.93, respectively. Comparative studies also demonstrate that the proposed method achieves better performance and accuracy than those of the two existing methods.
IEEE Geoscience and Remote Sensing Letters, 2015
This letter presents a 3-D object matching framework to support information extraction directly f... more This letter presents a 3-D object matching framework to support information extraction directly from 3-D point clouds. The problem of 3-D object matching is to match a template, represented by a group of 3-D points, to a point cloud scene containing an instance of that object. A locally affine-invariant geometric constraint is proposed to effectively handle affine transformations, occlusions, incompleteness, and scales in 3-D point clouds. The 3-D object matching framework is integrated into 3-D correspondence computation, 3-D object detection, and point cloud object classification in mobile laser scanning (MLS) point clouds. Experimental results obtained using the 3-D point clouds acquired by a RIEGL VMX-450 system showed that completeness, correctness, and quality of over 0.96, 0.94, and 0.91 are achieved, respectively, with the proposed framework in 3-D object detection. Comparative studies demonstrate that the proposed method outperforms the two existing methods for detecting 3-D objects directly from large-volume MLS point clouds.
IEEE Transactions on Geoscience and Remote Sensing, 2015
This paper proposes a novel algorithm for extracting street light poles from vehicleborne mobile ... more This paper proposes a novel algorithm for extracting street light poles from vehicleborne mobile light detection and ranging (LiDAR) point-clouds. First, the algorithm rapidly detects curb-lines and segments a point-cloud into road and nonroad surface points based on trajectory data recorded by the integrated position and orientation system onboard the vehicle. Second, the algorithm accurately extracts street light poles from the segmented nonroad surface points using a novel pairwise 3-D shape context. The proposed algorithm is tested on a set of point-clouds acquired by a RIEGL VMX-450 mobile LiDAR system. The results show that road surfaces are correctly segmented, and street light poles are robustly extracted with a completeness exceeding 99%, a correctness exceeding 97%, and a quality exceeding 96%, thereby demonstrating the efficiency and feasibility of the proposed algorithm to segment road surfaces and extract street light poles from huge volumes of mobile LiDAR point-clouds.
IEEE Transactions on Intelligent Transportation Systems, 2015
This paper presents a survey of literature about road feature extraction, giving a detailed descr... more This paper presents a survey of literature about road feature extraction, giving a detailed description of a Mobile Laser Scanning (MLS) system (RIEGL VMX-450) for transportationrelated applications. This paper describes the development of automated algorithms for extracting road features (road surfaces, road markings, and pavement cracks) from MLS point cloud data. The proposed road surface extraction algorithm detects road curbs from a set of profiles that are sliced along vehicle trajectory data. Based on segmented road surface points, we create Geo-Referenced Feature (GRF) images and develop two algorithms, respectively, for extracting the following: 1) road markings with high retroreflectivity and 2) cracks containing low contrast with their surroundings, low signal-to-noise ratio, and poor continuity. A comprehensive comparison illustrates satisfactory performance of the proposed algorithms and concludes that MLS is a reliable and cost-effective alternative for rapid road inspection.
IEEE Transactions on Intelligent Transportation Systems, 2015
Updating road markings is one of the routine tasks of transportation agencies. Compared with trad... more Updating road markings is one of the routine tasks of transportation agencies. Compared with traditional road inventory mapping techniques, vehicle-borne mobile light detection and ranging (LiDAR) systems can undertake the job safely and efficiently. However, current hurdles include software and computing challenges when handling huge volumes of highly dense and irregularly distributed 3-D mobile LiDAR point clouds. This paper presents the development and implementation aspects of an automated object extraction strategy for rapid and accurate road marking inventory. The proposed road marking extraction method is based on 2-D georeferenced feature (GRF) images, which are interpolated from 3-D road surface points through a modified inverse distance weighted (IDW) interpolation. Weighted neighboring difference histogram (WNDH)-based dynamic thresholding and multiscale tensor voting (MSTV) are proposed to segment and extract road markings from the noisy corrupted GRF images. The results obtained using 3-D point clouds acquired by a RIEGL VMX-450 mobile LiDAR system in a subtropical urban environment are encouraging.
Automated Extraction of Urban Road Facilities Using Mobile Laser Scanning Data
IEEE Transactions on Intelligent Transportation Systems, 2015
2013 Fifth International Conference on Geo-Information Technologies for Natural Disaster Management, 2013
Road surface markings are used on paved roadways to provide guidance and information to drivers a... more Road surface markings are used on paved roadways to provide guidance and information to drivers and pedestrians, which are a critical feature in the traffic management systems. This paper presents an automated approach to detection and extraction of road markings from mobile laser scanning (MLS) point clouds by taking advantages of multiple data features. To improve computational efficiency, the raw MLS point cloud data are first converted to geo-referenced images, based on elevation, intensity and point density, using inverse distance weighted interpolation, respectively. Afterwards, three filters are designed to extract road markings step -bystep:
MIPPR 2007: Pattern Recognition and Computer Vision, 2007
Rapid texture mapping of buildings is a key aspect for reconstruction of 3D city landscapes. An e... more Rapid texture mapping of buildings is a key aspect for reconstruction of 3D city landscapes. An effective approach by the way of coarse-to-fine 3D building model generation by integration of LIDAR and multiple overlap images is proposed. Classification and segmentation can be processed by combined multi-spectral information which is provided by color aerial image and geometric information from multi-return laser
Prenatal Exposure to Bisphenol A Disrupts Mouse Fetal Liver Maturation in a Sex-Specific Manner
Journal of Cellular Biochemistry, 2015
Bisphenol A (BPA) is one of the most prevalent endocrine disrupting chemicals in the environment.... more Bisphenol A (BPA) is one of the most prevalent endocrine disrupting chemicals in the environment. Developmental exposure to BPA is known to be associated with liver dysfunction and diseases, such as hepatic steatosis, liver tumors, metabolic syndrome, and altered hepatic gene expression, and DNA methylation profiles. However, the effects of BPA on rodent liver development are unknown. The present study was undertaken to address this important question using the mouse as an experimental model. Pregnant mice were exposed to BPA via diet from embryonic day 7.5 (E7.5) to E18.5. At E18.5, fetal livers were collected, and analyzed for changes in the expression of key hepatocyte maturation markers. We found the following significant alterations in BPA-exposed female but not male fetal livers: (a) levels of the mature hepatocyte markers, albumin and glycogen synthase proteins, were decreased (-65% and -40%, respectively); (b) levels of the immature hepatocyte marker, α-fetoprotein, were increased (+43%); (c) the level of C/EBP-α protein, the master transcription factor essential for hepatocyte maturation, was down-regulated (-50%); and (d) the level of PCNA protein (marker of proliferation) was elevated (+40%), while that of caspase-3 protein and activity (markers of apoptosis) was reduced (-40% and -55%, respectively), suggestive of a perturbed balance between cell proliferation and apoptosis in BPA-exposed female fetuses. Taken together, these findings demonstrate that prenatal exposure to BPA disrupts the mouse fetal liver maturation in a sex-specific manner, and suggest a fetal origin for BPA-induced hepatic dysfunction and diseases.
Vehicle Detection in High-Resolution Aerial Images via Sparse Representation and Superpixels
IEEE Transactions on Geoscience and Remote Sensing, 2015
2014 IEEE Geoscience and Remote Sensing Symposium, 2014
This paper presents a stepwise algorithm for extracting power-lines from mobile laser scanning (M... more This paper presents a stepwise algorithm for extracting power-lines from mobile laser scanning (MLS) data. This algorithm first extracts non-road points from MLS data by estimating road ranges with regard to scanning mechanism and applying elevation-difference and slope criteria to the road ranges scan-line by scan-line. Then, three filters, in terms of height, spatial density, and size-and-shape, are proposed to extract power-line points in the identified nonroad points, followed by Hough transform and Euclidean distance clustering. Finally, a 3D power line is modelled as a horizontal line in X-Y plane and a vertical catenary curve defined by a hyperbolic cosine function in X-Z plane. The proposed algorithm has been tested on a sample of point clouds acquired by a RIEGL VMX-450 MLS system. The results demonstrate the applicability of the proposed algorithm in extracting power transmission lines.