scholarly journals A Fast Algorithm for Rail Extraction Using Mobile Laser Scanning Data

2018 ◽  
Vol 10 (12) ◽  
pp. 1998 ◽  
Author(s):  
Yidong Lou ◽  
Tian Zhang ◽  
Jian Tang ◽  
Weiwei Song ◽  
Yi Zhang ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Automated Analysis ◽  
Video Data ◽  
Measurement Unit ◽  
Geometrical Properties ◽  
Physical Shape ◽  
Track Area ◽  
Fast Extraction ◽  
Reflection Intensity ◽  
Total Test

Railroads companies conduct regular inspections of their tracks to maintain and update the geographic data for railway management. Traditional railroad inspection methods, such as onsite inspections and semi-automated analysis of imagery and video data, are time consuming and ineffective. This study presents an automated effective method to detect tracks on the basis of their physical shape, geometrical properties, and reflection intensity feature. This study aims to investigate the feasibility of fast extraction of railroad using onboard Velodyne puck data collected by mobile laser scanning (MLS) system. Results show that the proposed method can be executed rapidly on an i5 computer with at least 10 Hz. The MLS system used in this study comprises a Velodyne puck/onboard GNSS receiver/inertial measurement unit. The range accuracy of Velodyne puck equipment is 2 cm, which fulfills the need of precise mapping. Notably, positioning STD is lower than 4 cm in most areas. Experiments are also undertaken to evaluate the timing of the proposed method. Experimental results indicate that the proposed method can extract 3D tracks in real-time and correctly recognize pairs of tracks. Accuracy, precision, and sensitivity of total test area are 99.68%, 97.55%, and 66.55%, respectively. Results suggest that in a multi-track area, close collaboration between MLS platforms mounted on several trains is required.

scholarly journals SEMI-AUTOMATED DETECTION OF SURFACE DEGRADATION ON BRIDGES BASED ON A LEVEL SET METHOD

2015 ◽  
Vol XL-3/W3 ◽  
pp. 15-21 ◽  
Author(s):  
A. Masiero ◽  
A. Guarnieri ◽  
F. Pirotti ◽  
A. Vettore
Keyword(s):  
Laser Scanning ◽  
Automated Analysis ◽  
Human Beings ◽  
Monitoring Cost ◽  
Public And Private ◽  
Skilled Personnel ◽  
Monitoring Procedure ◽  
Monitoring Effort ◽  
The One ◽  
Human Usage

Due to the effect of climate factors, natural phenomena and human usage, buildings and infrastructures are subject of progressive degradation. The deterioration of these structures has to be monitored in order to avoid hazards for human beings and for the natural environment in their neighborhood. Hence, on the one hand, monitoring such infrastructures is of primarily importance. On the other hand, unfortunately, nowadays this monitoring effort is mostly done by expert and skilled personnel, which follow the overall data acquisition, analysis and result reporting process, making the whole monitoring procedure quite expensive for the public (and private, as well) agencies. <br><br> This paper proposes the use of a partially user–assisted procedure in order to reduce the monitoring cost and to make the obtained result less subjective as well. The developed method relies on the use of images acquired with standard cameras by even inexperienced personnel. The deterioration on the infrastructure surface is detected by image segmentation based on a level sets method. The results of the semi-automated analysis procedure are remapped on a 3D model of the infrastructure obtained by means of a terrestrial laser scanning acquisition. <br><br> The proposed method has been successfully tested on a portion of a road bridge in Perarolo di Cadore (BL), Italy.

scholarly journals An Efficient and Accurate Method for Different Configurations Railway Extraction Based on Mobile Laser Scanning

2019 ◽  
Vol 11 (24) ◽  
pp. 2929 ◽  
Author(s):  
Rong Zou ◽  
Xiaoyun Fan ◽  
Chuang Qian ◽  
Wenfang Ye ◽  
Peng Zhao ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Point Clouds ◽  
Accurate Method ◽  
Average Density ◽  
Railway Track ◽  
Track Geometry ◽  
Fitting Algorithm ◽  
Railway Maintenance ◽  
Night Period ◽  
Reflection Intensity

The precision of railway map is becoming a significant issue for autonomous train scheduling, monitoring and maintenance, related location-based service (LBS), and further ensuring travel safety. Mobile 3D laser scanning is an efficient method for making relative high-precision railway track maps, particularly during the night period of railway maintenance, for light detection and ranging (LiDAR) can work without ambient light. In this paper, we propose an efficient and accurate railway track vectorization method based on the LiDAR point clouds from the self-built train Mobile Laser Scanning (MLS) system. Our method takes full use of railway track geometry and reflection intensity feature of LiDAR, without any trajectory prior information. Firstly, clear track points are filtered by intensity; then, a K-means clustering fused Region-Grow Fitting algorithm is applied. It can not only extract the line vector of railway track, but also can tell the track branches apart, especially on bends and turnout. Experiments were carried on using point clouds with an average density of 490 points per square meter. The experimental results show that the method not only can quickly extract linear objects such as railway track and catenary, but also can detect the railways even in complex real-world topologies such as at bends and turnouts. The precision of the detection area in bends and turnouts are 90.32% and 81.31% respectively, the sensitivity is 83.27% and 83.33%, respectively. Moreover, it can identify the track networks.

scholarly journals Semi-automated positional analysis using laser scanning microscopy of cells transfected in a regenerating newt limb.

1996 ◽  
Vol 44 (6) ◽  
pp. 559-569 ◽  
Author(s):  
L T Pecorino ◽  
J P Brockes ◽  
A Entwistle
Keyword(s):  
Laser Scanning ◽  
Positional Distribution ◽  
Marker Gene ◽  
Limb Regeneration ◽  
Automated Analysis ◽  
Laser Scanning Microscopy ◽  
Scanning Microscopy ◽  
Transfected Cells ◽  
Positional Analysis ◽  
Positional Identity

Limb regeneration in urodele amphibians such as the newt is a key system for investigating the positional identity of cells. The regenerate arises locally from blastemal cells, mesenchymal progenitors that normally give rise to structures distal to the amputation plane but which can be respecified (proximalized) by treatment with retinoic acid (RA) such that proximal structures are formed. To establish an assay for positional identity, cells of distal and RA-treated distal blastemas are labeled by transfection with an alkaline phosphatase marker gene using particle bombardment (biolistics). After grafting the distal blastema to a proximal stump, a context known as intercalary regeneration, the proximodistal distribution of labeled cells in the resulting regenerate is an index of positional identity. We use enzyme-labeled fluorescence (ELF) in conjunction with laser scanning microscopy to detect transfected cells within a section of the entire regenerate. A semi-automated analysis of the positional distribution of marked cells along the proximal-distal axis demonstrates that cells from both distal and RA-treated blastemas contribute to the regenerate. This procedure provides an efficient and accurate tool for positional analysis of transfected cells, and should be applicable for studying genes that play a role in specifying cell position during morphogenesis.

scholarly journals New Measurement Methods for Structure Deformation and Objects Exact Dimension Determination

2021 ◽  
Vol 906 (1) ◽  
pp. 012060
Author(s):  
Karel Pavelka ◽  
David Zahradník ◽  
Jaroslav Sedina ◽  
Karel Pavelka
Keyword(s):  
Laser Scanning ◽  
Data Transfer ◽  
Rapid Development ◽  
3D Models ◽  
Measurement Unit ◽  
Forthcoming Article ◽  
Repair Work ◽  
Close Range Photogrammetry ◽  
Laser Scanners ◽  
Close Range

Abstract The current rapid development of technologies enables new procedures for deformation and the detecting of construction defects and their modelling and monitoring in BIM. New instruments were developed for fast and sufficiently accurate mapping like personal mobile laser scanners (PLS). In the world of photography, the size of camera sensors is bigger, and the photographs are sharper. The rapid development of computer performance enables automatic and complex calculations, which lead to large sets of detailed 3D data and a high degree of automation. This influences photogrammetry and its methods. The results are more detailed and more accurate. Deformation, defects and exact dimensions (metrology) of different structures or objects can be currently measured by digital close-range photogrammetry. Cracks and cavities are monitored for structure status detection. This is important for planning reconstruction and for financial reasons. For structures like cooling towers, chimneys, or bridges can be created on a 3D model with a high texture resolution for finding and monitoring cracks and cavities. Deformations or defects that were found must be in scale, and measurable for the calculation of the scope of repair work and its price. The generated 3D object model can then be used for further measurements, for the price estimation of renovation, and for the creation of a BIM, in which all processes can be modelled and watched. Deformation can be monitored over time by creating additional models after a defined period. Captured 3D models from different periods can be compared in software like CloudCompare to determine the progress of degradational changes. The trend of the aging of the structure can be traced, which will be helpful for the reasonable planning of reconstruction. Based on the rapid development and miniaturization of measuring devices, new, smaller, easier to use, and more perfect devices are constructed. This also applies to the new group of laser scanners constructed for basic measurement and structure modeling for BIM. Conventional laser scanners can be accurate, but they are relatively large and heavy, difficult to transport and measuring with them is relatively slow (stop and go type). If the project goal is the classic construction, documentation of the object, data transfer to BIM or basic documentation of objects, PLS is the ideal device. Thanks to the development of accurate IMU (inertial measurement unit) and SLAM (simultaneous localization and mapping) technologies, these devices are on the rise. The forthcoming article will inform about the methods of accurate close-range photogrammetry and mobile laser scanning and will show their advantages with specific examples.

scholarly journals Forward collision warning system for motorcyclist using smart phone sensors based on time-to-collision and trajectory prediction

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Qun Lim ◽  
Yi Lim ◽  
Hafiz Muhammad ◽  
Dylan Wei Ming Tan ◽  
U-Xuan Tan
Keyword(s):  
Short Term Memory ◽  
Low Cost ◽  
Video Data ◽  
Measurement Unit ◽  
Trajectory Prediction ◽  
Data Set ◽  
Content Type ◽  
Collision Warning ◽  
Time To Collision ◽  
Forward Collision Warning

Purpose The purpose of this paper is to develop a proof-of-concept (POC) Forward Collision Warning (FWC) system for the motorcyclist, which determines a potential clash based on time-to-collision and trajectory of both the detected and ego vehicle (motorcycle). Design/methodology/approach This comes in three approaches. First, time-to-collision value is to be calculated based on low-cost camera video input. Second, the trajectory of the detected vehicle is predicted based on video data in the 2 D pixel coordinate. Third, the trajectory of the ego vehicle is predicted via the lean direction of the motorcycle from a low-cost inertial measurement unit sensor. Findings This encompasses a comprehensive Advanced FWC system which is an amalgamation of the three approaches mentioned above. First, to predict time-to-collision, nested Kalman filter and vehicle detection is used to convert image pixel matrix to relative distance, velocity and time-to-collision data. Next, for trajectory prediction of detected vehicles, a few algorithms were compared, and it was found that long short-term memory performs the best on the data set. The last finding is that to determine the leaning direction of the ego vehicle, it is better to use lean angle measurement compared to riding pattern classification. Originality/value The value of this paper is that it provides a POC FWC system that considers time-to-collision and trajectory of both detected and ego vehicle (motorcycle).

Digital video and laser microscopic studies of developmental events in living neurons and nervous systems

1989 ◽  
Vol 47 ◽  
pp. 832-832
Author(s):  
S. Smith ◽  
P. Forscher ◽  
M. Cooper ◽  
A. Waxman
Keyword(s):  
Laser Scanning ◽  
Digital Video ◽  
Cell Structure ◽  
Cell Signalling ◽  
Optical Memory ◽  
Cytosolic Calcium ◽  
Nervous System Development ◽  
Video Data ◽  
Microscopic Studies

Motility and structural change are extremely important aspects of nervous system development. We are working to refine digital video and laser confocal light microscopic methods for visualization of neuronal motility both in situ and in vitro. Our efforts are oriented especially toward the collection of digitally-enhanced time-lapse movies, for which purpose we especially favor the use of the optical memory disc video recorder. It is our feeling that such dynamic observations are yielding insights not obtainable from examination of fixed specimens. Work to be discussed includes video microscopic studies of the basic motility mechanisms of neuronal growth cones in vitro and laser confocal observations of mammalian CNS growth cone motility and cell proliferation and migration events in slices of embryonic rat cortex.As cell markers for the laser confocal studies, we have used a variety of fluorescent compunds including the lipid stain Dil(C18-3) and the Ca indicator Fluo-3. The latter compound is of special interest in revealing the cytosolic calcium transients associated with various forms of cell signalling as well as making cell structure and motility visible. We have found the use of slow-scan, single-sweep laser image acquisition especially valuable in the collection images from living, moving cells, as this mode circumvents the blurring of moving specimen details associated with the prolonged integration times of low-light-level video data acquisition and multi-sweep averaging in laser scanning systems.

scholarly journals Automated Analysis of Barley Organs Using 3D Laser Scanning: An Approach for High Throughput Phenotyping

Sensors ◽  
2014 ◽  
Vol 14 (7) ◽  
pp. 12670-12686 ◽  
Author(s):  
Stefan Paulus ◽  
Jan Dupuis ◽  
Sebastian Riedel ◽  
Heiner Kuhlmann
Keyword(s):  
High Throughput ◽  
Laser Scanning ◽  
Automated Analysis ◽  
3D Laser Scanning ◽  
High Throughput Phenotyping

scholarly journals SparkMaster: automated calcium spark analysis with ImageJ

2007 ◽  
Vol 293 (3) ◽  
pp. C1073-C1081 ◽  
Author(s):  
Eckard Picht ◽  
Aleksey V. Zima ◽  
Lothar A. Blatter ◽  
Donald M. Bers
Keyword(s):  
Laser Scanning ◽  
Low Frequency ◽  
Maximum Amplitude ◽  
High Sensitivity ◽  
Automated Analysis ◽  
Confocal Laser ◽  
Mammalian Skeletal Muscle ◽  
Full Width ◽  
Half Maximum ◽  
Experimental Conditions

Ca sparks are elementary Ca-release events from intracellular Ca stores that are observed in virtually all types of muscle. Typically, Ca sparks are measured in the line-scan mode with confocal laser-scanning microscopes, yielding two-dimensional images (distance vs. time). The manual analysis of these images is time consuming and prone to errors as well as investigator bias. Therefore, we developed SparkMaster, an automated analysis program that allows rapid and reliable spark analysis. The underlying analysis algorithm is adapted from the threshold-based standard method of spark analysis developed by Cheng et al. ( Biophys J 76: 606–617, 1999) and is implemented here in the freely available image-processing software ImageJ. SparkMaster offers a graphical user interface through which all analysis parameters and output options are selected. The analysis includes general image parameters (number of detected sparks, spark frequency) and individual spark parameters (amplitude, full width at half-maximum amplitude, full duration at half-maximum amplitude, full width, full duration, time to peak, maximum steepness of spark upstroke, time constant of spark decay). We validated the algorithm using images with synthetic sparks embedded into backgrounds with different signal-to-noise ratios to determine an analysis criteria at which a high sensitivity is combined with a low frequency of false-positive detections. Finally, we applied SparkMaster to analyze experimental data of sparks measured in intact and permeabilized ventricular cardiomyocytes, permeabilized mammalian skeletal muscle, and intact smooth muscle cells. We found that SparkMaster provides a reliable, easy to use, and fast way of analyzing Ca sparks in a wide variety of experimental conditions.

scholarly journals Feasibility of Mobile Laser Scanning towards Operational Accurate Road Rut Depth Measurements

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1180
Author(s):  
Aimad El Issaoui ◽  
Ziyi Feng ◽  
Matti Lehtomäki ◽  
Eric Hyyppä ◽  
Hannu Hyyppä ◽  
...  
Keyword(s):  
Inertial Measurement Unit ◽  
Laser Scanning ◽  
Satellite System ◽  
Measurement Unit ◽  
High Definition ◽  
Depth Measurement ◽  
Laser Scanners ◽  
Fully Automatic ◽  
Global Navigation Satellite ◽  
Automatic Algorithm

This paper studied the applicability of the Roamer-R4DW mobile laser scanning (MLS) system for road rut depth measurement. The MLS system was developed by the Finnish Geospatial Research Institute (FGI), and consists of two mobile laser scanners and a Global Navigation Satellite System (GNSS)-inertial measurement unit (IMU) positioning system. In the study, a fully automatic algorithm was developed to calculate and analyze the rut depths, and verified in 64 reference pavement plots (1.0 m × 3.5 m). We showed that terrestrial laser scanning (TLS) data is an adequate reference for MLS-based rutting studies. The MLS-derived rut depths based on 64 plots resulted in 1.4 mm random error, which can be considered adequate precision for operational rutting depth measurements. Such data, also covering the area outside the pavement, would be ideal for multiple road environment applications since the same data can also be used in applications, from high-definition maps to autonomous car navigation and digitalization of street environments over time and in space.

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