LIDAR Magazine

Points & Pixels

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Laser Scanning and 3D Model Determine New System Connections and Clearance Heights for Electrical Generating Station
Earlier this year, Sargent Lundy began planning the installation of a new ash collection and removal system for Public Services of New Mexico’s San Juan Generating Station located outside Farmington New Mexico. In order to facilitate the process they were looking for a Microstation model they could use to develop general arrangement and installation drawings for the new equipment and systems to be installed.

Sargent Lundy however, did not have complete 3D existing as-builts of the plant. Furthermore, the plant is in a remote area of New Mexico, making visits difficult to do on a consistent basis. It was also very important that the site be documented without interruptions to its normal operations. In May of this year PNM hired on Eco3d to help. Eco3d is a Phoenix based documentation company that captures existing conditions, creates 2d plans/3d models, and consults with others to help them do the same.

Eco3d signed the agreement to provide both laser scanning and 3D CAD modeling services. Being conscientious of time and costs, this laser scanning company was able to complete scanning and documentation in a single day with no revisits to the site anytime throughout the project.

A Faro Focus 3D ran at 2x resolution was used to capture the data. The point cloud that was used to create the 3D model consisted of 69 scans and the entire model was produced and turned over in less than a month. The client used the model to help determine new system connections as well as clearance heights for inputting new equipment. By having Eco 3D convert the point cloud file to a vector based 3D model S&L was able to insert the scan into their workflow without adjusting any processes on their end. With the increased efficiencies and added savings that they experienced they will be using this process for many projects to come.

Real-time LiDAR Data Collection Planning Method
In dynamic construction environments, LiDAR technologies can achieve rapid spatial data collection for construction and facility management. However, even skillful surveyors could not guarantee comprehensive 3D data collection in changing and cluttered environments. In practice, manual LiDAR imaging often produce data of insufficient coverage, accuracy and details, while wasting data collection time. Some automatic planning algorithms can produce LiDAR data collection plans automatically and ensure data coverage, but such methods need to use a Building Information Model (BIM) that specifies the targeted objects and relevant data quality requirements, such as levels of accuracy and detail. In many cases, a BIM is either not available, or outdated. In addition, multi-target LiDAR data collection planning is computational expensive and could hardly be realtime. The SWARM Lab (Sensing, Workflow, Algorithm, Recognition, and Modeling of the Construction Systems Laboratory), led by Dr. Pingbo Tang at Arizona State University, has been developing a real-time LiDAR data collection planning method that overcomes the difficulties specified above. Even without a BIM, this method can still achieve real-time generation of LiDAR data collection plans that specify the positions of putting the LiDAR, and the data collection parameters at each position (density of data, noise level, field of view, etc.). The generated LiDAR data collection plan can achieve minimum data collection time while ensuring the coverage of all needed objects with sufficient geometric details.

This LiDAR data collection planning method follows a philosophy of "the next best view based on sparse imageries." In the field, engineers can select the first position of the LiDAR based on their experiences, and quickly collect a low-resolution (sparse) 3D point cloud. The algorithm then conducts "visual complexity analysis" on the sparse point cloud and identifies parts of data that are "geometrically complicated," such as having large values of curvatures. Those parts are goals of data collection for ensuring level of detail of the data. Image 1 shows the geometric complexity of a sparse scan of an indoor environment. In this image, from blue to green to red, the geometric complexity is increasing. Obviously, the flat walls are simple, while edges and corners of the room, and furniture in the room have more complicated shapes that deserve denser LiDAR data.

Given goals of data collection, this method uses a LiDAR sensor model, and a "divide-and-conquer" strategy to achieve rapid and data-quality-oriented data collection planning. The sensor model describes the relationship between data quality and various factors influence the data quality, such as distance of data collection, colors of objects. The "divide-and-conquer" strategy uses an algorithm that automatically decomposes a building into parts that could hardly been captured simultaneously, and generates optimal "local" data collection plans for each part, and then aggregate the "local" plans for parts of the building into a complete plan for the whole building. The SWARM Lab researchers found that this automatic LiDAR data collection planning method outperformed an experienced user of LiDAR in several case studies. Image 2 shows the top view of a building and the suggested scans of LiDAR (positions, and scanning resolutions). Image 3 shows that the scanning plan generated by this method consumes the same amount of time, but can cover more areas of this complex building with LiDAR data denser than 1 inch.

Mapping a Gas Plant with UAV and Pix4Dmapper 2.0
Energy service provider Abacus Datagraphics mapped an operating gas plant in Canada, using a fixed-wing UAV and image-processing software Pix4Dmapper to produce an up-to-date, high-resolution map for improved localization of facilities for the plant operators.

Project Description
The aim of this project was to map an operating gas plant in Alberta, Canada, using high-resolution aerial imagery to obtain an orthomosaic. The orthomosaic was then underlayed with a survey drawing showing all underground facilities, creating a comprehensive and up-to-date map.

Using the fixed-wing senseFly eBee, the Abacus team flew one flight, capturing 326 photos of an 80 acre area in around one hour. Because the eBee would be flying over an operating gas plant, strict regulations regarding safety policy had to be followed: takeoff and landing were performed outside of the actual plant area.

Eight ground control points were established from a previous conventional survey of the plant site, though they did not contain the elevation values and were only used to improve the horizontal accuracy.

Achieved Results
A georeferenced orthomosaic of the entire gas plant site was generated by the latest version of Pix4Dmapper, 2.0.71. Results came out very well and in high-resolution. The orthomosaic required some manual editing, however, due to moving vehicles during the image acquisition, which had caused blurring, or "ghost effect." Additionally, the flight was executed in the evening and thus captured the significant movement of shadows, resulting in multiple long shadows on the orthomosaic.

The final result was underlayed with an existing as-built survey drawing that shows the underground facilities. After being printed and framed, the orthomosaic also hangs in the office of the gas plant.

Advantage of This New Technology
Before the use of UAVs, the only way to get an orthomosaic underlay for a project like this was to purchase aerial orthophotos or processed satellite imagery, which tend to be out-of-date and of much lower resolution.

"Such results were too pixelated to be of much value," said Kurtis Poettcker of Abacus Datagraphics. "Having a high-resolution image really enhances the usefulness of the underground map, allowing operators to really visualize the location of buried facilities."

For more information, please visit abacusdatagraphics.com

View the interactive 3D Mesh at sketchfab.com/models/bfdffa18c4fe43cc9a2c2574f7c1a698

Real Time Laser Mapping for Monitoring Coastal Erosion and Rockfall
3D Laser Mapping, a global laser scanning technology provider and Durham University have created an innovative monitoring system to provide real-time 3D data on coastal cliff erosion. The project is part of a KTP (Knowledge Transfer Partnership), a scheme funded by Innovate UK, which has a track record, improving businesses competitiveness, productivity and performance by accessing the knowledge and expertise available within UK Universities and Colleges.

The project aims to try to understand the processes of coastal erosion by looking at projected increases in sea level and stormy weather. Understanding the nature and mechanisms of cliff erosion is of vital importance to predicting the likely future movement of the coastline. Research on eroding coastlines has been limited by the need for surveys of coastal areas, which are restricted to periods of low tides each month.

The aim of the research project is to understand the process through which wave erosion at the base of the cliffs causes undercutting of the cliff slope, resulting in an unstable cliff and failure of material into the sea. Whilst this process may at first glance appear straight forward, research by Durham University over the last decade has shown that this understanding is largely anecdotal. The linkage between waves and erosion evolves gradually through time, and is one that responds to a wide range of factors, and not ju`st the action of waves alone.

The project seeks to take advantage of uniquely high-resolution, 3D data being continually captured, to generate unprecedented detail on the changes experienced at cliffs. The 3D Laser Mapping SiteMonitor system automatically schedules the capture and analysis of 3D laser scan data in parallel with environmental monitoring data. The seaside town of Whitby now has one of–if not the most–intensively monitored rock faces in the world.

The aim of the project is to provide constant and frequent measurement of the cliff face, to allow changes resulting from rockfall to be recorded and analysed in real-time.

The system is designed to scan the cliff face 24 hours a day at 30 minute intervals. Within each scan measurements of the cliff face are taken at approximately 10 cm intervals, generating over 2 million points per scan. Whilst this data capture is itself uniquely innovative, the analysis of such a large volume of information presents significant challenges. To overcome this, the system streams data live from Whitby to Durham, where new algorithms have been developed to process the 3D data to extract rockfall volumes in real-time.

Using these results, the project is designed to tackle the challenge of precisely monitoring coastal cliff erosion and gain a new understanding from this. For example, it is known that many landslides and rockfall are preceded by precursors, such as smaller-scale movements or smaller rockfall, yet capturing data with sufficient resolution and frequency has up until now not been possible. The intention of this analysis is to investigate these processes with a view to both better forecasting erosion, and also assessing whether such precursors can be used as warnings for future rockfall.

The implications of the research is to move beyond Whitby and the UKs coasts. The more usual location of 3D Laser Mapping’s SiteMonitor system is in some of the world’s largest open pit mines, where rockfall and slope failure presents a significant challenge for sustaining mine productivity. The insight into the fundamental mechanics of how rockfall evolves, gained from the research at the cliffs in Whitby, is designed to be transferrable to these settings and enhance the reliability of slope failure early warning systems.

The help of the local community has been key in enabling the infrastructure for this project, and with plans to soon make the findings available through an open access website, everyone involved will be able to see the results as they happen.

For further information please contact: tel: +44 (0)1949 838004, 3dlasermapping.com and dogweb.dur.ac.uk/cobra

Aerial Robots and Corona Cameras
The demand for small size corona cameras, capable of being mounted on aerial robots, is growing lately. This trend correlates the proliferation in the number of manufactured UAVs, their models and the variety of uses. Corona cameras pinpoint electrical and mechanical faults on overhead lines and are therefore very attractive to electrical utilities for their inspection tasks. Regulations and licensing issues are still being investigated; though in the USA there are already four utilities that got FAA licenses to operate unmanned vehicles. Implementing corona inspection on drones entails specific camera’s features, such as compact dimensions and weight, stabilized imaging and high sensitivity to signals and more. Ofil, the pioneer manufacturer of daytime corona detection systems, came up with a dedicated solution to comply with drones specifics and with utilities expectations.

The Purpose: Collecting Information
Electrical lines inspections are performed regularly in order to check their physical and electrical conditions. During inspection teams collect information in various formats. The collected information is documented and used as a reference for management reports & action items, and therefore must be accurate and reliable. Practically, the best equipment, sensors and detectors, like Ofil’s DayCor ROM, are implemented in aerial systems because of the involved high operational proficiency and complexity, not to mention costs. Drones and UAVs are less expensive or complex to operate and therefore the expected implemented solutions must match and be significantly cheaper. Whatever solution is selected, there is an adamant demand for reliable qualitative collected data.

Why Aerial Robots?
Safety–Using aerial robots contributes to the safety of maintenance crews. In particular before live line working when there is a need for teams to get the preliminary view and evaluation of the condition of the insulator / conductor / recloser / disconnected etc., in question. A corona camera mounted on a UAV provides a clear view of existing partial discharges that are created due to local high electrical fields. Electricians should be aware of such discharges before they approach installations. Using UAV before live line work can save lives.

Getting close to electrical high voltage elements is risky and involves precautious steps. In substations, crowded with: bushings, transformers, bus bars etc., inspection can be complicated in particular when there is a need to change angles of view. Yet with a UAV, getting a good view of suspected elements is simplified. UAV’s can hover around elements and relatively close to them while transmitting clear imaging, provided they make use of a high quality UV imager.

Feasibility–Rather than use bucket trucks, UAVs can easily take off and fly vertically. Using UAVs obviates the process of coordinating staff members to climb on towers, ordering bucket trucks, clearing ways to the trucks. UAVs can be operated by one or two operators, provided the remote controller integrates operating commands of both the corona camera and the robot.

ImmediacyCorona cameras’ main advantage is the immediacy of information. A brand name DayCor, stands for solid, highly sensitive and reliable corona cameras that provide valid immediate information of existing corona and partial discharge in real time. Moreover, only cameras with high sensitivity to UV signals can provide the expected information about corona signals. Therefore, operating UAVs with a DayCor camera guarantees immediate true pictures of the elements in question.

DocumentationOften it is requested to record pictures or video clips of the inspected area. Based upon the quality of the implemented UV camera and the integrated transmitting protocols, the output of corona cameras can be recorded. To ensure the high quality of the recordings, Ofil’s DayCor airborne cameras have special stabilizers and shock absorbers that neutralize the jerky movements of UAVs and guarantee smooth video streaming.

Compact UAV’s Corona Cameras: DayCor ROMpact & DayCor Swift
To assist utilities achieve their inspection requirements Ofil developed a series of compact corona cameras: ROMpact & Swift. Both cameras are bi-spectral solar blind UV–Visible cameras for scanning high and medium voltage electrical installations and implement Ofil’s proprietary technological innovations. These compact corona cameras are fit for UAVs of various sizes and configurations as well as for various payload mounts. They deliver in real time pinpointed imaging of corona and arcing emissions and of the emitting sources.

Main Features:
Weight 1.2kg | 2.6lb
Physical dimensions: L247 x W125 x H73 mm | L9.72" x W4.93" x H2.87"
Tested & certified sensitivity to UV signals of corona & arcing of 1pC @ 10 meters (RWE certified: IEC 60270:2000)
Zoom of 10 optical x 12 digital (120 optical x digital)
Nominal power consumption of 7.510 VDC, 14 Watt
Rigid and enduring encapsulation
Set for inspecting areas from 1.5m|4.9ft to infinity
Absolute solar blind Video streaming
UV photons counting
Wired remotely controlled using RS-232 (baud rate: 9.6 Kb/s, 19.2 Kb/s, 38.4 Kb/s, Stop bit: 1/2 selectable)
Fit for standard tripod mounts
Adaptable to customers’ needs
Uninterrupted continuous operation

For more information on Ofil and its complete line of products, visit www.ofilsystems.com or call 1-888-9505557

Samiotes Consultants Breaks New Ground with 3D Laser Scanning
Samiotes Consultants offers civil engineering and land surveying services throughout New England. To sustain their growth, the company turned to employee education and new technology. "We doubled our size and revenue in over two years," said Despina Samiotes, CEO, CFO and Principal. "Given the robust business conditions in New England, we knew that we needed to continue to invest in technology and training to stay competitive." Samiotes felt that 3D laser scanning was a logical next step in the firm’s capabilities and offerings.

Before investing in a 3D laser scanner, Samiotes Consultants reached out to IMAGINiT Technologies. The company had already worked with IMAGINiT on AutoCAD Civil 3D licensing, onsite training, and custom template design. "We knew that IMAGINiT was responsive, knowledgeable, and cared about our business," said Samiotes.

The IMAGINiT team organized a laser scanning summit with Samiotes Consultants. The purpose of this meeting was to answer technical questions and discuss a longer-term vision for how the company could expand its services by using a Leica high definition scanner. After the summit, Samiotes Consultants determined that moving forward with the hardware purchase and employee training would further their business. The rationale was fourfold:
1. The company views 3D scanning as the future of the survey industry and it wants to stay abreast of the newest technology.
2. 3D scanning creates efficiencies in the office. Work that used to take three days in the field is now reduced to one day with the 3D scanner.
3. The output from 3D scanners aligns with what clients like architects and landscape architects need for building information models in Revit.
4. Over the course of a project, clients sometimes decide to expand the scope of work. In most of those cases, the necessary information is already captured in the 3D scan.

In addition to these benefits, the 3D laser scanner has enabled Samiotes Consultants to offer new services to clients. The company now provides scanning of building faades and interiors, as well as airport runways to detect cracks, and sports fields to identify deviations after events.

"Anytime a vendor delivers on time and on budget, it’s a win. With IMAGINiT Technologies, we felt like we had a security blanket and could call at any time with questions or issues. After investing in our 3D scanner, we had complete peace of mind," said Samiotes.

For more information, visit http://www.samiotes.com or call 508-877-6688.

A 3.528Mb PDF of this article as it appeared in the magazine complete with images is available by clicking HERE

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