A 2.500Mb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE
The terrestrial laser scanning (TLS) market has evolved rapidly, and today’s laser scanning practitioner has an abundance of TLS systems to choose from. Trade-offs between system specifications has led to TLS market fragmentation by application, often limited by imaging range. Advancements in system design and manufacturing have led to lower-priced systems and entirely new types of `reality capture’ systems that push the boundaries of system size and cost further. A TLS practitioner needs to make decisions about how they are going to stay competitive, maximise their investments and grow their business.
With the recent launch of Teledyne Optech’s new Polaris system at the SPAR3D exhibition in April 2017, and as past sales manager at Teledyne Optech, I will discuss approaches in the design and workflow of today’s TLS systems that can help practitioners maximise their return on investment from new technology.
Evolution to today’s terrestrial laser scanning market
Rapidly changing industry
The TLS market is barely 20 years old, yet it has maintained an impressive pace of technological change to meet an ever-broadening set of market needs and applications. Arguably, the first system in commercial production was the Cyrax 2400 by Cyra Technologies in 1998. Within 5 years there were many competing systems available, including the Imager 5003 (Zoller & Fröhlich) and the GS 200 (Mensi), to name just a few. These early systems soon became part of the wider survey and equipment portfolio of firms such as Leica Geosystems (part of Hexagon) and Trimble respectively.
Since the mid-2000s the evolution of computing technology and the modernization of laser scanning systems and their design have progressed in dramatic steps, the key themes being downward pressure on system size and cost.
Wide range of TLS options available
The main TLS brands offer a strong portfolio of systems. Among the products there are variations in technical characteristics such as the imaging range capability, form, or industrial protection rating. There are also variations in the extent to which the systems offer enhancements in workflow functionality, such as offering the surveyor the opportunity to undertake resections or transections, or to assign scanner positions in an automated manner.
In my role as a laser scanner salesperson, I used to describe laser scanners as being `different types of fruit’. Apples and bananas are both fruit, but they have fundamentally different characteristics; the same can be said for different models of laser scanner.
The technical specifications of a terrestrial laser scanning system are typically characterised in these terms:
• Scan repetition rate: i.e. the number of points that are captured in a second. This rate has increased greatly; where an early system might have collected data at a rate of 10 Hz, it is now commonplace for systems to collect data at 500 kHz or higher.
• Relative range accuracy: On phase-based systems, this is typically quoted down to 3 mm.
• Imaging range: This has increased to the extent that the last 5 years have seen several time-of-flight scanners that can image a landslide 2000 m away.
The laws of physics dictate that there are trade-offs between these three characteristics. For example, scanners with a longer range will be slower, while the fastest systems will provide data with very fine accuracy tolerances but usually cannot collect data on targets more than 200 m away.
Application-led market segmentation
Relationships between scanner specifications can mean that a surveyor who has purchased a fast and highly accurate TLS predominantly to undertake as-built surveys can find that it cannot scan a quarry for a new customer. Conversely, the mine surveyor using a long-range scanner to collect volumetric data across an open pit may become frustrated by the slow speed at which it scans the buildings, conveyor belts, or other structures on the mine site for asset inventory purposes.
Hence, while all scanners can collect a point-cloud of the immediate environment, professional users have discovered that they may need to invest in multiple systems to be effective in their service delivery. This may lead to increased operating costs or a narrowing of client opportunities based on the equipment at hand.
Pricing pressures and specialist systems
Technology evolution inevitably leads to competition and pricing pressures, resulting in a race to the bottom in terms of price. With system purchase costs ranging from of $13,000 to $20,000 USD, many users, from architects, to kitchen designers to foremen on construction sites, are now able to capture their own data without needing to make what could have easily been a six-figure investment only a few years ago.
Lower prices bring trade-offs, though. Compared to entirely survey-focussed TLS systems, specifications in specialist reality-capture systems will be compromised. In addition, the simple workflow that makes these devices appealing to the mass market may be an oversimplification for specialist users.
What is required in the TLS of 2017?
The TLS user of 2017 has a multitude of systems available to them, but with every investment the user needs to think carefully about project availability and the extent that any one system can help produce the required deliverables.
In short, everyone is looking to maximise their investment. Singular technical specifications are important, but it is solutions designed to reduce overall infield project time over the greatest range of project environments that will enable a service provider’s profit margins to grow:
• Data resolution and accuracy need to be sufficient to collect data that meets specification.
• Speed of data acquisition needs to be considered, not only as a function of repetition rate and scan frequency but also in terms of how long all aspects of data capture and processing will take.
• Project type and range need to be evaluated. This may be characterised by the imaging range of the scanner. Consideration needs to be given to the extent that the types of projects that the firm undertakes will change in the future, and the extent that each item of equipment can be continuously billable.
Given the degree of innovation and consumerization in the TLS marketplace, it can be hard for a professional TLS practitioner to determine what types of system characteristics will keep their services relevant in a market that is becoming increasingly accessible to the non-practitioner.
How does the Optech Polaris fit the requirements of the TLS practitioner in 2017?
40 years of experience in the scanning business
For anyone unfamiliar with Teledyne Optech’s pedigree, the company was founded in 1974 as Optech Incorporated. In the 1990s, Optech was widely credited with the commercial development of the first airborne lidar terrain mapping system, and in 2007 Optech launched the first purpose-designed mobile mapping system. Optech also produced one of the first TLS systems, the ILRIS, originally designed in 1991 as part of space-related project for NASA. Made for long-range scanning applications, the ILRIS terrestrial laser scanner was commercially delivered in 2001.
Teledyne Optech’s portfolio has focussed on products that bring a return on investment to specific data capture operations, with current examples including the Eclipse airborne system. Released at a time when much of the market has been centered on the opportunities that unmanned aerial vehicle operation brings to data capture, Optech instead developed the Eclipse as a system for small-area and corridor mapping that only needs the pilot to operate. A similar perspective has been taken to the design of the Polaris.
Optech Polaris: Technical characteristics
Data acquisition quality and efficiency
Specializing in time-of-flight technology, Teledyne Optech’s strengths lie in data quality, with minimized noise and beam divergence over range, plus scanning patterns that reduce redundancy in the data collect. For the Polaris, a range accuracy of 2 mm is quoted, giving some indication of the clarity of data that is expected from this system.
Flexible hardware configuration
The Polaris is offered in three upgradeable configuration options, giving a variety of entry points with upgrade paths to meet future needs as they arise. The first option is the TLS-250, which has a $50,000 USD entry price and offers a quoted 250-m range at a 500-kHz repetition rate. Its relative accuracy stands up against the competition for users looking to implement as-built documentation projects, perhaps the largest single application market for terrestrial laser scanners.
The next two optional upgrades are the TLS-750 and TLS-1600, which provide additional options for collecting data up to 750 m and 1600 m. Yes, when operating in these additional modes, the raw repetition rate needs to fall. However, this does let the operator collect high-quality data at ranges where other systems collect no data at all. In terms of operational efficiency, having longer imaging ranges can reduce the number of scanning positions required when surveying a large site such as an industrial plant. This not only reduces time onsite but also reduces the data volumes that need to be processed back in the office. Again, this is all from the same hardware that can instantly switch to its highest repetition rate for short-range applications when required.
These upgrade paths offered by the Polaris means that service providers have the ability to pivot into new project types easily and quickly. The total cost of ownership is driven down because the Polaris can be expanded to fulfill the services of multiple systems, thereby removing investment and maintenance costs associated with owning and operating several units.
Emphasis on workflow–reducing project time
Optimising a scanning platform’s technical specifications and increasing its data collection functions are all good approaches to increasing a scanner’s use. However, it is how the scanner collects data (and the associated data products) that will have the biggest impact on project time and cost.
Regardless of how low the scanner’s price tag is, if the field costs (e.g. setup) and/or post-process times are not equally low then project costs will remain high indefinitely.
Execution directly from the scanner
Simplifying the data capture workflow means that there are fewer individual operations that need to be performed in the field. Standardizing those workflows also reduces the opportunity to minimize project risk. In the design of the Polaris, most operating functions have been moved to the scanner itself, such as setting basic parameters like resolution and region of interest. Further assistance is provided to less-experienced members of the survey team through a set of pre-defined operational templates that will execute a string of capture procedures.
Known survey workflows
Surveyors are trained in implementing systematic workflows. The concepts of resecting the position of an unknown point by taking bearings from two other points, or of linearly traversing to a new position relative to a known back-sight position, are standard practice to the survey community. Apply these concepts to the position of a TLS and the absolute position of a point cloud can be calculated with reduced ground control in the field.
What impact does implementing known workflows have on the bottom-line for the professional service provider? This was outlined by Sam Billingsley1 (speaking to new players in the market who might be operating cheaper scanners) in the context of using traverse and resection tools on the Leica Geosystems ScanStation C10 to stay competitive. While the survey-led approach that Sam describes takes a few minutes more scanning time in the field, it requires fewer targets (moving 4 rather than 8 targets around a construction site is much easier), and his in-office registration hours are reduced. By not compartmentalizing separate stages in the data capture process, such as by treating scan and registration time as separate silos, he can look at his entire workflow, ultimately leading to increasingly competitive costs on client rate sheets. While this type of functionality has been commonplace on systems such as the C10 or the Topcon GLS-2000 for some years now, it is encouraging that the Polaris adds these specific workflows to increase its usability as a true survey tool and boost data processing efficiency both onsite and in the office.
Maximising value from in-office processing time
Target-less registration functionality has been incorporated into the Teledyne Optech’s new unified data capture, registration and delivery platform, ATLAScan. This automates many in-office procedures and potentially reduces time onsite too. Additionally, the new software platform can convert raw data in the point cloud into geometric primitives or a range of meshes. These automated functions take the client deliverables to the next level beyond simply providing a point cloud, and increases the value of in-office time by delivering data in a format or structure that can be used more effectively by downstream application software.
Professional service providers need to focus on workflow and overall project costs
In 2017, the TLS practitioner has a wide and varied field of choice available to them. When deciding upon any investment in equipment, a practitioner needs to consider project costs that reach beyond the capital costs of equipment purchase. The practitioner needs to understand whether buying one or more lower-cost systems will ultimately enable them to minimise their project costs, or if investing in a workflow that reduces their overall project time and provides access to a greater range of projects will ultimately provide the potential for higher profitability.
Any TLS available will provide good quality data. Within the section "What is required in the TLS of 2017", I compartmentalized questions that we might ask ourselves, in terms of data accuracy, resolution, project type and range. From the proceeding discussion, specifications are important, but the practitioner needs to look more closely at the workflows of current and future projects. A wider view of operating requirements needs to be taken:
• Flexibility: What possibilities are there for upgrading data collection tools considering project requirements? What are the costs of purchasing and maintaining additional systems versus upgrades?
• Scanning efficiency: Do 100% of laser shots reach the region of interest, or are any of them wasted? What is the minimum number of scan positions required to collect the required coverage of data, and does the imaging range enable this?
• Execution: How can multistage capture operations be executed in a simplified and standardised manner?
• Onsite and in-office time: What can be done to reduce non-scanning operations (such as target setting) in the field? What types of survey-related georeferencing operations can be completed in the field to reduce time spent in the office?
The costs of all types of technology are falling, and the prescribed workflows for operating these systems are becoming more automated. If a service provider is going to be able to respond to the competition and expand their business, they need to expand their project offerings and deliverables. Rather than basing investment decisions entirely upon initial purchase costs, users can maximize their equipment utilization and project costs by looking at productivity improvements at all stages in their workflow, and employing equipment that is flexible to expand with their on-going business.
Will Tompkinson is the owner and consulting lead of Insightful Dimensions. Formerly Teledyne Optech’s Europe, Middle East and Africa sales manager, Will now operates the consulting practice, Insightful Dimensions, providing product management and marketing consulting services to a global list of vendors and service providers.
1 Sam Billingsley, "Low-Cost Lidar Changes the Game for Service Providers", SPAR 3D, February 1, 2017: http://www.spar3d.com/blogs/confessions-of-a-hired-gun/low-cost-lidar-changes-game-service-providers/
A 2.500Mb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE