Geo Week News

February 5, 2008

ASTM E57 Committee Advances Laser Scanning Standards


Standards for 3D imaging – wait, before you hit the <<DEL>> key, let me tell you about last week’s ASTM E57 Committee annual winter meeting in Tampa. The entrepreneurial energy, technical competence, and enthusiasm for getting the job done among members of this standards group is remarkable.

ASTM E57’s aim is practical. Developing terminology – trust me, that’s not easy – will help wring the ambiguity out of tomorrow’s laser scanning contracts. Developing instrument performance evaluation protocols will help users make sense of vendors’ performance claims. Codifying best practices for using imaging systems can only help improve the quality of field and office deliverables. Developing data exchange protocols holds real promise for allowing the application of 3D laser scanning and other imaging systems to all facets of engineering, manufacturing, construction and asset management. Full disclosure: I’m the membership secretary for E57 – plug coming.

E57 committee chairs, vice chairs and members volunteer their time – aside from the ASTM administrative arm, no members receive any compensation for this work. Most members are technical professionals with line or research responsibilities. Many own their own businesses. Individuals can join the ASTM for $75/year; organizational membership costs $400. Committees meet twice annually, often in nice places but where the costs are modest. ASTM is a thrifty, hardworking professional bunch. Don’t expect fancy gala dinners – think coffee shop, not bistro.

I’ve attended standards meetings in other industries where a fly buzzing in the corner of the room would be a welcome distraction from the droning discourse of professional meeting-goers – that’s not E57. At last week’s meeting in Tampa, FL, service provider CEOs Mike Falk (Falk-PLI) and Eric Hoffman (Quantapoint) had spirited, professional discussions about what constitutes best practice, how to ensure interoperability without stifling innovation, and more. NIST’s own Steve Phillips delivered a thoughtful introductory lecture on measurement uncertainty – next time we’ll video this for youtube. Among technology developers, the spirit of cooperation in the data-exchange working sessions was refreshing. Hats off to ASTM, the venerable 110-year-old organization that houses this effort – its time-tested protocols for voluntary, consensus-based development of technical standards are key to this successful cooperation among hardware and software vendors, government agencies, service providers, EPCs, asset owners, professional societies, trade associations and academia.

Latest developments of the E57 Committee will be the focus of an intensive half-day track at SPAR 2008, March 3-5, Houston, TX. Led by E57 Committee chair Alan Lytle, leader of NIST’s Construction Metrology & Automation Group, the track will update attendees on the committee’s work in four areas: terminology, test methods, best practices and data interoperability. The panel format will give attendees opportunity for open dialogue with E57 members on the status and direction of the standards effort. This is a great opportunity to start participating.



Discussions of terminology may not sound that compelling. But this language is what’s going to end up governing your contracts – use this session to gain insight from these experienced professionals. E57.01 Terminology subcommittee vice chair Kam Saidi, research engineer in NIST’s Construction Metrology & Automation Group, will update attendees on efforts to standardize terminology – common terms, definitions of terms, descriptions of terms, nomenclature and acronyms – commonly used for 3D imaging systems. The subcommittee developed a terminology standard, ASTM E 2544-07, in 2007, which contains terms specific to 3D imaging systems in addition to other common metrology terms.

The major challenges that the subcommittee faces when developing definitions include ensuring that the definition applies to or encompasses all instances, conditions and instruments to the extent possible; harmonizing the terms across disciplines; balancing simplicity and accuracy (technical correctness) of definition; and having members with expertise in the varied disciplines (e.g., optics, surveying, physics) required when defining terms. The subcommittee invites suggestions for additional terms, and requests that when suggesting a term, the following information be given: justification – why the term is needed; context – where/how the term is being used; examples of current usage; suggested definition.

Test methods

This topic will be an eye-opener for everyone interested in the inner workings of laser scanning and 3D imaging technology. Leading instrument manufacturers have provided senior technical people to participate in this work to develop an objective and verifiable suite of protocols that practitioners can use to compare performance of different instruments. We expect a number of SPAR 2008 attendees will find they can contribute to this effort as well.

E57.02 Test Methods subcommittee chair Dave Ober, product development manager at Metris, will detail how practitioners and manufacturers can give the Test Methods subcommittee input to help it prioritize what is most important in developing standard tests that will be used to characterize 3D system performance. “For example,” Ober says, “is defining standards that provide direct comparison between different 3D instruments a higher priority than characterizing the performance of each instrument itself against a target? While the latter approach appears to automatically solve the comparison direction, this is not necessarily true when we consider that, due to different instrument operational wavelengths, the comparison of performance results of one target against two instruments may not stay consistent with another different target.” This leads to some difficulty in developing a “standard” set of materials that may be fair across all instruments – how are standard target materials to be selected?

Next, Ober says, is to consider what a user does when a new material needs to be tested in order to help to make a purchase decision. “How much of that material needs to be characterized and specified such that any vendor/manufacturer could obtain the same material and be confident that the performance results that are obtained are applicable to the ‘same’ material that the user is interested in?” Last, the standard needs to define what target performance characteristics are important to measure: flatness, roundness, histogram of errors to a known surface, percentage of coverage, percentage of outliers? Ober invites attendees to help the Test Methods subcommittee set direction on these issues.

Best practices

The best tool is no better than the way it’s used. Best practices being defined by the E57 committee aim to help ensure successful and consistent application of the technology. The best practices begin with specifying a job – how end users can specify application requirements and deliverables, traceable to accepted standards – and extend to determining instrumentation, procedures, and quality control processes that will yield work product that satisfies the user’s application requirements.

E57.03 Best Practices subcommittee chair Ted Knaak, president of Riegl USA, will give an update on this group’s work to develop, validate, document and communicate best practices for successful and consistent application of the technology. These practices and guidance are meant to let end users “specify application requirements and associated deliverables traceable to accepted standards,” and to “determine instrumentation, procedures, and quality control processes yielding work product suited to application requirements.” Knaak’s presentation will use real project examples, notably road topo work, to illustrate best practices for maximizing productivity and ROI. Supporting Knaak will be E57.03 vice chair Eric Hoffman, CEO of Quantapoint.

Data interoperability

There’ll never be a better time for end users to get involved in defining data interoperability standards than now – while the laser scanning industry is still in its youth. From hard experience with other technologies, we know what happens when users don’t pay attention early enough to their interoperability needs – think CAD. That this is happening today in laser scanning is a very positive thing. Equally important, in our view the E57 committee recognizes the need to address this in ways that make interoperability practical without stifling innovation.

E57.04 Data Interoperability subcommittee chair Gene Roe, engineering and construction solutions product manager at Autodesk, will discuss the scope of the Data Interoperability subcommittee’s mission, review the committee’s work to date – producing a draft of the data format requirements document – and describe plans for 2008, which call for a draft standard by the end of the year. Roe will be seeking subcommittee members from both medium/long-range and short-range scanning markets, as well as corporate commitments of support.

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