3D Scanning: Terminology:
Professional Surveyor Magazine - October 2011
"Scanning" or "Hi-Def"?
or those who’ve read my many educational columns in Professional Surveyor Magazine about this technology over the years, you may have noticed that sometimes I refer to the technology as “laser scanning” and sometimes I refer to it as “high-definition surveying.” I get asked about these different terminologies, often from the perspective of “Well, which is it?”
The fact is that I am careful about how and when I use each term. In this article, I explain why I use each term when I do and, more importantly, when and how service providers should use these different terms as appropriate to better educate and favorably influence prospective clients.
Implications of Different Terms
As much as surveying and measurement professionals are familiar with this technology today, one thing remains crystal clear: Many prospective clients are not that familiar with it, may have distorted views of it, or have often never even heard of it. As a result, service organizations that have this technical capability as part of their tool kit typically spend a lot of time educating clients about it. This education/marketing task is important. If a prospective client “gets it,” it’s easier to reach the point of contracting services; if not, you can just get lots of blank stares.
Fundamentally, the term “laser scanning” and variants of it, such as “3D laser scanning,” “3D scanning,” or “terrestrial lidar,” all refer to the field method of data collection. The words “scan” or “scanning,” in particular, imply certain field-productivity and logistical advantages over other methods of field-data collection.
In contrast, the term “high definition surveying” and variants such as “high density surveying,” “hi-def surveying,” “hi-def,” “3D imaging,” etc. refer to the data that has been collected. These terms likewise imply certain benefits associated with high-definition survey data/information over survey data collected using traditional methods.
The very fact that this technology can provide valuable benefits both in the field methodology used for data collection and in the collected data/information itself is what has made it so interesting and exciting for professionals in the industry.
What “Scanning” Implies
Merriam-Webster’s online definitions of the verb “scan” are:
- to read or mark so as to show metrical structure <scan poetry>
- to examine by point-by-point observation or checking: a: to investigate thoroughly by checking point by point and often repeatedly <a fire lookout scanning the hills with binoculars> b: to glance from point to point often hastily, casually, or in search of a particular item <scan the want ads looking for a job>
- a: to examine systematically (as by passing a beam of radiation over or through) in order to obtain data especially for display or storage <scanned the patient’s heart> <radar scans the horizon> <scan the photos into the computer> b: to pass over in the formation of an image <the electron beam scans the picture tube>”
If the word “scan” or “scanning” is used to describe this technology, prospective clients might first think of these various other definitions. When they hear the term “laser scanning,” two key aspects are implied: 1) it’s fast, and 2) it uses remote sensing to make observations/measurements.
For surveying, both of these aspects relate to field-data collection and imply certain benefits. First, “scan” implies speed and high field productivity. So, if you’re talking to a prospective client whom you think values that a certain job could be done quicker, then using the word “scan” is appropriate.
Examples: “If your organization would benefit from getting the quantity survey results faster than you’ve been getting them in the past, then we can just scan it for you.” “If you have only a short time-window when that mapping has to be done, then we can scan it for you.”
This speed aspect can also be translated into projects being performed at potentially lower cost: “If you need to reduce your project cost, then we can use laser scanning.” Be careful here, though. Service providers often do projects faster with scanning but price them the same as when using slower, traditional methods. Higher profits from these projects help pay back their investment in laser scanning tools. In such cases, clients can still benefit from getting deliverables sooner and from other benefits of the technology described below based on its “high-definition survey” aspects, such as more complete and more informative survey data.
Remote sensing, the second key aspect implied by the word “scan” or “scanning,” not only contributes to completing projects faster (you don’t have to walk to and occupy each point to be surveyed), it also implies important logistical and safety advantages.
Examples: “If you want to avoid shutting down lanes, then we can scan the roadway for you remotely from the sidewalk, shoulder, or median.” “If the surfaces and scene are too delicate or you don’t want them disturbed, then we can scan the site for you.” “If those poles, overhead wires, rock faces, and tree tops are too hard to reach to measure them, then we can scan them for you from a convenient spot.”
So, when I use the term “laser scanning” in one of my articles, I am generally referring to field aspects of the technology and benefits that derive from its inherent high speed and remote sensing features. When I use the term “3D laser scanning,” I want to include the 3D aspect of data that is collected if “3D” is a relevant part of the point being made in the article. If “3D” is not important, then I leave it out of the terminology, as it otherwise confuses the audience or pigeon-holes the technology as only applying to 3D deliverables (which is not the case).
What “Hi-def” Implies
Merriam Webster’s online definition of the adjective “high-definition” is “being or relating to an often digital television system that has twice as many scan lines per frame as a conventional system, a proportionally sharper image, and a wide-screen format.”
The key implication here is that “high-definition” corresponds to higher density visual data that, in turn, enables a user to experience and benefit from a sharper, more informative image of a scene. It implies nothing about how the visual information was collected (that’s what the term “scanning” covers). So, in my articles, when I use the term “high-definition surveying,” or its variants, I am talking about features and benefits of the technology that directly relate to the high-density data itself.
If a client has projects that can benefit from complete, high-density data, then I will describe the technology as a “high-definition survey.” Types of sites and projects that benefit from the high-definition feature include:
- complex geometry, surfaces,
- structures and sites where a client is trying to detect slight variations, such as floor flatness or drainage/pooling problems,
- lots of detail; congested, tight fits,
- projects with fuzzy scope that can change over time,
- projects where as-built or as-is data may be used by multiple disciplines or may be re-used for purposes other than the original purpose, i.e., completeness of the data has value,
- sites that are remote and difficult to access, so completeness and assurance that everything has been captured the first time are valuable benefits, and
- projects where the client needs to be certain that the as-built information is accurate and complete, as there can be large consequences in downstream design, construction, and project costs if it’s not.
For clients with these needs, describing your solution as a “high-definition survey” or “high density survey” can immediately convey that this technology can offer pertinent, valuable benefits. Describing this as “laser scanning” in such cases may not connect at all with such a client.
In general, I don’t like and rarely use the term “3D imaging” because “imaging” is just that: pictures or graphics only. Nothing about the word “imaging” relates to measurement. Likewise, “3D” relates only to a viewing perspective, not to measurement. For me, some reference to the measurement aspect is critical when describing this technology, so I almost never use the term “imaging” or “3D imaging” as standalone descriptors.
Combining Two Terminologies
If you want to describe the technology in a way that implies both sets of benefits—those from field data collection and from the survey data itself—then I suggest saying something like, “Our laser scanner can provide a ‘high-definition’ or ‘high density’ survey for you.”
When Describing It to Lay People
When I talk with lay people who are not from the surveying, engineering, or construction fields and I use the term “laser scanning” or “3D laser scanning,” they rarely have any idea what I’m talking about. Instead, they often think of document scanners or bar code scanners.
Even the term “high-definition survey” may leave them cold if they are unfamiliar with surveying. So, instead, I try to first give an analogy of a panoramic camera in which every pixel has a 3D coordinate accurate to ¼’’ at a distance of 300’ away from the camera. This gets the audience in the right ballpark for further discussion. I’ve found that if I describe it this way and then give an example of using the instrument to quickly and accurately capture a complete forensic scene they generally appreciate what it is and how beneficial it can be.
So which is it, “laser scanning” or “high-definition surveying”? It’s both. However, depending on to whom you’re talking and what their needs are, it can be more effective to use one term instead of the other to describe it.
About the Author
Geoff JacobsGeoff is senior vice president, strategic marketing for Leica Geosystems, Inc.
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