3-D Laser Scanning Technology

Friday, December 2nd, 2011

Blog by John V. Mettee III, Prof. LS

In a recent magazine publication called “811 – Damage Prevention Professional” Fall 2011 issue (click for article), is found an article entitled “As-built Surveys: The Benefits of 3-D Laser Scanning” under the Mapping & Technology Section. This article highlights the declining role of field surveyors on construction sites due to the proliferation and increased sophistication of today’s technology. The article goes goes on to say that 3-D Laser Scanning technology is a cost-effective way to assist with construction monitoring and verification as well as providing a means for capturing data for as-built surveys. I certainly agree that this is the reality of this technology. One is able to gather much more data in the same amount of time it takes for conventional means to gather just a few points. Even better yet, with this technology you can acquire a background photograph that is geo-referenced to further visualize where the data was gathered. The article discusses how the technology works and shares a sample project. It also goes on to highlight the benefits of using this great technology. However, it did not speak to the drawbacks.

After personal experience with this technology, I have found that the amount of data found in the “point cloud” can be overwhelming. With conventional technology, one would be concerned with having enough data and having the data in the right areas. With 3-D laser scanning technology, the concern is having too much data and the need to properly filter out unneeded or bad information. The data can be analyzed and filtered, but one needs to exercise care. Furthermore, in my experience a 3-D laser scanning project will require more instrument set ups than conventional technology. This is primarily due to items being hidden from the scope of the instrument by something blocking the view. Again this is not a problem, it just requires additional instrument set ups to gain the data that was not in view from the previous set up. The fact that this technology acquires data so quickly; certainly there is ample time in the day to make more set ups than usual.

Lastly, what was pictured in the article was a 3-D Laser Scanning Instrument that is manufactured by Leica. There are other manufacturers for this technology. Trimble makes a 3-D laser scanner. In fact, Trimble integrated the technology with conventional total-station technology in an instrument known as the Trimble VX Spatial Station (click for article).

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