Tips on Purchasing a Laser Scanner

Written by Michale Olsen
Saturday, 26 May 2012

The selection of a laser scanner can be a difficult decision.  Let’s face it, they all are cool and it would be nice to have one of each!  But ultimately, it is a significant investment and you want to make sure that you get the optimal value out of your purchase.  Laser scanners may have specific purposes, environments, or applications for which they are best suited.  Caution must be used when comparing scanner specifications because there are no consistent standards for testing and reporting, although the ASTM E57 committee is working to address this issue.  For example, the accuracies of scanners vary non-linearly with distance and some manufacturers publish accuracies at 50 m and others at 100 m.  Overall accuracies are influenced by the surface being scanned, geometric configuration of the scanner and target, environmental conditions, laser properties, and many other factors.  Point of Beginning offers a very helpful list of specifications (usually updated yearly) for a variety of scanners and should be consulted by anyone looking to purchase a scanner.

As I have discussed in previous articles, scan geo-referencing can also induce error.  For example, the accuracy of a survey grade GPS unit is typically 1.0 cm in the horizontal and 2.0 cm in the vertical.  Thus, data acquired from a scanner with a millimeter level accuracy will no longer be of millimeter accuracy if GPS is used for the scan geo-referencing.

Some criteria that should be weighted in the selection of a scanner include (although not limited to):

1. Type of laser (wavelength) – How well does the laser reflect off the type of surfaces to be scanned?  Are you scanning metal objects, topography, wet surfaces, dark surfaces?

2. Spot size (pulse width, beam divergence) – What will be the size of the laser spot on the target?  Do features smaller than this need to be modeled?

3. Speed – The most common question/metric is: How many points does it collect per second?  Most scanners are fast so this is not the most crucial ifnormation.  A more important question is: How much setup time (e.g. mount the instrument, boot up, select scan window, acquire imagery\targets, and scan) is involved?  The latter can dominate a lot of the actual field time required.  Another question is how much processing is required and what workflow optimizations are presented by the scan manufacturer.

4. Field of View – How wide is the scan view? (Many scanners can scan 360 degrees horizontal, but have a limited vertical window).

5. Accuracy – What level of instrument measurement error is acceptable to fit into your overall error budget?  This will depend on the intended applications.

6. Resolution – What point density is achievable/required?

7. Range – How much coverage is needed in a single scan?

8. Geo-referencing – Does the scanner have a calibrated GPS mount for geo-referencing? Or are external targets required?

9. Level compensators\Inclination sensors – Can the scanner correct for out of level setups, improving data quality?

10. Mobility, durability – Is the scanner designed for field operation?  Or is it meant to be an indoor scanner?

11. Photography – Do you need photographic information? Does the scanner use an internal or external camera?  What steps need to be taken to map the photograph to the point cloud if it is external?  Is the photograph taken simultaneously or as an additional data collection procedure?  How long does this take?

12. Software – What software package is used for aligning and meshing the scans? What features are available?  How does this package integrate with the other packages you are currently using?

13. Effects on humans – Is it eye safe? Will it set off security alarms (e.g., in cultural heritage applications, you may be scanning in a museum with an alarm system (I have had that happen before!))?

14. Maintenance – What are the costs associated with maintaining the scanner?  Many manufacturers offer maintenance packages.

15. Upgrades – Scanner technology evolves quickly.  Would you be able to upgrade your scanner (or obtain a trade-in credit) when it is time to upgrade?

Obviously you would also want to do a cost/benefit analysis when comparing different systems.  Ultimately, invite the manufacturers out and have them demo the scanner in the environment you will be using it in most frequently.  Also, ask them to let you demo the software so you can get a feel for the workflow and how that will integrate into your current operations.

If your agency is looking to purchase multiple scanners, a few questions arise.  Do you want to go with various types of scanners so that you have a versatile amount of equipment for any job?  Or is it better to standardize your equipment so that all personnel are using the same scanner, reducing training costs?

Good luck in your new scanner purchase!

originally published at LiDAR News http://www.lidarnews.com/content/view/9015/

Trimble Adds CAD Point Creator Software to its Building Construction and MEP Portfolio

New Trimble Point Creator Office Software Provides the Ability for Contractors, Engineers,
Detailers, and Architects to Create 2D and 3D Points for Field Layout within their Native CAD Application
NEW ORLEANS, May 5, 2010 — Trimble (NASDAQ:TRMB) today introduced the Trimble® Point Creator Software for contractors, engineers, detailers, and architects supporting the building construction industry as well as mechanical, electrical, and plumbing trades. The application, available in two versions—Trimble Point Creator and Trimble Point Creator Pro—provides a platform where Computer Aided Design (CAD) users can create 2D and 3D points easily transferrable to and from a Trimble LM80, Trimble MEP, Trimble TS Series Total Stations as well as other total stations. The application is compatible with popular CAD platforms such as AutoCAD, Bricscad, and ZWcad.

The announcement was made today at the Associated Builders and Contractors 2010 Educational Conference, the association’s annual gathering of merit shop contractors, subcontractors, material suppliers, and related firms throughout the U.S.

As the construction industry continues to push the utilization of Building Information Modeling (BIM) practices for cost savings, overall efficiency, and project data collaboration. Trimble Point Creator Software enables users to create 2D and 3D points directly within familiar CAD platforms—and then easily share with field layout software/controllers. For the project manager utilizing CAD drawings for information as well as point creation for field layout, Trimble Point Creator works seamlessly inside CAD software, simplifying data preparation for layout.

By incorporating common industry standards and file formats such as .cnx, .dwg, .dxf, .csv, and many others, Trimble Point Creator Software supports the transfer of points to and from a Trimble LM80, Trimble MEP, Trimble TS Series Total Stations as well as other total stations on the market today. And with overall data integrity playing a key role in the effectiveness of deploying BIM throughout a project, Trimble Point Creator is designed to retain each point�s attribute data, even when imported from a field controller file.

The introduction of Trimble Point Creator Office Software to Trimble’s Building Construction portfolio demonstrates a continued commitment to leveraging technology to deliver solutions that provide a strong return on investment for a broad range of contractors and trades on the industrial, commercial, and residential construction jobsite.

Trimble Point Creator and Trimble Point Creator Pro Software are available now through Trimble’s worldwide Building Construction Distribution Network.

About Trimble’s Building Construction Business

Trimble’s Building Construction Division is a leading innovator of productivity solutions for the building construction contractor. Trimble’s solutions target site prep, general, concrete, mechanical, electrical, and plumbing contractors on large and small commercial, industrial and residential jobsites. Trimble is focused on delivering solutions that tightly link office based process and information with the field crew—including taking Building Information Modeling (BIM) and other design data to the field for highly accurate positioning and layout of foundations and mechanical, electrical, and plumbing systems. Trimble solutions provide a high-level of process and workflow integration from the design phase through to the finished project—delivering significant improvements in productivity throughout the building construction lifecycle.

About Trimble

Trimble applies technology to make field and mobile workers in businesses and government significantly more productive. Solutions are focused on applications requiring position or location—including surveying, construction, agriculture, fleet and asset management, public safety, and mapping. In addition to utilizing positioning technologies, such as GPS, lasers and optics, Trimble solutions may include software content specific to the needs of the user. Wireless technologies are utilized to deliver the solution to the user and to ensure a tight coupling of the field and the back office. Founded in 1978, Trimble is headquartered in Sunnyvale, Calif.