July 11, 2013

3D Laser Scanning: Different Type of Scanners

Hi this is Eugene A. O’Day, IX, an application Specialist with Ideate, Inc.

Did you know that 3D laser scanning is as much about precise measurement as it is about stunning visualization?  Are you intrigued with the concept of Scan-to-BIM?  Wait I might be getting ahead of myself.  Are you unfamiliar with the terms; 3D laser scanning, LiDAR, and point clouds?  If you are, then this blog might interest you.  Today’s blog will focus on the very basic of scanning terms and the different types of 3D laser scanners. 

Scanning Terms 101
3D Scanners:
Devices that analyzes a real-world object or environment to collect data on its shape and possibly its appearance i.e. color. The purpose of a 3D scanner is usually to create a point cloud of geometric samples on the surface of the subject.  The collected data can then be used to construct digital, three dimensional models. 
3D Object Scanning:
Allows enhancing the design process, speeds up and reduces data collection errors, saves time and money, and thus makes it an attractive alternative to traditional data collection techniques such as tap measure with pencil and paper. 3D scanning is also used for mobile mapping, surveying, scanning of buildings and building interiors, and in archaeology.

Is a remote sensing technology that measures distance by illuminating a target with a laser and analyzing the reflected light. The term LiDAR comes from combining the words light and radar.

Point Cloud:
A large group of 3D points that spatially represent the environment around the laser scanner.
Types of Scanners

There a handful of different types of scanners on the market; each type comes with its own limitations, advantages and costs.
Airborne laser scanning is a scanning technique for a data capture of the earth surface.  It’s an important data source for environmental applications, being able to map topographic height, and the height of surface objects, to high vertical and horizontal accuracy over large areas.

Ideal Usage:
• Exterior mapping
• Corridor
• Large scale mapping

Accuracy and Range:
• Accuracy +/- 10 CM Depending on conditions.
• Range 3.000 feet (typically flown at about 3,000 FT).

Mobile mapping is a non-invasive, state-of-the-art solution that incorporates the most advanced ground-based LiDAR sensors, cameras, and an inertial measuring unit to collect survey-quality point data quickly and accurately.

Ideal Usage:
• Rapid exterior mapping for corridors w/imaging.
• Mapping, Asset Management, Utilities, Planning,
Disaster Management, Tunnel, FAA airport design and layout. 

Accuracy and Range (Topcon IPS-2)
• Accuracy +/- 3 to 5 CM Depending on conditions.
• Range 30 to 100 meters depending on conditions.
Think Google maps

Phased Based:Constant waves of varying length are projected. Upon contact with an object, they are reflected back to the scanner. The distance from the scanner to the object is accurately measured by measuring the phase shifts in the waves of infrared light.

Ideal Usage:
• Exterior high accuracy longer range scans
• (Architectural Reconstruction, Surveying, Engineering, Planning, Forensics).

Accuracy and Range (Topcon GLS-1500)
•    Accuracy +/-2MM
•   Range 150 to 330 meters depending on conditions.

Time of Flight:
An active scanner that uses laser light to probe the subject(s).  At the meat and potatoes of this type of scanner is a time-of-flight “laser rangefinder”. The laser rangefinder finds the distance of a surface by timing the round-trip time of a pulse of light. A laser is used to emit a pulse of light and the amount of time before the reflected light is seen by a detector, is measured.

Ideal Usage:
• Interior high density high accuracy scans (MEP, Architectural, Structural, Facilities Management, and Forensics).

Accuracy and Range (FARO Focus3D)
•    Accuracy +/-2MM
•   Range 60 to 120 meters depending on conditions.

Stay tune for more Scanning definitions…

Eugene . O’Day, IX
AEC Application Specialist

Eugene A. O’Day, IX, with more than 25 years of architectural and mechanical experience, offers a trained focus on all things Revit and BIM. Teaching is a passion of his. Eugene has been an instructor in undergraduate degree programs, has traveled worldwide teaching Autodesk solutions to major corporations, has taught at accredited ATCs throughout the Northwestern region, and is a frequent and popular instructor, speaker, and presenter for AUGI® CAD Camps, Revit – and related product user groups. He has also been a trusted public school district advisor on new drafting instructor hires. At Ideate, Eugene provides training and support for Revit Architecture, Revit Structure and AutoCAD. Eugene is also a Revit Architecture Autodesk Certified Professional.

Get it. Know it. Use it.

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