Monday, February 18, 2008

Advantages of Simultaneous Aerial LIDAR/Ortho Image Acquisition

TopoSys North America Inc., Denver, Colo., will feature the advantages of simultaneous LIDAR/Ortho Image acquisition at the International LIDAR Mapping Forum (ILMF) in Denver, Colo. February 21-22 and will conduct a workshop titled “Complete, End-To-End, Workflow of Typical LIDAR Projects from Pre-Flight Planning through to Data Processing and Final Deliverables.”

The workshop will provide an in-depth view of the step-by-step processes and workflows of wide-area and corridor LIDAR/ortho imagery projects. It will focus on the use of the TopoSys line of LIDAR/imaging systems and using TopPIT, the pre-and-post processing software, to create deliverables such as Digital Surface Models (DSM), Digital Terrain Models (DTM) and True Ortho-Imagery.

The TopoSys line of LIDAR/Imaging systems is comprised of three systems: The state-of-the-art Falcon III features a fiber-based laser providing the most accurate, uniform LIDAR point-cloud and an integrated RGB/NIR line scanner; the versatile Harrier 56 with Full-Wave-Form echo digitization, 200 kHz pulse rate laser scanner combined with a calibrated 39M pixel camera; and Harrier 24 is an optimized entry-level system for helicopter-based mapping with the combination of a calibrated 39M pixel camera and a low-cost 10 kHz Laser.

All three sensor systems are complemented by TopPIT, the LIDAR processing software developed by TopoSys to handle all pre-and-post processing functions. It streamlines the entire workflow from pre-flight planning to the creation of deliverables such as DSM’s, DTM’s and true ortho-imagery. TopPIT co-registers the RGB/CIR imagery together with the LIDAR data and uses the DEM to rectify "true" orthophotos in one production flow. (To read article with images click:

The workshop will also look at the advantages the TopoSys LIDAR/Imaging systems provide aerial LIDAR surveys, such as: Reliability, Productivity, Quality and Accuracy.

1 – Complete line of sensor systems:
Totally integrated systems include GPS, IMU, data storage, flight planning, LIDAR sensor and RGB/CIR camera.

2 – No mechanical wear-out means no repetitive calibration or boresight:
The advanced systems TopoSys utilizes, such as the fixed-beam deflection of the fiber-based scanner, have eliminated all mechanical errors. Therefore, they do not require regular calibration or boresight tests. Toposys systems require calibration only once a year performed by a factory technician.

LIDAR coordinate systems change significantly on systems based on an oscillating mirror to deflect the laser beam, thus requiring frequent boresight flights. LIDAR technology based on an oscillating mirror needs to mechanically accelerate from side to side, deflecting the laser pulse onto the ground. This mechanical process of flipping the mirror from side to side, requires the mirror to start, speed up, then slow to a complete stop before reversing, speeding up and stopping again hundreds of times per second. This leads to mechanical wear-out causing the alignment with the IMU to drift and requiring a “boresight” before every mission.

3 – Highest quality data:
High-density, overlapping measurements and a uniform scan pattern allow for exact detection of objects and line objects such as power line cables, polygon structures and better representation of small vertical objects. Vertically stacked objects such as individual power line cables can also be identified.

A further consequence of the accelerating/decelerating oscilating mirror is that it paints the ground with a varying point density: More points are concentrated on the swath-ends than in the center where they are more useful for aerial LIDAR surveys.

4 – Production-proven:
TopPIT LIDAR/Imaging software has been used on a daily basis in a LIDAR/Ortho Image production environment for 12 years with proven productivity. One software handles the entire workflow from pre-flight planning to creation of final deliverables such as DSMs, DTMs, and True Digital-Orthos. The high quality data from the TopoSys sensors helps to automate and streamline the process.

5 – Productivity gains:
Save up to 50% in data acquisition times for projects requiring LIDAR and imagery by collecting accurate, high-density LIDAR simultaneously with high-resolution RGB/NIR ortho imagery.

6 – Proven reliability:
Twelve years of day-to-day, aerial survey operations in fixed-wing or helicopter platforms makes the TopoSys LIDAR/Imaging Systems the most reliable on the market - German-engineered, space-frame construction results in the most stable, durable and dependable LIDAR/Imaging systems.

7 – 12 years of practical experience as a service provider is built into systems, software and support for its customers’ LIDAR mapping business.

About TopoSys:
TopoSys Topographische Systemdaten GmbH was founded in 1995 as a spin-off of Dornier GmbH, one of the world’s leading air- and spacecraft manufacturers. Building on its long-standing expertise in the development and production of fibre-optic LiDAR scanners, TopoSys is committed to the manufacturing and worldwide marketing of turnkey LiDAR systems that include three newly developed products: Falcon III, Harrier 56 and Harrier 24. TopoSys offers a well-balanced family of sensor systems, allowing its customers to deliver all LiDAR applications from precise, wide-area topographic mapping to high-density corridor mapping. TopoSys North America Inc. was established as a wholly owned subsidiary in February 2007, with its North American headquarters situated in Denver, Colo.

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