Lidar Industry Pioneer Positions the New Leica TerrainMapper-2
I recently had the opportunity to speak with airborne lidar sensor pioneer, Ron Roth*, Product Manager for the new Leica TerrainMapper-2. This high performance, linear-mode lidar system features a major camera system upgrade from one 80 megapixel RGBN CCDs to two 150 megapixel CMOS nadir cameras – one RGB and the other near infrared. In addition, the TM-2 features a unique, mechanical forward motion compensation (FMC) feature that significantly improves data capture in low-light conditions. More on that below.
First, a little background. With the release of Leica CityMapper-2 last year at INTERGEO 2019, regional mapping customers quickly noticed the 150 megapixel cameras that were part of the new CityMapper-2 release. Naturally they wondered if their TerrainMapper could be upgraded to support higher resolution image products. This was the impetus and next logical step in the hybrid lidar sensor road map for Ron and his team.
The two guiding principles for the TerrainMapper-2 were that it (1) continues to deliver high performance by being a hybrid of lidar and camera sensors and (2) that, just like the CityMapper system, it be modular in design. The goal being to collect more data while maintaining, if not reducing, the flight times. In other words, reducing the cost per data point collected.
To increase performance the cameras and lenses were selected such that the field of view of the lidar sensor and the cameras were matched at about 40 degrees. This results in a “pixel for each lidar point,” thereby preventing the need for flying additional flight lines to obtain full coverage by both sensors.
The beauty of the design approach is that it is modular, meaning the system can be seamlessly upgraded to a CityMapper-2. Should the survey contractor decide that they need the additional four oblique cameras to serve the needs of city mapping customers, a service technician can install the new components in a few hours, converting the TerrainMapper-2 into a fully functioning CityMapper-2 while preserving the customer’s original investment.
While they were doing the camera upgrades, Leica Geosystems developed a more compact, integrated system controller including storage making it easier to install in any survey aircraft. This resulted in the entire system being inside the sensor pod, thereby eliminating a number of cable connections and an additional equipment rack, while reducing the overall weight. Although there is no actual change to the spec sheet for the Hyperion lidar module, there is less noise and cleaner data with the version used in TerrainMapper-2.
The FMC is built into each camera, eliminating focal blur. Without this feature the camera shutter speed would have to be set very high (limiting flying conditions for optimal exposures), or the plane would have to fly slower (limiting productivity). FMC is a unique feature to Leica Geosystems’ image cameras.
On the data processing front the first item to note is that the TerrainMapper-2 now collects all of the required data on the same media. In the office the data is processed in a unified, multi-sensor workflow using the Leica HxMap which is part of Leica Geosystems’ RealTerrain solution. For large projects, HxMap supports multi-node distributed processing, providing customers with the flexibility to adjust their data processing times to meet the needs of their customers.
Recognizing that lidar is the dominant data type in TerrainMapper-2, customers can increase efficiency and productivity with advanced filters and precise point cloud alignment algorithms. Using edge computing, the lidar data undergoes discrete return extraction from the full waveform data on the fly, allowing faster ground processing results. In addition, both discrete return and waveform data can be stored to allow the end user the ultimate in flexibility.
The target customer for the TerrainMapper-2 is an aerial mapping firm that has a need for a sensor for small to regional-size projects, but whose business is growing and wants to have an upgrade path built in and guaranteed for the future. The extended flight times due to FMC allows for the capture of higher resolution image products such as orthophotos even in low light conditions on the lidar projects. This provides the customer with greater flexibility in flight scheduling and competitive advantage.
Thank you to Ron for his comments and insights. Good luck with the launch.
For more information CLICK HERE.
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*Ron was involved with the development of one of the first commercial airborne lidar sensors in the late 1990’s.
