Dr. Qassim Abdullah
Dr. Qassim Abdullah is an accomplished scientist with more than 37 years of combined industrial, research and development, and academic experience in analytical photogrammetry, digital remote sensing, and civil and surveying engineering. His current responsibilities include designing and managing … More »
Geiger Mode Lidar and Single Photon Counting Lidar: Immediate Threat or Gold Mine of Opportunities
November 20th, 2015 by Dr. Qassim Abdullah
Do not feel intimidated with the names, but Geiger Mode Lidar (GML) and Single Photon Counting Lidar (SPCL) are no different from any other lidar in the sense that they deliver point cloud data for light-reflective ground surfaces. In layman’s terms, GML and SPCL are lidar systems that utilize a Focal Plane Array concept that is similar to a digital camera. Instead of a single detector, as is the case with the current linear lidar, both GML and SPCL utilize an array of detectors to receive the split pulse. In these new lidar systems, each laser pulse gets split into multiple sub-pulses to increase the data density and ground resolution. Depending on the system architecture and optics design, the pulse gets split either on departure or after it reflects back before it reaches the detectors.
These systems are commercially available now and a few of them are used in a full-production environment, providing data with a nominal point density of 8-12 points per square meters or higher according to the manufacturer’s claim. Such new lidar collects dense point cloud data from a higher altitude, resulting in wider ground coverage and therefore higher productivity. Such lidar systems will enable data providers to routinely deliver data according to Quality Level 1 of the USGS–NGP and 3DEP specifications.
With the little information available about these new lidar systems, some may perceive the new technology as a threat to their current investment in the linear lidar while others see in it as a gold mine of opportunities. In my opinion, at least for the next five years, the new lidar will neither eliminate the need for the current linear lidar nor will it be the gold mine that some anticipate.
I believe the two lidar technologies, linear and GML/SPCL, will coexist for a while and in many cases will complement each other as users’ needs and specifications vary widely.
Here are the arguments behind my belief:
Finally, although very little is known about them to many, Woolpert has participated in the development of an SPCL system and in the processing of its data over the last few years. My personal experience with the data accuracy and quality is very positive, and I would like to assure you that the GML and SPCL lidar systems are real and that technology are here to stay. It is just a matter of time before they become very popular.