Time of flight (ToF) LIDAR is a highly accurate distance mapping and 3D imaging technology. Time of Flight sensors emit a very short pulse of infrared light. The light pulse is reflected from objects in the scene. The ToF sensor precisely and accurately measures the pulse transit time. Since the speed of light is a constant, the measured transit time easily converted to a depth value.
The two most popular ToF sensor LIDAR architectures are global shutter flash and rolling shutter scanning. Global shutter flash LIDAR illuminates the entire field of regard with a single pulse of infrared illumination. The flash LIDAR detector consists of a proprietary focal plane array (FPA) in which each pixel independently measures the time of flight. The scanning LIDAR illuminates a narrow field of view with a narrow pulse of illumination and measures the time of flight. Subsequently, the laser and sensor must be physically scanned through the entire field of regard to capture the scene depth values. Global shutter flash LIDAR is preferred for real-time 3D mapping / imaging applications due to the simplicity, efficiency, and speed advantages.
ASC is continuously pursuing new technologies to enhance the performance, capabilities, and reliability of our gsf-LIDAR systems. Our current focus areas are:
Improved range performance
Improved field of view (FOV) performance
Improved instantaneous field-of-view (iFOV) performance
One gsf-LIDAR performance challenge is to maintain high spatial resolution and long range performance. Large gsf-LIDAR pixels are need to provide long range performance at the expense of spatial resolution. However high resolution point clouds can be created by fusing the larger long range LIDAR pixels with smaller, high resolution visible imager pixels. Merlin is a high resolution, moderate range, compact, lightweight 3D visualization system for advanced drone mapping and situational awareness applications. The system produces real time high resolution point clouds at video frame rates. The images are produced by fusing gsf-LIDAR imagery with high resolution visible imaging sensor imagery. Built-in IMU and GPS sensors enable the system to rectify and geo-locate each data point within the point cloud.