Real‐time 3D Tracking

Abstract

The ability to track objects in real time in a 3D environment has many real world applications, such as sensors that allow people to interact with electronic devices in very natural and intuitive ways. Controllers that can follow our hands or fingers and interpret our intentions could make human-machine interaction a more enjoyable, ergonomic and a more precise experience. Another application area is industrial automation, that heavily depends on the ability of robots to precisely locate and position objects.To address some of these needs, whilst with a highly flexible and low-cost solution, we have developed a tracking and position measurement technology, dubbed "MEMSEye", based on a beam steering MEMS mirror. It is capable of searching and tracking the position of a retro reflective target and providing position measurements at very fast update rates and with high resolution in a large volume. Multiple MEMSEyes can obtain 3D coordinates of the target utilizing triangulation methodologies. When multiple targets are used simultaneously, the system can obtain the orientation of an object as well as its location. A recent redesign and improvements of the system for an outdoor application resulted in a laser tracking system capable of direct sunlight operation at distances of up to approximately 150 m. IntroductionObtaining real-time 3D coordinates of a moving object has many applications such as gaming [1], robotics, human-machine interaction applications [2-4], industrial applications, construction, etc. Various technologies have been investigated for and used in these applications, including sensing via wire-interfaces [2], ultrasound and laser interferometry. However, a simple and low-cost solution that can provide enough precision and flexibility has not yet been available. The MEMSEye project at Mirrorcle Technologies has aimed for several years to utilize scanning MEMS mirrors as the technology platform for building high resolution and high speed 3D position measurement systems as depicted in Fig. 1. This technology can be used to build systems that allow users to interact with virtual and augmented reality environments in a natural and intuitive way.The technology utilizes simple and low cost subcomponents such as consumer-market laser diodes, silicon photodiodes, scanning MEMS mirrors and it does not require any special optics. Search and acquisition of targets in a field of view of ~20° was demonstrated at up to 150 m distance using simple raster search patterns. Subsequently, targets are tracked and illuminated with the laser beam using various direction correction algorithms.Demonstrations included hand-held target movement at different distances and speeds, tracking of targets on bicycles, cars and a specially made test platform for high-velocity testing.The tracker is geared towards highspeed, long-distance tracking. However, in the past we had demonstrated an indoor tracking system and patented a triangulation methodology for XYZ position measurement based on the use of two such trackers (two "eyes")...

A Study of Correction to the Point Cloud Distortion Based on MEMS LiDAR System

“…There are two main scanning methods for MEMS mirrors: point-to-point scanning and continuous scanning [17][18][19]. The frequency of point-to-point scanning is relatively low.…”