One of the keys to situational awareness is maintaining a clear view of the full 360 degrees around a point of interest. Panoramic vision systems are many and diverse, ranging from fisheye lenses and wide-angle mirrors such as may be seen in any large market to powerful pan-tilt-zoom cameras and complex, clever assemblies of lenses and mirrors designed for larger fields of view. IEM has been actively involved with developing improved panoramic vision systems for several years. Research has sprung from development of vision-based navigation systems for military Unmanned Ground Vehicles and development of automated surveillance systems for a number of security applications.
IEM has developed panoramic imaging systems based on several core technological approaches, including traditional approaches of ultra-wide angle lenses and catadioptric mirrors as well as custom designed systems by IEM such as our Agile Mirror Approach and our patented Synthetic Field of View or SynthFOV camera.
Ultra-Wide Angle Lenses
Ordinary cameras, and the human eye, cover only a small fraction of a panoramic field of view at a time. In many security and safety monitoring applications, this means that crucial events or situations can be missed. It is therefore of paramount importance in these circumstances to be able to provide wide-angle visible coverage.
IEM has a wide variety of experience with wide-angle lenses, ranging from careful evaluations of many commercial wide-angle and fisheye lenses for dozens of applications to designing our own lenses for visible, near-IR, and thermal infrared uses.
Catadioptric Systems
Complex lens systems can often be heavy and expensive. This is especially true for larger systems with a need for high light gathering capacity, because that capability is essentially dependent on the diameter of the objective lens.
Mirror-based systems with a simple lens objective component, called by the more precise term catadioptric systems, can often provide flexibility and lightweight alternatives at lower cost than precision-ground lens systems. IEM has developed panoramic systems passed on this technology including creation of software for automatically correcting for mirror-generated distortion
Synthetic Field-of-View (SynthFOV)
IEM’s patented SynthFOV™ Synthetic Field of View design emerged from attempts to develop a reasonably priced panoramic imaging system for a military UGV that would enable full resolution of the camera for the entire field of view. This would solve one of the inherent problems with wide angle lenses and catadioptric mirrors: the entire panorama is imaged at the full camera resolution thereby significantly limiting the resolution on a particular target, particularly when that target is in the distance. SynthFOV units may cover an entire panorama or any fraction thereof with high-resolution, low-distortion imagery. Moreover, SynthFOV units have no moving components and therefore are not subject to the physical breakdowns seen in other systems. In production such systems can also be quite inexpensive. Only very minor and simple image processing – easily performed by a single microcontroller – is necessary for SynthFOV systems to provide top-quality, easily understood imagery of the entire panorama.
Agile Mirror Panoramic System
Traditional pan-tilt-zoom systems, while commonly in use, have a number of serious limitations. The most obvious of these stem from the fact that the camera and lens systems must be constantly moved; such mechanical systems consume power and offer numerous opportunities for breakdown, both in the main mechanical systems themselves and in the camera as well, which suffers various strains and vibrations from being constantly moved, jerked in one direction or another, and so on. These stresses also wear on the wires connecting the camera to power and data transmission lines.
IEM’s patent-pending Agile Mirror system reduces or eliminates many of these challenges by asking a single question: why do we move the entire camera system when what we really want to move is the field-of view? The Agile Mirror uses a unique mounting which permits it to use a mirror to look in any direction – up, down, and all around – and direct that light to the camera, which remains immobile and protected in the Agile Mirror’s casing. IEM has demonstrated that the same Agile Mirror design can be made a multispectral fusion system, projecting the same view to both a visible light and thermal infrared camera.
