Flight assessment of a real time multi-resolution image fusion system for use in degraded visual environments

Abstract

Military helicopter operations are often constrained by environmental conditions, including low light levels and poor weather. Recent experience has also shown the difficulty presented by certain terrain when operating at low altitude by day and night. For example, poor pilot cues over featureless terrain with low scene contrast, together with obscuration of vision due to wind-blown and re-circulated dust at low level (brown out). These sorts of conditions can result in loss of spatial awareness and precise control of the aircraft. Atmospheric obscurants such as fog, cloud, rain and snow can similarly lead to hazardous situations and reduced situational awareness. Day Night All Weather (DNAW) systems applied research sponsored by UK Ministry of Defence (MoD) has developed a multi-resolution real time Image Fusion system that has been flown as part of a wider flight trials programme investigating increased situational awareness. Dual-band multi-resolution adaptive image fusion was performed in real-time using imagery from a Thermal Imager and a Low Light TV, both co-bore sighted on a rotary wing trials aircraft. A number of sorties were flown in a range of climatic and environmental conditions during both day and night. (Neutral density filters were used on the Low Light TV during daytime sorties.) This paper reports on the results of the flight trial evaluation and discusses the benefits offered by the use of Image Fusion in degraded visual environments.