Obstacle detection for helicopter flights by infrared images

Helicopters often strike against obstacles such as a power line. To reduce such collisions, we are developing an obstacle detection and warning system for helicopters. This paper describes the techniques to detect wire-like obstacles by infrared (IR) images. Measurements were conducted to gather IR images and to investigate the sensor performance to detect obstacles in different environments. IR images proved that the use of IR cameras could greatly increase the possibility of detecting obstacles that could never be found by naked eyes. The performance to suppress sunlight noise by the 8-12 mm IR camera was also demonstrated. However, the target-to-background contrast of the original IR images was not enough as the advisory by which a pilot maneuvers his helicopter. There were cases that even IR cameras failed to detect obstacles in adverse weather and background conditions. Image processing techniques were then proposed to enhance the contrast of IR images and to improve the coverage in adverse conditions. An experimental millimeter wave (MMW) radar is now being developed to improve the detection performance and to add distance information on the enhanced images. The configuration of the MMW radar and the results of preliminary measurements by the radar were presented.