COMPUTER AIDED INTERPRETATION OF TURN POINT PHOTOGRAPHS

Abstract

An image progessing system suitable for aiding in competition photographic interpretation has been described. The system allowsa positive image of the negative to be displayed on a standard video monitor. The computer image of the turn point photograph may be enhanced by the histogram equialisation technique which shows good results for hazy photographs. Thus, turn point photographs are instantly and easily viewed by the PI. Images may be stored on disk and easily recalled, thus obviating some of the problems of storing negatives. The glider position may be determined by computer aided analysis of the turn point photograph. This has been demonstrated to have a horizontal positional determination error of pnlf. 15.4 m for a photograpth at typical glider flying height. The system is thus, potentially accurate enough to resolve turn point penalties in situations where the PI is unable to assess correctly the penalty by visual interpretation. The ultimate limitation of tlie system will become apparent when more field experience has been gained. ln the context of surveying, rather than gliding, the equipment would be described as cheap. However, most of the components, particullarily the computer, are becoming increasingly available in gliding clubs thus reducing the overall cost.