STATIC AND DYNAMIC VISUAL FIELDS IN VEHICULAR GUIDANCE

Abstract

PERCEPTUAL PROBLEMS IN VEHICULAR GUIDANCE ARE CONSIDERED IN THE CONTEXT OF THE POSITIONAL, VELOCITY AND ACCELERATION FIELDS AROUND THE MOVING VEHICLE. THESE ARE VERY GENERAL AND PERSISTENT ASPECTS OF THE DRIVERS VISUAL ENVIRONMENT. THE EQUATIONS GOVERNING THESE FIELDS AND THE FIELDS THEMSELVES, ARE EXAMINED FOR FEATURES AND REGULARITIES WHICH MIGHT SERVE TO EXPLAIN HUMAN SPATIAL PERCEPTION. ANALYSIS SHOWS THAT THE KEY FACTOR IN SIZE, DISTANCE AND MOTION PERCEPTION IS THE INTERPRETATIVE SCALING OF VISUAL ANGLE, WHICH IS IN THE INVERSE OF PERSPECTIVE EFFECTS IN THE POSITIONAL FIELD. SIMPLE AND OBVIOUS FEATURES OF THE VISUAL ENVIRONMENT ARE BELIEVED TO PROVIDE THE MOST IMPORTANT AIDS FOR VEHICLE GUIDANCE. THE ROADWAY AHEAD OF THE VEHICLE, FOR EXAMPLE, MAY BE USED TO OBTAIN THE SCALE OF THE TERRAIN AND OBJECTS IN IT. THE VELOCITY FIELD FURNISHES A REFERENCE FOR THE SEEN MOVEMENT OF OBJECTS. SOME DIFFICULTIES ARE POINTED OUT IN THE MOTION PARALLAX INDICATION OF DISTANCE. ROADWAY BOUNDARIES AND LANE MARKINGS ARE USED IN ALIGNING THE MOVING VEHICLE WITH THE ROAD. THE FORMULAS DERIVED INDICATE THAT ANGULAR ACCELERATION INCREASES AS THE SQUARE OF VEHICULAR SPEED. SINCE THE PATTERN OF THE ANGULAR ACCELERATION FIELD DOES NOT RESEMBLE ANY FAMILIAR PATTERN OF VISUAL EXPERIENCE, EVIDENCE IS PROVIDED THAT ANGULAR ACCELERATION IS NOT DIRECTLY SENSED.