Aspect‐independent cylinder discrimination by human observers using broadband sonar pulses

Abstract

An experiment was conducted to determine the capabilities of four human subjects to discriminate broadband sonar echoes from cylindrical targets independent of target aspect. Digital recording of target echoes were obtained using dolphinlike echolocation signals, and played back to the subjects at 150 of the original sample rate. The targets, which were 17.8 cm long and 7.62 cm in diameter, included cylinders of solid aluminum and rock, hollow water‐filled steel, and hollow aluminum filled with water, air or powder. The subjects were first trained to discriminate between a pair of targets at 0°, 45°, and 90° until performance reached 100% correct at each aspect. Next the subjects were trained until they achieved near perfect performance with the three target aspects occurring randomly during a session. The subjects' abilities to generalize discrimination cues from the three previously learned aspects were measured by randomly presenting target echoes from seven aspects during a session, four of which were...