The Prediction of Target Detection Underwater: Some Limitations of a Visibility Model

Abstract

For some viewing conditions, it is possible to predict the theoretical visual detection distance of a target in water from the rate of reduction in its contrast with the water background. Experiments were conducted at three field sites to compare the predicted distances for gray tiles of different reflectance with those obtained from human observers. The predictions were relatively accurate in water having a low light-scattering component and when the predictions were based on visual estimates of contrast (rather than on photometric measurements). Data for water with a high degree of scatter call into question the indiscriminate application of a visibility model derived from the contrast reduction equation.

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