Norman A. Peppers

Determination of wave slopes from photographs of the ocean surface: a new approach

A general nonlinear technique is described for determining wave slopes from photographs of an area of the ocean surface that is illuminated by diffuse skylight. This technique is evaluated using uniform, overcast, and bright sky radiance distribution models, and results from its use are compared with the approximate results obtained by previous authors. Under certain clearly defined practical experimental conditions, it is theoretically possible to determine the total wave slope magnitude at the ocean surface.

Laser Damage Thresholds for Ocular Tissues

Abstract Safe laser exposure levels have enormous commercial and military ramifications and must be set neither too high nor too low. Linear thermal models indicate ranges over which thresholds increase with increasing exposure time and decreasing spot size. Reported thresholds depend on the damage criterion used. There are significant experimental uncertainties in determining energy distribution on the retina at both small and large spot sizes. Human threshold values extrapolated from animal data may be questionable, but human data are being gathered. Graphs comparing theoretical models, experimental threshold values, and recommended safe levels are shown; references to original data are given.