Comparison of airborne ocean lidar performance when operating in the obscuration and reflection modes

摘要

Abstract: On the base of a newly developed theory of image formation, which includes the effect of shadowing of the space behind an illuminated and observed object, the receiver time gating of an airborne ocean lidar system is simulated. Depending on the timing of the start of the gate, a reflected target or its shadow may be seen. The contrast and signal-to-noise ratio (SNR), for an image of the directly observed object (reflection) and the image of its shadow (obscuration), are compared. It is shown that in many cases the SNR of the object in the `shadow' (obscuration) mode can be greater than the SNR of the object observed in reflection compared at the same depth. In addition, the obscuration mode is advantageous for improving system performance in cases involving a priori choices of the start and duration of the gate. These advantages are most pronounced while observing an object in turbid shallow water through a windy roughened sea surface.!5