Restraint Method of Background Interference for Detection of Light Wakes

A restraint method of background interference for detection of light wakes is presented according to the source and characteristics of background interference. The theoretical and experimental investigations show that the valid ways to restrain the background interference are as follows: to set up a narrowband optical spectrum filter on a photoelectric detector with its narrowband spectrum width just covering the radiation spectrum of illuminating laser; to apply the forward scattering measurement to effectually restrain the scattering interference of water molecules and suspended solid particles; and to measure the scattered light′s spatial spectrum intensity distribution of air bubbles in water in order to characterize the air bubbles′spatial distribution by the full width at half maximum (FWHM) of the measured light distribution via Gaussian fitting and thus to detect ship wake, which can moreover restrain the interference of sunlight whose spectrum is coincidence with that of laser radiation. The result could be applied to detection of light wakes.