Measurement of the point spread function in the ocean.

A new instrument to measure the point spread function (PSF) in the ocean is described. This instrument uses a CCD solid state camera to measure the angular radiance field due to a pulsed Lambertian source. In this way the PSF can be measured easily at sea, when precise alignments over ranges >10 m cannot be maintained. With the large dynamic range of the camera system, the PSF can be measured over short ranges (10 m), and the variation of the PSF with depth, or range, can be investigated.