| Range-gating reduces the effect of backscattering. In this figure an underwater object at a distance of approx. 9m is imaged. The graph shows the reflected signal from a laser pulse as a function of time. The first peak of the curve corresponds to backscattering from particles in the water. The second, attenuated peak corresponds to the reflection from the object that we are interested in (e.g., a lobster). The camera shutter is kept closed for approximately 50ns before it opens. Since the image is created from an integration of all light received, when the first 50 ns is gated out, most of the backscattering contribution to the fundamental noise is removed. Image: courtesy of UTOFIA project. |
