Lasers give clearer underwater images than video.
Their blue-green pulses travel four to five times further underwater than the white beam from a video floodlight. Images recorded by the new laser radar can also reveal the size and distance of object s by timing how long it takes a light pulse to reflect back from a target. The company which developed the instrument has added a 'fish filter' to its software. When the filter is switched on, it removes swimming fishes from images of static objects such as pipelines. The company says that when the filter is switched off, t he images will show the fish living on the seabed.