New technology for subsea laser imaging and ranging system for inspection and mapping

Laser imaging and ranging systems offer 3‐D imaging of video quality at distances four to five times greater than conventional video and photographic systems. The Spotmap system is based on the laser radar approach, using a pulsed green solid state laser as a transmitter and detecting the time‐of‐flight and peak intensity of the reflected pulses. Images and maps of underwater scenes are obtained by scanning the laser beam across the objects in a raster pattern using a two‐axis optical scanner. The system can be used both in linescan and 2D scan modes of operation such that images can be obtained either from the linear movement of the remotely operated vehicle or from a stationary position. The system has a 90∞ cross‐track FOV and is capable of processing 8,000 points per second, which gives an imaging resolution comparable to video at ROV speeds up to 2m/s.