Described herein is an improved sensing system (30) and its method of operation. The system (30) includes a camera (16) for viewing an external scene, the camera comprising one or more detector(s) and has a field of view (40) which overlaps with the path (32) of a pulsed laser (12). The laser path (32) and radiation from the scene viewed (40) share a beamsplitter (36) and a window (38). In order to substantially reduce back-scattered radiation from the laser path (32) affecting operation of the detector(s) of the camera (16), the detector(s) is (are) switched in accordance with the operation of the laser (12) to be “off” or non-receiving when the laser (12) is “on” or firing.