Assessing audience exposure at laser shows

Lasers have been used in live entertainment since the 1970s. A high power laser beam is required to form visual effects of large image patterns generated by moving the laser beam by computer-controlled galvanometers. Many laser companies promote audience scanning. However, some scan patterns require the same location to be repeatedly scanned, which may lead to the potential for injury, particularly to the eye, where a person receives a burst of laser pulses as the pattern passes across the face. Although safety of laser shows is increasingly better appreciated, every year a few suspected eye injuries are reported. Prototype field measurement equipment is being developed which will assist with the safety assessment where intentional audience scanning is planned. The data captured during the show are analysed in real time to monitor the possible risk of overexposure. An emergency warning is sent to the remote operator if a hazardous level is observed. This equipment will provide a tool able to carry out a comprehensive real time assessment of a show. Details of the design and preliminary results will be presented.