"Audience scanning" means a volitional, momentary projection of visible laser light into the crowd of spectators. It is used for special effects like laser tunnels and the like - in order to visually integrate the spectator into the show.
Dependent on the respective country, audience scanning is handled very differently. Because of security concerns, this form of beam show is considered critically in the USA.
Nevertheless, audience scanning laser shows
are safe for the spectator - if safety precautions and physical law are observed.
The following applies generally for all audience scanning laser shows
- Only use continuous wave lasers (cw), never use pulsed lasers
- Do not exceed the MPE value (maximum permissible exposure)
- Always observe the minimum height and distance to the spectators
Factors deciding on the safety of an audience scanning laser show
- Distance to the audience
- Rotational speed of the laser beam, in combination with the point rate
- "Hot Points", where several points are matching in one point
- Beam widening (divergence)
- Safety zones
Other terms for audience scanning are "public scanning" and "crowd scanning".