Applying a scanning sound intensity p-u probe to optimize and reduce the noise radiation of an UAV developed for cinematography

Filming from unmanned aerial vehicles (UAV's) for movies and live action footage has gained significant market acceptance within the cinematography industry, however meeting the film industry's noise expectation has proven to be an issue. Currently it is a time consuming process to remove UAV noise from recorded audio and is very difficult to remove in real time. This paper shows progress that has been made on the reduction and redirection of noise by use of shrouds with incorporated acoustic nanofiber materials, mounted onto a UAV. The shroud works by reducing the tip vortex produced by the edge of the propeller blade, absorbing and shifting frequencies within the speech ranges and reducing the turbulence on the following propeller blade. To measure the effectiveness of a shroud, 2D sound intensity maps were obtained using a sound p-u intensity probe in combination with a scanning measurement technique. Applying this technology, the shroud design has been improved to provide directional noise enhancements.