Helmet incorporating an active noise cancellation system for use with a motor vehicle, and method of canceling noise in a helmet

摘要

An active noise cancellation helmet (100) includes a detection unit (102) which detects noise in a helmet body (10), and a sound outputting unit (104) which outputs a sound for canceling the noise detected by the detection unit (102). A control signal is generated by processing an output signal of the detection unit (102) through computation. The control signal is amplified by an amplification unit (108), and applied to the sound outputting unit (104). A ratio of sound pressures in different frequency ranges is determined on the basis of the output signal of the detection unit (102). Againof the amplification unit (108) isadjusted on the basis of the sound pressure ratio so as to approximate a spectrum of the output signal of the detection unit (102) to a predetermined target spectrum.