Patent ID: 8243941

Claim:
An active noise reduction system comprising: a selection function unit selecting and outputting an optimal control signal having a high noise reduction effect from among a plurality of control signal candidates serving as candidates of a control signal for generating a control sound for suppressing noise by using a plurality of residual noise estimated values for each of the control signal candidates, a speaker outputting said control sound generated by said optimal control signal from said selection function unit, an error microphone arranged in a noise reduction area forming an area where said noise should be reduced and detecting and outputting noise, as a residual noise signal, remaining after interference between said control sound from said speaker and said noise, a residual noise estimation function unit receiving as input said residual noise signal and said control signal, obtaining a noise component estimated value estimating a component of said noise, and using said noise component estimated value to estimate noise for said plurality of control signal candidates and output the plurality of residual noise estimated values, the residual noise estimation function unit having at least transfer characteristic simulated filters which simulate transfer characteristic of a spatial path between a pair of said speaker and said error microphone, and said selection function unit selecting the optimal control signal having the high noise reduction effect from among said control signal candidates based on said plurality of residual noise estimated values.