Patent ID: 8526627

Claim:
A noise reduction device comprising: a noise controller unit for generating a control sound signal to cancel out a noise; a control sound output unit for outputting a control sound according to the control sound signal from the noise controller unit; a residual sound detector for detecting a residual sound by superimposing the control sound on the noise; and an obstacle detector for detecting an obstacle having potential for influencing detecting performance of the residual sound detector, wherein the noise controller unit generates the control sound signal according to data from the residual sound detector and the obstacle detector, and wherein the noise controller unit comprises: a control filter unit for outputting a control signal by using a fixed filter coefficient set in advance; a signal storage unit for storing a residual sound signal detected by the residual sound detector; a filter coefficient calculation unit for calculating a filter coefficient by using the residual sound signal stored in the signal storage unit; and a filter coefficient updating unit for updating the fixed filter coefficient set in the control filter unit to the filter coefficient calculated by the filter coefficient calculation unit at a predetermined timing.