| 摘要 |
PROBLEM TO BE SOLVED: To calibrate the microphone sensitivity difference appropriately in multi-channel input acoustic signals, regardless of the frequency band of the input acoustic signals.SOLUTION: First and second directional signals having dead angles in first and second predetermined directions are formed by performing delay subtraction of an input acoustic signal, and coherence is obtained using these directional signals. Furthermore, a signal section arriving from the front is detected based on the coherence. An index value of microphone sensitivity is calculated by performing the same operation of respective input acoustic signals, by using respective input acoustic signals in the signal sections thus detected. A target sensitivity is determined from a plurality of index values of microphone sensitivity, calibration gains for respective input acoustic signals are calculated from the index values of microphone sensitivity and the target sensitivity of respective input acoustic signals, and then the input acoustic signal is calibrated by the calibration gain thus obtained. |
