| 摘要 |
PROBLEM TO BE SOLVED: To surely detect voices from dark noise in a noisy environment by dividing inputted signals into subsignals representing specific frequency bands and conducting voice activity discrimination based on the subdiscrimination signals calculated from the noise in the subsignals. SOLUTION: Inputted voice signals from a microphone 1 are sampled by an A/D converter and become digital signals X(n). A block 6 divides the signals X(n) into subsignals S(s) representing specific frequency bands. An estimation block 80 estimates noise N(s) in the subsignals S(s). A computing block 90 calculates subdiscrimination signals SNR(s) based on the noise N(s) in the subsignals S(s). Then, a VAD discrimination block 110 conducts voice activity discrimination Vind foll the X(n) based on the signals SNR(s). In other words, the value is calculated which is proportional to the sum of each signal vs. noise ratios representing the signals SNR(s). Then, the value is compared with a threshold value and the signals Vind are formed base on the comparison. |
