Detecting an early reflection sound contained in the impulse response measured in a room, We calculated the correlation factor between the early reflection and the impulse response.
Calculating the correlation factor every sampling period, and we make the correlation function. For the function, we set a threshold level. We detected the absolute correlation value larger than the threshold level. And, we set 0 value for sub threshold level. Following this algorithm, we generate a new signal with the high the correlation factor for the early reflection. We compared the signal with the impulse response by listening test.