Mfcc: Mel frequency cepstrum coefficient calculation of perceived frequency and actual frequency conversion

People's subjective perception frequency is not necessarily linear , Therefore, there is a corresponding relationship between the actual frequency and the perceived frequency . Use the above formula to calculate !

Because the basement membrane of human ear corresponds to different frequency groups (24 individual ), For the same frequency group, the frequencies will be superimposed in the brain for evaluation

Therefore, the critical band of the frequency group can be divided into some frequency groups , Form a filter bank , Namely Mel Filter banks

  Because I haven't understood what the book says before 1125*log(1 + f/700)

I found out later matlab Inside log Default is to e Calculate for the bottom

namely log(x) = loge(x)

If matlab It's going to be calculated in 2 Bottom , be log2

Let's verify the above mel Calculation formula of filter

hypothesis f = 1000