SpHEAR/sphear_bf_power_fons.m

%%
%% *SpHEAR Project
%%
%% sphear_a_power: return array of power for all capsules in a range of frequencies
%%
%% usage:
%%   [R] = sphear_a_power(fmin, fmax, N, Npre)
%%
%% fmin, fmax: range of frequencies to consider
%% Npre: number of samples before the main impulse
%% N: total number of samples to analyze
%%
%% The names of reference microphone impulse response and capsule measurements are
%% currently hardwired into this file, this needs to be fixed and turned into
%% input parameters
%%
%% Copyright Fernando Lopez-Lezcano 2016
%% 

function [B] = sphear_bf_power_fons(fmin, fmax, N, Fs, plotz)
  pkg load signal;

  %% indexes in array for frequency bins
  imin = round((N/2) * fmin / (Fs/2));
  imax = round((N/2) * fmax / (Fs/2));

  r_start = 0;
  r_end = 0;
  
  %% all measurements
  for m = 1:16
    %% all b format components, 4 channel soundfile
    bsignal = wavread(["../cal/2016.08.03/fons/b-format-rendered-" sprintf("%03.0f", m) "-16.wav"]);

    %% transform from FUMA to SN3D (the encoder is outputing FUMA)
    %% bsignal(:,1) = bsignal(:,1) * (sqrt(2)/2);
	
    %% find first peak, read samples around it
    Npre = 64;
    Nbuf = 256;

    [index, value] = findmaxpeak(bsignal(:,1));
    r_start = index - Npre;
    r_end = r_start + Nbuf -1;
    range = r_start:r_end;
    printf("%d: samples = %d -> %d (%d), imin:imax %d:%d\n", m, r_start, r_end, r_end-r_start, imin, imax);

    bfft = fft(bsignal(range,:), N);
    if (plotz == 0)
      %% calculate a forward facing cardiod
      cfft = fft(bsignal(range,1) + 1.0 * bsignal(range,2), N);
    end
    %% return total power of signal in frequency range
    scaler = 8;
    B(m, :) = sqrt(sum(bfft(imin:imax,:).*conj(bfft(imin:imax,:)))/size(bfft(imin:imax,:),1)) / scaler;
    %% make a cardiod if we don't want Z
    if (plotz == 0)
      B(m, 4) = sqrt(sum(cfft(imin:imax).*conj(cfft(imin:imax)))/size(cfft(imin:imax),1)) / (2 * scaler);
    end
  end
  
end