SpHEAR/calibration/src/sphear_af_calibrate.m

%% -*- mode: octave -*-
%%
%% *SpHEAR Project
%%
%% sphear_af_calibrate: read reference microphone signal, filter with convolution
%%                      kernel created by DRC and filter all recorded signals,
%%                      calibrated A format files are written to disk
%%
%% usage:
%%   [] = sphear_af_calibrate(measurements, keep, fade)
%%
%% keep: time to keep after main impulse in seconds
%% fade: fade out time after keep in seconds
%%
%% Copyright 2016-2017, Fernando Lopez-Lezcano, All Rights Reserved
%% nando@ccrma.stanford.edu
%%
%%  This program is free software: you can redistribute it and/or modify
%%  it under the terms of the GNU General Public License as published by
%%  the Free Software Foundation, either version 3 of the License, or
%%  (at your option) any later version.
%%
%%  This program is distributed in the hope that it will be useful,
%%  but WITHOUT ANY WARRANTY; without even the implied warranty of
%%  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
%%  GNU General Public License for more details.
%%
%%  You should have received a copy of the GNU General Public License
%%  along with this program.  If not, see <http://www.gnu.org/licenses/>.

function [] = sphear_af_calibrate(measurements, keep, fade);
  %% the measurement from the reference microphone is processed through
  %% DRC (Digital Room Correction) to create a convolution kernel that is
  %% used to equalize the measurements
  %%
  %% read the convolution kernel
  [ref, Fs] = wavread('../data/current/cal/drc-filter.wav');

  %% window the DRC generated filter, eliminate the stuff before the main
  %% peak and limit the length to the approximate useful length of the
  %% original recorded impulse response
  
  [peaks, locs] = findpeaks(abs(ref));
  [value, index] = max(peaks);
  loc = locs(index);
  
  %% truncate before the main peak
  b_len = 4;
  before = tukeywin(2 * b_len, 0.9)(1:end/2) .* ref(loc-2*b_len:loc-b_len-1);
  %% useful samples
  samples = keep * Fs/2;
  during = ref(loc-b_len:loc+samples-1);
  %% fade out after useful samples
  a_len = fade * Fs/2;
  after = tukeywin(2 * a_len, 0.9)(end/2:end) .* ref(loc+samples:loc+samples+a_len);
  %% and the whole thing is:
  trunc = cat(1, before, during, after);

  capnames = cellstr(['LF'; 'RF'; 'LB'; 'RB']);
  %% all requested measurements
  for m = measurements
    %% read in capsule signal and normalize it
    for c = 1:4
      printf("processing capsule %d\n", c);
      sig = wavread(["../data/current/af/a-format-" sprintf("%03d", m) "-" char(capnames(c)) ".wav"]);
      cal_sig(:,c) = conv(trunc, sig);
      wavwrite(cal_sig(:,c), Fs, ["../data/current/af/a-format-cal-" sprintf("%03d", m) "-" char(capnames(c)) ".wav"]);
      printf("end capsule %d\n", c);
    end
    wavwrite(cal_sig, Fs, ["../data/current/af/a-format-cal-" sprintf("%03d", m) ".wav"]);
  end
end