comparison matlab/bmm/carfac/CARFAC_Run_Linear.m @ 467:a2e184f0a7b4

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+% Copyright 2012, Google, Inc.
+% Author Richard F. Lyon
+%
+% This Matlab file is part of an implementation of Lyon's cochlear model:
+% "Cascade of Asymmetric Resonators with Fast-Acting Compression"
+% to supplement Lyon's upcoming book "Human and Machine Hearing"
+%
+% Licensed under the Apache License, Version 2.0 (the "License");
+% you may not use this file except in compliance with the License.
+% You may obtain a copy of the License at
+%
+%     http://www.apache.org/licenses/LICENSE-2.0
+%
+% Unless required by applicable law or agreed to in writing, software
+% distributed under the License is distributed on an "AS IS" BASIS,
+% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+% See the License for the specific language governing permissions and
+% limitations under the License.
+
+function [naps, CF] = CARFAC_Run_Linear(CF, input_waves, extra_damping)
+% function [naps, CF] = CARFAC_Run_Linear(CF, input_waves, extra_damping)
+%
+% This function runs the CARFAC; that is, filters a 1 or more channel
+% sound input to make one or more neural activity patterns (naps);
+% however, unlike CARFAC_Run, it forces it to be linear, and gives a
+% linear (not detected) output.
+
+saved_v_damp_max = CF.filter_coeffs.v_damp_max;
+CF.filter_coeffs.v_damp_max = 0.00;  % make it linear for now
+
+[n_samp, n_mics] = size(input_waves);
+n_ch = CF.n_ch;
+
+if n_mics ~= CF.n_mics
+  error('bad number of input_waves channels passed to CARFAC_Run')
+end
+
+for mic = 1:CF.n_mics
+  % for the state of the AGC interpolator:
+  CF.filter_state(mic).zB_memory(:) = extra_damping;  % interpolator state
+  CF.filter_state(mic).dzB_memory(:) = 0;  % interpolator slope
+end
+
+naps = zeros(n_samp, n_ch, n_mics);
+
+for k = 1:n_samp
+  % at each time step, possibly handle multiple channels
+  for mic = 1:n_mics
+    [filters_out, CF.filter_state(mic)] = CARFAC_FilterStep( ...
+      input_waves(k, mic), CF.filter_coeffs, CF.filter_state(mic));
+    naps(k, :, mic) = filters_out;  % linear
+  end
+  % skip IHC and AGC updates
+end
+
+CF.filter_coeffs.v_damp_max = saved_v_damp_max;
+