view matlab/bmm/carfac/CARFAC_Spatial_Smooth.m @ 593:40934f897a56

Fixed certain minor documentation bugs.
Added the CAR::designFilters and CAR::stageG methods. These methods design the CAR.coeff coefficients. They have been compared to be the same as the matlab coefficients.
An Ear is now contructed with a specific FS or, it uses the default.
Added the PsychoAcoustics class to do ERB and Hz conversions.
Added the EarTest.C main which allows the construction of an Ear class for testing.

% 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 stage_state = CARFAC_Spatial_Smooth(coeffs, stage, stage_state)
% function AGC_state = CARFAC_Spatial_Smooth( ...
%   n_taps, n_iterations, FIR_coeffs, AGC_state)

n_iterations = coeffs.AGC_spatial_iterations(stage);

use_FIR = n_iterations < 4;  % or whatever condition we want to try

if use_FIR
  FIR_coeffs = coeffs.AGC_spatial_FIR(:,stage);
  switch coeffs.AGC_spatial_n_taps(stage)
    case 3
      for iter = 1:n_iterations
        stage_state = ...
          FIR_coeffs(1) * stage_state([1, 1:(end-1)], :) + ...
          FIR_coeffs(2) * stage_state + ...
          FIR_coeffs(3) * stage_state([2:end, end], :);
      end
    case 5  % 5-tap smoother duplicates first and last coeffs:
      for iter = 1:n_iterations
        stage_state = ...
          FIR_coeffs(1) * (stage_state([1, 2, 1:(end-2)], :) + ...
          stage_state([1, 1:(end-1)], :)) + ...
          FIR_coeffs(2) *  stage_state + ...
          FIR_coeffs(3) * (stage_state([2:end, end], :) + ...
          stage_state([3:end, end, end-1], :));
      end
    otherwise
      error('Bad AGC_spatial_n_taps in CARFAC_Spatial_Smooth');
  end
else
  % use IIR method, back-and-forth first-order smoothers:
  stage_state = SmoothDoubleExponential(stage_state, ...
    coeffs.AGC_polez1(stage), coeffs.AGC_polez2(stage));
end