dicklyon@604: % Copyright 2013, Google, Inc.
dicklyon@604: % Author: Richard F. Lyon
dicklyon@604: %
dicklyon@604: % This Matlab file is part of an implementation of Lyon's cochlear model:
dicklyon@604: % "Cascade of Asymmetric Resonators with Fast-Acting Compression"
dicklyon@604: % to supplement Lyon's upcoming book "Human and Machine Hearing"
dicklyon@604: %
dicklyon@604: % Licensed under the Apache License, Version 2.0 (the "License");
dicklyon@604: % you may not use this file except in compliance with the License.
dicklyon@604: % You may obtain a copy of the License at
dicklyon@604: %
dicklyon@604: %     http://www.apache.org/licenses/LICENSE-2.0
dicklyon@604: %
dicklyon@604: % Unless required by applicable law or agreed to in writing, software
dicklyon@604: % distributed under the License is distributed on an "AS IS" BASIS,
dicklyon@604: % WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
dicklyon@604: % See the License for the specific language governing permissions and
dicklyon@604: % limitations under the License.
dicklyon@604: 
ronw@634: function [frame_rate, num_frames] = SAI_Run(CF, input_waves)
ronw@634: % function [CF, SAI_movie] = SAI_Run(CF, input_waves)
ronw@634: % This function runs the CARFAC and display an SAI movie.
dicklyon@604: 
dicklyon@604: n_ch = CF.n_ch;
dicklyon@604: [n_samp, n_ears] = size(input_waves);
dicklyon@604: if n_ears ~= CF.n_ears
dicklyon@604:   error('bad number of input_waves channels passed to CARFAC_Run')
dicklyon@604: end
dicklyon@604: fs = CF.fs;
dicklyon@604: 
dicklyon@623: seglen = round(fs / 30);  % Pick about 30 fps
dicklyon@623: frame_rate = fs / seglen;
dicklyon@604: n_segs = ceil(n_samp / seglen);
dicklyon@604: 
ronw@634: % Design the SAI parameters.
ronw@638: sai_struct.width = 256;
ronw@638: sai_struct.future_lags = sai_struct.width / 2;
ronw@634: sai_struct.window_width = seglen;
ronw@634: n_triggers = 2;
ronw@634: sai_struct.n_window_pos = n_triggers;
ronw@634: sai_struct.channel_smoothing_scale = 0;
dicklyon@604: 
dicklyon@608: 
ronw@634: % State stored in sai_struct.
ronw@634: % Make the history buffer.
ronw@634: buffer_width = sai_struct.width + ...
ronw@634:     floor((1 + (n_triggers - 1)/2) * sai_struct.window_width);
ronw@634: sai_struct.nap_buffer = zeros(buffer_width, n_ch);
ronw@634: % The SAI frame is transposed to be image-like.
ronw@634: sai_struct.frame = zeros(n_ch, sai_struct.width);
dicklyon@623: 
dicklyon@604: for seg_num = 1:n_segs
ronw@634:   % seg_range is the range of input sample indices for this segment
dicklyon@604:   if seg_num == n_segs
dicklyon@604:     % The last segment may be short of seglen, but do it anyway:
ronw@634:     seg_range = (seglen*(seg_num - 1) + 1):n_samp;
dicklyon@604:   else
ronw@634:     seg_range = seglen*(seg_num - 1) + (1:seglen);
dicklyon@604:   end
ronw@634:   % NOTE: seg_naps might have multiple channels.
ronw@634:   [seg_naps, CF] = CARFAC_Run_Segment(CF, input_waves(seg_range, :));
ronw@634: 
ronw@634:   % Rectify.
ronw@634:   % NOTE: This might not be necessary.
ronw@634:   seg_naps = max(0, seg_naps);  
ronw@634: 
dicklyon@604:   if seg_num == n_segs  % pad out the last result
dicklyon@604:     seg_naps = [seg_naps; zeros(seglen - size(seg_naps,1), size(seg_naps, 2))];
dicklyon@604:   end
dicklyon@604:  
ronw@634:   % Shift new data into the buffer.
ronw@634:   n_shift = size(seg_naps, 1);
ronw@634:   sai_struct.nap_buffer = [sai_struct.nap_buffer((1 + n_shift):end,:); seg_naps];
dicklyon@604: 
ronw@634:   sai_struct = SAI_StabilizeLayer(sai_struct);
dicklyon@623:   
dicklyon@604:   cmap = 1 - gray;  % jet
dicklyon@604:   figure(10)
ronw@634:   image(32 * sai_struct.frame);
dicklyon@604:   colormap(cmap);
ronw@634:   colorbar
dicklyon@604: 
dicklyon@604:   drawnow
ronw@634: %  imwrite(32*display_frame, cmap, sprintf('frames/frame%05d.png', seg_num));
dicklyon@604: end
dicklyon@604: 
dicklyon@604: num_frames = seg_num;
dicklyon@604: 
dicklyon@604: return