comparison trunk/matlab/bmm/carfac/SAI_Run.m @ 676:edfe3a98504b

Add simplified function to compute a simple (i.e. single-layer) SAI.

+% Copyright 2013, 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 [frame_rate, num_frames] = SAI_Run(CF, input_waves)
+% function [CF, SAI_movie] = SAI_Run(CF, input_waves)
+% This function runs the CARFAC and display an SAI movie.
+
+n_ch = CF.n_ch;
+[n_samp, n_ears] = size(input_waves);
+if n_ears ~= CF.n_ears
+  error('bad number of input_waves channels passed to CARFAC_Run')
+end
+fs = CF.fs;
+
+seglen = round(fs / 30);  % Pick about 30 fps
+frame_rate = fs / seglen;
+n_segs = ceil(n_samp / seglen);
+
+% Design the SAI parameters.
+sai_struct.width = 72;
+sai_struct.future_lags = 0;
+sai_struct.window_width = seglen;
+n_triggers = 2;
+sai_struct.n_window_pos = n_triggers;
+sai_struct.channel_smoothing_scale = 0;
+
+
+% State stored in sai_struct.
+% Make the history buffer.
+buffer_width = sai_struct.width + ...
+    floor((1 + (n_triggers - 1)/2) * sai_struct.window_width);
+sai_struct.nap_buffer = zeros(buffer_width, n_ch);
+% The SAI frame is transposed to be image-like.
+sai_struct.frame = zeros(n_ch, sai_struct.width);
+
+for seg_num = 1:n_segs
+  % seg_range is the range of input sample indices for this segment
+  if seg_num == n_segs
+    % The last segment may be short of seglen, but do it anyway:
+    seg_range = (seglen*(seg_num - 1) + 1):n_samp;
+  else
+    seg_range = seglen*(seg_num - 1) + (1:seglen);
+  end
+  % Process a segment to get a slice of decim_naps, and plot AGC state:
+  % NOTE: seg_naps might have multiple channels.
+  [seg_naps, CF] = CARFAC_Run_Segment(CF, input_waves(seg_range, :));
+
+  % Rectify.
+  % NOTE: This might not be necessary.
+  seg_naps = max(0, seg_naps);  
+
+  if seg_num == n_segs  % pad out the last result
+    seg_naps = [seg_naps; zeros(seglen - size(seg_naps,1), size(seg_naps, 2))];
+  end
+ 
+  % Shift new data into the buffer.
+  n_shift = size(seg_naps, 1);
+  sai_struct.nap_buffer = [sai_struct.nap_buffer((1 + n_shift):end,:); seg_naps];
+
+  sai_struct = SAI_StabilizeLayer(sai_struct);
+  
+  cmap = 1 - gray;  % jet
+  figure(10)
+  image(32 * sai_struct.frame);
+  colormap(cmap);
+  colorbar
+
+  drawnow
+%  imwrite(32*display_frame, cmap, sprintf('frames/frame%05d.png', seg_num));
+end
+
+num_frames = seg_num;
+
+return