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: 
dicklyon@604: function composite_frame = SAI_BlendFrameIntoComposite(new_frame, ...
dicklyon@604:   layer_struct, composite_frame)
dicklyon@604: 
dicklyon@604: alpha = layer_struct.alpha;
dicklyon@604: lag_curve = layer_struct.lag_curve;
dicklyon@604: target_columns = layer_struct.target_indices;
dicklyon@604: 
dicklyon@604: frame_width = size(new_frame, 2);
dicklyon@604: 
dicklyon@604: % Lags are measured from 0 at the right.
dicklyon@604: stretched_frame = interp1(new_frame', frame_width - lag_curve)';
dicklyon@604: alpha = repmat(alpha, size(new_frame, 1), 1);
dicklyon@604: composite_frame(:, target_columns) = ...
dicklyon@604:   (1 - alpha) .* composite_frame(:, target_columns) + ...
dicklyon@604:   alpha .* stretched_frame;