wolffd@0: function varargout = mirtonalcentroid(orig,varargin)
wolffd@0: %   c = mirtonalcentroid(x) calculates the 6-dimensional tonal centroid
wolffd@0: %       vector from the chromagram. 
wolffd@0: %   It corresponds to a projection of the chords along circles of fifths, 
wolffd@0: %       of minor thirds, and of major thirds.
wolffd@0: %   [c ch] = mirtonalcentroid(x) also returns the intermediate chromagram.
wolffd@0: %
wolffd@0: % C. A. Harte and M. B. Sandler, Detecting harmonic change in musical
wolffd@0: %   audio, in Proceedings of Audio and Music Computing for Multimedia
wolffd@0: %   Workshop, Santa Barbara, CA, 2006. 
wolffd@0: 
wolffd@0:         frame.key = 'Frame';
wolffd@0:         frame.type = 'Integer';
wolffd@0:         frame.number = 2;
wolffd@0:         frame.default = [0 0];
wolffd@0:         frame.keydefault = [.743 .1];
wolffd@0:     option.frame = frame;
wolffd@0: 
wolffd@0: specif.option = option;
wolffd@0: 
wolffd@0: varargout = mirfunction(@mirtonalcentroid,orig,varargin,nargout,specif,@init,@main);
wolffd@0: 
wolffd@0: 
wolffd@0: function [c type] = init(orig,option)
wolffd@0: if option.frame.length.val
wolffd@0:     c = mirchromagram(orig,'Frame',option.frame.length.val,...
wolffd@0:                                    option.frame.length.unit,...
wolffd@0:                                    option.frame.hop.val,...
wolffd@0:                                    option.frame.hop.unit);
wolffd@0: else
wolffd@0:     c = mirchromagram(orig);
wolffd@0: end
wolffd@0: type = 'mirtonalcentroid';
wolffd@0: 
wolffd@0: 
wolffd@0: function tc = main(ch,option,postoption)
wolffd@0: if iscell(ch)
wolffd@0:     ch = ch{1};
wolffd@0: end
wolffd@0: if isa(ch,'mirtonalcentroid')
wolffd@0:     tc = orig;
wolffd@0:     ch = [];
wolffd@0: else
wolffd@0:     x1 = sin(pi*7*(0:11)/6)';
wolffd@0:     y1 = cos(pi*7*(0:11)/6)';
wolffd@0:     % minor thirds circle
wolffd@0:     x2 = sin(pi*3*(0:11)/2)';
wolffd@0:     y2 = cos(pi*3*(0:11)/2)';
wolffd@0:     % major thirds circle
wolffd@0:     x3 = 0.5 * sin(pi*2*(0:11)/3)';
wolffd@0:     y3 = 0.5 * cos(pi*2*(0:11)/3)';
wolffd@0:     c = [x1 y1 x2 y2 x3 y3];
wolffd@0:     c = c';
wolffd@0:     tc = class(struct,'mirtonalcentroid',mirdata(ch));
wolffd@0:     tc = purgedata(tc);
wolffd@0:     tc = set(tc,'Title','Tonal centroid','Abs','dimensions','Ord','position');
wolffd@0:     m = get(ch,'Magnitude');
wolffd@0:     %disp('Computing tonal centroid...')
wolffd@0:     n = cell(1,length(m));  % The final structured list of magnitudes.
wolffd@0:     d = cell(1,length(m));  % The final structured list of centroid dimensions.
wolffd@0:     for i = 1:length(m)
wolffd@0:         mi = m{i};
wolffd@0:         if not(iscell(mi))
wolffd@0:             mi = {mi};
wolffd@0:         end
wolffd@0:         ni = cell(1,length(mi));    % The list of magnitudes.
wolffd@0:         di = cell(1,length(mi));    % The list of centroid dimensions.
wolffd@0:         for j = 1:length(mi)
wolffd@0:             mj = mi{j};
wolffd@0:             ni{j} = zeros(6,size(mj,2),size(mi,3));
wolffd@0:             for k = 1:size(mj,3)
wolffd@0:                 ni{j}(:,:,k) = c * mj(:,:,k);
wolffd@0:             end
wolffd@0:             di{j} = repmat((1:6)',[1,size(mj,2),size(mi,3)]);
wolffd@0:         end
wolffd@0:         n{i} = ni;
wolffd@0:         d{i} = di;
wolffd@0:     end
wolffd@0:     tc = set(tc,'Positions',n,'Dimensions',d);
wolffd@0: end
wolffd@0: tc = {tc,ch};