comparison toolboxes/MIRtoolbox1.3.2/MIRToolbox/mirzerocross.m @ 0:e9a9cd732c1e tip

first hg version after svn

+function varargout = mirzerocross(orig,varargin)
+%   mirzeroscross(x) computes the sign-changes rate along the signal x,
+%       i.e., how many time the waveform crosses the X-axis. When applied on
+%       an audio waveform, gives a notion of noise.
+%   Optional argument:
+%       mirzerocross(...,'Per',p) precises the temporal reference for the
+%           rate computation.
+%           Possible values:
+%               p = 'Second': number of sign-changes per second (Default).
+%               p = 'Sample': number of sign-changes divided by the total 
+%                   number of samples.
+%           The 'Second' option returns a result equal to the one returned
+%               by the 'Sample' option multiplied by the sampling rate.
+%       mirzerocross(...,'Dir',d) precises the definition of sign change.
+%           Possible values:
+%               d = 'One': number of sign-changes from negative to positive 
+%                   only (or, equivalently, from positive to negative only).
+%                       (Default)
+%               d = 'Both': number of sign-changes in both ways.
+%           The 'Both' option returns a result equal to twice the one
+%               returned by the 'One' option.
+
+
+        per.key = 'Per';
+        per.type = 'String';
+        per.choice = {'Second','Sample'};
+        per.default = 'Second';
+    option.per = per;
+
+        dir.key = 'Dir';
+        dir.type = 'String';
+        dir.choice = {'One','Both'};
+        dir.default = 'One';
+    option.dir = dir;
+    
+specif.option = option;
+     
+varargout = mirfunction(@mirzerocross,orig,varargin,nargout,specif,@init,@main);
+
+
+function [x type] = init(x,option)
+if not(isamir(x,'mirdata'))
+    x = miraudio(x);
+end
+type = 'mirscalar';
+
+
+function z = main(a,option,postoption)
+if iscell(a)
+    a = a{1};
+end
+d = get(a,'Data');
+f = get(a,'Sampling');
+v = cell(1,length(d));
+for h = 1:length(d)
+    v{h} = cell(1,length(d{h}));
+    for i = 1:length(d{h})
+        di = d{h}{i};
+        nc = size(di,2);
+        nf = size(di,3);
+        nl = size(di,1);
+        zc = sum( di(2:end,:,:).*di(1:(end-1),:,:) < 0 ) /nl;
+        if strcmp(option.per,'Second')
+            zc = zc*f{h};
+        end
+        if strcmp(option.dir,'One')
+            zc = zc/2;
+        end
+        v{h}{i} = zc;
+    end
+end
+z = mirscalar(a,'Data',v,'Title','Zero-crossing rate');