此示例显示了如何使用r
解散混合音频信号。您可以使用r
在包括预处理步骤时,执行独立分量分析(ICA)。ICA模型是
这里,是A.-by-1 vector of mixed signals,是A.-by-1 vector of offset values,是A.-by-混合矩阵,和是A.-1原始信号的1向量。首先假设是一个方形矩阵。如果你知道的话一个nd,您可以恢复原始信号from the data:
使用r
function, you can perform this recovery even without knowing the mixing matrixor the mean。Given a set of several observations那,......,r
提取原始信号那,......
加载一组六个音频文件,使用MATLAB®送货。将每个文件修剪到10,000个样本。
files = {'chirp.mat''gong.mat''handel.mat''laughter.mat''splat.mat''train.mat'}; S = zeros(10000,6);对于i = 1:6 test = load(文件{i});y = test.y(1:10000,1);s(:,i)= y;结束
Mix the signals together by using a random mixing matrix and add a random offset.
rng默认% For reproducibilitymixdata = S*randn(6) + randn(1,6);
To listen to the original sounds, execute this code:
对于i = 1:6 disp(i);声音(S(:,i));暂停;结束
To listen to the mixed sounds, execute this code:
对于i = 1:6 disp(i);声音(mixdata(:,i));暂停;结束
Plot the signals.
数字对于i = 1:6子图(2,6,i)绘图(s(:,i))标题(['声音',num2str(i)])子图(2,6,i + 6)绘图(Mixdata(:,i))标题(['Mix ',num2str(i)])结束
原始信号结构明显。混合信号结构较少。
To separate the signals effectively, "prewhiten" the signals by using theprewhiten
function that appears at the end of this example. This function transformsmixdata
因此它具有零均值和身份协方差。
这个想法是下面的。如果是A.zero-mean source with statistically independent components, then
然后the mean and covariance of是
假设你知道一个nd。在实践中,您可以从列的样本和协方差估计这些数量。你可以解决就......而言通过
后一程等式甚至持续不是方形可逆的矩阵。
假设是A.-by-正半纤维矩阵的左特征向量矩阵那一个ndis the-by-特征值的矩阵。然后
然后
There are many mixing matrices满足最后一个等式。如果是A.-by-正常的矩阵,然后
Substituting into the equation for那
is the prewhitened data.r
计算未知矩阵在假设的情况下是一个s independent as possible.
mixdata = prewhiten(mixdata);
超高斯源具有接近零的尖峰,例如声音1的直方图。
图表直方图(S(:,1))
在询问六个功能时执行重建ICA。表明每个来源是超级高斯。
q = 6;mdl = rica(mixdata,q,'NonGaussianityIndicator',(6,1));
Extract the features. If the unmixing procedure is successful, the features are proportional to the original signals.
解密=转换(MDL,MIXDATA);
绘制原始和解密的信号。
数字对于i = 1:6子图(2,6,i)绘图(s(:,i))标题(['声音',num2str(i)])子图(2,6,i + 6)plot(解密(:,i))标题(['Unmix ',num2str(i)])结束
解密信号的顺序与原始顺序不同。重新排序列,以便未混合信号与相应的原始信号匹配。缩放未混合信号以具有与相应的原始信号相同的规范。(r
无法识别原始信号的比例,因为任何刻度都可以导致相同的信号混合。)
解密=解密(:,[2,5,4,6,3,1]);对于i = 1:6 unmixed(:,i) = unmixed(:,i)/norm(unmixed(:,i))*norm(S(:,i));结束
绘制原始和解密的信号。
数字对于i = 1:6 subplot(2,6,i) plot(S(:,i)) ylim([-1,1]) title(['声音',num2str(i)])subplot(2,6,i+6) plot(unmixed(:,i)) ylim([-1,1]) title(['Unmix ',num2str(i)])结束
解密信号看起来类似于原始信号。要收听解密声音,请执行此代码。
对于i = 1:6 disp(i);声音(解密(:,i));暂停;结束
这是代码prewhiten
功能。
functionZ = prewhiten(X)% X = N-by-P matrix for N observations and P predictors% Z = N-by-P prewhitened matrix%1. X的大小。[n,p] = size(x);断言(n> = p);% 2. SVD of covariance of X. We could also use svd(X) to proceed but N% can be large and so we sacrifice some accuracy for speed.[u,sig] = svd(cov(x));sig = diag(sig);sig = sig(:)';%3.找出SIG的值是非零的。托尔=每股收益(类(X));idx = (Sig > max (Sig) * tol);一个ssert(~all(idx == 0));%4.获取SIG和U的相应列的非零元素。Sig = Sig(idx); U = U(:,idx);%5.计算预良数据。mu = mean(X,1); Z = bsxfun(@minus,X,mu); Z = bsxfun(@times,Z*U,1./sqrt(Sig));结束
ReconstructionICA
|r
|Sparsefilt.
|SparseFiltering