Question

我正在使用MATLAB 2013，现在包括Matching Pursuit算法。它有一个名为 wmpdictionary 的函数，用于创建字典。据我所知，能够使用下一个函数在字典中创建原子：

离散余弦变换-II基础
正弦
余弦
多项式
转移的Kronecker delta
有效的正交或双正交小波族

我想/需要使用 Gabor 原子。

有人知道如何在wmpdictionary中使用Gabor，或者是一种定制新种类原子的方法吗？

------------------最终解决了------------------ 我在论文中找到了Gabor原子的公式[1]。我使用这些函数生成了一个字典：

function atom = getGaborAtom(N,scale,timeShift,frequency,phase)
%This function obtains a Gabor atom of given parameters
%N- Length of the signal
%scale- must be in number of samples
%timeShift - must be in number of samples
%frequency - its normalized frequency from 0 to 0.5   f/fs;
%Phase - a value from 0 to 2 pi
%This version uses the number of samples but seconds can also be used.

atom =zeros(N,1);
for n=1:N
    atom(n,1) = (1/sqrt(scale))*exp(-pi*(n-timeShift)^2/scale^2) * cos(2*pi*frequency*    (n-timeShift)+phase);
end
atom = (1/norm(atom)) .* atom;   %Normalization
end

function [dictionary parameters]=constructDictionaryGabor()
%Construct a Gabor dictionary 
%parameters are scale timeshift and frequency

N=256;  %Size of the atom
scales = [2^1 2^2 2^3 2^4];  %More scales can be added
freqs  = [0 .001 .002 .05 .1 .2 .3 .4 .5];  % f/fs normalized frequency. More freqs can be added
timeShifts = [0 64 128];  %More time shifts can be added
phase =0; %More phase values can be added, here I'm fixinf phase to 0


dictionary = zeros(N,length(scales)*length(freqs)*length(timeShifts)*length(phase));
parameters = zeros(3,length(scales)*length(freqs)*length(timeShifts)*length(phase);
contador = 1;

for t=1:length(timeShifts)
    for f=1:length(freqs)
        for s=1:length(scales)
            dictionary(:,contador) = getGaborAtom(N,scales(s),timeShifts(t),freqs(f),phase);
            parameters(:,contador) = [scales(s) timeShifts(t) freqs(f)];
            contador = contador+1;
        end
    end
end
end

这个字典可以与函数wmpdictionary一起使用，矩阵参数有每个原子的参数。

[1]具有时频音频功能的环境声音识别

Answer 1

你应该下载并安装MPTK，这个工具包有几个功能，比wmpalg更快。您还可以轻松进行多声道分解并定义自己的词典。

Answer 2

你必须改变这一行

atom(n,1) = (1/sqrt(scale))*exp(-pi*(n-timeShift)^2/scale^2) * cos(2*pi*frequency*    (n-timeShift)+phase);

要

atom(n,1) = (1/sqrt(scale))*exp(-pi*(n-timeShift)^2/scale^2) * cos(2*pi*frequency*    (n-timeShift)/N+phase);

MATLAB Matching使用Gabor或定制原子追求wmpdictionary

2 个答案: