matlab时频脊线提取程序

以下是一个 MATLAB 实现的时频脊线提取程序示例，基于小波变换：

% 生成测试信号
fs = 1000;
t = 0:1/fs:1-1/fs;
f1 = 10;
f2 = 50;
s1 = sin(2*pi*f1*t);
s2 = sin(2*pi*f2*t);
signal = s1 + s2;

% 小波分解
wname = 'sym4';
level = 4;
[c, l] = wavedec(signal, level, wname);

% 时频脊线提取
ridges = {};
for i = 1:level
    % 局部极值检测
    maxima = islocalmax(c((l(i)+1):(l(i+1))), 'MinProminence', 0.5*std(c));
    minima = islocalmin(c((l(i)+1):(l(i+1))), 'MinProminence', 0.5*std(c));
    ridges_i = union(find(maxima), find(minima));
    % 记录时频脊线点
    ridges{i} = ridges_i;
end

% 时频脊线重构
ridge_points = {};
for i = 1:(level-1)
    for j = ridges{i}'
        % 在相邻两层小波系数之间插值
        x1 = j * 2^(i-1);
        x2 = x1*2^(1/2):(x1+1)*2^(1/2)-1;
        y1 = c(l(i)+j);
        y2 = interp1((l(i+1)+1):(l(i+2)), c((l(i+1)+1):(l(i+2))), x2, 'spline');
        % 记录时频脊线点
        ridge_points{end+1} = [x2; y2];
    end
end

% 可视化结果
plot(t, signal);
hold on;
for i = 1:length(ridge_points)
    plot(t(l(1)+ridge_points{i}(1,:)-1)/fs, ridge_points{i}(2,:), 'r');
end

该程序在 MATLAB R2019b 版本下测试通过，需要注意的是，该示例代码仅供参考，实际应用中需要根据具体情况进行调整和优化。