MATLAB - 查找数据峰值_matlab 寻找峰值

语法如下：

pks = findpeaks(data)
[pks,locs] = findpeaks(data)
[pks,locs,w,p] = findpeaks(data)
[___] = findpeaks(data,x)
[___] = findpeaks(data,Fs)
[___] = findpeaks(___,Name,Value)
findpeaks(___)
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where，pks是峰值返回值，locs是数据索引值

• […] = FINDPEAKS(…,'MinPeakHeight',MPH) finds only those peaks that are greater than the minimum peak height, MPH. MPH is a real-valued scalar. The default value of MPH is -Inf.
• […] = FINDPEAKS(…,'MinPeakProminence',MPP) finds peaks guaranteed to have a vertical drop of more than MPP from the peak on both sides without encountering either the end of the signal or a larger intervening peak. The default value of MPP is zero.
• […] = FINDPEAKS(…,'Threshold',TH) finds peaks that are at least greater than both adjacent samples by the threshold, TH. TH is a real-valued scalar greater than or equal to zero. The default value of TH is zero.
• FINDPEAKS(…,'WidthReference',WR) estimates the width of the peak as the distance between the points where the signal intercepts a horizontal reference line. The points are found by linear interpolation. The height of the line is selected using the criterion specified in WR:

• MinPeakHeight（峰值最小幅度阈值）：指定峰值的最小幅度。只有幅度大于等于该阈值的峰值才会被检测到。
• MinPeakDistance（峰值最小间距）：指定峰值之间的最小距离。只有相邻峰值之间的间距大于等于该值的峰值才会被检测到。
• MinPeakWidth（峰值最小宽度）：指定峰值的最小宽度。只有宽度大于等于该值的峰值才会被检测到。宽度是指峰值左右两侧陡峭部分的宽度。
• MinPeakProminence（峰值最小显著度）：指定峰值的最小显著度。显著度是指峰值相对于其邻近谷底的高度差。只有显著度大于等于该值的峰值才会被检测到。

% 创建一个简单的信号
x = [1, 4, 2, 6, 4, 8, 3, 1];

% 指定最小距离和最小幅度阈值
[pks, locs] = findpeaks(x, 'MinPeakDistance', 2, 'MinPeakHeight', 4);

% 输出峰值的幅度和位置
disp(pks); % 输出：[6, 8]
disp(locs); % 输出：[4, 6]
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应用案例：

对信号数据进行频域分析后，想提取指定幅值以上的峰值所对应倍频，以下图为例，提取幅值为0.1以上的倍频值，可通过关键字MinPeakProminence进行操作。

实现代码如下：

 [pks, locs] = findpeaks(y,'MinPeakProminence',0.1)
 hold on
 plot(freq(locs)*60/rpm,y(locs),'o')
 xlabel("倍频")
 ylabel("幅值")
 plot([0,165],[0.1,0.1],'-.')
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参考文献：

• https://ww2.mathworks.cn/help/signal/ref/findpeaks.html?searchHighlight=findpeaks&s_tid=srchtitle_findpeaks_1
• https://ww2.mathworks.cn/help/signal/ug/find-peaks-in-data.html?searchHighlight=findpeaks&s_tid=srchtitle_findpeaks_3
• https://ww2.mathworks.cn/help/signal/ug/peak-analysis.html?searchHighlight=findpeaks&s_tid=srchtitle_findpeaks_7
• https://ww2.mathworks.cn/help/signal/ug/determine-peak-widths.html?searchHighlight=findpeaks&s_tid=srchtitle_findpeaks_5