Python中的峰值检测算法 [英] Peak detection algorithm in Python

问题描述

我正在Python中实现峰值检测算法，该算法仅检测那些超过阈值幅度的峰值。我不想使用内置函数，因为我也必须将此模拟扩展到硬件实现。

I'm implementing a peak detection algorithm in Python that detects only those peaks that are above a threshold magnitude. I don't want to use the inbuilt function as I have to extend this simulation to Hardware implementation also.

from math import sin,isnan
from pylab import *

def peakdet(v, delta,thresh,x):
    delta=abs(delta)
    maxtab = []
    mintab = []

    v = asarray(v)

    mn, mx = v[0], v[0]
    mnpos, mxpos = NaN, NaN

    lookformax = True

    for i in arange(len(v)):
        this = v[i]
        if abs(this)>thresh:
            if this > mx:
                mx = this
                mxpos = x[i]
            if this < mn:
                mn = this
                mnpos = x[i]
            if lookformax:
                if (this < mx-delta):
                    if (mx>abs(thresh)) and not isnan(mxpos):
                        maxtab.append((mxpos, mx))
                    mn = this
                    mnpos = x[i]
                    lookformax = False
            else:
                if (this > mn+delta):
                    if (mn<-abs(thresh)) and not isnan(mnpos):
                        mintab.append((mnpos, mn))
                    mx = this
                    mxpos = x[i]
                    lookformax = True
    return array(maxtab), array(mintab)

#Input Signal
t=array(range(100))
series=0.3*sin(t)+0.7*cos(2*t)-0.5*sin(1.2*t)

thresh=0.95 #Threshold value
delta=0.0 #

a=zeros(len(t)) #
a[:]=thresh #

maxtab, mintab = peakdet(series,delta,thresh,t)

#Plotting output
scatter(array(maxtab)[:,0], array(maxtab)[:,1], color='red')
scatter(array(mintab)[:,0], array(mintab)[:,1], color='blue')
xlim([0,t[-1]])
title('Peak Detector')
grid(True)
plot(t,a,color='green',linestyle='--',dashes=(5,3))
plot(t,-a,color='green',linestyle='--',dashes=(5,3))
annotate('Threshold',xy=(t[-1],thresh),fontsize=9)
plot(t,series,'k')
show()

此程序的问题在于，即使它们超过阈值，也无法检测到某些峰。
这是我得到的输出：

The problem with this program is that it is unable to detect some peaks even though they are above the threshold. This is the output I got:

我看到了其他带有峰值检测问题的帖子，但找不到任何解决方案。请帮助并提出更正建议。

I saw other posts with peak detection problems but couldn't find any solution. Please help and suggest corrections.

推荐答案

这些代码

        if lookformax:
            if (this < mx-delta):
                if (mx>abs(thresh)) and not isnan(mxpos):
                    maxtab.append((mxpos, mx))
                mn = this
                mnpos = x[i]
                lookformax = False
        else:
            if (this > mn+delta):
                if (mn<-abs(thresh)) and not isnan(mnpos):
                    mintab.append((mnpos, mn))
                mx = this
                mxpos = x[i]
                lookformax = True

仅在以下条件下运行

    if abs(this)>thresh:

因此，只有在脱粒上方的下一个点小于该阈值时，您才能找到一个峰值。

so your can only find a peak when the next point above the thresh is smaller than it.

给出条件

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