Question

peak Detect algorithm Reference：感谢@endolith

我在峰值修整方面遇到了问题，基于以下算法，我能够找到某个光谱（峰值）的最大值和最小值。但是选择接近最大值的两个最小值的最佳方法是什么，换句话说：将其修剪下来。

如果峰值是完美的高斯并且我只需要处理一个中心最大值和两个极端极小值，那就不会有问题。但由于峰值不对称/带有噪音;应该出现具有多个最大值和最小值的挑战。

这是一个小型MWE（最小工作示例）：

import sys
from numpy import NaN, Inf, arange, isscalar, asarray, array


def peakdet_org(v, delta, x=None):
"""
Converted from MATLAB script at http://billauer.co.il/peakdet.html

Returns two arrays

function [maxtab, mintab]=peakdet(v, delta, x)
%PEAKDET Detect peaks in a vector
%        [MAXTAB, MINTAB] = PEAKDET(V, DELTA) finds the local
%        maxima and minima ("peaks") in the vector V.
%        MAXTAB and MINTAB consists of two columns. Column 1
%        contains indices in V, and column 2 the found values.
%      
%        With [MAXTAB, MINTAB] = PEAKDET(V, DELTA, X) the indices
%        in MAXTAB and MINTAB are replaced with the corresponding
%        X-values.
%
%        A point is considered a maximum peak if it has the maximal
%        value, and was preceded (to the left) by a value lower by
%        DELTA.

% Eli Billauer, 3.4.05 (Explicitly not copyrighted).
% This function is released to the public domain; Any use is allowed.

"""
maxtab = []
mintab = []

if x is None:
    x = arange(len(v))

v = asarray(v)

if len(v) != len(x):
    sys.exit('Input vectors v and x must have same length')

if not isscalar(delta):
    sys.exit('Input argument delta must be a scalar')

if delta <= 0:
    sys.exit('Input argument delta must be positive')

mn, mx = Inf, -Inf
mnpos, mxpos = NaN, NaN

lookformax = True

for i in arange(len(v)):
    this = v[i]
    if this > mx:
        mx = this
        mxpos = x[i]
    if this < mn:
        mn = this
        mnpos = x[i]

    if lookformax:
        if this < mx - delta:
            maxtab.append((mxpos, mx))
            mn = this
            mnpos = x[i]
            lookformax = False
    else:
        if this > mn + delta:
            mintab.append((mnpos, mn))
            mx = this
            mxpos = x[i]
            lookformax = True

return array(maxtab), array(mintab)


if __name__ == "__main__":
from matplotlib.pyplot import plot, scatter, show
#provide example Data:

yg = np.array([  1.57438571e+01,   7.61257196e+00,   1.52430926e-01,
     1.36516560e-01,   5.15979768e+00,   1.64124707e+01,
     1.89515520e+01,   1.42487909e+01,   3.54018477e+00,
     1.14062707e+01,   1.02388242e+01,   1.87826244e+01,
     1.95441484e+01,   2.24071140e+01,   2.02983868e+01,
     1.82032003e+01,   1.73453618e+01,   1.47026081e+01,
     1.78448059e+01,   2.58816032e+01,   6.56713725e+01,
     1.25462491e+02,   1.87772026e+02,   2.59049063e+02,
     3.51947933e+02,   4.53792943e+02,   5.19410345e+02,
     5.52208254e+02,   5.70822845e+02,   5.80361497e+02,
     5.89003135e+02,   6.06347208e+02,   6.43622339e+02,
     6.62009186e+02,   6.42148423e+02,   5.92902622e+02,
     5.20002943e+02,   4.41806277e+02,   3.48097035e+02,
     2.63343718e+02,   1.78357030e+02,   1.34485314e+02,
     1.17501271e+02,   1.09649638e+02,   8.43415105e+01,
     7.13899534e+01,   5.18412945e+01,   3.35901390e+01,
     2.08088661e+01,   3.07336351e+01,   4.79581429e+01])

series = yg
maxtab, mintab = peakdet_org(series, .3)
plot(series)
scatter(array(maxtab)[:, 0], array(maxtab)[:, 1], color='blue')
scatter(array(mintab)[:, 0], array(mintab)[:, 1], color='red')
show()

示例图1：蓝调是千里马，红色是最小值

示例图2：

噪声频谱中的峰值检测和隔离[1D]

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