lightlab.util.data.peaks module

Implementation of core peak finding algorithm. It is wrapped to be more user-friendly by findResonanceFeatures().

ResonanceFeature is a data storage class returned by findResonanceFeatures()

Summary

Exceptions:

PeakFinderError

Classes:

ResonanceFeature

A data holder for resonance features (i.e.

Functions:

findPeaks

Takes an array and finds a specified number of peaks

Reference

class ResonanceFeature(lam, fwhm, amp, isPeak=True)

Bases: object

A data holder for resonance features (i.e. peaks or dips)

lam

float – center wavelength

fwhm

float – full width half maximum – can be less if the extinction depth is less than half

amp

float – peak amplitude

isPeak

float – is it a peak or a dip

copy()

Simple copy so you can modify without side effect

Returns:new object Return type:ResonanceFeature

simplePlot(*args, **kwargs)

Plots a box to visualize the resonance feature

The box is centered on the peak lam and amp with a width of fwhm.

Parameters:

• *args – args passed to pyplot.plot
• **kwargs – kwargs passed to pyplot.plot

Returns:

whatever pyplot.plot returns

exception PeakFinderError

Bases: RuntimeError

findPeaks(yArrIn, isPeak=True, isDb=False, expectedCnt=1, descendMin=1, descendMax=3, minSep=0)

Takes an array and finds a specified number of peaks

Looks for maxima/minima that are separated from others, and stops after finding expectedCnt

Parameters:

• isDb (bool) – treats dips like DB dips, so their width is relative to outside the peak, not inside
• descendMin (float) – minimum amount to descend to be classified as a peak
• descendMax (float) – amount to descend down from the peaks to get the width (i.e. FWHM is default)
• minSep (int) – the minimum spacing between two peaks, in array index units

Returns:

indeces of peaks, sorted from biggest peak to smallest peak array (float): width of peaks, in array index units

Return type:

array (float)

Raises:

Exception – if not enough peaks found. This plots on fail, so you can see what’s going on