ADMITSegmentFinder — Finds segments of emission within a spectrum.

This module defines the class for spectral line segment detection.

class admit.util.segmentfinder.ADMITSegmentFinder.ADMITSegmentFinder(**keyval)

Define segments of ‘line’ emission where segments from data appear to be above a threshold. This routine comes out of ASTUTE, some parameters below are hardcoded.

Parameters:

freq : float array

Frequencies, GHz.

spec : float array

The y component of the spectrum (arbitrary units, could be linear, could be log).

f : float

Robustness parameter [1.5].

pmin : float

Signal above cuttoff, rmean+pmin*rstd.

minchan : int

Minimum number of channels needed for a line.

maxgap : int

Allowed channels with signal below cutoff [0].

nomean : bool

Remove the mean from any noise and cutoff calculations. This is useful if PVCorr based spectra are being processed to get a correct noise level. Default: False.

Returns:

4-tuple

channel_segments[], cutoff, noise, mean

Methods

find()	Method that does the segment finding
line_segments(spec, cutoff)	Method to find segments that where lines are located
set_options(\*\*keyval)	Set the options for the line finding algorithm.

find()

Method that does the segment finding

Parameters:

None

Returns:

Tuple containing a list of the segments, the cutoff used, the

noise level, and a mean baseline.

line_segments(spec, cutoff)

Method to find segments that where lines are located [ [start1,end1], [start2,end2], ....]

This function assumes you’ve subtracted a possible continuum (see the nomean parameter), and applied the absolute value, because this routine only segments above the cutoff.

Need some explanation on the use of abs here.

Parameters:

spec : numpy array (with a mask)

The spectrum to analyze

cutoff : float

The cutoff to use (line segments must be higher than this value)

Returns:

List of segment start and end channels, e.g. [[10,20],[30,40]]

set_options(**keyval)

Set the options for the line finding algorithm.

Parameters:

freq : float array

Frequencies, GHz.

spec : float array

The y component of the spectrum (arbitrary units, could be linear, could be log)

f : float

Robustness parameter [1.5]

pmin : float

Signal above cuttoff, rmean+pmin*rstd

minchan : int

Minimum number of channels needed for a line

maxgap : int

Allowed channels with signal below cutoff [0]