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imagepol.depolratio - Function

1.1.4 Linear depolarization ratio


Description

This function returns the linear depolarization ratio computed from two frequencies; this is the ratio of the fractional linear polarization at the two frequencies. Generally this is done when you have generated two images, each at a different frequency (continuum work). Thus if the fractional linear polarization images are mν1 and mν2 then the depolarization ratio is mν1∕mν2.

This function operates with two images; the first (at frequency ν1) is the one attached to your Imagepol tool. The second (at frequency ν2) is supplied via the argument infile, which is a String holding the name of the image file.

In generating the depolarization ratio, you may optionally debias the linearly polarized intensity. This requires the standard deviation of the thermal noise. You can either supply it if you know it, or it will be worked out for you with outliers from the mean clipped at the specified level.

You can get the depolarization ratio error image with function sigmadepolratio.

Arguments





Inputs

infile

Other image

allowed:

string

Default:

debias

Debias the linearly polarized intensity ?

allowed:

bool

Default:

false

clip

Clip level for auto-sigma determination

allowed:

double

Default:

10.0

sigma

Standard deviation of thermal noise. Default is auto determined.

allowed:

double

Default:

-1

outfile

Output image file name. Default is unset.

allowed:

string

Default:

Returns
image

Example

 
 
"""  
#  
#print "\t----\t depolratio Ex 1 \t----"  
#po.open(’stokes.4800’)  
#dpr = po.depolratio(infile=’stokes.8300’)        # m_4800 / m_8300  
#edpr = po.sigmadepolratio(infile=’stokes.8300’);  
#dpr.done()  
#edpr.done()  
#  
"""  
 

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