Bug 158887 - LFI differencing plugin for sky and reference data
Summary: LFI differencing plugin for sky and reference data
Status: RESOLVED FIXED
Alias: None
Product: kst
Classification: Applications
Component: general (show other bugs)
Version: 1.x
Platform: Compiled Sources Linux
: NOR wishlist
Target Milestone: ---
Assignee: kst
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2008-03-07 00:33 UTC by Andrew Walker
Modified: 2008-03-07 04:50 UTC (History)
0 users

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Description Andrew Walker 2008-03-07 00:33:24 UTC
Version:           1.6.0 (using KDE 3.5.9)
Installed from:    Compiled From Sources
OS:                Linux

The following was requested by the LFI team:

LFI reference loads are at a different temperature then the sky signal, therefore in order to reduce the 1/f noise it is necessary to include in the difference a scale factor r (sky - r * ref). 

The default LFI differencing procedure is to take the mean of 1 hour of sky and ref, compute the r factor as mean_sky/mean_ref, and then produce the differenced timestream by computing sky - r * ref. 

differencing plugin implementation
Inputs: 
  sampling_freq (the same for sky and ref) 
  sky datavector 
  ref datavector (of the same lenght and sampling rate) 
  timespan (hours) where to compute the r factor, default is 1, if empty the complete vectors are taken into account 

Pseudocode: 
  totaltime = (number of samples) / sampling_freq 
  for i  from 0 to totaltime/timespan:
    data_range = [ i * timespan * sampling_freq : (i+1) * timespan * sampling_freq ]
    mean_sky = mean(sky [data_range])
    mean_ref = mean(ref [data_range])
    r[i] =  mean_sky/mean_ref
    diff[data_range] = sky[data_range] - r[i] * ref[data_range] 

output: 
  r (vector containing computed r for each timespan, dimension is the number of timespans in the sky and ref datavectors) 
  diff (datavector of the same dimensions of sky and ref)
Comment 1 Andrew Walker 2008-03-07 04:33:30 UTC
SVN commit 783112 by arwalker:

CCBUG:158887 first draft of lfi difference plugin

 M  +1 -1      Makefile.am  
 A             lfidifference (directory)  
 A             lfidifference/Makefile.am  
 A             lfidifference/kstobject_lfidifference.desktop  
 A             lfidifference/lfidifference.cpp   [License: GPL (v2+)]
 A             lfidifference/lfidifference.h   [License: GPL (v2+)]


WebSVN link: http://websvn.kde.org/?view=rev&revision=783112
Comment 2 Andrew Walker 2008-03-07 04:50:29 UTC
SVN commit 783116 by arwalker:

BUG:158887 add plugin for doing lfi differencing

 M  +22 -0     lfidifference.cpp  


WebSVN link: http://websvn.kde.org/?view=rev&revision=783116