Thanks, Charles. Another paper on this general subject that deals with spectral imaging (overlap-ograms) was recently published by Figen Oktem (Oktem et al. 2014, IEEE Trans. on Image Processing, vol. 23, no. 12, p. 5707). Unfortunately, it doesn't seem to be available on ADS.
Cheers, Jim
-----Original Message----- From: Charles C. Kankelborg [mailto:kankel@solar.physics.montana.edu] Sent: Monday, June 29, 2015 12:39 PM To: Klimchuk, James A. (GSFC-6710) Cc: (Loops@solar.physics.montana.edu) Subject: Re: [Loops] new spectroscopic analysis tool
Hi Jim,
This is a needed improvement. This kind of interpolation has been available for some time, but I have not see in applied to spectra (where it is probably most needed, for all the reasons you point out). Sakurai and Shin derived analytically, in closed form, a spline interpolation with rigorous photon conservation:
Takashi Sakurai and Junho Shin, 2001 "Interpolation of One- and Two-Dimensional Images with Pixelwise Photon Number Conservation " http://pasj.oxfordjournals.org/content/53/2/361.full
With our usual detectors (rear-illuminated CCDs) there can be significant charge spreading in the field free region, so the pixels are well defined (in effect, they are fuzzy and overlapping). A proper flux-conserving interpolation scheme should take that into account. To my knowledge, that has not been done.
Best regards, Charles
On 2015 Jun 29, , at 6:59 AM, Klimchuk, James A. (GSFC-6710)
james.a.klimchuk@nasa.gov wrote:
Hi everyone,
You might be interested in a new tool that Spiros, Durgesh, and I have
developed for analyzing spectra. It can be downloaded fromhttp://lanl.arxiv.org/abs/1506.08102. The abstract is below.
Hope to see many of you at Loops VII,
Jim
The detailed shapes of spectral line profiles provide valuable information about the
emitting plasma, especially when the plasma contains an unresolvedline blends is another. We have developed an iterative procedure called Intensity Conserving Spline Interpolation (ICSI) that corrects for this effect. As its name implies, it conserves the observed intensity within each wavelength bin, which ordinary fits do not. Given the rapid convergence, speed of computation, and ease of use, we suggest that ICSI be made a standard component of the processing pipeline for spectroscopic data.
James A. Klimchuk
NASA Goddard Space Flight Center
Solar Physics Lab, Code 671
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Greenbelt, MD 20771
USA
Phone: 1-301-286-9060
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E-mail: James.A.Klimchuk@nasa.gov
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