Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
Hi, does somebody know abouts an optimal interpolation subrroutine. I am trying to compare some different interpolation techniques and this is the only one than I don't have programmed. thank you! ------------------------------------------------------------ Luis Prieto Godino Dpto. F�sica de la Tierra II. U.C.M. Spain ------------------------------------------------------------
GB Karas wrote: > > sinc interpolation relies on the following interpolating kernel: > > sinc(x)=sin(x)/x Why don't you use FFT's to do the interpolation then? You know, FFT the curve in question, zerofill (or truncate) the result and FFT back? paulv > > Paul van Delst <paul.vandelst@noaa.gov> wrote in message news:<3D653F9D.223EDD66@noaa.gov>... >> GB Karas wrote: >>> >>> oh well.. i think that really depends on your data >>> >>> i analyze MRI data, so I have to use sinc and windowed sinc >>> interpolation >> >> OT, but... >> >> What is sinc (and windowed sinc) interpolation? >> >> paulv -- Paul van Delst CIMSS @ NOAA/NCEP/EMC Ph: (301)763-8000 x7274 Fax:(301)763-8545
Paul van Delst wrote: > GB Karas wrote: > >> sinc interpolation relies on the following interpolating kernel: >> >> sinc(x)=sin(x)/x > > > Why don't you use FFT's to do the interpolation then? You know, FFT the curve in question, zerofill > (or truncate) the result and FFT back? If you check out a digital signal processing book on upsampling or downsampling (or perhaps multirate sampling) you'll see that it can be the way to go in some cases. (oppenheimer and schafer frinstance) Cheers, bob