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Smoothing image segments

tiffa019 wrote on Jan 30, 2009

I'm working on a set of images with IRAF. I have replaced a bad (over saturated) part of an image with another section from a good image, but I want to do a smooth transition between the two pieces (something like a 3rd order polynomial). I've been told that I can smooth these with IRAF, but I can't find an appropriate application. Any suggestions on what to use would be appriciated.

Thanks in advance!

Mike Fitzpatrick wrote on Jan 30, 2009

I think the task you're looking for is IMEDIT which has lots of options for replacing bad pixels, however it replaces pixels from another area of the same image. FIXPIX can be used to interpolate across rows/cols and if you've copied in a region of pixels might be useful to patch the transition region, but you may still have a different background level in the patched region to deal with.

Another option might be to use IMEXPR to select pixels from one image or the other depending on whether the value is saturated. For example,

cl> imexpr "(a > 65000 ? b : a)" fixed.fits a=saturated.fit b=patch.fits


This assumes the images are already registered (see tasks like WREGISTER if not) but will replace only those pixels above a certain value with the corresponding pixel from a second image.
Hope this helps.

-Mike

Last post on Jan 30, 2009