> Hmm. Make copies of images, convert them to B&W (1 bit color), pull into > Hugin and cpfind/optimize/etc on those. Save project, replace B&W versions > with color, stitch? >
Thanks David -- I did try two versions of that method: one where I did a curves adjustment that brought out the stars and crushed everything else to black, and one that just boosted everything (including the noise floor). Neither worked (cpfind found no points at all, which was even worse than before). I tried true 1bit as you suggest and hugin said it didn't support 1bit and suggested greyscale, so I converted the 1bit images to 8bit greyscale. None of the cpfind methods I tried with that found any CPs. Also, I don't recall if you mentioned this earlier. Do you do noise > reduction on your images before pulling them into Hugin? > No -- since the reason for the stack is that I intend to do a gmic median_image for the purpose of noise reduction I didn't want to do any per-image NR. Would it help for CP-creation? My experiment described just above seemed to imply it would not (since the first curve adjustment effectively removed a lot of noise.) I.e. it seems like the only way cpfind is finding anything at all is by matching subtle variations in the darker areas. How would -starfield mode define what a "star" is? A threshold of > brightness, size, what? > I confess cluelessness, but it seems like cpfind is not designed to look for little bright points in a dark field. but rather to match more textural image areas. Even on the stack that worked, half of the control points it found were in the ~black areas (though I assume it was still using the nearby stars to locate the CP) and there were plenty of CPs that were obviously wrong, where "obviously" is defined as a human looking at stars. :-) Meaning the CP is clearly not just using bright, contrasty points to make decisions. (Which makes sense, since it's not an astronomical imaging tool.) It seems like a "dumb" version of cpfind could be told to just find stars, defined as less than X pixels in diameter and with a certain degree of contrast to the background (or even just a brightness threshold as you describe). I'm sure the author(s) of cpfind don't want to create a special algorithm for every type of image in the world, but it seems like star field alignment is common enough application that it might make sense. And since it seems so hard to make cpfind do it (see above thread), and since it seems like it "should" be among the most simple kinds of alignment to do, that maybe it's a good suggestion? Or maybe it just belongs in a different CP tool altogether. (Or maybe someone knows some magic I can pass to cpfind on the command line to make it work!) -- A list of frequently asked questions is available at: http://wiki.panotools.org/Hugin_FAQ --- You received this message because you are subscribed to the Google Groups "hugin and other free panoramic software" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/hugin-ptx/f33f3129-bfb0-4fe2-b2f0-b44b3567a98e%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
