I am very much NOT an expert in either Hugin or astronomical photography, so consider that in reading the following. I believe that except for near bodies like planets the images are primarily different due to rotation. The amount of the rotation for a long sequence in time will be considerable. The amount of rotation can be readily calculated from the time stamp of the image. If you preprocess the images to reverse the rotation so that they are all at least nearly aligned, then I would expect your Hugin processing to be more successful. I believe you could do this with a program like ImageMagik ( www.*imagemagick*.org. You may need first to increase the size of the canvas so that the real portion of the image does not get cropped when the image's corner rotates off the initial canvas. HTH, JK
On Sunday, August 26, 2012 7:16:15 PM UTC-4, B. Schnieders wrote: > Hi all, > > I need your help aligning some images :) I have a sequence of 1000 night > sky images taken with just a tripod, so alignment is needed before > averaging them. > > The align_image_stack workflow does not seem to work properly for me - > the resulting images are aligned, but not very accurately, so that > averaging them results in a blurry mess. > Checking what went wrong, it seemed that align_image_stack did not find > >2 control points for each consecutive pair of images, but keeps on > stacking photos. When adding proper points, the result is better, but > far from acceptable. > > Another issue was the seemingly added-up error - I manually placed > control points between the first and last image, which seemed to lower > the blur by about 50%. > > Now, manual work is acceptable for smaller image sets, but I wished to > fully automate the process for the full 1000 picture series. Thus, a > couple of questions: > > > - What would be appropriate settings for align_image_stack to detect > more/better control points? I already use -s 0. > - Can I tell align_image_stack to search for control points between all > combinations of images? I know this will take a while.... > - What settings would be needed that align_image_stack can detect > control points that move about half of the image's width? > > Concerning the latter two points, I might rather use cpfind - > unfortunately, I have not yet figured out a way to let cpfind find any > control points on stars. > > - What would be appropriate settings for cpfind to detect control points > on pictures of stars? I already tried to use --fullscale. > > - Can I easily use either cpfind or align_image_stack from a script to > create control points in a pyramid-like manner (meaning, between > 0-1-2-3-4..., 0-2-4-6..., 0-4-8-12..., 0-8-16-24,.....) (to minimize > added up error and to keep CP count comparatively low) > > - Can I force align_image_stack or cpfind to connect each image to the > rest with at least 3-4 good control points, or die? > > > So far for now, happy to hear any recommendations :) > Thank you, > Benjamin > -- You received this message because you are subscribed to the Google Groups "Hugin and other free panoramic software" group. A list of frequently asked questions is available at: http://wiki.panotools.org/Hugin_FAQ To post to this group, send email to hugin-ptx@googlegroups.com To unsubscribe from this group, send email to hugin-ptx+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/hugin-ptx
