If I don't misunderstand your post . . . Yes, one wants a level horizon, but the horizon is an imaginary line and is only evident in certain perfect situations without obstructions (flat desert, seascape, etc.) In most natural situations like landscapes, the viewer's senses are not greatly offended by a slightly misaligned horizon and it can estimated and adjusted without difficulty. The manmade environment, where most pictures are taken, is positively chock full of obviously vertical and horizontal lines. When all these cues do not align properly it is can be offensively obvious and discordant, so you want them to be properly aligned. in a rectilinear projection, only a vertical line always appears vertical and straight (like the longitude lines on a globe.) The only horizontal line that is level and straight is the horizon (which really isn't a line at all since it's theoretical projection and is actually a huge circle. All the truly straight, non vertical lines actually appear slightly curved, to a greater or lesser extent. The only horizontal lines that appear close to straight are on objects that directly face the viewer, and only those that happen to be coincident with the horizon, and these only over a short distance. (Sorry if I have misunderstood and I'm stating the obvious to you.)
I suppose the proposed new Apple Inc. campus building (which will be huge and round with a round courtyard in the middle) would offer an opportunity to use horizontals for alignment. :-) http://theinspirationroom.com/daily/design/2011/8/apple_city_rendering_1.jpg On Nov 2, 9:18 pm, Robert Krawitz <r...@alum.mit.edu> wrote: > On Wed, 2 Nov 2011 20:04:03 +0000, Bruno Postle wrote: > > On Wed 02-Nov-2011 at 11:47 +0500, Emad ud din Bhatt wrote: > >> can we use vertical line detector by Setting equirect pitch to 90 > >> degree and than call vertical line detector. Than set pano pitch > >> to -90 and call vertical line detector again? > > > Yes (or roll), but you would have to manually change all the > > 'vertical control points' to 'horizontal'. > > > This doesn't solve the fundamental problem: vertical lines are > > parallel, but horizontal lines generally are not - This is why > > horizontal control points have very limited use for levelling > > panoramas. > > I don't understand this -- usually one wants a level horizon? > > -- > Robert Krawitz <r...@alum.mit.edu> > > Tall Clubs International -- http://www.tall.org/or 1-888-IM-TALL-2 > Member of the League for Programming Freedom -- http://ProgFree.org > Project lead for Gutenprint -- http://gimp-print.sourceforge.net > > "Linux doesn't dictate how I work, I dictate how Linux works." > --Eric Crampton -- 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
