On 22 Nov., 00:43, Bruno Postle <[email protected]> wrote: > On Mon 21-Nov-2011 at 18:37 -0500, Robert Krawitz wrote: > > >On Mon, 21 Nov 2011 22:59:46 +0000, Bruno Postle wrote: > > >>>1.) Only the actual horizon should be assigned as a "horizontal > >>>line" (unless you just want some line, or the average of some > >>>lines, to be straight and at the horizontal center (equator) of > >>>the panorama) because the horizon line is the only latitudinal > >>>line that lies upon a great circle line (the equator.) > > >> Yes, for spherical panoramas. Horizontal lines can also be > >> useful for removing perspective from façades of buildings, but > >> only when you are using rectilinear projection for the output. > > >What about equirectangular or cylindrical (or Mercator)? > > In these projections the only features in the scene that will be > horizontal in the output image are: the horizon at sea, or features > of circular buildings (so long as you are standing in the exact > centre of the building).
This is how I understand it: Horizontal line control points (HLCPs) in hugin only correlate two image points - unlike line control points, they cannot contain more than two points. Therefore, any two points in the scene which are equidistant from the viewer and at the same height should make valid HLCPs in projections which preserve horizontal lines, like equirect and cylindrical. Kay -- 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 [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/hugin-ptx
