OK. I figured out the problem by looking at the lens parameters, like Jim Watters suggested.
When I drag an image taken directly from my Ricoh Theta M15 camera, onto Hugin, and select "Equirectangular" projection, the lens horizontal field of view (HFOV) gets automatically set to 369.5 degrees. But the HFOV value should be 360 degrees. So the stitch ends up discarding part of my original image. On the other hand, when I drag an image that I resized onto Hugin, a dialog pops up ASKING me what the HFOV is, so I type "360" and all works OK. Presumably some metadata has been discarded from my resized image. Obviously, the workaround is to always manually set the HFOV to 360. The perfect world solution would be for either a) the Ricoh Theta M15 to write metadata that does not confuse Hugin, or b) for Hugin to not be confused by the metadata that the Ricoh Theta M15 writes. Thanks Cartolo and Jim for your help. On Mon, Jun 15, 2015 at 9:33 AM, Jim Watters <[email protected]> wrote: > Christopher, > > If you have seams where the original image met it might mean you have some > default values for lens distortion and sensor shift. a,b,c,d,e,f,g should > all be 0 > > Jim > > On 2015-06-13 11:28 AM, Christopher Bruns wrote: > >> I want to reproject some aerial equirectangular images taken with a Ricoh >> Theta camera. I want to rotate the images to a particular orientation, then >> write the image back out as a new equirectangular image of the same size, >> but with a different orientation. >> >> Here is what I have tried: >> * run Hugin. >> * Select "Add images..." and load my (already perfectly stitched) >> equirectangular image. >> * Select "Equirectangular" as the Lens type. >> * Select "Fast Preview Panorama". >> * Select the "Move/Drag" tab in the panorama viewer window. >> * Drag the image around until a) the horizon is perfectly level, and b) >> my desired reference point is horizontally centered in the image. >> * Select the "Stitcher" tab in the stitcher window. >> * Select Equirectangular projection >> * Select 3584x1792 (the original image size) as the canvas size >> * Select "Remapped Images"->"No exposure correction, low dynamic range" >> * Click "Stitch" >> >> But the resulting image has a dramatic exposure discontinuity seam, at >> the location where the original image left/right edges were, i.e. at the >> seam between the original horizontal +180/-180 degree boundary. What should >> I try next, to avoid this seam? >> >> Is there another program I should use to perform this sort of >> reprojection from equirectangular to equirectangular? >> > > -- > Jim Watters > http://photocreations.ca > > -- > A list of frequently asked questions is available at: > http://wiki.panotools.org/Hugin_FAQ > --- You received this message because you are subscribed to a topic in the > Google Groups "hugin and other free panoramic software" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/hugin-ptx/Sj5hKEOF8b0/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/hugin-ptx/557ED42F.5010808%40photocreations.ca > . > > For more options, visit https://groups.google.com/d/optout. > -- 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/CADXPhjfB4PX4ku_Rtn40kuecbq%2BSUXc3%3Du7u2EF74v%3DLe%3DC1Dg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
