Hello Paul,I thought your panorama was pretty good, but I don’t think you have fully overcome the problems of parallax resulting from creases and folds. The main cause, I suspect, is the camera tilt of 6 deg plus or minus from the vertical that the pitch values of the optimiser imply.
So while I would not normally expect to include the Plane Yaw and Pitch parameters in a truly planar photomosaic, it did seem worth trying them here. They do seem to help.
I attach panoa.pto, based on your file, which takes that approach and also includes some tuning of the control points and fuller lens optimisation. But I hung on to the h and v points, because I think they are one of Hugin’s strengths. I have resolved some remaining glitches, either with added control points – automatic control point finders seem to find otherwise featureless areas of grid-lines difficult to deal with – or with masking, but have not tried fully to resolve problems with the grid-square P25, where the different shapes of the square as captured in e.g. images 17 and 23 illustrate graphically the problems of the parallax present in places in your images. The end result yields an average error of 1.2 pixels and a maximum of 3.2, for a panorama matching that of pano.pto in size.
Broadly, I agree with Terry Duell (Wed, 27 May 2015 at 10:13:42 +1000) that the mosaic mode is working OK. He has given us a pto file (Wed, 27 May 2015 at 12:34:56 +1000) that does not use the Plane Yaw and Pitch parameters. It has an error of 0.5 average and 2.9 maximum, but is for a panorama of only about half the width of yours. Still pretty good, though, even at the full size.
Roger Broadie -----Original Message----- From: paul womack <[email protected]> To: [email protected] Sent: Tue 26 May 2015 12:36:00 Subject: [hugin-ptx] Mosiac model - convergence, accuracy? The convergence behaviour of the mosaic model is really quite poor. I have recently completed shooting a very careful trial, using a cantilevered tripod (Benbo) over a map on my dining table. (I shot at less than maximum resolution, at 3 Mp to cut down the data size) All the shots (30 in all) are accurately focused and sharp. I found that for this large image set, it is neccessary to perform step-wise addition and optimisation of the images (initially just X and Y). Simple hoping that the optimiser will just "sort it all out" doesn't work, at least with the kind of control point set found by automation. it works OK with "nigh-perfect" control point sets (I just found ;-) In practise I found that as I proceeded, I needed to hand edit a "fairly good" position of X and Y to get the optimisation to converge at all. This is doable (since my images form a simple matrix) but more work than I'd like. (I also regret that the ctrl-T short cut for "optimise" is not available on the preview window) My more significant concern is that my "final" optimisation, has a disappointingly large error, and (indeed) shows stitching glitches on final output. Since my map is nigh 2 dimensional, and I went to considerable pains to shoot a narrow FOV from a good distance above the map, I believe that the mosaic model should be able to get VERY close to perfect on this image set, and yet it doesn't. I am aware that I may be one of the more extreme users of the mosaic model; is it believed to be bug free? I would be able to test this by synthesizing scaled and YPR skewed sub-images from a high res original (e.g. a giga-pan) and then attempting to stitch them using mosaic mode. I would rather not go to this effort unless forced. I have uploaded the images and project file at https://www.hightail.com/download/bXBhZEV5VnNreEJEZU1UQw They will be there for a week. Note that I believe the map test subject to be in copyright. BugBear -- 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.
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panoa.pto
Description: application/ptoptimizer-script
