Mea Culpa. Can you please remove this posting. I, in no way, intended to cross- post the same content to the two groups. The problem is that when composing a long replay [or maybe the problem is just my long- windedness], when you get to the end to hit the Post button, you get notified that your session has expired. So, since it has happened to me twice today, at least I had a copy, but when I relogged in, I was in the other browser in the other group. Sorry, sorry, please delete. Thanks for the help on a complex problem from both group of scholars.
Terry Corbet On Mar 5, 12:23 am, tcorbet <[email protected]> wrote: > 01. I am restarting, hopefully for the benefit of all concerned. The > first thread has lots of problems, most of which are attributable to > my poor understanding of the basic terminology, methodologies and > fundamental algorithms that are both at the heart of PTGui [and its > sister products] and quite obviously at the heart of those of you who > have devoted so much professional time and energy to getting the suite > of capabilities that are 'out there'. > > I have also -- certainly from the standpoint of this specific forum -- > somewhat compounded the problem by mixing observations as between > different product implementations. While I apologize for that, as it > was clearly done to provide perspective, it can inflame passions. On > the other hand, since I have been pursuing the same challenge on the > Hugin forum, mostly because of the high degree of cross-pollination > that obviously [and quite helpfully, by the way] exists between the > two products, I know that coming at the problem from two points of > view has helped me sort through some of the issues which are generic. > > 02. So, let me relaunch the already helpful dialog with a new summary > that will be clearer because quite a few of you have actually looked > at the source images and now have a first-hand feel for the extent to > which they pose a similar and the extent to which they pose a rather > different challenge than what appears to be the sort of canonical set > of issues for those dealing with DSLR cameras and manual, semi- > automated, or almost-completely-automated tripod rigs designed > primarily for the creation of panoramas. > > The first thing that everyone notices is that despite a remarkable > achievement of hand-drawing, these images, in many respects are not as > "nicely behaved" as those you would get from the aforesaid, multi- > snapshot, automated tripod rig. That said, as I previously alluded, I > have been able to get a working set [of a 4x4 case] using Photoshop > and purely manual placement that is very, very good. Now, I had not > previously known how to show you that, but there have been two helpful > suggestions. First, while I have continued to work with uncompressed > inputs and outputs, it would be possible for me to rework the > Photoshop workflow with compressed images. That would, of course, > cause some loss of precision, but I would be willing to do that if it > would be the least difficult way to provide all interested parties > with a result set that would be a little larger than usually chokes > most mail servers, but less than the maximum I can send via my > YouSendIt account. Alternatively Jeff has taught me about the > WeTransfer site, and from trying that I know that I can successfully > upload the 320MB Photoshop tif composite [in about 3.5 hours of slow > uplink speed from my ISP.] That, then is my first action item: those > of you who would be interested in having an example of a successful > merge of this content, please give me an email address that I can use > to have WeTransfer notify you when the file is available for your > downloadl. > > 02. Let me move from there to a revised statement of what I think my > challenge is with either PTGui or Hugin. And to explain why I am > introducing Hugin, it's because half of the original responders to my > request here took umbrage with my short-shrifting of their product. > Moreover, for the last 24 hours persons who actively post to both > sites have been very helpful in trying to find a methodology for > configuring the parameters of that product to correctly perform the > transformation. And I believe I am correct in stating that the > parameters of their engine are almost identical to yours, so while the > specifics of how to 'fool the engine into doing the right thing' > probably differ, upon review of the various opinions from various, > conscientious, helpful, knowledgeable persons, I think they are > probably identical at the conceptual model level. > > So, let me first dare to disagree with the opinion that the set of > images are "not shots of one drawing". I believe that, in contrast to > what happens when a single camera takes multiple of shots of a scene > without changing its XYZ coordinates on the planet, the result of this > super-human drawing effort results in precisely one image, not the > patchwork of images that would result from a camera. What is > different about those 104 plates is that if they were placed on the > floor of a basketball court, but instead of letting the small [about > 1/4 inch] of overlap exist, you took out your box cutter and precisely > trimmed them to eliminate overlap, to people sitting in the bleachers, > the scene total would be displayed almost perfectly. > > There are not slightly different rotational angles and slightly > different azimuthal elevations -- they did not have a camera, they had > an arbitrary point and, in effect, drew the proper perspective to each > building that they carefully sketched at the proper location on what > could have been a single sheet of paper. Now, since there was no such > huge sheet of paper, rather there was the need to prepare material > that could be published in book format, they carefully, created each > independent patch, always doing whatever was humanly possible to > adhere to the proper projection from that single, unmoving point of > origin. > > Now, to the statements that the images are of different sizes, yes > they are. And I suspect that the differences were compounded by the > photo-lithographic process of producing the plates. There were, very > probably some differences in the height to the camera used for > photographing the plates, and there were probably some differences in > the exact dimensions of the bounding rectangle into which each plate > drawing had been made by the artist. All that notwithstanding, I > think that in your terminology the result is in the range of 'parallax > error' that your software deals with in the case of cameras that are > hand held or otherwise imprecisely rotated during the photographic > process. What I can say, but more importantly, what I can demonstrate > with the sample that I want to send you, is that the manual, > interactive stitching of "control points" deduced by Photoshop as a > result of my placement of overlaps via onion skinning, in more than > 90% of the cases results in an almost perfect match when I release the > mouse button to allow "Jump to Image". In about 5% of the cases, the > disproportionate overlay has no 'best fit', so I turn off "Jump to > Image" to make a human judgment of how to deal with the ambiguity > between the two layers that need to be blended along that common > edge. In the final result, this source of 'noise' or error is far > less noticeable than the problem I have with some images that I > cropped too closely, such that there are one or more pixel rows > completely missing along some edge. I am ever hopeful of getting > PTGui's workflow to the point where I can see and attempt to deal with > that problem of "holes". The Photoshop batch process goes into some > sort of "erasing hole" mode and fills in the missing pixels with some > very acceptable mirage! > > 03. As I am the neophyte, I have to leave to your better judgment as > to what to do. I very much appreciate the recommendation to crop the > images and just make them sit close to one another, but I am not ready > to give up. Again, I need to send you my intermediate results. The > sources from the LoC were cropped only insofar as eliminating the > borders to get a solid inside rectangle. As mentioned, in most cases, > that still leaves about a quarter inch that the engineer/architect/ > artists wisely duplicated as between adjacent plates. it is entirely > possible to recreate a single image so that my viewers [who, by the > way will be sitting at an AIR application taking advantage of > Zoomify's ability to deal with tiled content of this sort] will be > able to 'walk down broadway from one end to the other seemlessly'. > > So, back to my learning lessons of the last couple of days. The key > issues seem to be: > > A. Whatever facilities exist for "photometric rationalizaton", > they need to be turned off. There is no need, nor desire to try to > reconcile the obvious difference in the brightness or darkness of the > sepia images. If there is a nice way to do that later, I will come > back to it later, but every attempt I have seen so far, produces > almost useless changes of that sort. My users will simply have to > deal with the fact that while they are 'walking down broadway' > sometimes the sun goes behind a cloud, sometimes a tall building shuts > out the sunlight -- no problem in 1874. > > B. There seem to be two different ideas as to how to set the > parameters dealing with horizontal view or whatever the equivalent is > to the optical differences between a telephoto lens, and wide-angle > lens, or perhaps a micro lens. [Sorry, I am still happy with my Nikon > Photomic F, and till in debt for lenses that cost $300 in the sixties, > so I am not ready to even look at B&H to learn what a great job I > could do with an equivalent digital lens that costs as much as my car > did in the sixties.] An original suggestion here was to create the > smallest possible field of view. I think that idea stems from the > behavior that might be expected from placing the plates under a bed > scanner. The problem, I think, with that idea is that when I go to > the library and attempt to use a Size A4 bed for some topographic map > that probably is at least a yard square is that what I am imaging has > no perspective. Each image is really discrete and the result can be > stitched by aligning the correct pieces, sans overlap. That is not > how these 104 patches came into being. As I said, there never was one > basketball court sized sheet of paper that you might just break up > into A4 sheets of paper. Here, each A4 sheet represents a different > angular displacement in space from that single point of view two miles > across ... > > read more » -- 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
