Stitching scanned images; how and what software?

Discussion in 'Digital Darkroom' started by oskar_ojala, Feb 15, 2009.

  1. At some point last year I realized that with my DSLR and macro lenses I can take pretty high quality "scans" from my negs and slides. This setup also permits relatively high resolution if one neg frame is exposed in multiple pieces and then stitched together on the computer. However, the process I'm having now could be improved. I can trivially align and blend the subframes in PS, but that involves manual work and it gets really difficult if a slight error during the "scanning" phase has caused the subframes to get rotationally misaligned.
    So the next thing tried was to try the open source programs hugin and ale for aligning the subframes since they can handle rotation. Neither software is designed for this purpose. What happens is that ale produces excellent results part of the time and unusable stuff the rest of the time. It's also slow. Hugin can generally come out with something, but it requires some manual entering of options (again more manual involvement) and the results sometimes get distortions or do not align. Not aligning is rare so it's not that much of a problem, but distortions are a problem as is manual involvement. I'm skipping some of the details of what I did here not to make this explanation too long, feel free to ask if you think it's of any value.
    What I'm asking you is that now I can get reasonable results, but I need to less manual work and have higher quality work done automatically. Can you recommend me a software and/or way to use it correctly for achieving high quality stitched "scans"? I don't mind coding something, but I would like to get the whole package as ready to use as possible in order to save time and effort. I'm interested in having high quality digital versions of negs and slides of various formats so that I can print them.
     
  2. Maybe you could try panorama software which is designed to stitch images togther. I have gotten good results with Zoner Panorama Maker for a range of "stitching" tasks. This program is by far the best I have tried and is wizard based. It automatically aligns the separate images for best fit, compensates for exposure differences between them and can be tweaked for the lens focal length to get the right perspective in the final result then cropped to your requirements. Of course, it does not have to be used to make a panorama. Its very intuitive and easy to use but may lack some features or the degree of control you require for your specific application. Still its worth a try. Here is a link to a trial version.
    I got mine free at Giveawayof the day so if you Google further you may be lucky enough to find a completely free version. If not at 10 bucks its a steal.
    http://www.download.com/Zoner-Panorama-Maker/3000-12511_4-10578553.html
     
  3. You might try PTGui. this is my favorite stitching program. But if you have Photoshop CS4 try its implementation of the Photomerge tool first.
     
  4. I use Panorama Factory.
     
  5. Thanks for the answers so far. In order to get closer to my goal, I immediately tried some of the suggested software. I used a somewhat non-scientific approach of giving two non-trivial stitching cases, one "regular" panorama (I do these too, so if I'm buying software, I want my money's worth) and a 10 pieces from a 4x5" slide -scanning scenario. If these worked well, then I spent a bit more time with the program. Here are the results so far:
    • Zoner; simple wizard based interface and reasonably fast, but unfortunately the results were far from optimal. I can produce better results with free software (hugin) with a similar level of work.
    • PTGui; the user interface is so similar to hugin and the ancestry to PanoTools so obvious that firs I though "ripoff!". But the program is actually nicely polished compared to it's free relatives and it's reasonably fast. It produced an excellent result with the panorama image and a quite good result with the "scan case", only one visible seam being there. I didn't get rid of the seam, but believe I could do it by editing the final result in photoshop with the subframe layered on top of it. I probably need to evaluate this program a bit more, since it might be useful enough to buy, although the UI has some things to improve, my biggest gripe being the fact that it's either auto-everything or full manual, just like hugin. Also, the output seemed sharpened, but I assume it can be turned off.
    I don't have Photoshop CS4, I have to ask my buddies if anyone has it so that I could try. I didn't yet have time to try Panorama factory, but will do so as I feel that I haven't yet found the perfect software.
    The basic problem with all software that I've tried seems to be that their processing model seems to be very heavily oriented towards the user doing a traditional single-point panorama, i.e. one is sitting inside a sphere and then the image projected on the surface of the sphere. What this means is that the settings for the optimizer need to be by default totally different for scanned images than for panoramas and this point seems to be either missing or require heavy manual work. I'll continue to look into the programs mentioned and also accept new suggestions.
    Ellis , out of curiosity, did you try stitching frames taken with a shift lenses when shifted? If so, how did that turn out? That has been a little bit of a problem for me sometimes.
     
  6. Photomerge has been good stuff since maybe CS2 but they improve it in each version. CS4's version is really cool. I looked back at my travel albums, found pictures that were shot from about the same place but weren't for panorama'ing, tossed them together and Photomerge spat out darn near perfect results.
     
  7. Oskar,
    I feel your exact pain. I shoot panos quite a bit and stitch using PTgui, but I've recently had a job come up where I need to stitch flat images and I'm surprised to find most of the pano programs entirely unsuited to the task. I'm not stitching scans, rather I'm stiching images shot along a length of wall with a flat 50mm lens, which in the end is basically the same type of stitch. As you've also found, it seems most software really wants to stitch images that were shot around the same nodal point, and things get totally whacky when you try to get programs to recognize that the entire camera actually shifts between shots. So far PTgui has given me perfect control points but it can't seem to stitch anything acceptable yet, (it thinks its good pts are 80+ units off). So far my best results have come from Photoshop CS3 using the align and merge. The nice thing being that you can do a blend but keep the layers separate with masks in case you want to do manual tweaks.
    Regardless I'd still like to see Ptgui be able to handle these flat stitches as I have utmost faith in its stiching and blending for standard panos. If I discover a secret recipe I'll post back here.
    Also does anyone have any experience with PS CS3 vs CS4 photomerge. I'm wondering if an upgrade might not give me even better results.
    Duncan
    Redshift-Blueshift
     

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