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Thread: 8 Gigapixels in Cambridge

  1. #1

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    8 Gigapixels in Cambridge

    After fiddling with over 1000 photos in Autopano Pro, and Photoshop, I have managed to finally produce this 8 gigapixel image of the center for mathematical sciences in Cambridge, hosted on Gigapan:

    http://gigapan.org/viewGigapan.php?id=23168

    Its part of a whole bunch more that are available at http://lifeinmegapixels.com/bylocation.php?tag=6
    Last edited by wjh31; 25th September 2009 at 08:52 AM.

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    re: 8 Gigapixels in Cambridge

    Quote Originally Posted by wjh31 View Post
    after fiddling with over 1000 photos in autopano pro, and photoshop, i have managed to finally produce this 8 gigapixel image of the center for mathematical sciences in cambridge, hosted on gigapan:

    http://gigapan.org/viewGigapan.php?id=23168

    its part of a high resolution virtual tour of cambridge that im having reasonable success putting together at http://cambridge.lifeinmegapixels.com
    Interesting exercise, although no-doubt less frustrating on a faster connection (was fairly slow from this end).

    Looks like some pretty serious CCTV cameras on that right-hand building!

    I was guessing that I'd also see some detailed self-portraits in some of the window reflections, but I didn't find any!

    You might like to take a cloder look at the "mathematics" wording on one of the centre images -- looks like their might be a bit of ghosting there.

  3. #3

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    re: 8 Gigapixels in Cambridge

    Unfortunately the Gigapan site is just generally a bit slow, and hosting it on my own site like I do with some images isnt particularly possible due to webspace restrictions.

    There are various wierd effects across the image, some are due to the differences in lighting between times of day, and some because I had to use multiband instead of smartblend (if that doesnt mean anything to you, its slightly different methods of rendering the final image, smartblend is able to account for moving images to minimise ghosting and similar effects), unfortunately smartblend had the hard drive as a bottle neck, which meant it took a day then crashed with no results, whereas multiband 'only' took 2/3rds of a day to render. However having seen the bit I think you are refering to, that looks less like ghosting and more like the reflection or a second set of wording on another pane of glass behind the first.

    Nothing special was done to avoid self reflections, I guess I just got lucky.

    Its probably not the best use of 8 Gigapixels, I'd love to a multi-gigapixel cityscape, but its hard to find somewhere apropriate in Cambridge, so I settled with the CMS because there was a good run of weather at the time, and I wanted to see how far I could push the camera, my computer, and my patience.
    Last edited by Colin Southern; 23rd May 2009 at 11:54 PM.

  4. #4
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    Re: 8 Gigapixels in Cambridge

    These are great pictures. The first one of these I saw was a panoramic picture of Obama's inauguration day at the Capitol. Could you please explain briefly how this done and how you overcome changes in lighting and also moving objects/people.

    Thanks!

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    Re: 8 Gigapixels in Cambridge

    changes in lighting wernt completely avoidable, but i shot the source photos over a few days with a couple of hours each day to try and get it at vaguely the same time for the same lighting. I was lucky enough to have a stretch of a few sunny days so sunny vs cloudy lighting wasnt an issue. Being able to shoot the images in a shorter time would reduce issues further, but my camera is only a bridge rather than a DSLR so it takes it a little time to process the photos before its ready for the next.

    accounting for moving objects is a combination of waiting a minuite or two if someone/something is moving across the shot, and of clever software.

    how its done:
    The basic idea is take lots of photos, and stitch them together with software into a single high resolution and/or panoramic image.
    Taking the images isnt too dificult, find somewhere that looks nice and get clicking, about a 20% overlap between images is sufficient, but more if you are doing it free-hand or if there are alot of moving objects.
    using a tripod is recomended, as this makes it easier to shoot rows and columns of images, but it can be done free hand with much success. If objects in the image are close to the image, you will want to use a panoramic head to get the camera rotating around the no paralex point (aka NPP, quick explanation here: http://www.johnhpanos.com/epcalib.htm) to minimise artifacts in the stitching. Finally you will want to keep the camera settings the same between shots to keep from having different exposure levels across the image. (actually i typically use aperture priority as lighting can vary alot across a scene, so it avoid massively under-exposed or overexposed bits that might happen if you chose one setting, most of the time software is able to adjust colours, exposures etc to prevent too many funky effects)

    once you have the images there are a million and one bits of software available to stitch, but im going to recomend 3 particular packages, two are free, and the last is ~100, and a final comment on a 4th method

    first is autostitch, its simple to use, and gets the job done, but without too many extras. It starts to run into problems if yous pictures run into the 100's of megapixels. Its a one click solution that is a good way to experiment when youve not tried high res/panoramic photography before. works under windows, no offical linux/mac versions, but it works perfectly under wine in linux : http://www.cs.ubc.ca/~mbrown/autostitch/autostitch.html

    second is hugin (http://hugin.sourceforge.net/) more advanced than autostitch, but that comes with being a bit more fiddley, although i havent used it extensively. It seems to be the most recomeneded free stitcher for more advanced users. available in all OS.

    final is autopano pro which is what i used. A great UI, enableing one click processing of a panorama, but with easy to understand bits for more advanced users to tweak the images to perfection to correct colour, stitching errors, etc. The trial is acutally pretty comprehensive and just leaves a few watermarks on the final image. Available on mac, linux and windows, in 32 and 64 bit versions (http://www.autopano.net/en/buy-autopano/download.html). This software includes a blending method called smartblend which reduced the effect of movement in images, and helps remove ghosting. a little more info: http://wiki.panotools.org/SmartBlend.

    final mention: alot of cameras include a panorama mode which will stich a handfull of images together for you, while this is never going to be as powerfull as processing the images on a computer, its good for experimenting and just trying it out, or for checking the composition of a scene before you take the full set of images.

    now you got yourself a huge photos, what the hell do you do with it?
    to display it im going to recomend one of two choices.
    gigapan: as with my OP at the start of this threat, you could upload the image to gigapan and use their embedable viewer.
    otherwise i would suggest zoomify, similar display method to gigapan, i.e a flash viewer that lets you zoom and pan. It actually has a plugin built into photoshop, or theres a standalone package that you just stick the image into and it cuts it up for you ready to view in your browser, either locally or it can be uploaded to your site for public display

    There are a million and one tutorials on the other side of a google search if you want more

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    Re: 8 Gigapixels in Cambridge

    Quote Originally Posted by wjh31 View Post
    how its done:
    The basic idea is take lots of photos, and stitch them together with software into a single high resolution and/or panoramic image...

    ...There are a million and one tutorials on the other side of a google search if you want more
    Interesting. Thanks a lot for taking the time to explain it!

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