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The optimal overlap and settings for difficult images RRS feed

  • Question

  • Hi there,

    With hand-held (or tripod mounted, but without robotic panoramic head) panoramas, where images are shot in a regular row by row fashion, how do I optimize the images and their overlaps to either help ICE to match the right images or to minimize stitching artifacts?

    For instance, what is the optimal adjacent margin overlap?  I imagine too little can deprive ICE from enough unique features for matching, too much may introduce double-feature ghosts and shifts in the stitched regions.  Adjusting overlap amount is actually quite easy to do, since even if the overlaps are irregular (because of hand holding camera) the component images can be trimmed to the optimal overlap before subjecting them to ICE.  What's the advice?

    Also, with difficult to automatically match or large panoramas (such as those showing a lot of sky or water), I understand that Structured Panorama can be used even if the camera was hand-held, as long as the layout is regular.  What's the advice on the parameters (the actual optimal overlap margin size, and the ICE user-adjustable parameters: overlap and search radius)?

    Cheers!

    Saturday, September 17, 2011 9:39 AM

All replies

  • For panoramas shot 1 row handheld I almost always use the structured panorama interface.  It is a bit more robust than having ICE work out the order.  My advice is to overlap by 25-30%.  This is usually how I set the Gigapan to get good results.

    You need to be very careful if you "trim" the images.  It is important that the center point of the image remains unchanged, in other words you need to trim equal amounts from the left and right edges.  I believe that this should work although it isn't something we test for in ICE.

    Search radius comes down to how close your overlap estimate is.  When shooting with a Gigapan this can be very small 5% of the image.  When manually moving the camera you probably can't get that precise. It really depends on how much your overlap is varying.  If you vary from 20% to 50% overlap I would set the overlap estimate to half-way in between those - 35% and the search radius to 20% to cover your overlap range with a little slop.

    Hope this helps. 

    Happy shooting.

     

     

    Saturday, September 17, 2011 11:29 PM