Monday, 29 September 2008

Create a mini-world from your panorama pictures

This is a short description on how to create a so called mini-world from a panorama scene. This is one way to creatively display panoramas, which may otherwise be quite difficult considering the high width/height aspect ratio of your typical stitched panorama shot.

We start with the following panorama of the Hong Kong night skyline

And we and up with the following "Hong Kong" mini-world

For the purpose of this explanation I will assume you already managed to create a panorama photograph like the one I show above (using e.g. photoshop or another proprietary or freely available stitch software such as: canon photostitch or Hugin). You need to have a picture with a aspect ratio (width/height) greater than two. Panoramas with a well defined foreground (sand, floor) and a neutral background (sky) work best.

You will have to go through the following steps with, for example, Photoshop or Gimp.


(1) image -> resize image: deselect fix aspect ratio make height equal to width.
note: this can create a very big image! you might want to reduce the image size first ;-)
(2) image -> rotate canvas> 180 degrees
(3) filter -> distort -> polar coordinates: select rectangular to polar
(4) image -> rotate canvas: rotate the image to your prefered angle
Basically in this way the left edge and right edge of your panorama will be connected, this will work automatically well when you have a 360 degree panorama, although this is not necessary (in that case you may want to crop the edges such that the matching is improved).


(1) image -> scale image
(2) filters -> distorts > polar coords: check "to polar", un-check "map from top". For nice planet look set "circle depth" to 100 percent. Map backwards (un)check as you like. You can also rotate your image (you may want to experiment with the options here).

In some cases you may have to edit your panorama to optimize the final image. For example, you may want to crop some unwanted edges or straighten the horizon. To create the Hong Kong mini-world I removed the edge artifacts from the panorama before resizing (the image below shows what happens if you don't do that). You can still notice a small deviation at the connection of the left and right horizon (due to the slight skewed skyline).

A nice short tutorial, with examples, has been published also at photojojo.

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