• Subscribe

    Subscribe to This Week In Panospace by eMail.
    Subscribe in a reader
  • License

    Creative Commons License
    This work is © 2008-2012
    by Yuval Levy
    and licensed under a
    Creative Commons License.
  • Entries

    February 2008
    M T W T F S S
    « Jan   Mar »
     123
    45678910
    11121314151617
    18192021222324
    2526272829  
  • Archives

undistorted alignment


CP-screenshot

Control Points (CP), also known as Reference Points, are the holy grail of image stitching. They are identified in the overlap area between two images so that the images can be aligned to each other in space.In the old days, panorama photographers would tediously map these points manually, as a set of pixel coordinates on adjacent images. Even before that, they would patiently use scotch tape. Then came automated software.

The area is still the focus of much research, and was the subject of a Google Summer of Code project by Zoran Mesec, mentored by Dr. Herbert Bay, the inventor of the SURF algorythm. The project is still under development and Zoran has added new code to the hugin repository a few weeks ago, just before his exams.

The problem of most current software for automatic generation of CP is that it has troubles with those areas where the two photos have different kind of distortion. This is inevitable with fisheye lenses that are very popular for the production of full spherical panoramas.

A solution to this problem is to compare the photos after remapping them into a conformal projection. Bruno Postle announced recently an implementation of a perl tool that runs the usual automatic generation of CP on temporary stereographic versions of photos. Despite all the apparent overhead, it is not significantly slower than conventional software with the same feature detection algorithm.

For the moment it is a perl script, dependent on some extra CPAN perl modules and ImageMagick. And it runs from the command line. But it won’t take long until Hugin can feed it with the appropriate parameters. I’ve been delaying my next installer snapshot in the hope to be able to add it.

3 Responses

  1. match-n-shift works well from the command line with Perl.

  2. I spent a few hours figuring out Bruno’s new match-n-shift. It works well in Linux. Unfortunately Perl is not installed by default on Windows boxes.

  3. Added to the snapshot installer 18-Feb-2008.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s