[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

Re: Morph software



Todd Denniston wrote:
On Fri, 2009-02-06 at 16:02 -0500, Bill Davidsen wrote:
I'm looking for some morphing software, to take two images,
and generate some  "intermediate" images to show the effect
of a smooth transition from one to the other.
with gimp load image 1 on image 1's window select File->Open as
Layer-> pick image 2 Open the Layers dialog insert a Layer that is
background color (call it Clean). duplicate image 1's layer
(Background). Sort the layers such that you see image 2 Background
copy Clean Background Delete Background. on image 1's window select
Script-Fu -> Animators -> Blend set number of frames, blur and if
you want it looped (no loop I think.). hit OK.


This still isn't what the OP is looking for afaict. Bill is asking
about feature based image warping and metamorphosis - tools that
either automatically identifies common features between two images or
provides a means to manually specify feature alignment and that then
non-linearly project the source and destination images according to
some interpolation of these two feature sets, allowing a smooth
transition from source to destination.

The convert command -morph option performs simple superposition and
interpolation of pixel size and value rather than feature based
warping and interpolation.

It's the effect used in Michael Jackson's "Black or White" music video.

There are numerous algorithms that implement this type of morphing,
from the very simple (e.g. Bayer-Neely field warping[1]) to the
fiendishly complicated (spline surface energy minimisation[2]).

A lot of the simpler morphing packages you'll find (there seem to be a
tonne of shareware tools for Windows) implement an approach called
mesh warping where a spline grid is overlaid on the source and target
images and the operator adjusts the grid to identify the relationship
between features in the two images. This method has the advantage of
being fairly easy to implement while still offering reasonable control
of feature placement (it's also the method used in the Jackson video).

There's a GPL'ed mesh warping tool available here:

http://xmorph.sourceforge.net/

I haven't found an awful lot of other open source morphing tools or
libraries, although I'd be very happy to find counter examples to that.

When I was looking at this stuff I needed the ability to freely
specify feature constraints (so meshes weren't applicable) and had
some constraints on the resulting morph functions (C2 continuity & 1:1
properties) so I implemented an approach called multilevel free-form
deformations or MFFD[3]. It's an interesting algorithm and I'd really
like to go back to it one day and turn the work I did then into
something more generally useful (as usual, time is the problem there :).

Regards,
Bryn.


[1]  T. Beier, S. Neely, "Feature-Based Image Metamorphosis", siggraph
1992. http://www.hammerhead.com/thad/morph.html

[2] S. Lee, K.-Y. Chwa, J. Hahn, and S.Y. Shin, “Image Morphing
Using Deformation Techniques,” J. Visualization and Computer
Animation, vol. 7, no. 1, pp. 3-23, 1996

[3] S. Lee, G. Wolberg, K. Chwa, S. Shin, "Image metamorphosis with
scattered feature constraints", IEEE TVCG96, vol. 2, no. 4, pp. 337-354.


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]