15-463: Project 3: Morphing Some Faces

Student: Kristin Siu (kasiu)

Implementation

Again, the implementation was in Matlab.

Algorithm Outline

The basic outline can be considered as follows:

Takes input images and a list of predefined points This list of points was precomputed before hand using ginput and related functions.
Computes the triangulation by looking at the average of the points and using Matlab's delaunay function.
For each frame:
- Computes the dissolve and warp fractions.
- Calls the morph function using the two images, their point lists, the triangulation, and the fractions.
- Computes the warped mesh by linearly interpolating the two point sets.
- Splits the frame into two components: one from each image.
- For each pixel of each component:
  - Calculates its corresponding triangle in the old images and computes an affine transform for each image.
  - The affine transform is computed by finding transforms from the identity triangle to each triangle and combines these transforms (and their inverses) to come up with both the affine transform and its inverses.
  - Uses the affine transform to get the value at the pixel from the original image. Uses nearest- neighbor interpolation for speed.
- Cross dissolves the two components to get the frame.
- Outputs that frame to a file.

The Mean Face

For the mean face, I modified the morph function a bit (the warp_frac is effectively now 1 and the set of points im_2 is just the mean set of points) The morph function now just returned a warped image, which was then cross-dissolved outside of the function. I ran out of time to come up with points for everyone's face, so my solution uses only those people who had corresponding text files (or ones that I could match).

Issues

I was unable to get either of the C files for the mytsearch functions to compile and then spent the project using mainly the really slow mytsearch.m version of the code. As a result, my code is slow. Really slow. There are also was some unusual artifacts in the morph, so it doesn't look too great. Part of this problem was the points I specified (I believe the eyes on the point set for my face are a little too low (as in, I think I specified the eyelids instead of the eyebrows)... Oops. Also, the poorly-defined triangle mesh and interpolation badness (using nearest neighbor only) have left an ugly border where the mesh borders are. This probably could have been remedied by encompassing the rest of the image into the mesh (points at corners) and using a better interpolation scheme.

Results!

Face Morph

The following is the video of the face morph from my face to Luis's face (pictures 16 and 17 respectively).

Original pictures:

Here's a link to the video.

The Mean Face

Here is the mean face:

And here is my face warped to the mean:

For some reason, I think I'm a little horrified at how I got stretched out... Am I really that different from the mean?

References/Credits

Errr....thanks to everyone in the class who had a photo?