My Masters project presentation^_^

1. DIGITAL IMAGE
MORPHING THROUGH
“FIELD MORPHING”
Ankur Sakhuja

2. Example

3. Block Diagram for Algorithm Workflow
Generating an intermediate frame
Image IS Image I1
Fs → F warp
Feature Spec Feature
Fs Spec F
Morph
Color interpolate
Image
Image I2 Image IT
FT → F warp
Feature Feature
Spec F Spec FT

4. Algorithm overview
 Basic motivation: specification of feature points as lines – more expressive and
intuitive
 Line features specified in both source and target images and correspondence
established
 For every intermediate position in morph sequence, a line feature set is
generated by interpolating the two sets
 Between source and intermediate line feature sets:-
 Every pair of line features represents a coordinate transformation for a point
from source to target image – results in some spatial displacement
 A weighted sum of displacements due to all line pairs gives net displacement
of a point – the total warp function
 Warp both source and target images to get two intermediate images
 Color interpolate to obtain the morph image
 Repeat for every position in the sequence to obtain the morph sequence

5. The Math:
Pixel transformation
specified by single
pair of line segments

6. The Math (contd):
Pixel transformation specified by two pairs of line segments

7. The Math (contd):
weighting factor for combining transformations of multiple line segment pairs
b
Weighting factor for combining displacements: length p
Weight
a dist

8. Algorithm Pseudocode
• For each pixel X in the destination
• DSUM = (0,0)
• weightsum = 0
• For each line Pi Qi
• calculate u,v based on Pi Qi
• calculate X'i based on u,v and Pi'Qi'
• calculate displacement Di = Xi' - Xi for this line
• dist = shortest distance from X to Pi Qi
• weight = (lengthp / (a + dist))b
• DSUM += Di * weight
• weightsum += weight
• X' = X + DSUM / weightsum
• destinationImage(X) = sourceImage(X')

9. MATLAB Implementation and Results

10. Reference
1. Beier, T. and Neely, S. 1992. Feature-based image metamorphosis. In
Proceedings of the 19th Annual Conference on Computer Graphics and
interactive Techniques