Example 16



SweepDist


Spirals
Curves # Vertices Length
P 211 66.82169430866213
Q 41 5.059535432507317

Distance Value Iters
Fréchet 1.1585808408611906 0
VE Fréchet 1.1585808408611906 617

Animation: Fréchet morphing

This is the animation of the morphing computed that is both continuous and monotone.


Animation: VE Retractable Fréchet

This is the animation of the VE retractable morphing. It is potentially not monotone (but it is continuous.


Free space diagram heatmap:


graph + free space [PDF] : graph [PDF]

VE-Fréchet Retractable solution:


Monotonized...

Fréchet cont+monotone solution:


Discrete Fréchet

The resulting morphing - extended to continuous:

Specifically, to get a smooth animation, the leash is shown as moving continuously, by interpolating between the discrete locations.


The discrete retractable version


The discrete dynamic time warping


P # vertices: 211
P # vertices: 41
DFréchet iters : 8651
Retract DFréchet iters : 289

Refinement for removing monotonicity

By introducing vertices in the middle of parts of the curves that are being traversed in the wrong direction, one can refine the solution, till effectively reaching the optimal monotone solution. This process is demonstrated below. As one can see, the error is negligible after a few (say four) iterations. After that, it becomes a bit pointless.
We emphasize that a monotone morphing can always be extracted, by monotonizing the current solution. This is easy and fast to do, and is the error accounted for in the below graphics.

More info

Animation: Fréchet morphing as morphing


2025-03-08 20:39:51