Figure 11.

Optical traces obtained from contracting heart surface during ventricular fibrillation (VF) in voltage-sensitive optical mapping recordings before and after numerical motion tracking with 5 different GPU-accelerated motion tracking algorithms (Lucas-Kanade, TV-L1, Farnebäck, NVIDIA, Brox). (A) Left: Raw optical trace (black) obtained without numerical motion tracking exhibiting substantial motion artifacts. Right: Optical trace (green) after numerical motion tracking using Farnebäck GPU algorithm and motion-stabilization. The optical trace exhibits a series of action potentials (downstrokes correspond to action potential upstrokes). (B) Comparison of numerical motion-stabilization using different GPU algorithms. Left: without contrast-enhancement. Right: with contrast-enhancement. Most of the algorithms are less accurate without contrast-enhancement. With contrast-enhancement, all algorithms behave very similarly and provide similar, sufficiently accurate results. (C) Individual comparison of algorithms used with contrast-enhancement (color) and without (black).