[IPOL announce] new article: An Implementation of Combined Local-Global Optical Flow

[announcements about the IPOL journal]

A new article is available in IPOL: http://www.ipol.im/pub/art/2015/44/

Jorge Jara-Wilde, Mauricio Cerda, José Delpiano, and Steffen Härtel, An 
Implementation of Combined Local-Global Optical Flow, Image Processing 
On Line, 5 (2015), pp. 139–158. http://dx.doi.org/10.5201/ipol.2015.44

Abstract
Optical Flow (OF) approaches for motion estimation calculate vector 
fields for the apparent velocities of objects in image sequences. In 
1981 Horn and Schunck (HS) introduced two basic assumptions: 'brightness 
value constancy' and 'smooth variation' to estimate a smooth OF field 
over the entire image -global approach-. In parallel, Lucas and Kanade 
(LK) assumed constant motion patterns for image patches, estimating 
piecewise-homogeneous OF fields -local approach-. Several variations of 
these approaches exist today. Here we present the combined local-global 
(CLG) approach by Bruhn et al. which encompasses properties of HS-OF and 
LK-OF, aiming to improve the OF accuracy for small-scale variations, 
while delivering the HS-OF dense and smooth fields. A multiscale 
implementation is provided for 2D images, together with two numerical 
solvers: Successive Over-Relaxation and the faster Pointwise-Coupled 
Gauss-Seidel by Bruhn et al.. The algorithm works on gray-scale (single 
channel) images, with color images being converted prior to the OF 
computation.