An analysis of physics-based optical flow

Comparison between optical flow and cross-correlation methods for extraction of velocity fields from particle images

“…A mathematical analysis of the variational solution of Eq. (1) in the weaker conditions based on the L 1 -norm and an iterative numerical algorithm are given by Wang et al (2015). Although the first-order Tikhonov constraint functional is physically plausible, it is not derived from the first principles.…”

Hybrid particle image velocimetry with the combination of cross-correlation and optical flow method

“…Thus, Liu and Shen (2008) From the physics-based Optical Flow equation, they developed a theorem that confirms a unique solution of the minimization problem, thus verifying that the minimization preserves discontinuities in a fluid velocity field (B. Wang et al, 2014). Other work includes the study of optical flow with regards to an optimal control problem, where divergence free criteria, for flow conservation, is applied that leads to a proof for the optimal conditions for the optical flow (Barbu et al, 2016).…”

OpenOpticalFlow: An Open Source Program for Extraction of Velocity Fields from Flow Visualization Images

“…Optical flow computation can be conducted in a PC with Matlab to extract velocity fields at a spatial resolution of one vector per a pixel. The optical flow method has been used in some challenging flow measurements in which the traditional cross-correlation method in PIV could not provide sufficient high-resolution velocity fields in large domains [7][8][9][10][11][12]. Although there are research optical flow programs developed by different groups, an easy-to-use open source program is still lacking for non-expert users in various settings of fluid-mechanic applications.…”

“…The optical flow method has been used to study the flow structures of Jupiter's Great Red Spot (GRS), impinging jets, and laser-induced underwater shock wave [8][9][10][11]. A mathematical analysis of the variational solution of the optical flow and an iterative numerical algorithm are given by Wang et al [12]. The systematical error analysis of the optical flow method in velocity measurements is given by Liu et al [11] in comparison with the well-established cross-correlation method in particle image velocimetry (PIV).…”

“…(3) with the Neumann condition ∂u/∂n = 0 on the image domain boundary ∂Ω for the optical flow [7,12].…”