5. Convective regularization for optical flow
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José A. Iglesias
Abstract
We argue that the time derivative in a fixed coordinate frame may not be the most appropriate measure of time regularity of an optical flow field. Instead, for a given velocity field v we consider the convective acceleration vt +∇vv which describes the acceleration of objects moving according to v. Consequently, we investigate the suitability of the nonconvex functional ‖vt + ∇vv‖2L 2 as a regularization term for optical flow. We demonstrate that this term acts as both a spatial and a temporal regularizer and has an intrinsic edge-preserving property. We incorporate it into a contrast invariant and time-regularized variant of the Horn-Schunck functional, prove the existence of minimizers and verify experimentally that it addresses someof the problems of basic quadratic models. For the minimization we use an iterative scheme that approximates the original nonlinear problem with a sequence of linear ones.We believe that the convective acceleration may be gainfully introduced in a variety of optical flow models.
Abstract
We argue that the time derivative in a fixed coordinate frame may not be the most appropriate measure of time regularity of an optical flow field. Instead, for a given velocity field v we consider the convective acceleration vt +∇vv which describes the acceleration of objects moving according to v. Consequently, we investigate the suitability of the nonconvex functional ‖vt + ∇vv‖2L 2 as a regularization term for optical flow. We demonstrate that this term acts as both a spatial and a temporal regularizer and has an intrinsic edge-preserving property. We incorporate it into a contrast invariant and time-regularized variant of the Horn-Schunck functional, prove the existence of minimizers and verify experimentally that it addresses someof the problems of basic quadratic models. For the minimization we use an iterative scheme that approximates the original nonlinear problem with a sequence of linear ones.We believe that the convective acceleration may be gainfully introduced in a variety of optical flow models.
Chapters in this book
- Frontmatter I
- Contents V
-
Part I
- 1. Second-order decomposition model for image processing: numerical experimentation 5
- 2. Optimizing spatial and tonal data for PDE-based inpainting 35
- 3. Image registration using phase–amplitude separation 84
- 4. Rotation invariance in exemplar-based image inpainting 108
- 5. Convective regularization for optical flow 184
- 6. A variational method for quantitative photoacoustic tomography with piecewise constant coefficients 202
- 7. On optical flow models for variational motion estimation 225
- 8. Bilevel approaches for learning of variational imaging models 252
-
Part II
- 9. Non-degenerate forms of the generalized Euler–Lagrange condition for state-constrained optimal control problems 295
- 10 The Purcell three-link swimmer: some geometric and numerical aspects related to periodic optimal controls 314
- 11. Controllability of Keplerian motion with low-thrust control systems 344
- 12. Higher variational equation techniques for the integrability of homogeneous potentials 365
- 13. Introduction to KAM theory with a view to celestial mechanics 387
- 14. Invariants of contact sub-pseudo-Riemannian structures and Einstein–Weyl geometry 434
- 15. Time-optimal control for a perturbed Brockett integrator 454
- 16. Twist maps and Arnold diffusion for diffeomorphisms 473
- 17. A Hamiltonian approach to sufficiency in optimal control with minimal regularity conditions: Part I 496
- Index 517
Chapters in this book
- Frontmatter I
- Contents V
-
Part I
- 1. Second-order decomposition model for image processing: numerical experimentation 5
- 2. Optimizing spatial and tonal data for PDE-based inpainting 35
- 3. Image registration using phase–amplitude separation 84
- 4. Rotation invariance in exemplar-based image inpainting 108
- 5. Convective regularization for optical flow 184
- 6. A variational method for quantitative photoacoustic tomography with piecewise constant coefficients 202
- 7. On optical flow models for variational motion estimation 225
- 8. Bilevel approaches for learning of variational imaging models 252
-
Part II
- 9. Non-degenerate forms of the generalized Euler–Lagrange condition for state-constrained optimal control problems 295
- 10 The Purcell three-link swimmer: some geometric and numerical aspects related to periodic optimal controls 314
- 11. Controllability of Keplerian motion with low-thrust control systems 344
- 12. Higher variational equation techniques for the integrability of homogeneous potentials 365
- 13. Introduction to KAM theory with a view to celestial mechanics 387
- 14. Invariants of contact sub-pseudo-Riemannian structures and Einstein–Weyl geometry 434
- 15. Time-optimal control for a perturbed Brockett integrator 454
- 16. Twist maps and Arnold diffusion for diffeomorphisms 473
- 17. A Hamiltonian approach to sufficiency in optimal control with minimal regularity conditions: Part I 496
- Index 517