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Mixed-Derivative Total Variation

Published: September 28, 2025 | arXiv ID: 2509.23995v1

By: Vincent Guillemet, Michael Unser

Potential Business Impact:

Makes blurry pictures sharp and clear.

Business Areas:
Visual Search Internet Services

The formulation of norms on continuous-domain Banach spaces with exact pixel-based discretization is advantageous for solving inverse problems (IPs). In this paper, we investigate a new regularization that is a convex combination of a TV term and the $\M(\R^2)$ norm of mixed derivatives. We show that the extreme points of the corresponding unit ball are indicator functions of polygons whose edges are aligned with either the $x_1$- or $x_2$-axis. We then apply this result to construct a new regularization for IPs, which can be discretized exactly by tensor products of first-order B-splines, or equivalently, pixels. Furthermore, we exactly discretize the loss of the denoising problem on its canonical pixel basis and prove that it admits a unique solution, which is also a solution to the underlying continuous-domain IP.

Page Count
15 pages

Category
Mathematics:
Numerical Analysis (Math)