Fast Piecewise-Affine Motion Estimation Without Segmentation
Center for Biomedical Imaging (CIBM-SP), EPFL（洛桑联邦理工学院生物医学成像中心（CIBM-SP））；Universität Heidelberg（海德堡大学）；Helmholtz Zentrum München（慕尼黑亥姆霍兹中心）；Hochschule Darmstadt（达姆施塔特应用技术大学）
Denis Fortun, Martin Storath, Dennis Rickert, Andreas Weinmann, Michael Unser
Current algorithmic approaches for piecewise affine motion estimation are based on alternating motion segmentation and estimation. We propose a new method to estimate piecewise affine motion fields directly without intermediate segmentation. To this end, we reformulate the problem by imposing piecewise constancy of the parameter field, and derive a specific proximal splitting optimization scheme. A key component of our framework is an efficient one-dimensional piecewise-affine estimator for vector-valued signals. The first advantage of our approach over segmentation-based methods is its absence of initialization. The second advantage is its lower computational cost which is independent of the complexity of the motion field. In addition to these features, we demonstrate competitive accuracy with other piecewise-parametric methods on standard evaluation benchmarks. Our new regularization scheme also outperforms the more standard use of total variation and total generalized variation.
Accurate Recognition of Pneumonia and COVID-19 by Geometric Shape Normalization of Lung Region using Automatic Landmark Detection and Piecewise Affine Warping
Facultad de Ciencias de la Electrónica Benemérita Universidad Autónoma de Puebla（Benemérita自治大学电子科学学院）
Relaxed Total Generalized Variation Regularized Piecewise Smooth Mumford-Shah Model for Triangulated Surface Segmentation
School of Computer Science and Technology, Tiangong University, Tianjin, China（计算机科学与技术学院，天津工业大学）；School of Mathmatics, Tiangong University,Tianjin, China（数学学院，天津工业大学）
Linkage between piecewise constant Mumford-Shah model and ROF model and its virtue in image segmentation
University of Cambridge（剑桥大学）；University College London（伦敦大学学院）；City University of Hong Kong（香港城市大学）；University of Kaiserslautern（凯泽斯劳滕大学）；The Chinese University of Hong Kong（香港中文大学）
