MultiLink: Multi-class Structure Recovery via Agglomerative Clustering and Model Selection

TL;DR

MultiLink is a new clustering algorithm that efficiently recovers multiple geometric structures from noisy data by combining model fitting and selection, outperforming existing methods in speed and robustness.

Contribution

The paper introduces MultiLink, a novel linkage-based algorithm that simultaneously handles multiple model classes for structure recovery, improving robustness and efficiency over prior preference analysis methods.

Findings

MultiLink outperforms state-of-the-art methods on public datasets.

It is faster and less sensitive to inlier thresholds.

It effectively handles multiple classes of geometric models.

Abstract

We address the problem of recovering multiple structures of different classes in a dataset contaminated by noise and outliers. In particular, we consider geometric structures defined by a mixture of underlying parametric models (e.g. planes and cylinders, homographies and fundamental matrices), and we tackle the robust fitting problem by preference analysis and clustering. We present a new algorithm, termed MultiLink, that simultaneously deals with multiple classes of models. MultiLink combines on-the-fly model fitting and model selection in a novel linkage scheme that determines whether two clusters are to be merged. The resulting method features many practical advantages with respect to methods based on preference analysis, being faster, less sensitive to the inlier threshold, and able to compensate limitations deriving from hypotheses sampling. Experiments on several public datasets demonstrate that Multi-Link favourably compares with state of the art alternatives, both in multi-class and single-class problems. Code is publicly made available for download.