Proposal Flow: Semantic Correspondences from Object Proposals

TL;DR

Proposal flow is a novel semantic correspondence method that leverages object proposals for improved matching across images with intra-class variations, outperforming existing approaches.

Contribution

The paper introduces proposal flow, a new semantic flow technique utilizing object proposals, and provides new datasets for evaluation, demonstrating superior performance over prior methods.

Findings

Proposal flow outperforms existing semantic flow methods.

Object proposals exhibit high repeatability at multiple scales.

New datasets enable comprehensive evaluation of semantic flow techniques.

Abstract

Finding image correspondences remains a challenging problem in the presence of intra-class variations and large changes in scene layout. Semantic flow methods are designed to handle images depicting different instances of the same object or scene category. We introduce a novel approach to semantic flow, dubbed proposal flow, that establishes reliable correspondences using object proposals. Unlike prevailing semantic flow approaches that operate on pixels or regularly sampled local regions, proposal flow benefits from the characteristics of modern object proposals, that exhibit high repeatability at multiple scales, and can take advantage of both local and geometric consistency constraints among proposals. We also show that the corresponding sparse proposal flow can effectively be transformed into a conventional dense flow field. We introduce two new challenging datasets that can be used to evaluate both general semantic flow techniques and region-based approaches such as proposal flow. We use these benchmarks to compare different matching algorithms, object proposals, and region features within proposal flow, to the state of the art in semantic flow. This comparison, along with experiments on standard datasets, demonstrates that proposal flow significantly outperforms existing semantic flow methods in various settings.