# NM-Net: Mining Reliable Neighbors for Robust Feature Correspondences

## TL;DR

NM-Net introduces a hierarchical network that mines compatible neighbors for robust feature correspondence selection, outperforming previous methods across multiple datasets with diverse inlier ratios.

## Contribution

The paper proposes a compatibility-specific neighbor mining method and a hierarchical NM-Net architecture for improved feature correspondence selection.

## Key findings

- Achieves state-of-the-art performance on four datasets.
- Effective in handling various inlier ratios.
- Robust to the irregular distribution of false correspondences.

## Abstract

Feature correspondence selection is pivotal to many feature-matching based tasks in computer vision. Searching for spatially k-nearest neighbors is a common strategy for extracting local information in many previous works. However, there is no guarantee that the spatially k-nearest neighbors of correspondences are consistent because the spatial distribution of false correspondences is often irregular. To address this issue, we present a compatibility-specific mining method to search for consistent neighbors. Moreover, in order to extract and aggregate more reliable features from neighbors, we propose a hierarchical network named NM-Net with a series of convolution layers taking the generated graph as input, which is insensitive to the order of correspondences. Our experimental results have shown the proposed method achieves the state-of-the-art performance on four datasets with various inlier ratios and varying numbers of feature consistencies.