# Reconstruction-based Out-of-Distribution Detection for Short-Range FMCW Radar

## TL;DR

This paper introduces a novel reconstruction-based out-of-distribution detection method tailored for short-range FMCW radar data, utilizing an autoencoder and new scoring metrics, achieving high AUROC and suitability for embedded systems.

## Contribution

The study presents a new OOD detection approach for radar data using autoencoder-based reconstruction scores, outperforming existing methods and suitable for embedded deployment.

## Key findings

- Achieved 90.72% AUROC on radar dataset.
- Outperforms baseline and state-of-the-art methods.
- Model size of 641 kB enables embedded use.

## Abstract

Out-of-distribution (OOD) detection recently has drawn attention due to its critical role in the safe deployment of modern neural network architectures in real-world applications. The OOD detectors aim to distinguish samples that lie outside the training distribution in order to avoid the overconfident predictions of machine learning models on OOD data. Existing detectors, which mainly rely on the logit, intermediate feature space, softmax score, or reconstruction loss, manage to produce promising results. However, most of these methods are developed for the image domain. In this study, we propose a novel reconstruction-based OOD detector to operate on the radar domain. Our method exploits an autoencoder (AE) and its latent representation to detect the OOD samples. We propose two scores incorporating the patch-based reconstruction loss and the energy value calculated from the latent representations of each patch. We achieve an AUROC of 90.72% on our dataset collected by using 60 GHz short-range FMCW Radar. The experiments demonstrate that, in terms of AUROC and AUPR, our method outperforms the baseline (AE) and the other state-of-the-art methods. Also, thanks to its model size of 641 kB, our detector is suitable for embedded usage.