# Progressive LiDAR Adaptation for Road Detection

## TL;DR

This paper introduces PLARD, a novel method that progressively adapts LiDAR data into visual image-based road detection, significantly improving robustness and accuracy in challenging urban scenes by effectively fusing multi-sensor information.

## Contribution

The paper proposes a new progressive LiDAR adaptation approach that aligns LiDAR data and features with visual data for enhanced road detection performance.

## Key findings

- PLARD outperforms existing models on the KITTI benchmark.
- It achieves more robust detection in challenging urban environments.
- The method is top-ranked on the public leaderboard.

## Abstract

Despite rapid developments in visual image-based road detection, robustly identifying road areas in visual images remains challenging due to issues like illumination changes and blurry images. To this end, LiDAR sensor data can be incorporated to improve the visual image-based road detection, because LiDAR data is less susceptible to visual noises. However, the main difficulty in introducing LiDAR information into visual image-based road detection is that LiDAR data and its extracted features do not share the same space with the visual data and visual features. Such gaps in spaces may limit the benefits of LiDAR information for road detection. To overcome this issue, we introduce a novel Progressive LiDAR Adaptation-aided Road Detection (PLARD) approach to adapt LiDAR information into visual image-based road detection and improve detection performance. In PLARD, progressive LiDAR adaptation consists of two subsequent modules: 1) data space adaptation, which transforms the LiDAR data to the visual data space to align with the perspective view by applying altitude difference-based transformation; and 2) feature space adaptation, which adapts LiDAR features to visual features through a cascaded fusion structure. Comprehensive empirical studies on the well-known KITTI road detection benchmark demonstrate that PLARD takes advantage of both the visual and LiDAR information, achieving much more robust road detection even in challenging urban scenes. In particular, PLARD outperforms other state-of-the-art road detection models and is currently top of the publicly accessible benchmark leader-board.