Radar Guided Dynamic Visual Attention for Resource-Efficient RGB Object Detection

TL;DR

This paper introduces a radar-guided spatial attention mechanism for RGB object detection in autonomous vehicles, enhancing detection of small and distant objects while reducing computational costs.

Contribution

It proposes a novel fusion approach combining radar data with RGB detectors, improving small object detection and computational efficiency in dynamic environments.

Findings

14% increase in recall for small and long-range objects

Threefold reduction in computational resource requirements

Effective fusion of radar and RGB data demonstrated on nuScenes dataset

Abstract

An autonomous system's perception engine must provide an accurate understanding of the environment for it to make decisions. Deep learning based object detection networks experience degradation in the performance and robustness for small and far away objects due to a reduction in object's feature map as we move to higher layers of the network. In this work, we propose a novel radar-guided spatial attention for RGB images to improve the perception quality of autonomous vehicles operating in a dynamic environment. In particular, our method improves the perception of small and long range objects, which are often not detected by the object detectors in RGB mode. The proposed method consists of two RGB object detectors, namely the Primary detector and a lightweight Secondary detector. The primary detector takes a full RGB image and generates primary detections. Next, the radar proposal framework creates regions of interest (ROIs) for object proposals by projecting the radar point cloud onto the 2D RGB image. These ROIs are cropped and fed to the secondary detector to generate secondary detections which are then fused with the primary detections via non-maximum suppression. This method helps in recovering the small objects by preserving the object's spatial features through an increase in their receptive field. We evaluate our fusion method on the challenging nuScenes dataset and show that our fusion method with SSD-lite as primary and secondary detector improves the baseline primary yolov3 detector's recall by 14% while requiring three times fewer computational resources.