Bulletin of Surveying and Mapping ›› 2025, Vol. 0 ›› Issue (3): 33-38.doi: 10.13474/j.cnki.11-2246.2025.0306

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3D small object detection method based on image and point cloud fusion

HAO Jia1, YAO Guoying1, ZHOU Jian2, WANG Siyuan3, XIAO Jinsheng3   

  1. 1. Troops 92942, Beijing 100161, China;
    2. State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan 430072, China;
    3. School of Electronic Information, Wuhan University, Wuhan 430072, China
  • Received:2024-08-27 Published:2025-04-03

Abstract: Object detection technology plays a pivotal role in key fields such as artificial intelligence, facial recognition, and autonomous driving. 3D point cloud object detection, especially for small objects, remains a significant challenge in technological development. To address this challenge, this paper proposes a novel 3D detection network that integrates image and point cloud data to significantly enhance the accuracy of 3D small object detection. The approach begins by leveraging Yolov5 for precise 2D object detection and establishing a 3D constraint using the coordinate mapping relationship between cameras and LiDAR to extract conical regions of interest from the raw point cloud data. Furthermore, to tackle the issue of detecting small objects in distant point clouds, a cluster-optimized 3D detection network architecture is introduced. This architecture simultaneously inputs the point clouds of the regions of interest into both the PointNet and clustering modules, and then fuses their detection results to improve the accuracy of 3D small object detection. Testing on the KITTI dataset shows that, compared to existing techniques, the proposed algorithm improves the average precision (AP) for two small object categories by 15.94% and 2.29% under moderate difficulty conditions, and by 13.34% and 2.86% under high difficulty conditions. These results underscore the significant impact and practical application potential of this algorithm in enhancing the accuracy of 3D small object detection.

Key words: 3D object detection, small object, area of interest, point cloud clustering, image and point cloud fusion

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