Lin Zhao

Adversarial attacks on deep networks have received significant attention recently. However, most existing research focuses on classification tasks, with limited exploration of adversarial attacks on human pose estimation networks. To bridge this gap, we propose a novel attack framework specifically tailored for human pose estimation by exploiting unique HPE characteristics including heatmap-sensitive localization, joint-influence imbalance, and keypoint-focused perception. Our objective is to substantially diminish object keypoint similarity while introducing minimal perturbations to the image. We have devised a two-stage framework to implement the attack. The first stage involves a gradient attack framework that induces deviation in the adversarial heatmap from the original heatmap by exploiting heatmap-sensitive localization. In the second stage, the perturbations are optimized and restricted to the vicinity of keypoints to make the attacks imperceptible by exploiting joint-influence imbalance and keypoint-focused perception. To achieve this, we incorporate low-frequency constraints to limit the perturbations to high-frequency components and utilize a perceptual color distance metric to control the perturbation's magnitude. Extensive experimental results on the COCO and MPII datasets demonstrate that our attack can generate adversarial examples with high strength and low detectability.

With the rapid development of autonomous driving, LiDAR-based 3D Human Pose Estimation (3D HPE) is becoming a research focus. However, due to the noise and sparsity of LiDAR-captured point clouds, robust human pose estimation remains challenging. Most of the existing methods use temporal information, multi-modal fusion, or SMPL optimization to correct biased results. In this work, we try to obtain sufficient information for 3D HPE only by modeling the intrinsic properties of low-quality point clouds. Hence, a simple yet powerful method is proposed, which provides insights both on modeling and augmentation of point clouds. Specifically, we first propose a concise and effective density-aware pose transformer (DAPT) to get stable keypoint representations. By using a set of joint anchors and a carefully designed exchange module, valid information is extracted from point clouds with different densities. Then 1D heatmaps are utilized to represent the precise locations of the keypoints. Secondly, a comprehensive LiDAR human synthesis and augmentation method is proposed to pre-train the model, enabling it to acquire a better human body prior. We increase the diversity of point clouds by randomly sampling human positions and orientations and by simulating occlusions through the addition of laser-level masks. Extensive experiments have been conducted on multiple datasets, including IMU-annotated LidarHuman26M, SLOPER4D, and manually annotated Waymo Open Dataset v2.0 (Waymo), HumanM3. Our method demonstrates SOTA performance in all scenarios. In particular, compared with LPFormer on Waymo, we reduce the average MPJPE by 10.0mm. Compared with PRN on SLOPER4D, we notably reduce the average MPJPE by 20.7mm.