Sparse Trajectory Prediction

Pedestrian trajectory prediction is crucial for ensuring safe decision-making in intelligent robotic systems. While this task demands real-time performance, previous works have primarily focused on improving prediction accuracy, often neglecting efficiency. Dense predictions with time-consuming post-clustering steps and global interactions with quadratic computational complexity result in a trade-off between accuracy and speed. In this paper, we propose a novel Sparse Trajectory Prediction (STP) model that aims to achieve both high accuracy and real-time speed by following an efficient principle: leveraging sparse structures to achieve global effects. STP instantiates this principle within a transformer-style encoder-decoder framework. In the encoder, STP introduces irregular interaction, which builds sparse interactions with dynamic interactive positions, reducing computational complexity to linearithmic/linear while maintaining global interaction. In the decoder, STP applies an early-sparsity strategy to generate sparse motion modes that represent global motion behaviors. These modes are shared across all predictions, eliminating redundant computations. By harnessing the expressive power of transformers, STP maps these sparse motion modes into multimodal future trajectories, significantly improving prediction speed while ensuring accuracy. Experimental results on four commonly used datasets demonstrate that STP maximizes both accuracy and prediction speed, achieving state-of-the-art performance and significantly improving prediction speed by about 100× - 150× to satisfy the real-time demand.