Temporal-Spatial Mapping for Action Recognition

TL;DR

This paper introduces Temporal-Spatial Mapping (TSM), a novel method for capturing temporal and spatial dynamics in videos, leading to improved human action recognition performance.

Contribution

The paper proposes a new VideoMap representation and a shallow CNN with temporal attention, advancing video action recognition accuracy.

Findings

Achieves 4.2% higher accuracy than TSN on HMDB51.

Introduces a simple, effective operation for modeling temporal evolution.

Demonstrates state-of-the-art performance on benchmark dataset.

Abstract

Deep learning models have enjoyed great success for image related computer vision tasks like image classification and object detection. For video related tasks like human action recognition, however, the advancements are not as significant yet. The main challenge is the lack of effective and efficient models in modeling the rich temporal spatial information in a video. We introduce a simple yet effective operation, termed Temporal-Spatial Mapping (TSM), for capturing the temporal evolution of the frames by jointly analyzing all the frames of a video. We propose a video level 2D feature representation by transforming the convolutional features of all frames to a 2D feature map, referred to as VideoMap. With each row being the vectorized feature representation of a frame, the temporal-spatial features are compactly represented, while the temporal dynamic evolution is also well embedded. Based on the VideoMap representation, we further propose a temporal attention model within a shallow convolutional neural network to efficiently exploit the temporal-spatial dynamics. The experiment results show that the proposed scheme achieves the state-of-the-art performance, with 4.2% accuracy gain over Temporal Segment Network (TSN), a competing baseline method, on the challenging human action benchmark dataset HMDB51.