Title
Caesar: cross-camera complex activity recognition
Abstract
Detecting activities from video taken with a single camera is an active research area for ML-based machine vision. In this paper, we examine the next research frontier: near real-time detection of complex activities spanning multiple (possibly wireless) cameras, a capability applicable to surveillance tasks. We argue that a system for such complex activity detection must employ a hybrid design: one in which rule-based activity detection must complement neural network based detection. Moreover, to be practical, such a system must scale well to multiple cameras and have low end-to-end latency. Caesar, our edge computing based system for complex activity detection, provides an extensible vocabulary of activities to allow users to specify complex actions in terms of spatial and temporal relationships between actors, objects, and activities. Caesar converts these specifications to graphs, efficiently monitors camera feeds, partitions processing between cameras and the edge cluster, retrieves minimal information from cameras, carefully schedules neural network invocation, and efficiently matches specification graphs to the underlying data in order to detect complex activities. Our evaluations show that Caesar can reduce wireless bandwidth, on-board camera memory, and detection latency by an order of magnitude while achieving good precision and recall for all complex activities on a public multi-camera dataset.
Year
DOI
Venue
2019
10.1145/3356250.3360041
Proceedings of the 17th Conference on Embedded Networked Sensor Systems
Keywords
Field
DocType
action detection, camera networks, computer vision, edge computing, mobile sensing
Computer vision,Activity recognition,Computer science,Real-time computing,Artificial intelligence
Conference
ISBN
Citations 
PageRank 
978-1-4503-6950-3
4
0.40
References 
Authors
0
6
Name
Order
Citations
PageRank
Xiaochen Liu11610.79
Pradipta Ghosh2134.02
Oytun Ulutan341.75
B. S. Manjunath47561783.37
kevin chan528422.53
ramesh govindan6154302144.86