MotionRec: A Unified Deep Framework for Moving Object Recognition

Abstract

In this paper we present a novel deep learning framework to perform online moving object recognition (MOR) in streaming videos. The existing methods for moving object detection (MOD) only computes class-agnostic pixel-wise binary segmentation of video frames. On the other hand, the object detection techniques do not differentiate between static and moving objects. To the best of our knowledge, this is a first attempt for simultaneous localization and classification of moving objects in a video, i.e. MOR in a single-stage deep learning framework. We achieve this by labelling axis-aligned bounding boxes for moving objects which requires less computational resources than producing pixel-level estimates. In the proposed MotionRec, both temporal and spatial features are learned using past history and current frames respectively. First, the background is estimated with a temporal depth reductionist (TDR) block. Then the estimated background, current frame and temporal median of recent observations are assimilated to encode spatiotemporal motion saliency. Moreover, feature pyramids are generated from these motion saliency maps to perform regression and classification at multiple levels of feature abstractions. MotionRec works online at inference as it requires only few past frames for MOR. Moreover, it doesn’t require predefined target initialization from user. We also annotated axis-aligned bounding boxes (42,614 objects (14,814 cars and 27,800 person) in 24,923 video frames of CDnet 2014 dataset) due to lack of available benchmark datasets for MOR. The performance is observed qualitatively and quantitatively in terms of mAP over a defined unseen test set. Experiments show that the proposed MotionRec significantly improves over strong baselines with RetinaNet architectures for MOR.