For many applications such as action detection or robotic interaction, segmenting all moving objects is a crucial first step. While this problem has been well-studied under the formulation of spatiotemporal video segmentation, virtually none of the prior works use learning-based approaches, despite significant advances in single-frame instance segmentation. We propose the first deep-learning based approach for spatio-temporal grouping. Our model extends the state-of-the-art Mask R-CNN architecture to the video domain. It takes a video frame together with its optical flow as input, and passes them through appearance and motion streams respectively. It then combines the motion cues, which provide a bottom-up signal for object detection, with appearance cues that allow capturing the full extent of the object via a joint RPN module. We show state-of-the-art results on the Freiburg Berkeley Motion Segmentation dataset by a wide margin. One potential worry with learning-based methods is that they might overfit to the particular type of objects that they have been trained on. While current recognition systems tend to be limited to a "closed world" of N objects on which they are trained, our model can segment almost anything that moves.
@cite_26: We present a new dataset with the goal of advancing the state-of-the-art in object recognition by placing the question of object recognition in the context of the broader question of scene understanding. This is achieved by gathering images of complex everyday scenes containing common objects in their natural context. Objects are labeled using per-instance segmentations to aid in precise object localization. Our dataset contains photos of 91 objects types that would be easily recognizable by a 4 year old. With a total of 2.5 million labeled instances in 328k images, the creation of our dataset drew upon extensive crowd worker involvement via novel user interfaces for category detection, instance spotting and instance segmentation. We present a detailed statistical analysis of the dataset in comparison to PASCAL, ImageNet, and SUN. Finally, we provide baseline performance analysis for bounding box and segmentation detection results using a Deformable Parts Model.
Object Detection The task of segmenting object instances from still images has seen immense success in recent years, bolstered by large, standard datasets such as COCO @cite_26 . However, this standard task focuses on segmenting every instance of objects belonging to a fixed list of categories, leading to methods that are designed to be blind to objects that fall outside the categories in the training set.