scholarly journals OSCILLATORY OPTICAL FLOWS IMPROVE THE PERCEPTION OF TRAVELLED DISTANCE IN STATIC OBSERVERS

2016 ◽  
Vol 16 (12) ◽  
pp. 768 ◽  
Author(s):  
Martin Bossard ◽  
Jean-Claude Lepecq ◽  
Daniel Mestre
Keyword(s):  
Optical Flows ◽  
Static Observers

scholarly journals Every Frame Counts: Joint Learning of Video Segmentation and Optical Flow

2020 ◽  
Vol 34 (07) ◽  
pp. 10713-10720
Author(s):  
Mingyu Ding ◽  
Zhe Wang ◽  
Bolei Zhou ◽  
Jianping Shi ◽  
Zhiwu Lu ◽  
...  
Keyword(s):  
Optical Flow ◽  
Video Segmentation ◽  
Video Clip ◽  
Semantic Segmentation ◽  
Temporal Consistency ◽  
Flow Estimation ◽  
Optical Flow Estimation ◽  
Optical Flows ◽  
Benchmark Datasets ◽  
Spatio Temporal

A major challenge for video semantic segmentation is the lack of labeled data. In most benchmark datasets, only one frame of a video clip is annotated, which makes most supervised methods fail to utilize information from the rest of the frames. To exploit the spatio-temporal information in videos, many previous works use pre-computed optical flows, which encode the temporal consistency to improve the video segmentation. However, the video segmentation and optical flow estimation are still considered as two separate tasks. In this paper, we propose a novel framework for joint video semantic segmentation and optical flow estimation. Semantic segmentation brings semantic information to handle occlusion for more robust optical flow estimation, while the non-occluded optical flow provides accurate pixel-level temporal correspondences to guarantee the temporal consistency of the segmentation. Moreover, our framework is able to utilize both labeled and unlabeled frames in the video through joint training, while no additional calculation is required in inference. Extensive experiments show that the proposed model makes the video semantic segmentation and optical flow estimation benefit from each other and outperforms existing methods under the same settings in both tasks.

scholarly journals Vision-Based Obstacle Avoidance Strategies for MAVs Using Optical Flows in 3-D Textured Environments

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2523 ◽  
Author(s):  
Gangik Cho ◽  
Jongyun Kim ◽  
Hyondong Oh
Keyword(s):  
Cost Effectiveness ◽  
Optical Flow ◽  
Obstacle Avoidance ◽  
Weighting Function ◽  
Light Weight ◽  
Complex Environments ◽  
Aerial Vehicles ◽  
Focus Of Expansion ◽  
Heading Direction ◽  
Optical Flows

Due to payload restrictions for micro aerial vehicles (MAVs), vision-based approaches have been widely studied with their light weight characteristics and cost effectiveness. In particular, optical flow-based obstacle avoidance has proven to be one of the most efficient methods in terms of obstacle avoidance capabilities and computational load; however, existing approaches do not consider 3-D complex environments. In addition, most approaches are unable to deal with situations where there are wall-like frontal obstacles. Although some algorithms consider wall-like frontal obstacles, they cause a jitter or unnecessary motion. To address these limitations, this paper proposes a vision-based obstacle avoidance algorithm for MAVs using the optical flow in 3-D textured environments. The image obtained from a monocular camera is first split into two horizontal and vertical half planes. The desired heading direction and climb rate are then determined by comparing the sum of optical flows between half planes horizontally and vertically, respectively, for obstacle avoidance in 3-D environments. Besides, the proposed approach is capable of avoiding wall-like frontal obstacles by considering the divergence of the optical flow at the focus of expansion and navigating to the goal position using a sigmoid weighting function. The performance of the proposed algorithm was validated through numerical simulations and indoor flight experiments in various situations.

scholarly journals Kerr metric, static observers and Fermi coordinates

2005 ◽  
Vol 22 (22) ◽  
pp. 4729-4742 ◽  
Author(s):  
Donato Bini ◽  
Andrea Geralico ◽  
Robert T Jantzen
Keyword(s):  
Kerr Metric ◽  
Fermi Coordinates ◽  
Static Observers

scholarly journals Consistent Video Style Transfer via Compound Regularization

2020 ◽  
Vol 34 (07) ◽  
pp. 12233-12240
Author(s):  
Wenjing Wang ◽  
Jizheng Xu ◽  
Li Zhang ◽  
Yue Wang ◽  
Jiaying Liu
Keyword(s):  
State Of The Art ◽  
Video Data ◽  
Experimental Results ◽  
Temporal Consistency ◽  
Challenging Problem ◽  
Style Transfer ◽  
Single Frame ◽  
Optical Flows ◽  
Training Strategies ◽  
Art Style

Recently, neural style transfer has drawn many attentions and significant progresses have been made, especially for image style transfer. However, flexible and consistent style transfer for videos remains a challenging problem. Existing training strategies, either using a significant amount of video data with optical flows or introducing single-frame regularizers, have limited performance on real videos. In this paper, we propose a novel interpretation of temporal consistency, based on which we analyze the drawbacks of existing training strategies; and then derive a new compound regularization. Experimental results show that the proposed regularization can better balance the spatial and temporal performance, which supports our modeling. Combining with the new cost formula, we design a zero-shot video style transfer framework. Moreover, for better feature migration, we introduce a new module to dynamically adjust inter-channel distributions. Quantitative and qualitative results demonstrate the superiority of our method over other state-of-the-art style transfer methods. Our project is publicly available at: https://daooshee.github.io/CompoundVST/.

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