ISSN 0253-2778

CN 34-1054/N

2021 Vol. 51, No. 10

Information Science
A low-latency inpainting method for unstably transmitted videos
WEI Yutong, BAO Bingkun, ZHANG Ziqi, ZHU Jin
2021, 51(10): 717-724. doi: 10.52396/JUST-2020-0032
Video traffic has gradually occupied the majority of mobile traffic, and video damage in unstable transmission remains a common and urgent problem. The difficulty of inpainting these damaged videos is that the holes randomly appear in random video frames, which are hard to be well settled with both low latency and high accuracy. We are the pioneer to look into the video inpainting task in unstable transmission and propose a low-latency video inpainting method which consists of two stages: In the coarsely inpainting stage, we achieve the extraction of damaged two-dimensional optical flow from reference frames, and establish a linear prediction model to coarsely inpaint the damaged frames according to the temporal consistency of motions. In the fine inpainting stage, a Partial Convolutional Frame Completion network(PCFC-Net) is proposed to synthesize all reference information and calculate a fine inpainting result. Compared with that of the state-of-the-art baselines, the waiting time for reference frames is greatly reduced while PSNR and SSIM are improved by 4.0%~12.7% on DAVIS dataset.
Recent progress in electronic skin: Materials, functions and applications
MA Chao, ZHAO Gang
2021, 51(10): 725-746. doi: 10.52396/JUST-2021-0075
Electronic skin refers to a device that imitates the characteristics of human skin and has similar perception functions. Benefiting from its excellent wearability and versatility, it has shown great applications in the fields of health monitoring, human-computer interaction and machine perception in recent years and has attracted much attention.This article summarizes the research progress of electronic skin in recent years from three aspects of material properties, functional properties and typical applications. It focuses on how to realize the stretchability, self-repairing and biocompatibility of electronic skin, and the real-time monitoring of physical, chemical and electrophysiological signals. Finally, the challenges and possible solutions for the further development of electronic skin are discussed and prospected.As an emerging research hotspot, electronic skin requires the cooperation of scientists in many fields, such as materials science, informatics, engineering, and biology, in order to fully realize its potential.
Generation and application of petal-like structured light based on spatial light modulator
FENG Wenfei, JI Shengyun, LI Jiawen, WU Dong, HU Yanlei
2021, 51(10): 747-752. doi: 10.52396/JUST-2021-0032
The phase hologram of petal-like structured light is realized by the circular arrangement of the sector phase mask obtained from the one-dimensional Airy beam.Femtosecond laser is reflected by the spatial light modulator encoded with the designed phase hologram, and then passes through a lens. In this way, petal-like light is formed in the focal plane of the lens. With the proposed phase generation method, one can conveniently adjust the number of lobes of the light field. By introducing the vortex phase in the central region of the phase hologram, the intensity of the structured light can be freely tuned. The microstructures array is prepared by two-photon polymerization with generated structured light. The particle capture experiment enabled by the microstructure array is carried out, and the experimental result unfolds the potential application of the structured light in microfluidic chips.
Relation aware network for weakly-supervised temporal action localization
ZHAN Yongkun, YANG Wenfei, ZHANG Tianzhu
2021, 51(10): 753-765. doi: 10.52396/JUST-2021-0061
Temporal action localization has become an important and challenging research orientation due to its various applications. Since fully supervised localization requires a lot of manpower expenditure to get frame-level or segment-level fine annotations on untrimmed long videos, weakly supervised methods have received more and more attention in recent years. Weakly-supervised Temporal Action Localization (WS-TAL) aims to predict action temporal boundaries with only video-level labels provided in the training phase. However, the existing methods often only perform classification loss constraints on independent video segments, but ignore the relation within or between these segments. In this paper, we propose a novel framework called Relation Aware Network (RANet), which aims to model the segment relations of intra-video and inter-video. Specifically, the Intra-video Relation Module is designed to generate more complete action predictions, while the Inter-video Relation Module is designed to separate the action from the background. Through this design, our model can learn more robust visual feature representations for action localization. Extensive experiments on three public benchmarks including THUMOS 14 and ActivityNet 1.2/1.3 demonstrate the impressive performance of our proposed method compared with the state-of-the-arts.
Engineering and Materials Science
Research progress of interfacial mechanical behavior and design of nanocellulose-based sequentially architected materials
SONG Rongzhuang, HOU Yuanzhen, HE Zezhou, XIA Jun, ZHU Yinbo, WU Hengan
2021, 51(10): 766-786. doi: 10.52396/JUST-2021-225
Nanocellulose exhibits superior mechanical properties and is a renewable natural biomass material. Nanocellulose-based sequentially architected materials are expected to become a new generation of environment-friendly high-performance structural and functional materials leading sustainable development. The construction of reasonable multiscale nonlinear coupling relationship between interfacial mechanical behavior and material microstructure is pivotal to the strengthening-toughening design of nanocellulose-based materials. Recent research progress of interfacial mechanical behavior and design of nanocellulose-based sequentially architected materials was reviewed here. The interfacial hydrogen-bonding behavior, multiscale interfacial mechanics, and some design cases of interfaces and microstructures were discussed. At last, the summary and perspective of key points in this field were given. This paper would aim to provide new perspectives for the design and preparation of high-performance nanocellulose-based sequentially architected materials based on micro-nano mechanics and multiscale mechanics.