34 research outputs found
ViP-Mixer: A Convolutional Mixer for Video Prediction
Video prediction aims to predict future frames from a video's previous
content. Existing methods mainly process video data where the time dimension
mingles with the space and channel dimensions from three distinct angles: as a
sequence of individual frames, as a 3D volume in spatiotemporal coordinates, or
as a stacked image where frames are treated as separate channels. Most of them
generally focus on one of these perspectives and may fail to fully exploit the
relationships across different dimensions. To address this issue, this paper
introduces a convolutional mixer for video prediction, termed ViP-Mixer, to
model the spatiotemporal evolution in the latent space of an autoencoder. The
ViP-Mixers are stacked sequentially and interleave feature mixing at three
levels: frames, channels, and locations. Extensive experiments demonstrate that
our proposed method achieves new state-of-the-art prediction performance on
three benchmark video datasets covering both synthetic and real-world
scenarios.Comment: Under revie
Towards Real-World Visual Tracking with Temporal Contexts
Visual tracking has made significant improvements in the past few decades.
Most existing state-of-the-art trackers 1) merely aim for performance in ideal
conditions while overlooking the real-world conditions; 2) adopt the
tracking-by-detection paradigm, neglecting rich temporal contexts; 3) only
integrate the temporal information into the template, where temporal contexts
among consecutive frames are far from being fully utilized. To handle those
problems, we propose a two-level framework (TCTrack) that can exploit temporal
contexts efficiently. Based on it, we propose a stronger version for real-world
visual tracking, i.e., TCTrack++. It boils down to two levels: features and
similarity maps. Specifically, for feature extraction, we propose an
attention-based temporally adaptive convolution to enhance the spatial features
using temporal information, which is achieved by dynamically calibrating the
convolution weights. For similarity map refinement, we introduce an adaptive
temporal transformer to encode the temporal knowledge efficiently and decode it
for the accurate refinement of the similarity map. To further improve the
performance, we additionally introduce a curriculum learning strategy. Also, we
adopt online evaluation to measure performance in real-world conditions.
Exhaustive experiments on 8 wellknown benchmarks demonstrate the superiority of
TCTrack++. Real-world tests directly verify that TCTrack++ can be readily used
in real-world applications.Comment: Accepted by IEEE TPAMI, Code:
https://github.com/vision4robotics/TCTrac
Siamese Object Tracking for Unmanned Aerial Vehicle: A Review and Comprehensive Analysis
Unmanned aerial vehicle (UAV)-based visual object tracking has enabled a wide
range of applications and attracted increasing attention in the field of
intelligent transportation systems because of its versatility and
effectiveness. As an emerging force in the revolutionary trend of deep
learning, Siamese networks shine in UAV-based object tracking with their
promising balance of accuracy, robustness, and speed. Thanks to the development
of embedded processors and the gradual optimization of deep neural networks,
Siamese trackers receive extensive research and realize preliminary
combinations with UAVs. However, due to the UAV's limited onboard computational
resources and the complex real-world circumstances, aerial tracking with
Siamese networks still faces severe obstacles in many aspects. To further
explore the deployment of Siamese networks in UAV-based tracking, this work
presents a comprehensive review of leading-edge Siamese trackers, along with an
exhaustive UAV-specific analysis based on the evaluation using a typical UAV
onboard processor. Then, the onboard tests are conducted to validate the
feasibility and efficacy of representative Siamese trackers in real-world UAV
deployment. Furthermore, to better promote the development of the tracking
community, this work analyzes the limitations of existing Siamese trackers and
conducts additional experiments represented by low-illumination evaluations. In
the end, prospects for the development of Siamese tracking for UAV-based
intelligent transportation systems are deeply discussed. The unified framework
of leading-edge Siamese trackers, i.e., code library, and the results of their
experimental evaluations are available at
https://github.com/vision4robotics/SiameseTracking4UAV
Apple Quality Evaluation Based on Entropy Weight Method, Grey Relational Degree Method and Low-field Nuclear Magnetic Resonance Detection
To study the quality characteristics of different apple varieties and establish a comprehensive evaluation model of apple quality, taking five varieties of apples (Tianshui Huaniu, Aksu Tangxin, Marshal Huang, Cream Fuji, and Luochuan Red Fuji) as the research object, the four texture characteristics, including hardness, adhesion, chewability, cohesion, and four physical and chemical indicators, including water content, titratable acid (TA), soluble sugar (SS), and soluble solid content (SSC) were tested. Combining the low-field nuclear magnetic resonance detection technology, the correlation between the water distribution and the physicochemical and texture characteristics of apple was explored, and the main indicators for evaluating apple quality were established by principal component analysis. Based on the entropy weight method, each core index was given weight, and a grey correlation degree evaluation model was established. The results showed that there were significant differences in various indexes of different varieties of apples (P<0.05), and there was a high correlation between their water distribution and texture characteristics and physical and chemical indexes. The spin-spin relaxation time T22 (immobilized water), T21 (bound water) and TA, SS, SSC were established as the core indexes. The weight calculated by entropy weight method showed that the sum of T22 and T21 was 35.31%, accounting for the largest proportion, indicating that the water distribution had the greatest impact on apple quality. The grey correlation analysis showed that the quality of Tianshui Huaniu and Aksu Tangxin was better. The method adopted in this study could quickly and accurately establish the quality evaluation model of apples, and provide a new method for the quality evaluation of fruits and vegetables including apples
What Went Wrong? Closing the Sim-to-Real Gap via Differentiable Causal Discovery
Training control policies in simulation is more appealing than on real robots
directly, as it allows for exploring diverse states in a safe and efficient
manner. Yet, robot simulators inevitably exhibit disparities from the real
world, yielding inaccuracies that manifest as the simulation-to-real gap.
Existing literature has proposed to close this gap by actively modifying
specific simulator parameters to align the simulated data with real-world
observations. However, the set of tunable parameters is usually manually
selected to reduce the search space in a case-by-case manner, which is hard to
scale up for complex systems and requires extensive domain knowledge. To
address the scalability issue and automate the parameter-tuning process, we
introduce an approach that aligns the simulator with the real world by
discovering the causal relationship between the environment parameters and the
sim-to-real gap. Concretely, our method learns a differentiable mapping from
the environment parameters to the differences between simulated and real-world
robot-object trajectories. This mapping is governed by a simultaneously-learned
causal graph to help prune the search space of parameters, provide better
interpretability, and improve generalization. We perform experiments to achieve
both sim-to-sim and sim-to-real transfer, and show that our method has
significant improvements in trajectory alignment and task success rate over
strong baselines in a challenging manipulation task
Evaluate the effects of low-intensity pulsed ultrasound on dental implant osseointegration under type II diabetes
Objective: The objective of this study is to assess the impact of low-intensity pulsed ultrasound (LIPUS) therapy on the peri-implant osteogenesis in a Type II diabetes mellitus (T2DM) rat model.Methods: A total of twenty male Sprague-Dawley (SD) rats were randomly allocated into four groups: Control group, T2DM group, Control-LIPUS group, and T2DM-LIPUS group. Implants were placed at the rats’ bilateral maxillary first molar sites. The LIPUS treatment was carried out on the rats in Control-LIPUS group and T2DM-LIPUS group, immediately after the placement of the implants, over three consecutive weeks. Three weeks after implantation, the rats’ maxillae were extracted for micro-CT, removal torque value (RTV), and histologic analysis.Results: Micro-CT analysis showed that T2DM rats experienced more bone loss around implant cervical margins compared with the non-T2DM rats, while the LIPUS treated T2DM rats showed similar bone heights to the non-T2DM rats. Bone-implant contact ratio (BIC) were lower in T2DM rats but significantly improved in the LIPUS treated T2DM rats. Bone formation parameters including bone volume fraction (BV/TV), trabecular thickness (Tb.Th), bone mineral density (BMD) and RTV were all positively influenced by LIPUS treatment. Histological staining further confirmed LIPUS’s positive effects on peri-implant new bone formation in T2DM rats.Conclusion: As an effective and safe treatment in promoting osteogenesis, LIPUS has a great potential for T2DM patients to attain improved peri-implant osteogenesis. To confirm its clinical efficacy and to explore the underlying mechanism, further prospective cohort studies or randomized controlled trials are needed in the future