Utilizing spaceborne precipitation radar (SR) to evaluate ground-based weather radar (GR) reflectivity consistency is essential for the early detection of performance issues. However, existing SR versus GR matching methods often overlook some error sources, such as insufficient beam coverage and nonuniform precipitation. This study introduces enhanced methods for SR versus GR matching, including beam blocking identification, precipitation uniformity assessment, and improved time matching. Validation was performed using the FY-3G satellite’s precipitation measurement radar (PMR) and four S-band radars in Hunan Province, China. Our analysis demonstrates that integrating clear-sky ground clutter, long-duration precipitation echoes, and terrain data effectively detects actual beam blocking in GR. Selecting data with a time difference of 180 s or less, within 230 km of the GR center, GR reflectivity between 20 and 35 dBZ, and a signal-to-noise ratio (SNR) above 15 dB significantly mitigates random errors in SR versus GR matching results. Additionally, we explore a method for tracking reflectivity deviations within a “ground-satellite-ground” radar network, validated through adjacent GR comparisons. This approach is based on the Changsha Meteorological Radar Calibration Center’s reference radar. The method was validated using adjacent ground radar comparison, showing a correlation between the two methods with a minimum deviation transfer difference of 0.29 dB and a maximum of 1.13 dB. Additionally, the Yiyang radar exhibited slightly higher reflectivity, indicating that the method is both reliable and practically applicable.

3D face animation has been a critical component of character animation in a wide range of media since the early 90’s. The conventional process for animating a 3D face is usually keyframe-based, which is labor-intensive. Therefore, the film and game industries have started using live-action actors’ performances to animate the faces of 3D characters, the process is also known as performance-driven facial animation. At the core of performance-driven facial animation is facial motion retargeting, which transfers the source facial motions to a target 3D face. However, facial motion retargeting still has many limitations that influence its capability to further assist the facial animation process. Existing motion retargeting frameworks cannot accurately transfer the source motion’s semantic information (i.e., meaning and intensity of the motion), especially when applying the motion to non-human-like or stylized target characters. The retargeting quality relies on the parameterization of the target face, which is time-consuming to build and usually not generalizable across proportionally different faces. In this survey paper, we review the literature relating to 3D facial motion retargeting methods and the relevant topics within this area. We provide a systematic understanding of the essential modules of the retargeting pipeline, a taxonomy of the available approaches under these modules, and a thorough analysis of their advantages and limitations with research directions that could potentially contribute to this area. We also contributed a 3D character categorization matrix, which has been used in this survey and might be useful for future research to evaluate the character compatibility of their retargeting or face parameterization methods.

3D facial motion retargeting has the advantage of capturing and recreating the nuances of human facial motions and speeding up the time-consuming 3D facial animation process. However, the facial motion retargeting pipeline is limited in reflecting the facial motion's semantic information (i.e., meaning and intensity), especially when applied to nonhuman characters. The retargeting quality heavily relies on the target face rig, which requires time-consuming preparation such as 3D scanning of human faces and modeling of blendshapes. In this paper, we propose a facial motion retargeting pipeline aiming to provide fast and semantically accurate retargeting results for diverse characters. The new framework comprises a target face parameterization module based on face anatomy and a compatible source motion interpretation module. From the quantitative and qualitative evaluations, we found that the proposed retargeting pipeline can naturally recreate the expressions performed by a motion capture subject in equivalent meanings and intensities, such semantic accuracy extends to the faces of nonhuman characters without labor-demanding preparations.

Challenging motion, which tends to cause artifacts, is a key problem in the video denoising task. Recent video denoising methods have attempted to address this problem. However, they usually provide general performance evaluation on the overall dataset and cannot provide a comprehensive analysis for the influence of different motion levels. Thus, we questioned whether these methods can effectively deal with different scene motions. To this end, we synthesize a dataset containing videos with different motion levels and capture a new dataset that consists of videos involving large-scale motion. Then, we provide a comprehensive analysis on the elaborately collected datasets and find that, as the motion level increases, the performance of the denoising models based on implicit motion estimation (IME) declines sharply, while explicit motion estimation (EME) contributes to a more robust denoising quality. Therefore, in this work, we present an EME-embedded progressive denoising framework that fully considers the relationship between the noise removal and motion estimation. Specifically, we decouple video denoising into spatial denoising, EME-based frame reconstruction, and temporal refining processes. Spatial denoising improves the accuracy of EME process in the case of videos suffering from heavy noise, while the temporal refining process refines the denoised frame by utilizing temporal redundancy of the reconstructed motion-free frames. Extensive experiments demonstrate that the proposed method outperforms existing state-of-the-art methods, especially for videos containing large-scale motion.

The visual quality of a single image captured by a digital camera usually suffers from limited spatial resolution and low dynamic range (LDR) due to sensor constraints. To address these problems, recent works have independently applied convolutional neural networks (CNNs) to super-resolution (SR) and high dynamic range (HDR) imaging and made significant improvements in visual quality. However, directly connecting SR and HDR networks is an inefficient way to enhance image quality, because these two tasks share most of the same processing steps. To this end, we propose a deep neural network for the joint task of SR and HDR imaging, termed Deep SR-HDR, which reconstructs a high-resolution (HR) HDR image from a set of differently exposed low-resolution (LR) LDR images of a dynamic scene. Specifically, we merge the shared processing steps, including feature extraction and alignment of these two tasks. In particular, to handle large-scale complex motions, we design a multi-scale deformable module (MSDM) that estimates the sampling location offsets in a coarse-to-fine manner and then flexibly integrates useful information to compensate for the missing content in the motion regions. Then, we divide the fusion stage into two branches for HDR generation and high-frequency information extraction. With the cooperation and interactions of these modules, the proposed network reconstructs high-quality HR HDR images. Extensive qualitative and quantitative experimental results demonstrate the superiority and high efficiency of the proposed network.

Global structure and local detailed texture have different effects on image enhancement tasks. However, most existing works treated these two components in the same way, without fully considering the characteristics of the global structure and local detailed texture. In this work, we propose a structure-texture aware network (STANet) that successfully exploits structure and texture features of low-light images to improve perceptual quality. To construct STANet, a fine-scale contour map guided filter is introduced to decompose the image into a structure component and a texture component. Then, structure-attention and texture-attention subnetworks are designed to fully exploit the characteristics of these two components. Finally, a fusion subnetwork with attention mechanisms is utilized to explore the internal correlations among the global and local features. Furthermore, to optimize the proposed STANet model, we propose a hybrid loss function; specifically, a color loss function is introduced to alleviate color distortion in the enhanced image. Extensive experiments demonstrate that the proposed method improves the visual quality of images; moreover, STANet outperforms most other state-of-the-art approaches.

Most existing studies performed video denoising by using multiple adjacent noisy frames to recover one clean frame; however, despite achieving relatively good quality for each individual frame, these approaches may result in visual flickering when the denoised frames are considered in sequence. In this paper, instead of separately restoring each clean frame, we propose a multiframe-to-multiframe (MM) denoising scheme that simultaneously recovers multiple clean frames from consecutive noisy frames. The proposed MM denoising scheme uses a training strategy that optimizes the denoised video from both the spatial and temporal dimensions, enabling better temporal consistency in the denoised video. Furthermore, we present an MM network (MMNet), which adopts a spatiotemporal convolutional architecture that considers both the interframe similarity and single-frame characteristics. Benefiting from the underlying parallel mechanism of the MM denoising scheme, MMNet achieves a highly competitive denoising efficiency. Extensive analyses and experiments demonstrate that MMNet outperforms the state-of-the-art video denoising methods, yielding temporal consistency improvements of at least 13.3$\%$and running more than 2 times faster than the other methods.

Most of the recent image segmentation methods have tried to achieve the utmost segmentation results using large-scale pixel-level annotated data sets. However, obtaining these pixel-level annotated training data is usually tedious and expensive. In this work, we address the task of semisupervised semantic segmentation, which reduces the need for large numbers of pixel-level annotated images. We propose a method for semisupervised semantic segmentation by improving the confidence of the predicted class probability map via two parts. First, we build an adversarial framework that regards the segmentation network as the generator and uses a fully convolutional network as the discriminator. The adversarial learning makes the prediction class probability closer to 1. Second, the information entropy of the predicted class probability map is computed to represent the unpredictability of the segmentation prediction. Then, we infer the label-error map of the segmentation prediction and minimize the uncertainty on misclassified regions for unlabeled images. In contrast to existing semisupervised and weakly supervised semantic segmentation methods, the proposed method results in more confident predictions by focusing on the misclassified regions, especially the boundary regions. Our experimental results on the PASCAL VOC 2012 and PASCAL-CONTEXT data sets show that the proposed method achieves competitive segmentation performance.

It is essential to enhance the ability of wind speeds forecasting for wind energy and wind resource planning. For this purpose, a hybrid strategy has been proposed based on spatio-temporal covariance model which combined the spatio-temporal ordinary kriging (STOK) technology with autoregressive integrated moving average (ARIMA) regression smoothing method. This is because wind speed time series exhibits a long-term dependency. In the case study, both STOK method and ARIMA method are employed and their performances are compared. The ARIMA model can obtain a necessary and sufficient smoothing condition for them to be smoothed. Meanwhile, further theoretical analysis is provided to discuss why the STOK method is potentially more accurate than the ARIMA method for wind speed time series prediction. Results show that the proposed method outperforms the Non-Sep-Gneiting model by 9% and 7.2% in terms of mean absolute error (MAE) and root-mean-square error (RMSE).

Short-term wind speed prediction is an essential task for wind resource and wind energy planning. However, most of this literature does not take into account the spatio-termporal correlation of wind data from the geographical field. For this reason, we propose an integrated spatio-temporal kriging and functional kriging strategy to exploit such spatio-temporal correlation into the wind speed prediction. First, the deterministic trend component in wind data is estimated to be removed. The residuals are used for spatio-temporal modeling and prediction. Based on the spatio-temporal kriging framework, four spatio-temporal covariance models (product-sum model, separable exponential product model, separable and nonseparable Gneiting models) are considered which describe the spatio-temporal correlation of wind data. In particular, the flexibility of using the nonseparable Gneiting model is highlighted. More specifically, four spatio-temporal random fields are modeled from the 12 wind monitoring stations over Ireland. We also use an involved weighted least squares method for estimating parameters of the four covariance models involved in the spatio-temporal kriging strategy. We apply the fitted covariance models to generate day-ahead wind speed predictions at both observed and nonobserved locations where wind station already exist but also to nearby locations. Leave-one-out cross-validation is applied to check the significance of the difference among the four models, these spatio-temporal ordinary kriging (STOK), functional ordinary kriging (FOK) and autoregressive integrated moving average (ARIMA) methods are compared for day-ahead wind speed predictions. Forecasting results indicate that the predicting accuracy is improved almost 33.5% using FOK compared with three approaches which confirm the effectiveness of the functional kriging method in the paper.

Most existing image denoising methods focus on improving denoising quality. However, when applying denoising methods to practical tasks, in addition to the denoising quality, the number of parameters, and the computational complexity should be fully considered. In this article, we propose a demand-oriented framework (DOF) for image denoising, which can give preference to the number of parameters, the computational complexity, and the denoising quality or balance these three performance metrics. To perform the demand-oriented denoising, we first design a scale encoder to help the denoising model extract fewer but more representative features. Then, the split-flow module is introduced to fully exploit the input features by sharing the information of one network branch with other network branches. Finally, the scale decoder is utilized to reconstruct the final noise map without using any parameters. Through extensive experiments, we demonstrate that the proposed framework can be applied to several existing methods to help them achieve a more competitive denoising performance in terms of the number of parameters, and computational complexity.

In this paper, an efficient control system development method based on real-time virtual hardware-in-the-loop simulation is presented. Instead of developing and testing control system after physical prototype is produced, it can be conducted immediately after concept of controlled system is designed by developing a pure software real-time simulator. In this simulator, all the hardware is virtual. The appearance and operation of these virtual hardware is programmed to imitate corresponding physical prototypes so as to implement real-time virtual hardware-in-the-loop simulation. So The control software and the control logic of control system can be developed quickly. And the source code is compatible with both the simulation platform and physical platform. Moreover, It's much easier and faster to debug and test the control logic in such a way. An example of a large and high-groove density ruling engine is provided to explain detail implementation of the proposed method.

This paper presents a motion planning approach to coordinating multiple mobile robots in moving along specified paths. The robots are required to fulfill formation requirements while meeting velocity/acceleration constraints and avoiding collisions. Coordination is achieved by planning robot velocities along the paths through a velocity optimization process. An objective function for minimizing formation errors is established and solved by a linear interactive and general optimizer. Motion planning can be further adjusted online to address emergent demands such as avoiding suddenly-appearing obstacles. Simulations and experiments are performed on a group of mobile robots to demonstrate the effectiveness of the proposed coordinated motion planning in multirobot formations.

This paper presents a new approach to formation forming of multiple mobile robots with decentralized motion planning. When the robots enter the required formation, there exists the formation-structure constraint, which causes disorder or even deadlock of the formation. A dynamic priority strategy is developed to solve the problem of the formation-structure constraint, and coordinate the robots to form the formation in a proper order. Simulations are performed on a group of mobile robots to demonstrate the validity of the proposed strategy to the formation system.