Fingerprint biometrics plays a crucial role in biometric identification, especially in applications such as criminal investigations. Although recent progress in recognition methodology has significantly enhanced automated fingerprint recognition, these systems still rely heavily on the quality of the input fingerprints. In criminal investigations, fingerprints are often of low quality due to their incidental deposition from natural oils and sweat, rather than being deliberately captured under controlled conditions. This degradation can significantly impact usability and identification accuracy, underscoring the need for effective Fingerprint Quality Assessment (FQA) methods. In this paper, we establish the Crime Scene Fingerprints quality assessment Dataset (CSFD-10k), the largest dataset of its kind, containing 11,500 fingerprint images from real criminal investigations. Of these, 10,000 samples are assigned Mean Opinion Scores (MOSs) for correlation testing, while the remaining 1,500 are labeled based on matching performance for generalizability testing. All labels are provided by frontline criminal police officers. Using this dataset, we propose a deep neural network-based Dual-Branch FQA (DB-FQA) framework that integrates image-level and edge-level features. The DB-FQA enhances ridge details by transforming raw grayscale fingerprints into edge maps using the Logical/Linear operator. A dual-branch network processes both the raw fingerprint and the edge map, and the Multi-scale Adaptive Cross feature Fusion (MACF) module fuses these features, guided by the edge map to highlight quality-related regions of interest. Extensive experiments demonstrate the robustness and superiority of our proposed method, offering substantial support for forensic fingerprint biometrics. The code and dataset are available at https://github.com/wzhsysu/FIQA.

Underwater images often suffer from color distortion, reduced contrast, and blurriness due to light refraction, absorption, and scattering. In this paper, we propose a coarse-to-fine deepPyramid network forUnderwaterImageEnhancement (PyUIE). Specifically, PyUIE begins by decomposing the input image into high- and low-frequency components using a Laplacian pyramid. The low-frequency residual, which primarily contains lighting and color information, is processed with a lightweight deterministic color mapping network to correct global illumination and color distortions. Concurrently, the high-frequency components containing the fine details are enhanced in a coarse-to-fine manner, such that each higher scale is guided by the reconstruction from the adjacent lower scale. This hierarchical strategy effectively mitigates the risk of over-enhancement by avoiding excessive modifications to the high-frequency components. Additionally, we implement a multi-scale supervised training strategy, enabling the model to learn and reconstruct features across multiple scales, which enhances its ability to capture diverse details and improves its generalization and robustness. Extensive experiments demonstrate that our method successfully restores fine details and small structures in underwater images while producing vivid and visually appealing colors, thereby outperforming existing enhancement methods in both qualitative and quantitative evaluations. The code is available athttps://github.com/ttttllt/PyUIE.git.

Considering the potential of using multi-frame information to solve the occlusion problem, we introduce a novel idea of multi-frame information integration, which uses the attention mechanism to fuse the temporal information from the previous frame. The idea can effectively improve the estimation accuracy in occluded regions and optimize the inference speed under multi-frame settings. Meanwhile, we suggest the concept of attention confidence to provide an explicit value criterion for the model to utilize useful attention information more efficiently. Furthermore, we propose an Efficient Temporal Attention network (ETA), which achieves promising results on Sintel and KITTI benchmarks, especially with a 9.4% error reduction compared to the baseline method GMA on Sintel (test) Clean.

Considering that scene flow estimation has the capability of the spatial domain to focus but lacks the coherence of the temporal domain, this study proposes long-term scene flow estimation (LSFE), a comprehensive task that can simultaneously capture the fine-grained and long-term 3D motion in an online manner. We introduce SceneTracker, the first LSFE network that adopts an iterative approach to approximate the optimal 3D trajectory. The network dynamically and simultaneously indexes and constructs appearance correlation and depth residual features. Transformers are then employed to explore and utilize long-range connections within and between trajectories. With detailed experiments, SceneTracker shows superior capabilities in addressing 3D spatial occlusion and depth noise interference, highly tailored to the needs of the LSFE task. We build a real-world evaluation dataset, LSFDriving, for the LSFE field and use it in experiments to further demonstrate the advantage of SceneTracker in generalization abilities.

Predicting cognitive load is a crucial issue in the emerging field of human-computer interaction and holds significant practical value, particularly in flight scenarios. Although previous studies have realized efficient cognitive load classification, new research is still needed to adapt the current state-of-the-art multimodal fusion methods. Here, we proposed a feature selection framework based on multiview learning to address the challenges of information redundancy and reveal the common physiological mechanisms underlying cognitive load. Specifically, the multimodal signal features [electroencephalogram (EEG), electrodermal activity (EDA), electrocardiogram (ECG), electrooculogram (EOG), & eye movements] at three cognitive load levels were estimated during multiattribute task battery (MATB) tasks performed by 22 healthy participants and fed into a feature selection-multiview classification with cohesion and diversity (FS-MCCD) framework. The optimized feature set was extracted from the original feature set by integrating the weight of each view and the feature weights to formulate the ranking criteria. The cognitive load prediction model, evaluated using real-time classification results, achieved an average accuracy of 81.08% and an average F1-score of 80.94% for three-class classification among 22 participants. Furthermore, the weights of the physiological signal features revealed the physiological mechanisms related to cognitive load. Specifically, heightened cognitive load was linked to amplified $\delta$ and $\theta$ power in the frontal lobe, reduced $\alpha$ power in the parietal lobe, and an increase in pupil diameter. Thus, the proposed multimodal feature fusion framework emphasizes the effectiveness and efficiency of using these features to predict cognitive load.

Electroencephalography (EEG) plays a crucial role in neuroscience research and clinical practice, but it remains limited by nonuniform data, noise, and difficulty in labeling. To address these challenges, we develop a pretraining framework named DMAE-EEG, a denoising masked autoencoder for mining generalizable spatiotemporal representation from massive unlabeled EEG. First, we propose a novel brain region topological heterogeneity (BRTH) division method to partition the nonuniform data into fixed patches based on neuroscientific priors. Second, we design a denoised pseudo-label generator (DPLG), which utilizes a denoising reconstruction pretext task to enable the learning of generalizable representations from massive unlabeled EEG, suppressing the influence of noise and artifacts. Furthermore, we utilize an asymmetric autoencoder with self-attention as the backbone in the proposed DMAE-EEG, which captures long-range spatiotemporal dependencies and interactions from unlabeled EEG data across 14 public datasets. The proposed DMAE-EEG is validated on both generative (signal quality enhancement) and discriminative tasks (motion intention recognition). In the quality enhancement, DMAE-EEG outperforms existing statistical methods with normalized mean squared error (nMSE) reduction of 27.78%-50.00% under corruption levels of 25%, 50%, and 75%, respectively. In motion intention recognition, DMAE-EEG achieves a relative improvement of 2.71%-6.14% in intrasession classification balanced accuracy across 2-6 class motor execution and imagery tasks, outperforming state-of-the-art methods. Overall, the results suggest that the pretraining framework DMAE-EEG can capture generalizable spatiotemporal representations from massive unlabeled EEG and enhance the knowledge transferability across sessions, subjects, and tasks in various downstream scenarios, advancing EEG-aided diagnosis and brain-computer communication and control, and other clinical practice.

Objective Image Quality Assessment (IQA) aims to design computational models that can automatically predict the perceived quality of images. The state-of-the-art full-reference IQA metric – Deep Image Structure and Texture Similarity (DISTS), neglects the fact that natural images often consist of local structure and texture, and requires supervised training on the annotated dataset. In this article, we introduce multiple adaptive strategies to improve DISTS, resulting in an opinion-unaware IQA metric, named A-DISTS. Specifically, A-DISTS first uses the dispersion index as a statistical feature to adaptively localize structure and texture regions at different scales. Second, it adaptively assigns the spatial weights between local structure and texture similarity measurements according to the estimated structure or texture probability maps. Finally, it calculates the entropy of image representation to adaptively weigh the importance of each feature map. As a result, A-DISTS is adapted to local image content and does not require any training. The experimental results demonstrated that the proposed metric correlates well with human rating in the standard and algorithm-dependent IQA databases, and exhibits competitive performance in the optimization tasks of single image super-resolution, motion deblurring, and multi-distortion removal.

Previous studies have made great efforts to expand the instruction set in steady-state visual evoked potential (SSVEP)-based brain-computer interfaces. However, most systems are limited to single persons and expand the instruction set by increasing the flicker stimulation frequency range or via multiple frequencies sequential coding or joint frequency/phase coding. In this article, we propose a multibrain coding SSVEP paradigm that encodes the SSVEP instructions generated byNindependent subjects withMflicker stimuli, thus increasing the instruction set toMNinstructions. A total of 40 subjects participated in online experiments in this article. The results show that there is no significant difference in accuracy (p> 0.05, paired t test) between the multibrain and single-brain coding systems, while the information transfer rate (ITR) increases significantly (pN= 3 andM= 5. In summary, the proposed multibrain coding paradigm exponentially increases the number of instructions without increasing the output instruction time, which is of great significance to the application and promotion of BCIs.

Cognitive load prediction is one of the most important issues in the nascent field of neuroergonomics, and it has significant value in real-world applications. Most of the previous studies of cognitive load prediction only utilized electroencephalography (EEG)-based spectral signatures or interchannel connectivity, ignoring abundant temporal microstate features, which may represent the transient topologies of EEG signals. Furthermore, previous studies have mostly focused on the binary-level classification of cognitive load for single-type cognitive tasks. To date, there are few studies on the multilevel prediction of cognitive load during mixed cognitive tasks. Here, we first designed a new paradigm termed the “finding fault game,” mixing multiple tasks of memory, counting, and visual search, and then developed a multidimensional analysis framework to improve cognitive load prediction using a fusion of spatial, temporal, and spectral EEG features. Specifically, EEG-based functional connectivity, microstates and power spectral densities (PSD) were calculated for three cognitive load levels. Twelve adult subjects participated in the study. The experimental results show that increased cognitive load was associated with elevated theta and degraded alpha power and significant changes in interchannel connectivity and microstates, and that fusing the three types of EEG features improved the performance of three-level cognitive load prediction, achieving the accuracies of greater than 80% in the cross-validation, real-time, and over-time prediction. The findings suggest that all three types of EEG features can serve as signatures of cognitive load and that their fusion can improve multilevel prediction.

In this study, a dynamic user interface (UI) is proposed in visual P300 Brain-Computer Interface (BCI) based environmental control system. A head-mounted Augmented Reality (AR) glass is used as the interactive media, which is used to assists the BCI system to build the dynamic UI with the scene in subject’s field of view. In the dynamic UI, based on the objects detected by the AR glass, options are dynamically generated. The subject can assign tasks by selecting different options in the dynamic UI. Five subjects successfully completed the task of controlling household appliances and navigating wheelchairs to designated destinations. Compared to static UI, the proposed dynamic UI has a 17.4% improvement in time delay. On average, only 1.9% of the commands resulted in incorrect operations. The dynamic UI makes progress in reducing time delay and incorrect operations. The proposed system provides a brand-new interactive method in BCI based applications.

A classical visual event relative potential (ERP) brain–computer interface (BCI) system relies on visual stimuli to choose commands. Users obtain most information about their surroundings visually as well. This large amount of information can aggravate visual burden and fatigue. In our study, we proposed a novel approach to evoke ERP with a tactile stimulus. To achieve this approach, we first designed a wireless stimulus module with vibrators to provide a tactile stimulus for the system. The vibrators were located on the subject’s arm to imitate the joint motion of a robotic arm. Then, the ERP feature and the parameters of classifiers were obtained through offline experimental data analysis. Based on the analysis, the suitable electrode channels, stimulus onset asynchrony (SOA), and filter upper limit were different for different subjects. According to those outcomes, a unique classifier was designed for each subject. Finally, 10 healthy BCI-naive subjects participated in online experiments to evaluate the performance of our tactile BCI system; they achieved an accuracy range from 78.67% to 100% with an average of 89.1% and an instantaneous transmission rate (ITR) range from 7.77 to 28.70 bits/min with an average of 14.77 bits/min. The accuracy of different subjects and SOAs remained relatively stable, the ITR fluctuated mainly due to the different SOAs, and we achieved balance between ITR and accuracy.

This study presents a brain–computer interface (BCI) system aimed at providing disabled patients with mobile solutions for practical use. The proposed system employs an omnidirectional chassis and a bionic robot arm to construct a multi-functional mobile platform. In addition, the system is equipped with a Kinect and 12 ultrasonic sensors to capture environment information. Based on artificial intelligence technology, the mobile system can understand the environment and smartly completes certain tasks. A hybrid BCI combined with movement imagery paradigm and asynchronous P300 paradigm is designed to translate human intent to computer commands. The users interact with the system in a flexible way: on the one hand, the user issues commands to drive the system directly; on the other hand, the system searches for predefined operable targets and reports the results to the user. Once the user confirms the target, the system will automatically complete the associated operation. To evaluate the system’s performance, a testing environment with a small room, aisle, and an elevator was built to simulate the mobile tasks in the daily scene. Participants were instructed to operate the mobile system in the room, aisle, and using the elevator to go outdoors. In this study, four subjects participated in the test, and all of them completed the task.

Brain-computer interfaces (BCIs) not only can allow individuals to voluntarily control external devices, helping to restore lost motor functions of the disabled, but can also be used by healthy users for entertainment and gaming applications. In this study, we proposed a hybrid BCI paradigm to explore a feasible and natural way to play games by using electroencephalogram (EEG) signals in a practical environment. In this paradigm, we combined motor imagery (MI) and steady-state visually evoked potentials (SSVEPs) to generate multiple commands. A classic game, Tetris, was chosen as the control object. The novelty of this study includes the effective usage of a “dwell time” approach and fusion rules to design BCI games. To demonstrate the feasibility of the proposed hybrid paradigm, ten subjects were chosen to participate in online control experiments. The experimental results showed that all subjects successfully completed the predefined tasks with high accuracy. This proposed hybrid BCI paradigm could potentially provide those who suffer disability or paralysis with additional entertainment options, such as brain-actuated games, that could improve their happiness and quality of life.Abbreviations: BCI: brain-computer interface; EEG: electroencephalogram; MI: motor imagery; SSVEP: steady-state visually evoked potential; ERP: event-related potential; SMR: sensorimotor rhythm; VEP: visual evoked potential; TCP/IP: transmission control protocol/internet protocol; GUI: graphical user interface; ERD/ERS: event-related desynchronization/synchronization; CIC: control intention classifier; LRC: left/right classifier; CSP: common spatial pattern; LDA: linear discriminant analysis; ROC: receiver operating characteristic; TPR: true positive rate; FPR: false positive rate; CCA: canonical correlation analysis.

This study presents the self-paced operation of a brain–computer interface (BCI) speller, which can be voluntarily turned on/off by merging a motor imagery (MI)-based brain switch into a P300-based BCI speller. From an off state (idle state), the users can generate a “control signal” by consciously changing the cognitive state differential from the idle state to turn on a P300-based spelling system when he or she wants to spell words. With the system turned on, the user can spell words, and then, the spelling system can be voluntarily turned off and switched to the initial state using a command. In this paradigm, the participants tried to perform the two different cognitive tasks sequentially, rather than simultaneously, and multiple EEG components were processed sequentially. The practicability and effectiveness of the proposed approach were validated by eleven participants, and all of them achieved a satisfactory performance. For the P300 speller, they achieved an average PITR of 42.61 bits/min. The preliminary results indicated that the proposed hybrid BCI system with different mental strategies operating sequentially is feasible and has potential applications for practical self-paced control.

The majority of previously developed assistive communication brain–computer interface systems have primarily focused on languages that are written in alphabetic scripts. However, languages that are written in logographic scripts, such as those in Chinese hanzi (or sinograms), pose a challenge for the implementation of visual spelling systems because it is impossible to simultaneously display thousands of items in a stimulus matrix of a reasonable size. In this study, a P300 visual spelling system that uses a novel method to input Chinese sinograms developed with a Hanyu Pinyin-based method is presented. This method transcribes a Chinese Pinyin into initial consonant and vowel components according to its Mandarin pronunciation. In this paradigm, each sinogram is input by selecting the initial consonant and then the vowel components and subsequently selecting the sinogram itself. Ten healthy subjects participated in the study and achieved an average offline accuracy of 92.6% with a mean information transfer rate of 39.2 bits/min and an average online input speed of one sinogram per 43.9 s. The preliminary results presented here indicated that the online input of Chinese text using a Pinyin-based visual speller is feasible.