Event-based vision sensors provide significant advantages for high-speed perception, including microsecond temporal resolution, high dynamic range, and low power consumption. When combined with Spiking Neural Networks (SNNs), they can be deployed on neuromorphic hardware, enabling energy-efficient applications on embedded systems. However, this potential is severely limited by the scarcity of large-scale labeled datasets required to effectively train such models. In this work, we introduce SpikeCLR, a contrastive self-supervised learning framework that enables SNNs to learn robust visual representations from unlabeled event data. We adapt prior frame-based methods to the spiking domain using surrogate gradient training and introduce a suite of event-specific augmentations that leverage spatial, temporal, and polarity transformations. Through extensive experiments on CIFAR10-DVS, N-Caltech101, N-MNIST, and DVS-Gesture benchmarks, we demonstrate that self-supervised pretraining with subsequent fine-tuning outperforms supervised learning in low-data regimes, achieving consistent gains in few-shot and semi-supervised settings. Our ablation studies reveal that combining spatial and temporal augmentations is critical for learning effective spatio-temporal invariances in event data. We further show that learned representations transfer across datasets, contributing to efforts for powerful event-based models in label-scarce settings.
Learning-to-Defer routes each input to the expert that minimizes expected cost, but it assumes that the information available to every expert is fixed at decision time. Many modern systems violate this assumption: after selecting an expert, one may also choose what additional information that expert should receive, such as retrieved documents, tool outputs, or escalation context. We study this problem and call it Learning-to-Defer with advice. We show that a broad family of natural separated surrogates, which learn routing and advice with distinct heads, is inconsistent even in the smallest non-trivial setting. We then introduce an augmented surrogate that operates on the composite expert–advice action space and prove an ℋ-consistency guarantee together with an excess-risk transfer bound, yielding recovery of the Bayes-optimal policy in the limit. Experiments on tabular, language, and multi-modal tasks show that the resulting method improves over standard Learning-to-Defer while adapting its advice-acquisition behavior to the cost regime; a synthetic benchmark confirms the failure mode predicted for separated surrogates.
Learning-to-defer (L2D) routes each decision to a system's own predictor or to an external expert. Streaming time-series settings break the offline-L2D assumptions: the data are non-stationary, expert availability shifts over time, and the internal predictor is trained online. We propose L2D-SLDS, a one-stage online L2D framework based on a factorized switching linear-Gaussian state-space model over all potential residuals: a discrete regime, a shared global factor, and per-expert idiosyncratic states. The always-observed internal residual continuously updates beliefs about every unqueried expert through the shared factor, and a learner-aware query score balances immediate cost against latent-state information gain and one-step learner improvement. We prove an oracle inequality against a time-varying learn-and-defer comparator, decomposing regret into a query-bonus budget, an SLDS predictive-cost-error term ℰ_SLDS, and the internal learner's interval dynamic regret. On synthetic, Melbourne, Jena, and 24-expert Delhi benchmarks, L2D-SLDS is competitive with or improves on contextual- and non-stationary-bandit baselines while deferring on <2% of real-data rounds.
Learning-to-Defer (L2D) methods route each query either to a predictive model or to external experts. While existing work studies this problem in batch settings, real-world deployments require handling streaming data, changing expert availability, and shifting expert distribution. We introduce the first online L2D algorithm for multiclass classification with bandit feedback and a dynamically varying pool of experts. Our method achieves regret guarantees of O((n+n_e)T^2/3) in general and O((n+n_e)√(T)) under a low-noise condition, where T is the time horizon, n is the number of labels, and n_e is the number of distinct experts observed across rounds. The analysis builds on novel ℋ-consistency bounds for the online framework, combined with first-order methods for online convex optimization. Experiments on synthetic and real-world datasets demonstrate that our approach effectively extends standard Learning-to-Defer to settings with varying expert availability and reliability.
Existing _Learning-to-Defer_ (L2D) frameworks are limited to _single-expert deferral_, forcing each query to rely on only one expert and preventing the use of collective expertise. We introduce the first framework for _Top-$k$ Learning-to-Defer_, which allocates queries to the $k$ most cost-effective entities. Our formulation unifies and strictly generalizes prior approaches, including the _one-stage_ and _two-stage_ regimes, _selective prediction_, and classical cascades. In particular, it recovers the usual Top-1 deferral rule as a special case while enabling principled collaboration with multiple experts when $k>1$. We further propose _Top-$k(x)$ Learning-to-Defer_, an adaptive variant that learns the optimal number of experts per query based on input difficulty, expert quality, and consultation cost. To enable practical learning, we develop a novel surrogate loss that is Bayes-consistent, $\mathcal{H}_h$-consistent in the one-stage setting, and $(\mathcal{H}_r,\mathcal{H}_g)$-consistent in the two-stage setting. Crucially, this surrogate is independent of $k$, allowing a single policy to be learned once and deployed flexibly across $k$. Experiments across both regimes show that Top-$k$ and Top-$k(x)$ deliver superior accuracy–cost trade-offs, opening a new direction for multi-expert deferral in L2D.
Learning-to-Defer routes each input to the expert that minimizes expected cost, but it assumes that the information available to every expert is fixed at decision time. Many modern systems violate this assumption: after selecting an expert, one may also choose what additional information that expert should receive, such as retrieved documents, tool outputs, or escalation context. We study this problem and call it Learning-to-Defer with advice. We show that a broad family of natural separated surrogates, which learn routing and advice with distinct heads, is inconsistent even in the smallest non-trivial setting. We then introduce an augmented surrogate that operates on the composite expert–advice action space and prove an ℋ-consistency guarantee together with an excess-risk transfer bound, yielding recovery of the Bayes-optimal policy in the limit. Experiments on tabular, language, and multi-modal tasks show that the resulting method improves over standard Learning-to-Defer while adapting its advice-acquisition behavior to the cost regime; a synthetic benchmark confirms the failure mode predicted for separated surrogates.
The growth of online educational content, particularly slide-based video lectures, has created a need for tools that enhance navigation, comprehension, and accessibility. Many existing systems for video analysis are closed-source, hindering reproducibility and extension. To address this, we present the Lecture Video Analysis Toolkit, an open-source, proof-of-concept application designed for the multimodal analysis of slide video lectures. The toolkit integrates a processing pipeline that includes scene detection, visual entity extraction, transcription, optical character recognition (OCR), and semantic linking between spoken and visual content using embeddings. A key contribution is its interactive interface, motivated by early user feedback, that allows for customization of the viewing experience to suit individual preferences. The entire system is openly available and serves as a research prototype for validating the potential of multimodal analysis in creating more inclusive and improved learning experiences. A live demo is accessible at https://travis-seng.fr/svla, and the source code is openly available at https://github.com/travisseng/svla-toolkit.
Two-stage Learning-to-Defer (L2D) enables optimal task delegation by assigning each input to either a fixed main model or one of several offline experts, supporting reliable decision-making in complex, multi-agent environments. However, existing L2D frameworks assume clean inputs and are vulnerable to adversarial perturbations that can manipulate query allocation-causing costly misrouting or expert overload. We present the first comprehensive study of adversarial robustness in two-stage L2D systems. We introduce two novel attack strategies-untargeted and targeted-which respectively disrupt optimal allocations or force queries to specific agents. To defend against such threats, we propose SARD, a convex learning algorithm built on a family of surrogate losses that are provably Bayes-consistent and (R, G)-consistent. These guarantees hold across classification, regression, and multi-task settings. Empirical results demonstrate that SARD significantly improves robustness under adversarial attacks while maintaining strong clean performance, marking a critical step toward secure and trustworthy L2D deployment.
We introduce the first one-stage Top-k Learning-to-Defer framework, which unifies prediction and deferral by learning a shared score-based model that selects the k most cost-effective entities-labels or experts-per input. While existing one-stage L2D methods are limited to deferring to a single expert, our approach jointly optimizes prediction and deferral across multiple entities through a single end-to-end objective. We define a cost-sensitive loss and derive a novel convex surrogate that is independent of the cardinality parameter k, enabling generalization across Top-k regimes without retraining. Our formulation recovers the Top-1 deferral policy of prior score-based methods as a special case, and we prove that our surrogate is both Bayes-consistent and ℋ-consistent under mild assumptions. We further introduce an adaptive variant, Top-k(x), which dynamically selects the number of consulted entities per input to balance predictive accuracy and consultation cost. Experiments on CIFAR-10 and SVHN confirm that our one-stage Top-k method strictly outperforms Top-1 deferral, while Top-k(x) achieves superior accuracy-cost trade-offs by tailoring allocations to input complexity.
The Two-Stage Learning-to-Defer (L2D) framework has been extensively studied for classification and, more recently, regression tasks. However, many real-world applications require solving both tasks jointly in a multi-task setting. We introduce a novel Two-Stage L2D framework for multi-task learning that integrates classification and regression through a unified deferral mechanism. Our method leverages a two-stage surrogate loss family, which we prove to be both Bayes-consistent and (G, R)-consistent, ensuring convergence to the Bayes-optimal rejector. We derive explicit consistency bounds tied to the cross-entropy surrogate and the L-1-norm of agent-specific costs, and extend minimizability gap analysis to the multi-expert two-stage regime. We also make explicit how shared representation learning-commonly used in multi-task models-affects these consistency guarantees. Experiments on object detection and electronic health record analysis demonstrate the effectiveness of our approach and highlight the limitations of existing L2D methods in multi-task scenarios.
Learning-to-Defer (L2D) enables hybrid decision-making by routing inputs either to a predictor or to external experts. While promising, L2D is highly vulnerable to adversarial perturbations, which can not only flip predictions but also manipulate deferral decisions. Prior robustness analyses focus solely on two-stage settings, leaving open the end-to-end (one-stage) case where predictor and allocation are trained jointly. We introduce the first framework for adversarial robustness in one-stage L2D, covering both classification and regression. Our approach formalizes attacks, proposes cost-sensitive adversarial surrogate losses, and establishes theoretical guarantees including $\mathcal{H}$, $(\mathcal{R }, \mathcal{F})$, and Bayes consistency. Experiments on benchmark datasets confirm that our methods improve robustness against untargeted and targeted attacks while preserving clean performance.
Although existing Learning-to-Defer (L2D) frameworks support multiple experts, they allocate each query to a single expert, limiting their ability to leverage collective expertise in complex decision-making scenarios. To address this, we introduce the first framework for Top-$k$ Learning-to-Defer, enabling systems to defer each query to the $k$ most cost-effective experts. Our formulation strictly generalizes classical two-stage L2D by supporting multi-expert deferral-a capability absent in prior work. We further propose Top-$k(x)$ Learning-to-Defer, an adaptive extension that learns the optimal number of experts per query based on input complexity, expert quality, and consultation cost. We introduce a novel surrogate loss that is Bayes-consistent, $(\mathcal{R}, \mathcal{G})$-consistent, and independent of the cardinality parameter $k$, enabling efficient reuse across different values of $k$. We show that classical model cascades arise as a special case of our method, situating our framework as a strict generalization of both selective deferral and cascaded inference. Experiments on classification and regression demonstrate that Top-$k$ and Top-$k(x)$ yield improved accuracy--cost trade-offs, establishing a new direction for multi-expert deferral in Learning-to-Defer.
The increasing amount of slide presentations in various sectors has amplified the need for effective slide layout and semantic analysis. However, we found that current slide datasets contain inconsistencies, mislabels, and incomplete annotations. Using them as a basis for developing deep learning-based slide analysis models could lead to models that are not robust and suboptimal. Addressing these challenges, we introduce SlideCraft, a tool for creating synthetic slide datasets that imitate real-world presentations. This tool overcomes the drawbacks of existing datasets by allowing users to create balanced, diverse, and accurately annotated slide data. We demonstrate SlideCraft's efficacy in enhancing slide layout analysis algorithms, focusing on its capability to improve dataset quality and object detection performance.
Large Language Models excel in generative tasks but exhibit inefficiencies in structured text selection, particularly in extractive question answering. This challenge is magnified in resource-constrained environments, where deploying multiple specialized models for different tasks is impractical. We propose a Learning-to-Defer framework that allocates queries to specialized experts, ensuring high-confidence predictions while optimizing computational efficiency. Our approach integrates a principled allocation strategy with theoretical guarantees on optimal deferral that balances performance and cost. Empirical evaluations on SQuADv1, SQuADv2, and TriviaQA demonstrate that our method enhances answer reliability while significantly reducing computational overhead, making it well-suited for scalable and efficient EQA deployment.
The old film restoration process involves many operations, one of which is the ability to identify defects that altered the film. This operation can be formulated as a binary segmentation problem and solved using state-of-the-art segmentation networks such as DeepLab v3+ or NAS-FPN. While being very powerful at describing the spatial characteristics of defects, these methods fail to take into account the fact that defects are also temporal anomalies. We therefore propose an architecture that builds on the correlation layer introduced in FlowNet to compensate for motion and eliminate potential false positives, features that look like defects but can be tracked over multiple images and are actually part of the scene. We also introduce a self-supervised pre-training process of the network, which precedes a fine-tuning phase to specifically adapt the detector to each film. Results show that our architecture, while being more compact and less resource-consuming than state-of-the-art methods, achieves higher precision and recall.
Accurate detection of spheres in images holds significant value for photometric 3D vision techniques such as photometric stereo.1 These techniques require precise calibration of lighting, and sphere detection can help in the calibration process. Our proposed approach involves training neural networks to automatically detect spheres of three different material classes: matte, shiny and chrome. We get fast and accurate segmentation of spheres in images, outperforming manual segmentation in terms of speed while maintaining comparable accuracy.
Visual neuroprostheses are devices that restore limited visual perception for visually impaired patients.Some of these neuroprostheses, implanted in the retina or the visual cortex, include an implant, a computing device and an external camera to capture the scene.Microstimulation of the retina or the visual cortex activates white spots called phosphenes, which restores a limited visual perception.Indeed, the resolution of current implants (i.e., the number and spacing of the electrodes) that have passed clinical trial phases remains low.Such a low resolution, coupled with the limited number of different colours rendered by the implants, limits the information that can be transferred.Hence, the regular rendering process used in the implants, called scoreboard, is insufficient to provide implanted patients with a good understanding of the visual scene and complex sensorimotor processes such as wayfinding.Ongoing research mainly aims at maximising the quality and quantity of the phosphenes provided by the implant.We set up a comparative study between different renderings, and we showed that providing the implanted patient with the possibility to switch between different renderings significantly increases the understanding of the environment.
Oge Marques合作论文数Department of Computer Science and Engineering
Florida Atlantic University5
Jean-Denis Durou合作论文数Universite Paul Sabatier5