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Fengxiang He

34 accepted papers

2025

Human-Imperceptible, Machine-Recognizable Images

IJCAI 2025

Massive human-related data is collected to train neural networks for computer vision tasks. A major conflict is exposed relating to software engineers between better developing AI systems and distancing from the sensitive training data. To reconcile this conflict, the paper proposes an efficient pri

2025

Task-Aware Clustering for Prompting Vision-Language Models

CVPR 2025poster

Prompt learning has attracted widespread attention in adapting vision-language models to downstream tasks. Existing methods largely rely on optimization strategies to ensure the task-awareness of learnable prompts. Due to the scarcity of task-specific data, overfitting is prone to occur. The resulti…

2024

Adaptive Time-Stepping Schedules for Diffusion Models

UAI 2024poster

This paper studies how to tune the stepping schedule in diffusion models, which is mostly fixed in current practice, lacking theoretical foundations and assurance of optimal performance at the chosen discretization points. In this paper, we advocate the use of adaptive time-stepping schedules and de…

2023

Class-Aware Patch Embedding Adaptation for Few-Shot Image Classification

ICCV 2023poster

"A picture is worth a thousand words", significantly beyond mere a categorization. Accompanied by that, many patches of the image could have completely irrelevant meanings with the categorization if they were independently observed. This could significantly reduce the efficiency of a large family of…

Cited by 32PDFcodeScholar
2023

Decentralized SGD and Average-direction SAM are Asymptotically Equivalent

ICML 2023poster

Decentralized stochastic gradient descent (D-SGD) allows collaborative learning on massive devices simultaneously without the control of a central server. However, existing theories claim that decentralization invariably undermines generalization. In this paper, we challenge the conventional belief…

2023

Improving Heterogeneous Model Reuse by Density Estimation

IJCAI 2023poster

This paper studies multiparty learning, aiming to learn a model using the private data of different participants. Model reuse is a promising solution for multiparty learning, assuming that a local model has been trained for each party. Considering the potential sample selection bias among different…

2023

Learning to Generalize Provably in Learning to Optimize

AISTATS 2023poster

Learning to optimize (L2O) has gained increasing popularity, which automates the design of optimizers by data-driven approaches. However, current L2O methods often suffer from poor generalization performance in at least two folds: (i) applying the L2O-learned optimizer to unseen optimizees, in terms…

2023

Reject Decoding via Language-Vision Models for Text-to-Image Synthesis

AAAI 2023technical

Transformer-based text-to-image synthesis generates images from abstractive textual conditions and achieves prompt results. Since transformer-based models predict visual tokens step by step in testing, where the early error is hard to be corrected and would be propagated. To alleviate this issue, th…

2022

Adversarial Auto-Augment with Label Preservation: A Representation Learning Principle Guided Approach

NeurIPS 2022accept

Data augmentation is a critical contributing factor to the success of deep learning but heavily relies on prior domain knowledge which is not always available. Recent works on automatic data augmentation learn a policy to form a sequence of augmentation operations, which are still pre-defined and re…

2022

Benefits of Permutation-Equivariance in Auction Mechanisms

NeurIPS 2022accept

Designing an incentive-compatible auction mechanism that maximizes the auctioneer's revenue while minimizes the bidders’ ex-post regret is an important yet intricate problem in economics. Remarkable progress has been achieved through learning the optimal auction mechanism by neural networks. In this…

Cited by 12SourcePDFScholar
2022

Bridged Transformer for Vision and Point Cloud 3D Object Detection

CVPR 2022poster

3D object detection is a crucial research topic in computer vision, which usually uses 3D point clouds as input in conventional setups. Recently, there is a trend of leveraging multiple sources of input data, such as complementing the 3D point cloud with 2D images that often have richer color and fe…

Cited by 53PDFScholar
2022

DisPFL: Towards Communication-Efficient Personalized Federated Learning via Decentralized Sparse Training

ICML 2022spotlight

Personalized federated learning is proposed to handle the data heterogeneity problem amongst clients by learning dedicated tailored local models for each user. However, existing works are often built in a centralized way, leading to high communication pressure and high vulnerability when a failure o…

2022

Huber Additive Models for Non-stationary Time Series Analysis

ICLR 2022poster

Sparse additive models have shown promising flexibility and interpretability in processing time series data. However, existing methods usually assume the time series data to be stationary and the innovation is sampled from a Gaussian distribution. Both assumptions are too stringent for heavy-tailed a…

2022

Robust Unlearnable Examples: Protecting Data Privacy Against Adversarial Learning

ICLR 2022poster

The tremendous amount of accessible data in cyberspace face the risk of being unauthorized used for training deep learning models. To address this concern, methods are proposed to make data unlearnable for deep learning models by adding a type of error-minimizing noise. However, such conferred unlea…

2022

Siamese Network with Interactive Transformer for Video Object Segmentation

AAAI 2022technical

Semi-supervised video object segmentation (VOS) refers to segmenting the target object in remaining frames given its annotation in the first frame, which has been actively studied in recent years. The key challenge lies in finding effective ways to exploit the spatio-temporal context of past frames…

2022

Text-to-Image Synthesis Based on Object-Guided Joint-Decoding Transformer

CVPR 2022poster

Object-guided text-to-image synthesis aims to generate images from natural language descriptions built by two-step frameworks, i.e., the model generates the layout and then synthesizes images from the layout and captions. However, such frameworks have two issues: 1) complex structure, since generati…

Cited by 17PDFScholar
2022

Topology-aware Generalization of Decentralized SGD

ICML 2022spotlight

This paper studies the algorithmic stability and generalizability of decentralized stochastic gradient descent (D-SGD). We prove that the consensus model learned by D-SGD is $\mathcal{O}{(m/N\unaryplus1/m\unaryplus\lambda^2)}$-stable in expectation in the non-convex non-smooth setting, where $N$ is…

2022

VITA: A Multi-Source Vicinal Transfer Augmentation Method for Out-of-Distribution Generalization

AAAI 2022technical

Invariance to diverse types of image corruption, such as noise, blurring, or colour shifts, is essential to establish robust models in computer vision. Data augmentation has been the major approach in improving the robustness against common corruptions. However, the samples produced by popular augme…

Cited by 5SourcePDFScholar
2022

Visual Semantics Allow for Textual Reasoning Better in Scene Text Recognition

AAAI 2022technical

Existing Scene Text Recognition (STR) methods typically use a language model to optimize the joint probability of the 1D character sequence predicted by a visual recognition (VR) model, which ignore the 2D spatial context of visual semantics within and between character instances, making them not ge…

2022

When to Update Your Model: Constrained Model-based Reinforcement Learning

NeurIPS 2022accept

Designing and analyzing model-based RL (MBRL) algorithms with guaranteed monotonic improvement has been challenging, mainly due to the interdependence between policy optimization and model learning. Existing discrepancy bounds generally ignore the impacts of model shifts, and their corresponding alg…

2021

Tighter Generalization Bounds for Iterative Differentially Private Learning Algorithms

UAI 2021poster

This paper studies the relationship between generalization and privacy preservation of machine learning in two steps. We first establish an alignment between the two facets for any learning algorithm. We prove that $(\varepsilon, \delta)$-differential privacy implies an on-average generalization bou…

Cited by 18SourcePDFScholar
2020

Piecewise linear activations substantially shape the loss surfaces of neural networks

ICLR 2020poster

Understanding the loss surface of a neural network is fundamentally important to the understanding of deep learning. This paper presents how piecewise linear activation functions substantially shape the loss surfaces of neural networks. We first prove that {\it the loss surfaces of many neural netwo…

Cited by 36SourceScholar
2019

Collect and Select: Semantic Alignment Metric Learning for Few-Shot Learning

ICCV 2019poster

Few-shot learning aims to learn latent patterns from few training examples and has shown promises in practice. However, directly calculating the distances between the query image and support image in existing methods may cause ambiguity because dominant objects can locate anywhere on images. To addr…

Cited by 183PDFcodeScholar
2019

Control Batch Size and Learning Rate to Generalize Well: Theoretical and Empirical Evidence

NeurIPS 2019poster

Deep neural networks have received dramatic success based on the optimization method of stochastic gradient descent (SGD). However, it is still not clear how to tune hyper-parameters, especially batch size and learning rate, to ensure good generalization. This paper reports both theoretical and empi…

2019

Fast Spatio-Temporal Residual Network for Video Super-Resolution

CVPR 2019poster

Recently, deep learning based video super-resolution (SR) methods have achieved promising performance. To simultaneously exploit the spatial and temporal information of videos, employing 3-dimensional (3D) convolutions is a natural approach. However, straight utilizing 3D convolutions may lead to an…

Cited by 169PDFScholar
2019

Progressive Reconstruction of Visual Structure for Image Inpainting

ICCV 2019poster

Inpainting methods aim to restore missing parts of corrupted images and play a critical role in many computer vision applications, such as object removal and image restoration. Although existing methods perform well on images with small holes, restoring large holes remains elusive. To address this i…

Cited by 213PDFcodeScholar