Harnessing Hard Mixed Samples with Decoupled Regularizer (2203.10761v3)

Abstract: Mixup is an efficient data augmentation approach that improves the generalization of neural networks by smoothing the decision boundary with mixed data. Recently, dynamic mixup methods have improved previous static policies effectively (e.g., linear interpolation) by maximizing target-related salient regions in mixed samples, but excessive additional time costs are not acceptable. These additional computational overheads mainly come from optimizing the mixed samples according to the mixed labels. However, we found that the extra optimizing step may be redundant because label-mismatched mixed samples are informative hard mixed samples for deep models to localize discriminative features. In this paper, we thus are not trying to propose a more complicated dynamic mixup policy but rather an efficient mixup objective function with a decoupled regularizer named Decoupled Mixup (DM). The primary effect is that DM can adaptively utilize those hard mixed samples to mine discriminative features without losing the original smoothness of mixup. As a result, DM enables static mixup methods to achieve comparable or even exceed the performance of dynamic methods without any extra computation. This also leads to an interesting objective design problem for mixup training that we need to focus on both smoothing the decision boundaries and identifying discriminative features. Extensive experiments on supervised and semi-supervised learning benchmarks across seven datasets validate the effectiveness of DM as a plug-and-play module. Source code and models are available at https://github.com/Westlake-AI/openmixup

Overview of "Harnessing Hard Mixed Samples with Decoupled Regularizer"

In "Harnessing Hard Mixed Samples with Decoupled Regularizer," the authors address a critical aspect of mixup data augmentation. Mixup is a technique aimed at improving the generalization of neural networks by creating synthetic samples through linear combinations of training samples and labels. While dynamic mixup methods have sought to refine these policies further, computational efficiency remains a concern. The authors propose an innovative solution, Decoupled Mixup (DM), which simplifies the objective function in mixup training through a decoupled regularizer, enabling efficient mining of discriminative features without sacrificing computational efficiency.

Key Insights and Methodology

The paper identifies a redundancy in additional computations associated with optimizing mixed samples according to mixed labels, challenging the idea that label-mismatched samples should be avoided. The novel Decoupled Mixup (DM) objective function emphasizes retaining the original smoothness of mixup while leveraging hard mixed samples to uncover discriminative features. This is achieved by decoupling the mixup loss and introducing a regularizer that focuses on the informative value of hard mixed samples.

The Decoupled Mixup approach involves:

• Decoupled Regularizer: Enhancing the ability of models to identify discriminative features by using a regularizer that independently computes predicted probabilities for each class.
• Mixup Objective Function: DM balances smoothing of decision boundaries with identifying characteristics that enhance model confidence in predictions.

Results and Implications

Experiments on both supervised and semi-supervised learning benchmarks across seven datasets, including CIFAR-100 and ImageNet-1k, validate the efficacy of DM. The results suggest significant improvements across various tasks. For instance, DM enables static mixup methods to perform comparably to dynamic methods without additional computational overhead. The additional computational efficiencies translate into improved training times and prediction accuracies.

Key empirical results include:

• Improved training efficiency, enabling faster convergence compared to traditional and dynamic mixup methods.
• Enhanced performance accuracy by effectively utilizing hard mixed samples, especially in semi-supervised learning scenarios.

Implications for Future Research

The introduction of the decoupled regularizer in mixup methods suggests a compelling avenue for future mixup training objectives. The research opens several potential paths:

• Exploration of Hard Sample Mining: Further investigation into how models can autonomously adapt to dynamically identify and prioritize hard mixed samples.
• Integration into Other Learning Paradigms: The principles of DM could be extended to other domains where data augmentation plays a crucial role, such as natural language processing or advanced self-supervised learning tasks.
• Theoretical Underpinnings: An in-depth theoretical analysis of why decoupling enhances model confidence could yield insights applicable to broader areas of machine learning.

In conclusion, this paper contributes significantly to the field of data augmentation by presenting a practical, efficient approach that aligns with the goals of improving model generalization while maintaining computational efficiency. The research further invites exploration into simplifying complex methodologies while maximizing their impact, a principle that could reshape future AI model training paradigms.