Towards Machine Unlearning Benchmarks: Forgetting the Personal Identities in Facial Recognition Systems
Dasol Choi, Dongbin Na
TL;DR
This paper critiques the prevalence of class-based unlearning benchmarks and introduces task-agnostic benchmarks MUFAC and MUCAC to study forgetting personal identities while preserving the original facial recognition tasks. It defines evaluation via model utility and a forgetting score derived from a Membership Inference Attack, combined into a Normalized Machine Unlearning Score (NoMUS). Through experiments with multiple unlearning methods, including an Enhanced NegGrad, the authors demonstrate that some state-of-the-art approaches underperform in these realistic settings. The work provides public datasets, code, and trained models to advance research in privacy-preserving and robust machine unlearning for facial analysis tasks.
Abstract
Machine unlearning is a crucial tool for enabling a classification model to forget specific data that are used in the training time. Recently, various studies have presented machine unlearning algorithms and evaluated their methods on several datasets. However, most of the current machine unlearning algorithms have been evaluated solely on traditional computer vision datasets such as CIFAR-10, MNIST, and SVHN. Furthermore, previous studies generally evaluate the unlearning methods in the class-unlearning setup. Most previous work first trains the classification models and then evaluates the machine unlearning performance of machine unlearning algorithms by forgetting selected image classes (categories) in the experiments. Unfortunately, these class-unlearning settings might not generalize to real-world scenarios. In this work, we propose a machine unlearning setting that aims to unlearn specific instance that contains personal privacy (identity) while maintaining the original task of a given model. Specifically, we propose two machine unlearning benchmark datasets, MUFAC and MUCAC, that are greatly useful to evaluate the performance and robustness of a machine unlearning algorithm. In our benchmark datasets, the original model performs facial feature recognition tasks: face age estimation (multi-class classification) and facial attribute classification (binary class classification), where a class does not depend on any single target subject (personal identity), which can be a realistic setting. Moreover, we also report the performance of the state-of-the-art machine unlearning methods on our proposed benchmark datasets. All the datasets, source codes, and trained models are publicly available at https://github.com/ndb796/MachineUnlearning.
