Robust Semi-Supervised Anomaly Detection via Adversarially Learned Continuous Noise Corruption
This work addresses the problem of robust anomaly detection for applications like industrial inspection and plant disease detection, offering an incremental improvement over prior adversarial training methods by enhancing efficiency and performance.
The paper tackles overfitting in deep autoencoders for anomaly detection by introducing Adversarially Learned Continuous Noise (ALCN) to corrupt inputs before denoising, resulting in improved AUC scores across datasets such as MNIST (up to 0.989), CIFAR-10 (up to 0.742), MVTEC-AD (0.780), and Plant Village (0.770).
Anomaly detection is the task of recognising novel samples which deviate significantly from pre-establishednormality. Abnormal classes are not present during training meaning that models must learn effective rep-resentations solely across normal class data samples. Deep Autoencoders (AE) have been widely used foranomaly detection tasks, but suffer from overfitting to a null identity function. To address this problem, weimplement a training scheme applied to a Denoising Autoencoder (DAE) which introduces an efficient methodof producing Adversarially Learned Continuous Noise (ALCN) to maximally globally corrupt the input priorto denoising. Prior methods have applied similar approaches of adversarial training to increase the robustnessof DAE, however they exhibit limitations such as slow inference speed reducing their real-world applicabilityor producing generalised obfuscation which is more trivial to denoise. We show through rigorous evaluationthat our ALCN method of regularisation during training improves AUC performance during inference whileremaining efficient over both classical, leave-one-out novelty detection tasks with the variations-: 9 (normal)vs. 1 (abnormal) & 1 (normal) vs. 9 (abnormal); MNIST - AUCavg: 0.890 & 0.989, CIFAR-10 - AUCavg: 0.670& 0.742, in addition to challenging real-world anomaly detection tasks: industrial inspection (MVTEC-AD -AUCavg: 0.780) and plant disease detection (Plant Village - AUC: 0.770) when compared to prior approaches.