Proximity-based density description with regularized reconstruction algorithm for anomaly detection

This study addresses unsupervised anomaly detection using one-class classification, which constructs a decision boundary to determine if a new instance belongs to the target class. Existing one-class classification methods often fail in real-world scenarios due to their sensitivity to noise and inability to handle complex structures. We propose a proximity-based density description with a regularized reconstruction algorithm to overcome these limitations. Our method defines density-descriptive coefficients to reconstruct initial density and derives optimal coefficients by minimizing reconstruction error subject to sparsity and smoothness constraints. The sparsity constraint reduces noise effects, while the smoothness constraint encourages a flexible decision boundary. We evaluate our algorithm on benchmark datasets and compare it to existing methods, demonstrating superior performance. •We propose a density-based OCC method, PDDRR, for anomaly detection.•We formulate the method as a density reconstruction subject to sparsity and smoothness.•The proposed method adeptly handles complex data distribution and robust to noise.•Experimental studies demonstrate our method outperforms the existing methods.