Real-world supervision is often soft or uncertain due to annotator disagreement, class ambiguity, and distribution shift, yet most dimensionality-reduction methods and classical Neighborhood Components Analysis (NCA) in particular, assume hard labels. We propose Fuzzy Neighborhood Components Analysis (Fuzzy-NCA), a linear metric-learning method that directly optimizes a stochastic k-Nearest Neighbors (kNN) objective under fuzzy supervision. Each sample carries a row-stochastic membership vector over classes; pairwise supervision is defined by a principled fuzzy overlap between membership vectors, optionally sharpened by a power parameter to emphasize confident assignments. Ambiguous anchors can be attenuated via an entropy-based reliability weight, yielding an objective that maximizes a reliability-weighted expected fuzzy hit rate. The formulation reduces exactly to classical NCA when memberships are one-hot and admits a closed-form gradient, enabling efficient optimization with standard first-order methods. To scale training, we restrict stochastic neighbors to an input-space k-nearest-neighbor graph, which preserves local geometry while reducing the per-iteration complexity from quadratic to near-linear in the dataset size. The framework is compatible with multiple ways of constructing fuzzy supervision including label smoothing, fuzzy kNN, calibrated posteriors, and type-2 fuzzy reductions making it broadly applicable. Empirically, across a diverse suite of benchmarks, Fuzzy-NCA yields stable, discriminative embeddings under noisy or ambiguous labels, improving both linear separability and neighborhood quality and exhibiting consistent robustness across settings.
扫码关注我们
求助内容:
应助结果提醒方式:
