Prior Distribution and Model Confidence

Maksim Kazanskii, Artem Kasianov

Keywords: Out-of-Distribution Detection, OOD, Confidence Estimation, Representation Geometry, Embedding Space Analysis, Nearest-Neighbor Methods, Distribution Shift, Self-Supervised Learning, Image Classification

TL;DR: Embedding Density estimates prediction confidence by distance to the training distribution in embedding space. Without retraining, filtering low-density samples improves accuracy and provides competitive OOD detection.

Abstract: We study how the training data distribution affects confidence and performance in image classification models. We introduce Embedding Density, a model-agnostic framework that estimates prediction confidence by measuring the distance of test samples from the training distribution in embedding space, without requiring retraining. By filtering low-density (low-confidence) predictions, our method significantly improves classification accuracy. We evaluate Embedding Density across multiple architectures and compare it with state-of-the-art out-of-distribution (OOD) detection methods. The proposed approach is potentially generalizable beyond computer vision.

Submission Number: 12