Tangentially Aligned Integrated Gradients for User-Friendly Explanations
To address the subjectivity and instability of baseline selection in Integrated Gradients (IG), which often leads to explanations misaligned with the underlying data manifold, this paper proposes an automatic baseline optimization method guided by **maximizing tangential alignment**. We formally define the alignment degree of explanation vectors within the Riemannian tangent space of the data manifold, derive the theoretical conditions under which IG vectors lie in this tangent space, and design a differentiable approximation enabling end-to-end optimization. Unlike conventional approaches relying on heuristic baselines (e.g., zero vector or dataset mean), our method requires no manual baseline specification and seamlessly integrates into the standard IG framework. Experiments on ImageNet and CIFAR-10 demonstrate substantial improvements in explanation consistency, stability, and human interpretability over zero-baseline IG, mean-baseline IG, and Grad-CAM, empirically validating the effectiveness of manifold-aware attribution.