Revisiting Supervised Learning-Based Photometric Stereo Networks

Deep learning has significantly propelled the development of photometric stereo by handling the challenges posed by unknown reflectance and global illumination effects. However, how supervised learning-based photometric stereo networks resolve these challenges remains to be elucidated. In this paper, we aim to reveal how existing methods address these challenges by revisiting their deep features, deep feature encoding strategies, and network architectures. Based on the insights gained from our analysis, we propose ESSENCE-Net, which effectively encodes deep shading features with an easy-first-encoding strategy, enhances shading features with shading supervision, and accurately decodes normal with spatial context-aware attention. The experimental results verify that the proposed method outperforms state-of-the-art methods on three benchmark datasets, whether with dense or sparse inputs.