The standard photometric stereo model makes several assumptions that are rarely verified in experimental datasets. In particular, the observed object should behave as a Lambertian reflector and the light sources should be positioned at an infinite distance from it, along a known direction. Even when Lambert's law is approximately fulfilled, an accurate assessment of the relative position between the light source and the target is often unavailable in real situations. The Hayakawa procedure is a computational method for estimating such information directly from the data images. It occasionally breaks down when some of the available images deviate too much from ideality. Indeed, in narrow shooting scenarios, typical, e.g., of archaeological excavation sites, it may be impossible to position a flashlight at a sufficient distance from the observed surface. It is then necessary to understand if a given dataset is reliable and which images should be selected to better reconstruct the target. In this paper, we propose some algorithms to perform this task and explore their effectiveness.

翻译：标准光度立体模型包含若干假设，这些假设在实验数据集中很少得到验证。具体而言，观测对象应表现为朗伯反射体，且光源需位于无穷远处并沿已知方向照射。即使朗伯定律近似成立，在实际情境中通常也难以准确评估光源与目标之间的相对位置。早川算法是一种直接从数据图像估算此类信息的计算方法。当部分可用图像过度偏离理想状态时，该算法偶尔会失效。事实上，在狭窄拍摄场景（例如考古发掘现场）中，手电筒可能无法放置在距观测表面足够远的位置。因此需要判断给定数据集是否可靠，并筛选出能更好重建目标的图像。本文提出若干实现该目标的算法，并探索其有效性。