We present an outdoor photometric stereo method using images captured in a single day. We simulate a sky hemisphere for each image according to its GPS and timestamp and parameterize the obtained sky hemisphere into quadratic skylight and Gaussian sunlight distributions. Our previous work recovered an outdoor scene on a clear day, whereas the current paper shows that cloudy days can provide better illumination conditions for surface orientation recovery, and hence we propose a modified sky model to represent a well-conditioned skylight distribution for outdoor photometric stereo. The proposed method models natural illumination according to a sky model, providing sufficient constraints for shape reconstruction from 1-day images. We tested the proposed method to recover various sized objects and scenes from real-world outdoor daylight images and verified the method using synthetic and real data experiments.

中文翻译：

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使用天窗估计的一日室外光度立体

我们使用一天内捕获的图像提出了一种室外光度立体方法。我们根据每个图像的 GPS 和时间戳为每个图像模拟一个天空半球，并将获得的天空半球参数化为二次天光和高斯阳光分布。我们之前的工作在晴朗的日子恢复了室外场景，而当前的论文表明阴天可以为表面方向恢复提供更好的照明条件，因此我们提出了一个修改后的天空模型来表示室外光度立体的良好条件的天光分布. 所提出的方法根据天空模型对自然光照进行建模，为 1 天图像的形状重建提供了足够的约束。