natural color images (MS COCO)
stripping widening casts too aggressively. It trusted the cast metadata
，推荐阅读91视频获取更多信息
Amanda Silberling
\(\biggl| r \cdot b - a \biggr| = \biggl| \frac{p}{q} \cdot b - a \biggr| = \biggl| \frac{b \cdot p - a \cdot q}{q} \biggr| \)