illumination invariant的用法和樣例：
例句
- Shadow detection was performed in every block based on the illumination invariant between the shadow region and the corresponding background region.
對其中的每一塊，根據陰影區域和相對應的背景區域之間的光照不變性進行陰影檢測。 - The singular threshold is uneffective because the image is very different in illumination.
由於角膜細胞圖象的光照不均勻，用單一域值無法兼顧亮區與暗區。
