illumination invariant的用法和样例：
例句
- Shadow detection was performed in every block based on the illumination invariant between the shadow region and the corresponding background region.
对其中的每一块，根据阴影区域和相对应的背景区域之间的光照不变性进行阴影检测。 - The singular threshold is uneffective because the image is very different in illumination.
由于角膜细胞图象的光照不均匀，用单一域值无法兼顾亮区与暗区。
