shadow region

基本解释

The diffraction effect is the phenomenon of wave propagation into shadow region.
衍射则是电波绕射传播到遮蔽区的现象。
The recognition results show that 40 features are effective on the target region and is not useful on the shadow region.
最终识别结果是：图像中目标区域的40个特征组合可以达到较高的识别概率，而阴影区域的40个特征组合的识别概率比较低。
Wave optics, however, tells us that no sharp shadows can exist , since some of the light does reach into the geometrical shadow region.
而波动光学却告诉我们，清晰的阴影绝不会存在，因为有一些光会进入几何阴影区域之内。

For decades, the conflict between Israelis and Arabs has cast a shadow over the region.
WHITEHOUSE: Moment of Opportunity: American Diplomacy in the Middle East & North Africa The White House
But BP's disastrous oil spill in the Gulf of Mexico has cast another dark shadow over the region.
ECONOMIST: New Orleans five years after Katrina