gray threshold

例句：

1. 1.The gray threshold between light and dark is where everything in between exists.
   光与暗之间的灰色区域是介于两者之间的一切存在的。
2. 2.In color science, the gray threshold is the point at which a color changes from one to another.
   在颜色科学中，灰色阈值是指一种颜色从另一种颜色过渡的点。
3. 3.The gray threshold for detecting a signal can be adjusted based on the sensitivity of the detector.
   检测信号的灰色阈值可以根据探测器的灵敏度进行调整。