visual contrast threshold

例句：

1. 1.The visual contrast threshold between the two colors is very low.
   这两种颜色的视觉对比阈值非常低。
2. 2.The scientist found that the visual contrast threshold for red and green was about 50% less than what he expected.
   科学家发现红色和绿色之间的视觉对比阈值比预期的少了大约50%。
3. 3. The visual contrast threshold can be adjusted by adjusting the brightness of the display.
   通过调整显示器的亮度可以调整视觉对比阈值。