photoelectric comparator

例句：

1. 1. The photoelectric comparator is used to comparethe brightness of two images.
   光电比较器用于比较两幅图像的亮度。
2. 2.The photoelectric comparator was usedto measure the distance between the two points.
   光电比较器被用来测量两点之间的距离。
3. 3.The photoelectric comparator was usedto detect the presence of a target objectin the scene.
   光电比较器被用来检测场景中目标物体的存在。