I turned to the optical sensors for confirmation, and found it there also.

Why were the optical sensors and the mass detector at odds with each other?

I cannot clearly see directly with my own optical sensors what is happening ahead.

The high measurement rate of optical sensors is well suited for this task.

There were so many places that could shelter a small body from the optical sensors.

First in 3V, then through his own optical sensors.

Instead, optical sensors monitor the film position and its passage through the camera.

An optical sensor is placed above or under the web to be controlled.

Might do some damage if it hit an optical sensor.

Wait a second, he thought, increasing the magnification on his optical sensors.