CPC G01B 9/02092 (2013.01) [G01P 5/26 (2013.01); G01S 17/58 (2013.01)] | 20 Claims |
1. A device, comprising:
a frame;
an optical element attached to the frame and having a known optical thickness between a first surface and a second surface of the optical element;
an SMI sensor attached to the frame and configured to,
emit a modulated beam of electromagnetic radiation toward the first surface of the optical element; and
generate an SMI signal containing disturbances caused by reflections or backscatters of the modulated beam of electromagnetic radiation from the first surface and the second surface; and
a processor configured to,
relate the disturbances to the known optical thickness of the optical element; and
determine a distance between two objects using the SMI signal and the relationship of the disturbances to the known optical thickness of the optical element.
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