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converted to a distance, based on the following equation:
The difficulty in implementing the direct time-of-flight measurement method resides in
the time intervals to be measured. In order to resolve a distance to centimeter-level
accuracy, the required accuracy for the timers is 67 ps. Implemented in digital logic,
this would require a 15 GHz clock speed, which is obviously not practical. Therefore,
various time-to-digital conversion methods are typically used.
5.1.2 Range-gated Imaging ToF
Whereas direct time-of-flight relies on measurements made on the immediate value of
the received signal, range-gated imaging uses signal integration methods, typically
with CCD or CMOS imagers.
