Opti-Logic micro series Operating Instructions Manual page 6

Distance Measuring w/ Time-of-Flight Rangefinders:
• Opti-Logic Ballistics Compensated Laser Rangefinders emit invisible, eye-safe pulses of
infrared light. Distances are determined by reflecting the laser beam off an object and mea-
suring the round-trip time-of-flight of the laser beam to and from the object. The laser beam
emitted by the rangefinder is in the form of a vertical stripe of invisible light, which enhances
the rangefinder's ability to hit thin vertical targets. The maximum distance measurable by
any laser rangefinder is determined by several factors including the size, shape, reflectivity,
and orientation of the object as well as atmospheric conditions. Color and surface finish of
the target also affect the reflectivity and therefore can influence the range as well. A good
quality target is a non-gloss (matte) object that is light in color and has enough surface area
for the laser beam to efficiently reflect back to the rangefinder.
• Vertical objects tend to make better targets than horizontal ones. White objects tend to
range farther than black objects. Target surfaces that are perpendicular to the laser beam are
better than surfaces tilted away from the rangefinder. Targets made of "retro-reflectors"
provide the greatest range capability.
• Retro-reflectors are made of special materials designed to reflect light back toward the
light source, for example, stop signs, street signs, license plates, and specially made Opti-
Logic retro-reflectors. Contrary to expectation, extremely glossy surfaces like windows and
mirrors do not make good targets, because they tend to reflect light away from the
instrument.
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