LTI TruSense S300 Series Integration Manual 3nd Edition
Page 74
Copyright © [2016] Laser Technology, Inc. All Rights Reserved. Unauthorized duplication, in whole or in part, is strictly prohibited.
Frequency:
the number of repeating events per unit of time. A 14 Hz laser firing rate means a
laser is firing 14 times per second.
Gage height:
also known as Stage, it is the height of the water in the stream above a reference
point. Gage height refers to the elevation of the water surface in the specific pool at the stream
gaging station, not along the entire stream. Gage height also does not refer to the depth of the
stream. Measurements of gage height are continually recorded by equipment inside a gage-house
on the streambank.
Harsh ambient conditions
: the challenging atmosphere between the sensor and a target.
Infrared
light
: invisible light with wavelengths roughly between 700 nm and 1550 nm.
Instrument Offset:
allows the user to add or subtract a fixed constant to the measurement. An
offset is generally used to compensate for the sensor being in a different location from the desired
zero point of an intended target. An offset value can be a positive or negative number.
Laser
: acronym for light amplification by stimulated emission of radiation. A device that produces
a monochromatic coherent beam of light by energizing atomic energy levels.
Lens:
an optical element that converges or diverges light.
Maximum range:
the maximum distance the sensor can acquire a measurement.
Measurement Span
: the distance between the maximum (full) and minimum (empty) levels of
the intended target.
Minimum range:
accuracy may be compromised if a measurement is made from less than this
distance.
Non-contact:
a measurement made without a sensor touching the target. A preferred
measurement method in many applications.
Non-Cooperative target:
a target not designed to reflect light and that has less than 90%
reflectivity.
Opacity:
the degree to which light is not allowed to travel through.
Parallax:
displacement or difference in a focus along two different optical axes; e.g., closing the
left eye and viewing an object with the right eye-the object will appear to shift when the right eye
is closed and viewed with the left eye.
Precision:
the repeatability of a series of test results; whether the method gives the same answer
under the same set of circumstances or sampling criteria.
Reflectance:
the fraction of incident light returned by a surface. Higher target reflectance will
increase range. General surface reflectance (R) ratios are: reflective=90+%, white=90%,
gray=20%, black=5%.
Refraction:
the change in direction of light as it passes from one medium to another of a
different density; e.g., from air to liquid surface.
