Flir ThermovisionVoyager II Operators Manual

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Weather
Environmental conditions, including time of day, humidity, and 
precipitation, will aff ect image quality and contrast. Fog, smog and rain 
will decrease the range at which you can detect a given target. After sunset, 
objects warmed by the sun during the day will radiate their stored heat for 
several hours. Early in the morning, many of these objects will appear 
cooler than their surroundings, so be sure to look for subtle temperature 
diff erences in the scene, not just hot (white) targets. 
						

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MORE ABOUT INFRARED
At fi  rst blush, new technologies can appear intimidating. Infrared cameras 
may seem imposing, but they are not so diff  erent from digital camcorders. 
In fact, you can get years of enjoyable, productive use out of your Voyager 
without knowing anything in this section. But, if you would like to learn 
more about thermal imaging – how it was discovered and developed – 
read on.
Infrared – the early years
Th  e road to modern thermal imaging began way back in 1666, when Sir 
Isaac Newton used a prism to split white light into the colors of the rainbow.  
Today, we call this rainbow the 
“Visible Light Spectrum.”  
Newton’s experiment proved that 
sunlight was not an indivisible 
whole, as was once thought, but was 
made of a range of subtly diff erent 
light energies.
In 1800, Sir William Herschel 
took this discovery one step further, 
when he found that the diff erent 
colors of the Visible Light Spectrum 
have diff erent temperatures, which 
increase from the violet band of the 
spectrum to the red.
He did this by splitting sunlight 
with a prism and placing the 
darkened bulb of a thermometer in 
each color band.  When he moved 
a thermometer past the red color 
band, Herschel found that the 
energy beyond visible red light was 
warmer than the red light itself. His 
name for this energy was “Calorifi c 
Rays.” Today we call it “infrared 
radiation” or “thermal energy,” and 
use the two terms interchangeably. 
						

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High school physics revisited
Infrared radiation combines with Gamma rays, X-rays, Ultra Violet, 
Visible Light, Microwaves and Radio Waves to form a range of energy 
called the Electromagnetic Spectrum. 
Th  ese are not independent types of energy – in fact, the primary diff erence 
between each of these types of radiation is wavelength: Radio Waves have 
the longest wavelength and Gamma Rays have the shortest.  Wavelengths 
are measured in micrometers, or “microns” (μ), which are equal to one 
millionth of a meter. 
Infrared radiation wavelengths are longer than those of visible light. 
Visible light wavelengths range from 0.4μ to 0.75μ, while infrared is 
between 1μ and 15μ. Th  ermal imagers make pictures from either the 3-5μ 
range (called mid-wave IR [MW IR]), or the 8-12μ range (called long-
wave IR [LWIR]).
Th  ermal images may look like black & white photographs, but the two 
types of images are actually quite diff erent. Photographic cameras create 
images from refl ected light energy, while infrared cameras create images 
from radiated thermal energy.
Th  e amount of radiated thermal energy that reaches the Voyager’s imager 
is a function of the viewed object’s temperature and emissivity. Th is 
relationship between temperature and emissivity can be a complex one, 
but we’ ll sum it up with two basic rules: 
1) Th  e hotter an object gets, the more infrared energy it radiates. Even 
a small increase in temperature can result in a dramatic increase in the 
amount of radiated thermal energy. 
						

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2) At a given temperature, the amount of thermal energy radiated by an 
object depends on its emissivity. Emissivity is the measure of an object’s 
effi  ciency at radiating thermal energy.  For example, shiny metals are poor 
emitters.  Instead of radiating their own thermal energy, they tend to 
refl ect radiation from their surroundings. 
Infrared, from theory to practical application
Infrared imagers operate by detecting the relative intensities of thermal 
energy radiated from the surfaces of objects, and displaying these intensities 
in black and white video as shades of gray.  Th  ey do not show a “heat 
picture.”  Even if an object is very hot, it may not display well if there is 
little or no temperature contrast between the object and its surroundings.
Th  ermal imagers primarily detect thermal energy radiated from an object’s 
surface; thermal imagers can’t “see through” much of anything, except 
some plastics and nylon materials. 
As you look at the thermal images created with your Voyager, you will 
see multiple sources of thermal energy in addition to your main object of 
interest.  When looking at a scene with a large number of heat sources, it 
can get confusing trying to sort it all out.  Kirchhoff  ’s Law is an easy way 
to account for the diff erent sources of thermal radiation you see in your 
images.  Kirchhoff  says that all of the thermal radiation in an image has 
been Emitted (given off  by an object), Transmitted (passed through an 
object), or Refl ected (bounced off  an object). 
Most of the strong energy sources you will see in a given scene are from 
“emitted ” energy. Th  at is, they are giving off  heat energy. Examples of 
strong emitters of thermal energy include people and boat engines.  
						

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Th  ermal energy doesn’t pass through much, but it does “transmit” through 
some plastics. When a material is not transparent to infrared radiation, 
it is said to be “opaque.” Most commonly viewed materials are opaque to 
infrared radiation.
Materials that mirror the infrared signatures around them are “refl ective.”  
Ever y thing is refl ective to one degree or another, but the most highly 
refl ective objects are those made of polished, unpainted metal.  Painted 
metals, glass, and even wood can display greater or lesser degrees of 
refl ectivity, but this becomes dependent upon myriad factors like their 
surface coatings, textures, and the angles from which they are viewed. 
Refl ections can appear hotter or colder than they really are, based on 
what they are refl ecting. Sun refl ecting off  of polished chrome looks quite 
bright, and a common mistake is to think that this section of chrome 
has suddenly become very hot. It hasn’t, it is just refl ecting energy from 
the sun. Look also at the two images on the previous page, and note the 
refl  ections of thermal energy from the bridge and boat off   the water, which 
can readily refl ect thermal energy. 
Another reason to care about the weather
Th  e time of day and weather conditions in which you use your Voyager can 
have a signifi cant infl uence on how objects look on the screen. Remember 
that thermal imagers detect and display diff erences in infrared radiation. 
If an object and its background do not display any appreciable temperature 
diff erence, that object will be very diffi  cult to detect. Th  erefore, the time 
of day during which your Voyager is used can have a direct impact on your 
ability to detect and recognize objects. 
When things are exposed to the sun, they absorb infrared radiation. As the 
duration of this exposure increases throughout the day, thermal contrast 
between targets decreases. 
When the sun begins to set, objects begin to cool. In doing so they radiate 
some of this stored thermal energy back into the atmosphere, and a certain 
degree of thermal contrast is restored.  Th  is increase in contrast continues 
until the sun comes up the following morning. Th  is daily sequence of 
heating and cooling is called the “Diurnal Cycle.”
Atmospheric conditions can limit the range and imaging performance of 
your Voyager. Under ideal conditions, most of the infrared energy radiated 
from an object gets through the atmosphere and to the imager.  
						

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Under typical conditions however, atmospheric moisture and dust scatter 
can absorb some of the radiated energy before it reaches the imager. Th e 
eff  ect of this is to weaken the overall thermal signal and shorten the range 
at which you can detect it.
Th  e weather can impact more than just the range at which the Voyager can 
detect a specifi  c object – it can also aff  ect an entire scene’s thermal contrast 
and aff ect overall system performance.
Cloud cover aff ects the diurnal cycle in two ways:
First, cloud cover decreases the amount of solar radiation allowed to strike 
the earth’s surface, keeping days cooler and nights warmer.
Second, clouds form a layer of insulation over the earth that prevents heat 
from being radiated back into space at night.
Like clouds, humidity tends to reduce contrast and wash out the eff ects 
of the diurnal cycle.  While humidity doesn’t block out solar radiation 
during the day, it does tend to keep nights warmer.  
Rain acts diff erently because water tends to cool the surfaces it touches.  
Remember that thermal imagers only detect diff  erences in thermal energy 
radiated from an object’s surface; therefore, rain can markedly reduce a 
scene’s contrast.  While rain reduces contrast between objects with no 
heat source, it will allow objects with a heat source (like, people, animals, 
running vehicles, some structures) to show up with even more contrast to 
their now-cooler surroundings.
Conclusion
If you see something through your Voyager that looks suspicious, it is best 
to play it safe and steer clear of it. You will likely run into situations where 
even the Voyager will not provide a perfect image of what is ahead of you. 
But in most conditions it should serve you well as a valuable addition to 
your navigation tools. ! 
						

							APPENDIX
PARTS LIST AND ACCESSORIES
SYSTEM OVERVIEW 
						

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APPENDIX
Parts List
Th  e Voyager includes the following thermal imaging components:
If the components you have are diff erent from those enumerated in this parts list, 
please call us immediately at 888.747.3547.
Vo y a g e rFLIR Part Number
Camera Body7. 3 ”x 4 . 0 ”x 8 . 0 ”
432-0002-01-00
432-0002-01-00S
432-0002-02-00
432-0002-02-00S
Bulkhead Box6lb500-0348-00
Joystick Control Unit (JCU)500-0353-00
Camera Cable
50’ 
or 
10 0 ’308-0149-50
or 
308-0149-100
JCU Cable10 0 ’ 308- 0139- 0 0
Operator’s Manual432-0002-00-11 
Accessories
Dual Control Station Accessory KitJCU, 100’ cable (one end terminated)500-0353-00
JCU Ex tension Cable
terminated both ends6lb308-0139-101 
						

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SYSTEM OVERVIEW 
Size15” x 23”
Weight45 lb.
Azimuth Field-of-Regard360° Continuous
Elevation Field-of-Regard+/-90°
Slew RateVariable to 120°/sec.
Thermal Imaging Performance
Sensor Type2 Microbolometer Cameras
Wide FOV Imager20° x 15° (35mm) 
Narrow FOV Imager5° x 3.75° (140mm)
Spectral Range7.5 to 13.5 μm
Daylight Imaging Performance
Sensor Type1/4” Super HAD
Wide FOV Limit42° horiz. @ F1.6
Narrow FOV Limit1.6° horiz. @ F3.8
System Speci cations
Pan/Tilt Coverage360° Az./ +/-90° El.
Video outputNTSC or PAL
Power Requirements24VDC
Environmental
Operating Temp. Range-28°C to 55°C
Non-Operating Temp. Range-50°C to 85°C
VibrationPer MIL-STD-810
Vo y a g e r  II™