Changing Object Parameters; General; Types Of Parameters; Recommended Values - FLIR T420 User Manual

16 Working with measurement tools
3. Move the joystick up/down and left/right to resize or move the tool.
4. When completed, push the joystick and select

16.5 Changing object parameters

16.5.1 General

For accurate measurements, you must set the object parameters.

16.5.2 Types of parameters

The camera can use these object parameters:
• External IR window compensation, i.e., the temperature of any protective windows, ex-
ternal lenses (e.g., the close-up lens), etc., that are set up between the camera and the
object of interest. If no protective window, protective shield, or external lens is used, this
value is irrelevant and should be left inactive.
• Object distance, i.e., the distance between the camera and the object of interest.
• Atmospheric temperature, i.e., the temperature of the air between the camera and the
object of interest.
• Relative humidity, i.e., the relative humidity of the air between the camera and the ob-
ject of interest.
• Reflected temperature, which is used when compensating for the radiation from the
surroundings reflected by the object into the camera. This property of the object is
called "reflectivity".
• Emissivity, i.e., how much radiation an object emits, compared with the radiation of a
theoretical reference object at the same temperature (called a "blackbody"). The oppo-
site of emissivity is reflectivity. The emissivity determines how much of the radiation
originates from the object as opposed to being reflected by it.
Note There is an Emissivity mode setting, which you can use to enter the emissivity
by material instead of by value. Select
> Emissivity mode > Select from materials table.
Of the object parameters, Emissivity is the most important parameter to set correctly. If the
Emissivity is set to a low value, the Reflected temperature also becomes important. The
parameters Object distance, Atmospheric temperature, and Relative humidity are relevant
for longer distances. The External IR window compensation must be activated if a protec-
tive window or external lens is used.

16.5.3 Recommended values

If you are unsure about the values, the following are recommended:
Object distance
Atmospheric temperature
Relative humidity
Reflected temperature
Emissivity

16.5.4 Procedure

You can set the object parameters globally. You can also change the Emissivity, Reflected
temperature, and Object distance parameters locally for a measurement tool.
#T559879; r. AO/35410/35410; en-US
(Done).
(Settings) > Device settings > Set up camera
1.0 m (3.3')
20°C (69°F)
50%
20°C (69°F)
0.95
45