FLIR GF7 Series, Руководство пользователя

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Working with measurement tools 18
• 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 op-
posite 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 ( Settings ) > Device settings > User inter-
face options > Emissivity mode > Select from materials table .
Emissivity is the most important measurement 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 protective win-
dow or external lens is used.
18.5.3 Recommended values
If you are unsure about the values, the following are recommended:
Object distance 1.0 m (3.3 ft.)
Atmospheric temperature 20°C (69°F)
Relative humidity 50%
Reflected temperature 20°C (69°F)
Emissivity 0.95
18.5.4 Procedure
You can set the measurement parameters globally. You can also change the Emissivity ,
Reflected temperature , and Object distance parameters locally for a measurement tool.
Local parameters are normally only effective for a fixed setup, where each measurement
tool is set for a specific object of interest. For a general handheld application, the global
parameters are usually sufficient.
Note Emissivity and Reflected temperature are the two most important measurement
parameters to set correctly in the camera.
18.5.4.1 Setting global parameters
Follow this procedure:
1. Push the navigation pad to display the menu system.
2. Select ( Measurement parameters ) and push the navigation pad. This displays a
submenu.
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