KCTE-80
Thermal Imager
www.grupotemper.com
6.4-Lens
The Thermal Imager has a Lens.
FOV is the largest area that your imager can see at a set distance.
This table lists the horizontal FOV, vertical FOV and IFOV for lens.
Focal Length
Horizontal FOV
Vertical FOV
IFOV
9mm
17°
17°
3.78mrad
IFOV (Instantaneous Field of View) is the smallest detail within the FOV that can be detected or seen at a set
distance, the unit is rad. The formula is this:
IFOV = ( Pixel Size )/ ( Lens focal length );
D:S theoretical ( = 1/ IFOV theoretical) is the calculated spot size based on the pixel size of the Thermal
Imager detector array and lens focal length.
Example: If Thermal Imager uses 9mm lens, because the Pixel Size of detector is 34um. Horizontal FOV is
17°, Vertical FOV is 17°, the IFOV is
34um/9mm = 3.78mrad;
D:S theoretical ( = 1/ IFOV theoretical) = 265:1
Spot Size = 100.00cm*100.00cm
(Based upon IFOVtheoretical)
D:Smeasure ( = 1/ IFOV measure) is the spot size needed to provide an accurate temperature measure.
Typically, D:Smeasure is 2 to 3 times smaller than D:S theoretical, which means the temperature measurement
area of the target need to be 2 to 3 times larger than that determined by the calculated theoretical D:S.
Note:
IFOV theoretical represents the smallest objects that the thermal imager can detect or see. IFOV measure
represents the smallest object form which an accurate temperature can be measured by the thermal imager.
