Product Manual
Table Of Contents
- 1 Disclaimers
- 2 Safety information
- 3 Notice to user
- 4 Customer help
- 5 Quick Start Guide
- 6 Description
- 7 Operation
- 7.1 Charging the battery
- 7.2 Turning on and turning off the camera
- 7.3 Saving an image
- 7.4 Recalling an image
- 7.5 Deleting an image
- 7.6 Deleting all images
- 7.7 Measuring a temperature using a spotmeter
- 7.8 Measuring the hottest temperature within an area
- 7.9 Measuring the coldest temperature within an area
- 7.10 Hiding measurement tools
- 7.11 Changing the color palette
- 7.12 Changing image mode
- 7.13 Changing the temperature scale mode
- 7.14 Setting the emissivity as a surface property
- 7.15 Setting the emissivity as a custom material
- 7.16 Changing the emissivity as a custom value
- 7.17 Changing the reflected apparent temperature
- 7.18 Changing the settings
- 7.19 Updating the camera
- 8 Technical data
- 9 Declaration of conformity
- 10 Cleaning the camera
- 11 Application examples
- 12 About FLIR Systems
- 13 Glossary
- 14 Thermographic measurement techniques
- 15 History of infrared technology
- 16 Theory of thermography
- 17 The measurement formula
- 18 Emissivity tables
Theory of thermography
16
Figure 16.5 Wilhelm Wien (1864–1928)
The sun (approx. 6 000 K) emits yellow light, peaking at about 0.5 μm in the middle of
the visible light spectrum.
At room temperature (300 K) the peak of radiant emittance lies at 9.7 μm, in the far infra-
red, while at the temperature of liquid nitrogen (77 K) the maximum of the almost insignif-
icant amount of radiant emittance occurs at 38 μm, in the extreme infrared wavelengths.
Figure 16.6 Planckian curves plotted on semi-log scales from 100 K to 1000 K. The dotted line represents
the locus of maximum radiant emittance at each temperature as described by Wien's displacement law. 1:
Spectral radiant emittance (W/cm
2
(μm)); 2: Wavelength (μm).
16.3.3 Stefan-Boltzmann's law
By integrating Planck’s formula from λ = 0 to λ = ∞, we obtain the total radiant emittance
(W
b
) of a blackbody:
This is the Stefan-Boltzmann formula (after Josef Stefan, 1835–1893, and Ludwig Boltz-
mann, 1844–1906), which states that the total emissive power of a blackbody is propor-
tional to the fourth power of its absolute temperature. Graphically, W
b
represents the
area below the Planck curve for a particular temperature. It can be shown that the radiant
emittance in the interval λ = 0 to λ
max
is only 25% of the total, which represents about the
amount of the sun’s radiation which lies inside the visible light spectrum.
#T559828; r. AC/ 9610/10386; en-US
43