User Manual
Table Of Contents
- 1 Legal disclaimer
- 2 Warnings & Cautions
- 3 Notice to user
- 4 Customer help
- 5 Quick Start Guide
- 6 Parts lists
- 7 A note about ergonomics
- 8 Camera parts
- 9 Screen elements
- 10 Navigating the menu system
- 11 External devices and storage media
- 12 Pairing Bluetooth devices
- 13 Configuring Wi-Fi
- 14 Fetching data from external Extech meters
- 15 Handling the camera
- 15.1 Charging the battery
- 15.2 Inserting the battery
- 15.3 Removing the battery
- 15.4 Turning on and turning off the camera
- 15.5 Adjusting the angle of lens
- 15.6 Mounting an additional lens
- 15.7 Removing an additional infrared lens
- 15.8 Attaching the sunshield
- 15.9 Using the laser pointer
- 15.10 Calibrating the compass
- 15.11 Calibrating the touchscreen LCD
- 16 Working with images and folders
- 17 Working with fusion
- 18 Working with video
- 19 Working with measurement tools and isotherms
- 20 Annotating images
- 21 Programming the camera
- 22 Changing settings
- 23 Cleaning the camera
- 24 Technical data
- 25 Pin configurations
- 26 Dimensions
- 27 Application examples
- 28 About Flir Systems
- 29 Glossary
- 30 Thermographic measurement techniques
- 31 History of infrared technology
- 32 Theory of thermography
- 33 The measurement formula
- 34 Emissivity tables
Theory of thermography32
Figure 32.9 Spectral emissivity of three types of radiators. 1: Spectral emissivity; 2: Wavelength; 3: Black-
body; 4: Graybody; 5: Selective radiator.
32.4 Infrared semi-transparent materials
Consider now a non-metallic, semi-transparent body – let us say, in the form of a thick flat
plate of plastic material. When the plate is heated, radiation generated within its volume
must work its way toward the surfaces through the material in which it is partially ab-
sorbed. Moreover, when it arrives at the surface, some of it is reflected back into the interi-
or. The back-reflected radiation is again partially absorbed, but some of it arrives at the
other surface, through which most of it escapes; part of it is reflected back again.
Although the progressive reflections become weaker and weaker they must all be added
up when the total emittance of the plate is sought. When the resulting geometrical series
is summed, the effective emissivity of a semi-transparent plate is obtained as:
When the plate becomes opaque this formula is reduced to the single formula:
This last relation is a particularly convenient one, because it is often easier to measure re-
flectance than to measure emissivity directly.
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