HT instruments THT60 - Manual (Page 30)

THT47 - THT60
EN - 28
5.2.2.5 Control parameters of temperature measurement
The thermal camera allows correcting the measured value of temperature by means of the
tools (Spots, Lines and Areas) in the following ways:
 Global mode  the values of the control parameters associated to all tools are defined
globally.
 Custom mode  each tool may independently take different values of control
parameters according to the selections made by the user.
Parameter Emissivity
In order to carry out accurate temperature measurements, it is important to define the
correct emissivity value (
), which represents the ability of a body to emit infrared radiation,
according to the kind of material the measured object is made of Table 2 shows the
emissivity values for the most common materials. Emissivity takes values between 0
(mirror or perfectly reflecting surface) and 1 (perfectly radiating blackbody). Most of the
painted or oxydized surfaces have an emissivity value of approximately 0.95.
Material

Material

Black body 1 00 Steel (oxidized) 0.79
Smooth carbon surface 0.98 Very oxydized copper 0.78
Ice crystals 0.98 Cotton cloth 0.77
Human skin 0.98 Sand 0.76
Slate 0.97 Non-enameled silicone 0.75
Distilled water 0.96 Oxydized iron at 100°C 0.74
Smooth ice 0.96 C20A coating 0.73
Wet ground 0.95 Basalt 0.72
Carbon soot 0.95 Graphitized carbon at 500°C 0.71
Clean glass plate 0.94 Red rust 0.70
Paint, oil 0.94 Very rusty iron 0.69
Red brick 0.75 Water 0.67
White paper 0.93 Black soil 0.66
Cement 0.97 White cement 0.65
Dry ground 0.92 Oxydized wrought iron 0.64
Rough plaster coating 0.91 Oxydized lead at 1100°Z 0.63
Oak wood 0.90 Zirconium on inconel 0.62
Enameled earthenware 0.90 Oxydized copper-zinc 0.61
Firn 0.89 Inconel sheets at 760°C 0.58
Enameled silicone 0.88 Dressed white marble 0.56
Copper oxyde at 38°C 0.87 Anodized chrome 0.55
Ground corundum 0.86 Clean wrought iron 0.21
Snow 0.85 Ground brass 0.20
Oxydized stainless steel at
800°C
0.85 18-8 stainless steel 0.16
Oxydized iron at 500°C 0.84 Coarse aluminium 0.09
Oxydized copper at 260°C 0.83 Clean steel 0.07
Fine snow 0.82 Clean aluminium 0.05
Non-oxydized brass 0.81 Clean copper 0.05
D convex glass 0.80 Bright brass 0.03
Table 2: Emissivity values of typical materials
Associated to each control tool (Spots, Lines, Areas) there is an internal table from which
to select the emissivity value of common materials and define a custom value (see §
5.2.2.1, § 5.2.2.2 and § 5.2.2.3).