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Calibir GXM640 IR Camera User's Manual
Introduction to Microbolometers
21
The following images demonstrate the effect of this reflected energy; depending on the
angle, the stainless steel blade reflects the heat from the nearby hot object onto the IR
sensor making it appear hotter than it actually is. Note that the reflection on the angled
blade shows the difference in emissivity between the camera body and the Teledyne
DALSA logo paint.
Flat blade
Angled blade reflecting energy
Emissivity tables for many types of material are available from a variety of sources. The
following table lists approximate emissivity values for some common surfaces.
Table 5: Emissivity Values for Common Materials
Material
Emissivity
Aluminum, anodized
0.77
Aluminum, polished
0.05
Asphalt
0.88
Brick
0.90
Concrete, rough
0.91
Copper, polished
0.04
Copper, oxidized
0.87
Glass, smooth (uncoated)
0.95
Ice
0.97
Limestone
0.92
Marble (polished)
0.89 to 0.92
Paint (including white)
0.9
Paper, roofing or white
0.88 to 0.86
Plaster, rough
0.89
Sand
0.9
Silver, polished
0.02
Silver, oxidized
0.04
Skin (human)
0.98
Snow
0.8 to 0.9
Water
0.98