M310-HT Manual Appendix A: Calibration & Emissivity • 22
Example 2: The M310-HT (450 °C) blackbody was factory calibrated to provide effective
emissivity = 1.0 at 8-14 µm. You wish to use this source for an imager that has spectral response
of 3-5 µm. The mean value between 3-5 µm from the graph above = 0.943. The blackbody exit
radiance at 3-5 µm will be approximately equivalent to a blackbody that has emissivity = 0.943.
This will cause your imager to receive 5.7% less infrared energy causing it to read a lower
temperature. The table below shows the expected radiance temperatures and errors. At 250 °C,
your imager will read 245.5 or 4.5° low so you should set the blackbody setpoint to
254.5 = (250 + 4.5) to force the exit radiance to be equal to 250 °C at 3-5 µm.
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