Omron uses Micro-ElectoMechanical System (MEMS) thermopile to measure temperature at a distance. The D6T series sensors use the thermoelectric effect (Seebeck effect) in which temperature is converted directly to voltage. They are sensitive to Longware Infrared (LWIR) at wavelength between 8 and 12 micrometers.
The sensors are intended to detect human presence in a volume the size of a room. The optics are fixed, and the angular field of view is wide. The highest resolution sensor, 32 x 32 pixels has a 90 degree angular field of view. A reasonable human size field of view (1550 mm x 1550 mm) requires a short working distance of 800 mm.
Omron D6T-32L-01A specs
Price $125
Resolution 32 x 32 pixels (1024 total pixels)
Power supply voltage 4.5 to 5.5 VDC
Current consumption: 19 mA
Accuracy: +- 3 degrees C in the center 16 pixels.
Temperature resolution 0.33 degrees C
Communication format: I2C
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| Omron example image 32 x 32 pixels. |
To get usable detail in the visible spectrum I would recommend narrowing the angular field of view. An inexpensive USB camera that is <GenICam> complaint is the Basler dart daA1280-54uc (S-Mount).
Paired with an f4.2 mm focal length s-mount lens (with IR cut filter), the 800 mm working distance gives a 685 x 915 mm field of view. But the camera needs to be rotated on its side.
The resulting field of view with both the Omron and the Basler sitting next to each other:
Thermal 1572 x 1572 mm @ 49.125 mm/pixel
Visible 685 x 915 mm @ 0.714 mm/pixel
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