Panasonic Quick Clips: Grid-EYE®, Human Detection vs. Distance


Hello everyone, today we’ll be
discussing how to optimize the usage of the Grid-EYE Thermal Array Sensor, by
understanding how a human subject’s heat signature varies, depending on its distance
from the sensor. The Grid-EYE Sensor utilizes an 8 by 8 pixel array of thermopile detection
elements, that each has a 7.5 degree field of view. As the distance from the sensor increases, the
field of view of each pixel also increases. However, when a human subject increases in distance
from the sensor, its angular size appears smaller to the sensor, all while the field
of view is expanding. It’s because of this converse relationship, that a human subject
appears much smaller in the sensor’s detection zone at longer distances. At such a small relative size,
the heat signature received by the sensors diminished, due to the fact that the subject
only partially covers the relevant pixels, and the heat from the subject is blended
in with the background. This is further compounded by the fact that
the infrared radiation produced by a warm body decays as the distance to the object increases.
These relationships make the effective temperature reading lower than it should be, and increases
the difficulty of identifying human subjects at distances over 6 meters. As the subject approaches the sensor, it
covers more of the thermopile array. Thus providing a more accurate body temperature
reading, and can clearly show a traceable body shape, that can be used when the tracking of
humans is critical, such as in security, digital signage, and medical obligations. If you have any questions, or would like to
learn more, please give us a call, or visit our website at pewa.panasonic.com.

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