We have integrated the temperature sensor into a test board and we were checking the accuracy of the temperature sensor when we noticed that the temperatures that were returned by the sensor vary from time to time.They show a jump of 5 degrees from ground truth values at times. We are testing it on people’s faces and we got this result.Since this is a medical accuracy temperature sensor and the test case is also related to human temperature reading , such a jump is not desirable.
The temperature sensor also showed high values and hence we had to change the emissivity to compensate. I have attached a table(mlx90614EmissivityVDistance.png) showing Temperature at different distance vs emissivity and We picked emissivity as 30 at 30cm since it was the closest to expected result and I have attached test results(Mlx90614TempMeasurements.png) at 30 emissivity. What could be the reason for such varying temperature readings?
What are some parameters that must be looked upon to improve the accuracy of the temperature sensor? We are testing it at 30cm distance and from looking at some forums this sensor provides accurate readings till 50cm. If our assumption is wrong ,could someone provide more info on best distance to use the temperature sensor for maximum accuracy?
