Self-calibration and data fusion for humidity measurement system

The multi-benchmark resources are used for self-calibration in humidity measurement circuit. The precision and stability on entire circuit system are converted to that on benchmark resources by treating with information from multi-benchmark resources. The humidity measurement error which is caused by temperature changing is usually corrected by linear interpolation. Linear interpolation is simple but is not precise. Two-dimension nine-points method is proposed related to humidity U,the capacity C of capacitive sensor and temperature t,in which two-dimension polynomial fusion formula is established according to 9 calibration points in the neighbourhood of (C, t) and U is obtained by this formula. The validity of self-calibration method is demonstrated by simulative test. Contrast results indicates that the precision of two-dimension nine-points method is much higher than precision that of linear interpolation and the absolute error maximum is less than 0.8% R. H in 0 similar to 90 degrees C and 30% similar to 90%.