Subsequently, the average hue for the chosen region along with the measured temperature forms a data point of the calibration curve (Figure 6.4(c).

Figure 6.4(c) Calibration curve of the LC sheet relating hue (H), saturation (S), and intensity (I) with temperature

In the experience of the authors, a typical calibration curve consists of 40-50 points. One can expect this data set to be sufficient to resolve the hue-temperature relationship. Further, a suitably high order polynomial can be used to analytically represent the calibration data. This approach can be used for saturation and intensity as well.

Figure 6.4(c) shows a typical calibration curve drawn for a liquid crystal sheet used by the authors.