Various aspects of camera settings and image processing in the calibration of thermo-chromic liquid crystals for accurate particle image thermometry measurements

Step-by-step calibration procedures of particle image thermometry (PIT) for non-invasive and accurate temperature measurements using thermo-chromic liquid crystals (TLCs) are described in this paper. The purpose of this study is to examine the effects of various aspects of camera settings and image and data processing on the calibration of TLCs, and reveal the optimal parameter settings for achieving the best calibration curve of temperature versus color. Based on this study, an optimal window size has been proposed for median filtering to achieve the best compromise between noise removal and retaining of the true color information of the original experimental photographs; an optimal white balance settings in terms of the color temperature has been revealed for the present optical system; and finally, an optimal configuration of neural networks has been identified for obtaining the best hue–temperature correlation for further experiments.Graphical Abstract

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