RT Journal Article ID 64a54290287feff7 A1 Matsuda, Hisashi A1 Ikeda, Kazutaka A1 Nakata, Yuji A1 Otomo, Fumio A1 Suga, Takeo A1 Fukuyama, Yoshitaka T1 A NEW THERMOCHROMIC LIQUID CRYSTAL TEMPERATURE IDENTIFICATION TECHNIQUE USING COLOR SPACE INTERPOLATIONS AND ITS APPLICATION TO FILM COOLING EFFECTIVENESS MEASUREMENTS JF Journal of Flow Visualization and Image Processing JO JFV YR 2000 FD 2000-06-01 VO 7 IS 2 OP 20 AB A new color-temperature identification technique using thermochromic liquid crystals (TLC) and image processing has been developed. The technique is based on the finding that there exists a one-to-one correspondence between a temperature value and a set of TLC tristimulus values (rgb) in a color space (rgb space). Calibration points expressed in terms of rgb values corresponding to various temperatures are plotted in rgb space and then interpolated to obtain a smooth space calibration curve. This space calibration curve does not generally intersect with itself, and therefore the entire reflection region, which is not effectively used by the conventional hue-capturing technique, becomes available. Also, because the calibration curve can be obtained by simple algebraic interpolation, a more complex approach such as a neural network is not required. Moreover, the acceptable region around the calibration curve is clearly defined, and so doubtful pixel information is easily excluded by controlling this region.
A temperature measurement system based on this technique has been established using a CCD color camera, image analyzing application board, and Visual C++ programs. With this system, film cooling effectiveness over a flat plate through a round hole, a diffusion-shaped hole, and a diffusion-shaped hole with a vortex generator was studied. PB Begell House LK https://www.dl.begellhouse.com/journals/52b74bd3689ab10b,38eff7355b976017,64a54290287feff7.html