This thesis reports an optical temperature measurement based on the two-colour method using colour-band filters to examine the application of it in novel ways. This technique uses a high-speed camera to detect the visible radiation from grey bodies. As a result of using the R and G channels, this modified two-colour method was found to be calibrated well with the standard temperature. The uniqueness of this research is the use of SiC fibre as a grey body emitter, allowing the temperature measurement to carry out in the situation of the hot gas and flame with soot deficiency. By conducting the numerical analysis the time taken to achieve the thermal equilibrium between the fibre and its adjacent gas was found to be in a few milliseconds.