# Color CCD High-Temperature Measurement Method Based on Matrix Searching
## 4 Results and Discussion
### Solution Accuracy  
Combined with the experimental parameters of Table 1 and the non-perturbation spectral emissivity model in Equation (12), the temperature mapping matrix for this measurement is calculated. The \(p\) and q values of the temperature mapping matrix established in this experiment are 30 and 40, respectively. The reason is that p is the indexing of the red component, and q is the indexing of the green component. The rate of the red component rising with the radiation is higher, and the temperature range of the red component is smaller, while that of the green is relatively large in the range of 0-255. For a more uniform distribution of the temperature matrix, the case of \(p=30\) and \(q=40\) is selected to solve the problem.  
After ten consecutive triggers, the chromaticity data of 99 pixels within a specified pixel region of the image (corresponding to the pixel of the thermocouple detection position) are read, and the mapping matrix is searched to obtain the corresponding position temperature. If \(h\) is the ordinal number of pixels, \(N\) is the total number of pixels in the region, \(T_{maa}\) is the temperature measurement value obtained by the point thermometer, and \(T_{cal,h}\) is the temperature solution value of the \(h\) pixel obtained by this method, then the solution error is expressed as follows:  
\[Error=\frac{T_{maa}-\sum\limits_{h=1}^{N}T_{cal,h}/N}{T_{maa}} \tag{14}\]  
Equation (13) takes the average value of all the temperature solution values in the specified pixel region as the region temperature and compares it with the point thermometer measurement data of the corresponding time period to obtain the measurement error within the trigger time period. The calculation results are shown in Figure 11.  
\begin{table}
\begin{tabular}{c c} \hline
**Parameter** & **Parameter Value** \\ \hline Lens focal length & \(75\times 10^{-3}\) (m) \\ Aperture size & f/2.8 \\ Magnification & 0.5 \\ Gamma value & 1 \\ Pixel dimensions & \(20\times 10^{-6}\) (m) \\ Exposure time & 300 (us) \\ Camera distance & 1 (m) \\ \hline \end{tabular}
\end{table}
Table 1: Table of experimental parameters.  
It can be seen in Figure 11 that the error of this method can be stabilized within the range of 2.5-2.7%. Considering that the measurement uncertainty of the thermocouple is 0.04%, the overall error range of the measurement is modified to 2.5% (\(\pm\)0.04%)-2.7% (\(\pm\)0.04%).  
In principle, the error comes from the following three aspects: the first is the calibration data fitting error. In the calculation, in order to ensure that \(s_{i}(\lambda)\epsilon(\lambda)I(\lambda,T)\) is integrable, the spectral response curve is fitted as a continuous function, which results in some measurement errors. Secondly, the spectral reflectance ignores the error. When the thermal radiation is transferred to the camera lens and image plane, part of the radiation is reflected, and the reflection is also spectral dependent. Although this point is also ignored in the calibration experiment, the spectral reflection of the lens and image plane still affects the actual temperature measurement because of the difference between the radiation behavior of the heat source and the calibration experiment. Finally, there is an error caused by the division of the minimum chromaticity interval. Because the pixels in the range of chromaticity interval \(\Delta R\) and \(\Delta G\) will be solved to the same temperature, the error of the solution will be caused. This error will be discussed quantitatively below.