## 5 Conclusions  
This paper proposed a three-wavelength radiation temperature measurement method for turbine blades based on ambient radiation correction. The method was used to measure the temperature of the surface of turbine blades with unknown emissivity subjected to ambient radiation. The first-stage rotor blade of the aero-turbine engine was selected as the target blade, and the adjacent guide vanes and the upper blades were selected as the adjacent blades. A three-dimensional dynamic reflection model of the turbine blades was established, and the target blades were analyzed under different rotation positions and different temperatures. Moreover, a three-wavelength radiation temperature measurement algorithm based on reflection error correction was proposed. Through theoretical deduction and analysis, the uniqueness of the algorithm for solving the temperature was proved. Ultimately, an experiment was designed to verify the method. The experimental results show that, compared with colorimetric temperature measurement methods, the maximum measurement error of the selected blade measurement points decreases from 6.09% to 2.13%, and the average measurement error decreases from a maximum of 2.82% to 1.20%. This indicates that the proposed method can eliminate the influence of reflected radiation and accurately obtain the temperature of a blade surface with unknown emissivity. The method would lead to a performance improvement in the radiation temperature measurement of aero-turbine engines. It should be noted that our analysis does not take into account the deformation of the turbine blade in the process of rotation. In future work, we will analyze the influence of deformation on the rotating blade temperature measurement. Additionally, we will calibrate the temperature error through modeling the deformed surface of turbine blades.  
Figure 14: Comparison between the inversion errors of the three-wavelength temperature measurement method and the colorimetric temperature measurement methods.  
Figure 13: Temperature measurement results of turbine blades.  
**Author Contributions:** Conceptualization, K.Z. and J.L. ([PERSON]); methodology, K.Z. and Y.Q.; software, K.Z. and Y.Z.; validation, J.L. ([PERSON]) and Q.S.; formal analysis, K.Z. and W.W.; investigation, K.Z. and J.T.; writing--original draft preparation, K.Z.; writing--review and editing, J.L. ([PERSON]), Y.Z., and Y.C.; funding acquisition, C.W. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by the National Natural Science Foundation of China (Grant numbers 61727818, 61627819, 61805239), the National Key Research and Development Program of China under Grant 2019 YFB2006000, the Jilin Scientific and Technological Development Program (Grant numbers 20190303063 SF, 20150520101 JH, 20180201024 GX), and the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant numbers 2018254).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The study did not report any data.  
**Conflicts of Interest:** The authors declare no conflict of interest.