Turbine Blade Surface Recovery Based On Photometric Stereo

In this paper, we proposed an aero-engine turbine blade measurement technique based on photometric stereo, which can reconstruct the blade surface quite accurately and efficient from the images captured under multi-illuminations. In this work, a measurement system is designed by using 8 LEDs as the point light sources, a light propagation process under the point light illumination is developed. Based on this process, a normal estimation method is provided for the reconstruction process. The system calibration is implemented on a USAF resolution target manufactured by Edmund, which proves the method is capable of performing the surface recovery with the repeatability error down to 0.0272mm. The experiments are performed through a turbine blade from aero-engine, where the comparison result is also provided by using a commercial portable laser scanner from Creaform, which shows the better performance of the methodology presented in this paper.