High-precision composite 3D shape measurement of aeroengine blade based on parallel single-pixel imaging and high-dynamic range N-step fringe projection profilometry

Aeroengine blade is a core component of aircrafts. Accurate measurement of its profile has a great significance for flight safety. However, obtaining a high-quality 3D model of blade is difficult because traditional methods are limited in simultaneously meeting the requirements of large-scale measurement of smooth areas and high-precision measurement of fine structures. We develop a high-precision composite 3D shape measurement method of aeroengine blade. The proposed system consists of two sensors: a global sensor for large-range measurement and a local sensor for high-precision measurement. The global sensor based on parallel single-pixel imaging is used for smooth areas such as blade body and back, which undertakes most of the measurement tasks. The local sensor based on high-dynamic range N-step fringe projection profilometry has a high resolution to measure fine structures such as blade edge and top. We also use the local sensor to complete the missing point cloud of strong reflective areas. A phase-based data alignment method is developed to obtain coordinate transformation between the global and local sensors. Experiment results demonstrate that the proposed method can achieve accurate measurement and finally reconstruct the high-quality 3D model of aeroengine blade.