A New 3D reconstruction method for pressure-sensitive paint measurements under limited optical access

Reconstruction of 3D pressure field is crucial for pressure-sensitive paint measurements in turbomachinery experiments. Existing methods impose high requirements on feature points in terms of quantity, spatial distribution, and positional accuracy, and is difficult to apply under limited optical access, such as in planar cascade wind tunnels. We propose a novel direct linear transformation method based on contour matching (CM-DLT). This method leverages model contours captured from a tilted camera perspective, which provides the basis for identifying the projection matrix linking image pixels to 3D spatial points. The subsequent optimization of the projection matrix significantly enhances the accuracy and robustness of 3D pressure field reconstruction. In a benchmark experiment, the efficiency and reprojection accuracy of 3D reconstruction are investigated. Subsequently, the CM-DLT method is successfully applied in the cascade wind tunnel experiment. The obtained 3D pressure fields of two surfaces of adjacent blades are analyzed.