Improved Pressure Sensitive Paint Measurement Using Natural Feature Tracking and Piecewise Linear Resection

Abstract

Wind tunnel Pressure Sensitive Paint (PSP) ratio techniques require accurate registration between wind-on and wind-off camera image pairs. The Piecewise Linear Resection (PLR) method of removing registration due to physical wind tunnel model motion and deformation errors can account for nonlinear deformations and benefits from increased tracking point coverage in the image. This work presents a method to increase the accuracy of PLR by tracking natural features in addition to standard fiducial markers. This is accomplished with Speeded-Up Robust Features (SURF) and a modified disparity gradient filtering technique. This work shows that this method of automatic PLR is feasible on wind tunnel imagery and that the resulting pressure data has reduced misregistration noise without the need to perform 3D resection using virtual models and pre-defined deformation equations.

Markerless Image Alignment Method for Pressure-Sensitive Paint Image

“…This is because the images obtained in the PSP measurement usually consist of white solid color (luminescence from PSP) and black solid color (background) parts with few features. Kuzub et al [36] proposed the method using feature points. Since the features on the PSP such as small scratches and defects are usually affected by the illumination, the mismatching of the features between the reference and the run images will occur due to the change of the illumination condition.…”