Method for simultaneous measurement of velocity and temperature fields based on temperature-sensitive phosphorescent particles

A method for simultaneous measurement of velocity and temperature fields based on temperature-sensitive phosphorescent particles, comprising the steps of:

• establishing a lifetime-temperature curve by measuring lifetimes of the temperature-sensitive phosphorescent particles,
• capturing time-sequential images of the temperature-sensitive phosphorescent particles under illumination,
• processing the time-sequential images via three-view separation to obtain processed images,
• performing three-dimensional (3D) reconstruction and trajectory fitting on the processed images to obtain a 3D velocity field,
• acquiring red full-resolution images of the temperature-sensitive phosphorescent particles following the illumination,
• calculating intensities of the temperature-sensitive phosphorescent particles from the red full-resolution images, and determining a phosphorescence lifetime based on the intensities of the particles,
• determining a 3D temperature field based on the lifetime-temperature curve and the phosphorescence lifetime, and
• fusing the 3D velocity field and the 3D temperature field to obtain a 3D velocity-temperature field, wherein
• the performing 3D reconstruction and trajectory fitting on the processed images to obtain a 3D velocity field comprises the steps of:
• obtaining a 3D particle distribution of a first portion of the processed images via triangulation;
• performing a particle position prediction on a second portion of the processed images using the 3D particle distribution and a Wiener filter, to obtain a prediction result;
• performing a coordinate shift on 3D world coordinates of the prediction result to obtain shifted coordinates;
• obtaining a residual-displacement relationship curve from residuals between reprojection images of the shifted coordinates and the processed images;
• re-predicting particle positions by applying the residual-displacement relationship curve to the prediction result to obtain particle trajectories;
• and
• deriving the 3D velocity field from a 3D distribution of the particle trajectories;
• and
• the calculating intensities of the temperature-sensitive phosphorescent particles from the red full-resolution images, and determining a phosphorescence lifetime based on the intensities of the particles comprise the steps of:
• performing two-dimensional (2D) particle tracking on the red full-resolution images using the 3D velocity field to obtain a red particle distribution;
• and
• calculating the phosphorescence lifetime from the red particle distribution and a phosphorescence decay equation.