Particle image velocimetry suitable for X-ray projection imaging

摘要

A 2D or 3D velocity field is reconstructed from a cross-correlation analysis of image pairs of a sample, without first reconstructing images of the sample spatial structure. The method can be implemented via computer tomographic X-ray particle image velocimetry, using multiple projection angles, with phase contrast images forming dynamic speckle patterns. Estimated cross-correlations may be generated via convolution of a measured autocorrelation function with a velocity probability density function, and the velocity coefficients iteratively optimized to minimize the error between the estimated cross-correlations and the measured cross-correlations. The method may be applied to measure blood flow, and the motion of tissue and organs such as heart and lungs.

主权项

1. A method for imaging of a sample, the method being automated and including:
recording images from at least one projection angle and carrying out image pair cross-correlation analysis encoding velocity data tor the sample in terms of Cartesian coordinates to measure encoded parameters of: (i) velocity (u, v and w) against time opposite Cartesian co-ordinates (x, y and z), and (ii) a further physical parameter (p) chosen from the group comprising pressure or volume; and reconstructing, without first reconstructing 2D or 3D images, a 2D or 3D velocity field directly from the image pair cross-correlations from the analysis, the reconstructing including: (a) integrating the measurements to provide a single 3D velocity field; and (b) describing regional compliance in terms of derivatives defined by (δu/δx+δv/δy+δw/δz)/δp.