Time inversion photoacoustic image reconstruction method based on time domain finite difference

Abstract

The invention discloses a time inversion photoacoustic image reconstruction method based on time domain finite difference. The method comprises the steps: obtaining the scanning data of a photoacoustic image; carrying out the discretization of a sound wave equation, and building a calculation grid of time domain finite difference; building a grid absorption boundary condition of the time domain finite difference according to a unidirectional wave equation; carrying out the time reversal of the photoacoustic signal, and loading the photoacoustic signal to a corresponding receiving position after time reversal; finally carrying out the time stepping of a time domain finite difference formula, calculating a maximum variance norm, stopping the time stepping when the maximum variance norm reaches a minimum value, and outputting a reconstructed image. The method can be used for mediums with uniform and nonuniform sound speeds, is not limited by a scanning mode, achieves the dual focusing of the photoacoustic signal in time and space, can precisely reconstruct the optical absorption distribution of biological tissues, and is great in actual application value.

Description

technical field [0001] The invention belongs to the technical field of medical imaging, and in particular relates to a time-reversal photoacoustic image reconstruction method based on time domain finite difference. Background technique [0002] Photoacoustic imaging technology combines the advantages of high penetration and high resolution of pure acoustic imaging technology with the advantages of high contrast of pure optical imaging, while avoiding the influence of high scattering in optical imaging. In addition, photoacoustic imaging has the advantages of non-ionizing radiation. characteristics, no damage to biological tissue during the detection process. At present, photoacoustic imaging has been used for structural imaging such as tumor detection and vascular imaging, and functional imaging such as hemodynamic detection. [0003] Photoacoustic imaging uses pulsed laser light to irradiate biological tissue, and when the tissue absorbs light energy, it produces elastic e...

AI Technical Summary

Problems solved by technology

[0004] The above methods do not need iteration, and the imaging speed is fast, but they all have two disadvantages. First, the above methods are based on the assumption that the imaging object is a medium with a uniform sound velocity; second, these methods are limited to specific scanning methods, most of which are circular. or linear scan

However, the above two points are often not satisfied in practical applications.

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