Frequency domain laser speckle imaging based blood flow velocity measuring method

Abstract

The invention discloses a frequency domain laser speckle imaging based blood flow velocity measuring method. The frequency domain laser speckle imaging based blood flow velocity measuring method comprises the following steps of illuminating laser beams on a measured object, imaging the measured object through an imaging system, collecting an original speckle image of the measured object through an image sensor, transferring dynamic speckle intensity with single pixel points being in a time domain of the collected original speckle image into a frequency domain, calculating the power spectral density, performing polynomial fitting on the power spectral density to obtain a smooth curve, transferring the smooth curve into the time domain through Fourier transform, calculating an autocovariance function of the pixel points and performing normalization, establishing a blood velocity measuring model, obtaining a relationship between the covariance function and the blood velocity and finally performing fitting to obtain a blood velocity value. The frequency domain laser speckle imaging based blood flow velocity measuring method has the advantages of not only eliminating static noise, improving the blood velocity measuring accuracy, avoiding influences from imaging environmental factors such as intensity and illumination angles and improving the measuring stability.

Description

technical field [0001] The invention relates to the field of biological tissue blood flow imaging, in particular to a blood flow velocity measurement method based on frequency-domain laser speckle imaging. Background technique [0002] Laser speckle contrast imaging is a technology that uses an optical imaging system to transmit laser speckle images to image blood flow in the whole field. The laser speckle contrast imaging system is mainly composed of a coherent light source and an image acquisition device. The coherent light is randomly superimposed after being scattered by biological tissue, and the random speckle pattern is collected by the image acquisition device for spatial contrast analysis, and finally the blood flow velocity is estimated. The laser speckle contrast imaging method has the characteristics of simple operation and strong practicability, so it has been widely used in the fields of biomedical research, clinical diagnosis, surgical guidance, skin, dentistr...

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Problems solved by technology

Although the effectiveness of the speckle contrast value has been greatly improved through the above methods, since the speckle image is still affected by various imaging environmental factors, the laser speckle contrast imaging method is used to directly measure the blood flow velocity The error problem existing in the still has not been effectively solved

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