Motion Field Estimation Method for Movie MRI Image Sequences Based on Fractional Differentiation

A film nuclear magnetic resonance and fractional differential technology, which is applied in image enhancement, image analysis, image data processing and other directions, can solve the problems of no rotation invariance, poor anti-noise performance, low accuracy, etc., and achieves high estimation accuracy, Good anti-noise performance and the effect of improving estimation accuracy

Inactive Publication Date: 2017-04-26
HARBIN INST OF TECH
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  • Summary
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Problems solved by technology

[0005] Purpose of the invention: In order to solve the problem of estimating the motion field of movie MRI image sequences by applying the existing technology by using integer-order differential image enhancement and directly establishing the optical flow equation, the texture details of the images are lost, and the estimation results are affected by illumination changes and do not have rotation invariance , the anti-noise performance is poor, which leads to the problem of low accuracy of motion estimation based on movie nuclear magnetic resonance images. The present invention proposes a motion field estimation method based on fractional differential of movie nuclear magnetic resonance image sequences

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  • Motion Field Estimation Method for Movie MRI Image Sequences Based on Fractional Differentiation
  • Motion Field Estimation Method for Movie MRI Image Sequences Based on Fractional Differentiation
  • Motion Field Estimation Method for Movie MRI Image Sequences Based on Fractional Differentiation

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specific Embodiment approach 1

[0020] Specific implementation mode one: combined with figure 1 , the specific implementation steps of the method for estimating the motion field of the film nuclear magnetic resonance image sequence based on fractional differential in this embodiment are as follows:

[0021] 1. Texture enhancement of movie MRI image sequences using fractional differentiation;

[0022] 2. Extract the phase, azimuth, and amplitude of the image through Riesz transform, and construct the signal;

[0023] 3. Establish the optical flow equation by using the phase vector of the single-cast signal;

[0024] 4. Estimate the motion field of the cine-MRI image sequence through the optical flow equation.

specific Embodiment approach 2

[0025] Specific Embodiment 2: This embodiment is a further limitation of the specific implementation step 1 of the method for estimating the motion field of a film MRI image sequence based on fractional differential in the specific embodiment 1, combined with the attached figure 2 , attached image 3 , the process of using fractional differential to enhance the texture of the film MRI image sequence described in step 1 is:

[0026] Starting from the integer-order derivative of a continuous function, the differential order is extended from integers to fractions, and a basic v-order Grümwald–Letnikov fractional differential equation is constructed,

[0027]

[0028] Here the continuous function s(u) represents the one-dimensional image signal, s(u)∈[a,u], a Represents a collection of integers; when v>0, k is not less than [v], Indicates the length of the signal; is the Gamma function, Represents the Grümwald–Letnikov-fractional differential operator; when the value of ...

specific Embodiment approach 3

[0037] Specific implementation mode three: this implementation mode is a further limitation of the specific implementation step two of the method for estimating the motion field of a movie MRI image sequence based on fractional order differential in the specific implementation mode one, combined with the attached Figure 4 , the process of extracting the solo phase, solo orientation, and solo amplitude of the image through Riesz transform described in step 2, and constructing solo signals is as follows:

[0038] a. Separate the local amplitude, local phase and local direction of the corresponding point of the image through three two-dimensional spatial orthogonal filters; the two-dimensional spatial orthogonal filter used is a differential Poisson filter; the spatial orthogonal filter Consists of 1 rotation invariant even bandpass filter b e (Z) and 2 odd bandpass filters b o1 (Z), b o2 (Z) Composition;

[0039] b. Asking for a single phase Solo direction θ(Z) and solo am...

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Abstract

The invention belongs to the field of nuclear magnetic resonance imaging data processing, and relates to a movie nuclear magnetic resonance image sequence motion field estimation method based on a fractional order differential. The method aims to solve the problems that the method of enhancing and directly building a light stream equation through integer order differential images in the prior art is used for estimating a movie nuclear magnetic resonance image sequence motion field, grain details of the images are lost, an estimation result is influenced by illumination changes, the rotation unchanging performance does not exist, the noise resisting performance is poor, and precision based on movie nuclear magnetic resonance image sequence motion field estimation is low. The method mainly comprises the steps that firstly, grain enhancing is carried out on a movie nuclear magnetic resonance image through the fractional order differential; secondly, monogenic signals of the image are extracted through Riesz transformation, namely, the monogenic phase, the monogenic direction and the monogenic amplitude; thirdly, the light stream equation is built through the phase vector of the monogenic signals; fourthly, the movie nuclear magnetic resonance image sequence motion field is estimated through the light stream equation. The method is used for estimating the motion of an imaging object by the movie nuclear magnetic resonance image.

Description

technical field [0001] The invention belongs to the field of nuclear magnetic resonance imaging data processing. Background technique [0002] Magnetic resonance imaging (Magnetic Resonance Imaging, MRI) technology has become an important auxiliary means of clinical diagnosis. Motion field estimation based on Cine-MRI is a research direction that cannot be ignored. Because the gray levels of Cine-MRI are very similar, it is difficult to find dense corresponding feature points, so motion estimation for Cine-MRI is more difficult than motion estimation for tagged MRI images (Tagged-MRI). few. Aiming at the challenge of Cine-MRI with similar gray levels and few features, differential operations have been widely used to enhance images. Applying integer-order differential image enhancement methods (such as Sobel, Prewitt, and Laplacian operators) loses the texture of the image while enhancing the image. The details, especially the texture of the smooth area, are seriously lost...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06T5/00G06T7/20
Inventor 刘宛予高镔郐子翔帕特里克·克拉里斯
Owner HARBIN INST OF TECH
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