Method for processing spots of three-dimensional ultrasonic image

Abstract

The invention discloses a method for processing spots of a three-dimensional ultrasonic image, belonging to the technical field of the digital image processing. The method comprises the following steps: (1) decomposing the three-dimensional ultrasonic image into seven high-frequency parts and one low-frequency part by using the time and frequency separation characteristic of the multi-resolution of a three-dimensional wavelet; and (2) processing the high-frequency parts of the three-dimensional ultrasonic image subjected to wavelet decomposition by adopting an normalized anisotropic diffusion method according to the multiplicative properties of the spots of the three-dimensional ultrasonic image so as to remove the spots; and (3) reconstructing the three-dimensional ultrasonic image by carrying out three-dimensional wavelet inverse transformation to the processed high-frequency parts and the original low-frequency part. The method disclosed by the invention can be used for rapidly and effectively inhibiting the ultrasonic spots to improve the quality of the image, is very beneficial to the cutting, segmentation, feature analysis and recognition of the ultrasonic image and can be also used to process the image with multiplicative noise.

Description

technical field [0001] The invention belongs to the field of computer digital image processing, and in particular relates to a method for suppressing spots of three-dimensional ultrasonic images. Background technique [0002] Ultrasound imaging is a technology that uses ultrasonic waves of a specific wavelength to generate backscattered signals after being detected. It has the advantages of high safety, fast imaging speed, convenient operation and low cost. It is widely used in zoological research and clinical applications. It is very extensive, especially the exploration of abdominal organs, such as the heart, liver, kidney, etc., as well as the three-dimensional imaging and real-time four-dimensional dynamic imaging of the fetus, as well as the monitoring and dynamic evaluation of the growth and development of animals in the mother's body. [0003] However, in this imaging technology using ultrasonic backscattering signals, due to the ultrasound having a certain wavelength...

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Problems solved by technology

[0003] However, in this imaging technology using ultrasonic backscattering signals, due to the ultrasound having a certain wavelength, it encounters a tiny tissue interface and produces a large amount of scattering, resulting in a large number of spots in the image, which reduces the image quality and resolution , image contrast and resolution are low, tissue scattering and absorption effects blur the boundaries of tissues and organs, etc., which affect the accurate judgment of animal researchers or sonographers, as well as calculation-assisted analysis, such as target segmentation, classification recognition, quantitative parameter determination, etc.

[0004] Speckle suppression filtering algorithms mainly include adaptive weighted median filtering, adaptive speckle suppression filtering and Lee filtering, and speckle processing methods based on pyramid multi-level decomposition, etc. These filtering methods have the following deficiencies: (1) the size and shape of the filtering window Very sensitive; (2) The edge and detail features are only preserved as much as possible rather than enhanced; (3) The selection of filtering control parameters is often determined based on experience, and there is a large randomness; (4) Isotropic, that is, all pixels in the filtering window Participate in filtering operations with the same weight

Although the performance of anisotropic diffusion is better than most speckle filtering methods, it has the following disadvantages: (1) Based on the spatial domain and gray gradient information, since noise and signal are mixed together, it affects its suppression of speckle noise and The ability to preserve detail features; (2) The multiplicative noise model that does not consider speckle, in the dark area with small gray value, it has a strong suppression effect on speckle, and in the high brightness area with strong gray value, its very limited

[0011] Since ultrasonic speckle is a kind of multiplicative noise, the calculation of the gray gradient of the image is greatly different in the homogeneous area and the non-homogeneous area due to the influence of the speckle. Therefore, the traditional anisotropic diffusion method cannot be effective. remove them

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