基于偏微分方程的医学图像去噪研究

发布时间：2019-01-13 09:52

【摘要】：在医学图像成像技术领域,医学B超成像技术具有成本低、无损检测以及实时成像等优点,广泛应用于医学诊断的相关领域中。医学B超图像固有的形成机制,会导致获得的图像有相应的斑点噪声点存在,在影响临床诊断同时也给图像的后续处理带来困难。本文针对医学B超图像去噪同时,保持边缘信息较弱,不利于后续处理的特点,提出针对医学B超图像的改进去噪模型算法。首先,为了解决医学超声斑点噪声同时边缘保持不清晰的问题,本文利用偏微分方程数学方法,通过将偏ROF微分方程去噪模型以及Y-K微分方程去噪模型结合,分析医学B超形成特点以及斑点噪声数学模型,构建了一个基于B超图像去噪保真项,提出了一个去除医学B超图像斑点噪声的RYK综合去噪模型,达到提高医学B超图像去噪保持边缘效果同时提高去噪的效率目的。其次,为了进一步提升B超图像降噪和边缘保持效果,本文通过提出改进扩散系数计算方法,应用自适应选取的扩散门阀K,该系数分别在纹理区以及其他区域使用不同的扩散系数,保持纹理及边缘信息,将新的系数计算方法引入到基于B超图像改进RYK模型中去,该模型能够更有效的处理斑点噪声等乘性噪声,更好的控制去噪的扩散过程,进一步提高B超图像降噪和边缘保持效果同时提高去噪效率的目的。
[Abstract]:In the field of medical image imaging, medical B-ultrasound imaging technology has the advantages of low cost, nondestructive testing and real-time imaging, and is widely used in the related fields of medical diagnosis. The inherent formation mechanism of medical B-mode ultrasound images will lead to the existence of corresponding speckle noise points in the images, which will not only affect the clinical diagnosis but also bring difficulties to the subsequent processing of the images. In this paper, an improved denoising model algorithm for medical B-ultrasound images is proposed in view of the characteristics that the edge information is weak while the medical B-ultrasound images are denoised, which is not conducive to the subsequent processing. First of all, in order to solve the problem that medical ultrasonic speckle noise is not clear at the same time, in this paper, the partial ROF differential equation denoising model and Y-K differential equation denoising model are combined by using partial differential equation mathematical method. In this paper, the characteristics of medical B-ultrasound and the mathematical model of speckle noise are analyzed. Based on the fidelity term of B-ultrasound image denoising, a RYK comprehensive denoising model is proposed to remove the speckle noise of medical B-ultrasound image. In order to improve the edge effect of medical B-ultrasound image denoising and improve the efficiency of de-noising. Secondly, in order to further improve the effect of B-mode ultrasound image noise reduction and edge preservation, this paper proposes an improved diffusion coefficient calculation method, and applies the self-adaptive diffusion valve K. The coefficients use different diffusion coefficients in the texture region and other regions respectively to preserve the texture and edge information. A new method for calculating the coefficients is introduced to the improved RYK model based on B-mode ultrasound images. The model can deal with speckle noise and multiplicative noise more effectively, control the diffusion process of denoising better, and further improve the effect of noise reduction and edge preservation of B-ultrasound image and improve the efficiency of denoising.
【学位授予单位】：哈尔滨工程大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TP391.41;O175.2

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