基于剪切波变换的辐射图像泊松噪声降噪技术研究

Denoising Technology for Radiation Image with Poisson Noise Based on Shearlet Transform

  • 摘要: 为了降低由统计涨落引起的辐射图像噪声,提出了一种基于剪切波变换的降噪方法。该方法以低剂量射线或质量厚度大的物体的辐射图像为研究对象,对此类辐射图像进行了噪声分析,利用Anscombe变换将统计涨落引起的泊松噪声转换为高斯噪声,再运用剪切波分解、阈值去噪、剪切波重构和Anscombe逆变换得到降噪图像。结果表明,当剪切波分解层数为5,采用改进阈值函数及极小极大原理阈值时可达到最优降噪效果,该方法能较好地去除辐射图像中的泊松噪声并保留边缘、细节信息,在视觉和量化指标上均优于传统降噪方法。

     

    Abstract: In order to reduce the radiation image noise caused by statistical fluctuation, a denoising method based on shearlet transform was proposed. The radiation image of lowdose radiation or object with large mass thickness was taken as research objects. Through noise analysis, Anscombe transform was used to convert Poisson noise caused by statistical fluctuation into Gaussian noise, then shearlet decomposition, threshold denoising, shearlet reconstruction and Anscombe inverse transform were utilized to obtain the denoised image. The results show that the optimal denoising effect can be achieved when the scale of shearlet decomposition is 5 and the improved thresholding and the threshold of minimax principle are chosen. This method can reduce Poisson noise and retain image details. Moreover, it is superior to the traditional methods in both visual feeling and quantitative parameter.

     

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