基于子空间投影和边缘增强的低剂量CT去噪

Low-dose CT Denoising Based on Subspace Projection and Edge Enhancement

低剂量计算机断层扫描(CT)是一种相对安全的疾病筛查手段,但低剂量CT图像往往包含较多噪声和伪影,严重影响医生的诊断。针对该问题,本文提出一种基于子空间投影和边缘增强网络(SPEENet)。SPEENet为自编码器结构,包含双流编码器和解码器两个主要模块。双流编码器可以被分为噪声图像编码流及边缘信息编码流两部分,噪声图像编码流对低剂量CT图像进行特征提取,利用图像特征去除低剂量CT中的噪声和伪影;边缘信息编码流部分主要关注低剂量CT图像的边缘信息,利用边缘信息保护图像结构。为充分利用编码器特征,本文引入噪声基投影模块,构建基于编码器和解码器特征的基,并利用该基将编码器提取的特征投影到对应的子空间,获取更好的特征表示。本文在公开数据集上进行实验以验证提出网络的有效性,实验结果表明,相较于其他低剂量CT去噪网络,SPEENet可以取得更好的去噪效果。

Low-dose computed tomography(CT)is a relatively safe method for disease screening.But low-dose CT images often contain severe noise and artifacts,which seriously affect the subsequent diagnosis.To solve this problem,this paper proposes a subspace projection and edge enhancement network(SPEENet).SPEENet hold an architecture of autoencoder,including two main modules:dual stream encoder and decoder.The dual stream encoder can be divided into two parts:noise image coding stream and edge information coding stream.The noise image coding stream removes the noise and artifacts in low-dose CT images by using the image features extracted from the low-dose CT images.The edge information coding stream mainly focuses on the edge information of lowdose CT images and fully utilize the edge information to preserve the structures.In order to make full use of the encoder features,this paper introduces the noise basis projection module to establish a basis based on the features of encoder and decoder,and uses this basis to project the features extracted by the encoder into the corresponding subspace to obtain better feature representation.In this paper,experiments are conducted on the public database to verify the effectiveness.The experimental results show that SPEENet can achieve better denoising performance than other low-dose CT denoising networks.