目的　研究射线图像中保持细节的滤噪方法 .方法　依据图像中噪声的特点 ,提出三种去噪方法 ,即差分梯度法、邻域比较法、σ滤波与邻域比较相结合 .结果　采用这些方法对射线图像进行处理 ,有明显的去噪效果 ,且保持细节 .结论　这些方法对于图像滤噪具有普遍意义 ,特别对于含有微小细节、颗粒脉冲噪声的图像更适合 Objective To study the method of preserving details in ray images.Methods According to the characteristics of noise in images, three denoising methods were proposed, that is, differential gradient method, neighborhood comparison method, σ filtering and neighborhood comparison.Results Using these methods Ray images have obvious denoising effect and maintain the details.Conclusion These methods have general significance for image filtering, especially for images with minute details and particle impulse noise