【摘要】 为了实现动态射线数字成像(DR)系统的快速降噪,分析了X射线数字实时成像系统的噪声特点和原始的基于图像序列的NL-means降噪算法的不足,提出了一种改进的NL-means序列图像降噪算法。同时,为了解决NL-means降噪算法计算量大、运算速度慢的问题,利用可编程图形处理单元(GPU)并行计算和高速浮点计算特性,将图像映射为GPU中的纹理,采用多线程并行计算,使得NL-means算法在GPU中加速执行。实验结果表明,改进之后的算法有效地抑制了动态DR图像中的随机噪声,同时保留了图像的细节信息。GPU加速方法可以在不损失图像信息的前提下,实现实时降噪。更多还原

【Abstract】 In order to realize the fast noise reduction in the dynamic digital radiography(DR) imaging system,the system’s noise characteristics and the disadvantages of the original NL-means denoising algorithm were studied.An improved NL-means noise reduction algorithm was proposed.Meanwhile,in order to solve its calculation complexity problem,graphic processing unit(GPU) was applied to make use of its high parallel and fast floating-point calculation abilities.In the implementation,the image was mapped to the GPU’s texture and multi-thread parallel calculation was adopted.The experimental results showed that the improved NL-means noise reduction algorithm could effectively restrain the quantum noise and improve the resolution of DR image sequences.In addition,the acceleration with GPU could realize the real-time denoising without the loss of image information.更多还原