为得到清晰的麦粒重建切片,利用共轭射线弥补Radon空间数据缺失,在FDK(Feldkamp-Davis-Kress)重建算法的基础上,引入z轴权重函数来优化麦粒切片图像的重建结果。针对三维头模型,z-FDK算法重建结果的均方根误差比FDK算法的小3.6927,大大抑制了FDK算法中的z轴方向强度下降。实验结果表明,针对卵期、低龄幼虫期和高龄幼虫期的麦粒投影图像,z-FDK算法的平均梯度和对比度噪声比均大于FDK算法,重建麦粒茸毛端和胚部端两个区域的灰度值增大,伪影得到改善。

In order to obtain clear wheat grain reconstruction slices, the conjugated ray is used to compensate for the missing data of Radon space. Based on the FDK (Feldkamp-Davis-Kress) reconstruction algorithm, the z-axis weight function is introduced to optimize the reconstruction results of the grain slice images. For the three-dimensional head model, the root mean squared error of the reconstruction result by the z-FDK algorithm is 3.6927 smaller than that of the FDK algorithm and the z-axis strength drop in the FDK algorithm is greatly suppressed. As for the projection images of wheat grains at egg stage, young larva stage and old larva stage, the experimental results show that the average gradient and the contrast noise ratio of the z-FDK algorithm are both larger than those of the FDK algorithm. The gray values of the reconstructed two regions of the hair end and the embryo end of wheat grains increase and the artifacts are improved.