CT图像“条状”伪影校正方法研究

The research of streak artifact correcting method in CT reconstruction

在CT重建中,当断层射线衰减系数的变化呈非连续性的跳跃变化,如一种材质密度远远大于另一种材质的密度时,CT图像中高密度物质周围就会产生条状伪影。利用重投影技术分别获取高密度物质和低密度物质的正弦图,低密度物质正弦图中的数据缺失区用线性插值技术进行平滑过渡。利用两幅正弦图分别进行CT重建,然后将两幅CT图像进行相加,得到校正后的图像。实验结果表明,该方法能有效抑制条状伪影,同时提高了图像对比度。

In practice CT reconstruction, when the attenuation coefficients of the material in the reconstructed slice are non-continuous or jumpy changing, for instance, the density of one material is much higher than that of another, the streak artifact in the CT image will be caused. The re-projection method was used to obtain the sinogram of the material with low density and the material with high density. The missed data in the former sonogram were made up by linear interpolation smoothing method. Then through filtering back proieetion reconstruction, the CT images of the low density and high density material were created separately. Fusing the two CT images together, the final corrected image was obtained. The experimental results prove that this method can decrease the influence of the streak artifact effeetively and improve the contrast of the CT image.