摘要
目的:修正CT投影图像中心和实际旋转中心之间的误差,提高重建图像的质量。方法:分析了投影中心和实际的旋转中心偏差对重建图像产生的影响,提供了一种根据投影图像中物体和背景的灰度值差异特点来计算旋转中心的方法,并根据计算出的旋转中心对投影图像进行修正。结果:根据5～10组相差180°的对称投影图像计算出的投影中心与实际旋转中心偏差在1个像素内,大大提高了重建图像的质量。结论:该校正方法直接从已经获得的投影图像出发,不需要增加辅助条件和投影图像数量,并且计算量较小,作为重建前处理对投影图像进行纠正,基本不影响重建的速度,准确率较高。
Objective To amend the errors between projective image center and the actual rotational center and improve the quality of reconstructed images. Methods The impact of reconstructed image in which the projection center and the actual center caused the deviation is analyzed, and provides the ways that is based on the gray value difference of objects and background in projection image to calculate actual rotational center, and then mends the projective image based on the actual rotational center. Results The difference between the actual rotational center and the calculated projective image center is less than one pixel. The quality of the reconstructed images is improved greatly. Conclusion The correction method is based on projective images, no need to increase the auxiliary conditions and the number of projection images. And the way as the pre-process of reconstruction, only needs small amount calculation, doesn＇t affect the reconstructive speed. [Chinese Medical Equipment Journal,2009,30（3） ：4-6]
出处
《医疗卫生装备》
CAS
2009年第3期4-6,共3页
Chinese Medical Equipment Journal
基金
国家重点基础研究发展计划(973计划)项目(2006CB601200)
关键词
FDK
旋转中心
投影中心
校正
FDK
rotational center
projective center
correction
