一种影像增强器失真图像的校正方法

Distortion Correction Method for X-ray Image Intensifier

针对基于X线透视的骨科手术导航系统中影像增强器图像失真的问题,在多项式变换校正影像增强器失真图像的基础上,提出了基于正交多项式和加权正交多项式变换的影像增强器失真图像校正方法。利用正交多项式的正交特性和递推关系,提高影像增强器失真图像校正的精度、速度和灵活性;加权正交多项式变换中考虑控制点对不同像素点影响的不同,改善图像的局部形变。实验数据表明,相同阶数的正交多项式方法比多项式方法精度高,加权正交多项式方法则精度更高,能用较低阶的加权正交多项式实现较高的精度。在骨科手术导航系统中,作者利用三阶加权正交多项式方法校正影像增强器透视图像,降低了图像几何失真给病人空间与图像空间配准带来的误差,提高了手术定位的精度。

To correct the image distortions in orthopedic surgery based on the X-ray fluoroscopic image, an orthogonal polynomial and a weighted orthogonal polynomial methods are proposed. The orthogonal polynomial method can improve the precision, the speed and flexibleness of image correction, due to the orthogonality and recursion; the weighted orthogonal polynomial method has better local correcting capability according to different influences of control points on different points. Experimental data show that, as the same order, the orthogonal polynomial method is more precise than the polynomial method, and the weighted orthogonal polynomial method has better precision than others, thus obtaining the higher precision on the lower order weighted orthogonal polynomial. In orthopedic surgery, the third-order weighted orthogonal polynomial reduces the error of registration between the space and the image on account of the image distortions, and improves the precision of localization.