一种快速、自动的三维超声标定方法

A Rapid and Automatic Calibration for Freehand 3D Ultrasound

三维超声系统越来越多地被应用到微创手术过程中,但是,在三维超声系统使用前必须对三维超声系统进行标定求解出超声图像平面坐标系和附属在超声探头上定位装置坐标系之间的转换关系,传统的标定方法比较繁琐,为此,开发了一种多"N"形线框标定模板。首先自动提取几张图像的特征点,利用相似三角形原理,得到超声图像特征点在模板中的同源点,利用直接求解方法快速地标定出结果。实验结果证明,整个标定过程在3min之内,满足临床应用的需求,同时,该方法同样具有高精度。

Freedhand 3D ultrasound systems have been more and more used as minimally invasive surgical navigation systems. A prerequisite for establishing an ultrasound navigation system in clinic application is calibration, whose aims is to determine the rigid body transformation between the US image and tracking device attached to the probe. However, most existing methods require a complex phantom and tedious experiment. We developed a multi- ＂N＂ fiducials phantom. In the calibrating produces, only several US images were used to detect the character points and character exaction was semi-automatic. The homologous points in the phantom were found according to those in US images based on similar triangles theory, After that, the matrix was computed by closed-form solution. The result of experiments showed that the calibration process was less than 3 minutes and meet, the demand for clinical application. In addition, our proposed approach were accurate and feasible.