基于L-M算法的机械臂三维超声图像标定方法

3D Ultrasonic Image Calibration of Mechanical Arm Based on L-M Algorithm

为了在三维超声成像中获得更多、更详细的位置信息,得到更准确的定位精度,采用机械臂夹持超声探头并利用L-M算法进行超声图像标定。标定过程中,通过将N线模板放在水槽中,从而得到更准确的定位装置接收器与超声图像之间的位置转换关系,利用六自由度机械臂控制超声探头水平移动扫描模板以获取超声图像,并利用区域提取与缺陷分割技术获得图像中的像素坐标,以及扫描点在模板中对应的实际坐标,最后运用L-M算法进行标定计算,获得所需的标定转换矩阵。实验结果证明,该方法简单易行且效率较高,提高了标定精度,可满足实际检测精度需求,避免了手动扫描误差,为后续三维重建奠定了基础。

In order to obtain more detailed position information in 3D ultrasound imaging,more accurate positioning accuracy is obtained.The ultrasonic probe is clamped by the robot arm and the ultrasonic image calibration is performed by the L-M algorithm.During the calibration process,a more accurate position conversion relationship between the receiver of the positioning device and the ultrasonic image is obtained by placing the N-line template in the water tank,and the ultrasound probe horizontally moving the scanning template is controlled by a six-degree-of-freedom robotic arm to obtain an ultrasound image.The region extraction and defect segmentation techniques are used to obtain the pixel coordinates in the image and the actual coordinates of the scan points corresponding to the template.Finally,the LM algorithm is used for calibration calculation to obtain the required calibration transformation matrix.The experimental results show that the method is simple and efficient and can improve the calibration accuracy,meet the accuracy requirements of the actual detection,and avoid the error of manual scanning,which lays a foundation for the subsequent 3D reconstruction process.