Ultrasonic image distortion correction approach for open-loop scanning system
Ultrasonic microscopy is widely used in industrial nondestructive testing.Compared with the closed-loop and semi-closed-loop scanning systems,the hardware structure of the open-loop scanning system is simple and the cost is low.However,the non-linear motion of the stepping motor will lead to image distortion of the pixel dislocation due to the lack of feedback mechanism.Therefore,eliminating the dislocation distortion caused by nonlinear motion is the key to realize high-quality ultrasonic imaging using open-loop scanning system.In this paper,a MIP-Otsu-C3M method is proposed.It integrates the maximum intensity projection(MIP)method,the maximum between-cluster variance(Otsu)method and the central coordinate correction method(C3M).For the echo data obtained by the open-loop scanning system,the MIP method is used to obtain the initial gray image,the Otsu method is used to obtain the edge pixel positions of the B-scan image of the region of interest,and the C3M method is used to eliminate the pixel dislocation.The coin images demonstrated that the ultrasonic C-scan image distortion is successfully eliminated.The time of flight method and Fourier transform method are used to reconstruct the echo data which have been corrected from the dislocation distortion,and the undistorted three-dimensional image and perspective image are obtained directly.The new algorithm also verifies that the MIP method can be extended to the application of image distortion correction.
NETL
NSTL
万方数据
维普
