Research On Dynamic Tracking And 3D Visualization Based On Visual Ultrasonic Detection

Ultrasonic testing is widely used in quality inspection of composite materials as a general non-destructive inspection method,and the demand for three-dimensional visualization of ultrasonic inspection results has increased with the improvement of inspection criteria of composite materials.The demand for three-dimensional visualization of ultrasonic testing results is more and more intense.Although the current ultrasonic imaging method can image the internal defects of the tested object in two dimensions,it can not obtain the spatial location information of the whole defect.In order to obtain more accurate ultrasonic inspection and spatial position information of the defect,the present ultrasonic testing apparatus is difficult to track and three-dimensional visualization is low.This paper combines ultrasonography and binocular technologies to construct a visual ultrasound nondestructive testing system to realize dynamic tracking of ultrasound testing equipment.The work done with this paper is as follows:(1)According to the principle of phased array ultrasonic testing and binocular vision measurement,the dynamic tracking system of ultrasonic testing based on vision is built.The system mainly includes ultrasonic testing module,camera tracking module and data processing module.(2)A dynamic tracking method for ultrasonic detection based on various invariant poses is proposed.Use the Zhang Zhengyou plane calibration method to calibrate the internal and external parameters of the binocular camera.The ultrasonic motion line fits the ultrasonic motion plane by the least square method.Compared to the ultrasonic probe calibration method based on the characteristics of the workpiece,after fitting,the angular error between the ultrasonic motion plane and the ideal motion plane is reduced by 2.029o,and the maximum depth error is reduced by 2.3636 mm.This method effectively reduces the position deviation of the ultrasonic testing device during the tracking process and realizes the realtime tracking of the ultrasonic testing device.(3)A Synchronization technology based on time series ultrasonic data is proposed.The time series synchronization of the ultrasonic inspection data and binocular examination data reduces the discrepancy between different data simultaneously.According to the ratio of defect area and prefabricated defect area in the energy characteristic image and the calculation of defect roundness,the timing synchronization accuracy is verified,the defect consistency of the data processed by the synchronization criterion is 96.66%,and the degree of roundness of the defect is 0.9935.This will resolve the distortion of the shape and the mismatch of the detection result by erroneous data matching during the synchronization process.(4)We propose an optimization algorithm of ICP splicing based on ultrasonic intensity.According to the K-D tree point cloud search technology,the ultrasonic point cloud data is extracted,the point cloud data acquired from multiple stations is roughly spliced,and the point cloud data is finely spliced by the optimization algorithm.Curvature is used to determine the ultrasonic intensity and overlap area.Points are constrained.Calculates the mean(?),standard deviation(?)and surface mutual penetration measurements(SIM)of the stitching error in the overlap region of the ultrasonic point group before and after the stitching.Compared with the ICP algorithm,the ? and ? of this paper decreases 0.0192 and 0.0154,SIM increased by 22.05%.Compared with the ICPIF algorithm,the ? and ? in this paper decreased by 0.0118 and 0.0069,SIM increased by 10.82%.Three-dimensional visualization of ultrasonic point group data of large carbon fiber tube structure was realized by this algorithm.The research of dynamic tracking and three-dimensional visualization based on visual ultrasonic inspection carried out in this paper can effectively reduce the defect positioning error and solve the problems of the ultrasonic inspection equipment being difficult to track and the low degree of three-dimensional visualization.It is of great significance to realize the three-dimensional visualization of industrial-grade ultrasonic non-destructive testing in the future.