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The morphology of high-voltage cable sealing layer has an important impact on the sealing characteristics. Aiming at the measurement problem of high-voltage cable sealing layer morphology, this paper uses a lattice laser to irradiate the target to form a laser lattice on the surface of the target, and then obtains the target image with a binocular polarization camera. The polarized light is used to overcome the influence of metal reflected flare, and then a pair of target images are matched. Then the parallax of each point is calculated. Finally, these points are used to reconstruct the point cloud to obtain the three-dimensional(3D) shape of lead sealing layer. The method in this paper provides a method for the measurement of the 3D shape of lead sealing layer, which is of great significance for the quality control of lead sealing layer.

Lead has good corrosion resistance and sealing property, which is often used in cable lead sealing process and various processes. In the production process, there may be small defects in the lead products, which may affect the quality of the products. Therefore, it is of great economic significance to inspect them to ensure their reliability. Due to the variety of lead products, the use of traditional ultrasonic detection is limited, and laser ultrasound has the ability to detect all kinds of surface samples. However, when the inner defect size of lead products is submillimeter or smaller, the echo signal-to-noise ratio(SNR) is low, so the traditional laser ultrasonic technology is difficult to locate the defects. In this paper, the synthetic aperture focusing (SAFT) technology is applied to the laser ultrasonic detection of lead internal defects. The minimum defect identification ability and resolution ability of laser ultrasonic combined with SAFT are studied, which provides reference for practical application.

Synthetic Aperture Focusing (SAFT) is one of the methods to improve the spatial resolution in laser ultrasound. However, the research on laser ultrasonic SAFT technology is mainly focused on block or plate samples. In order to study the detection capability of laser ultrasonic SAFT technology on the samples with curved surface, a finite element simulation model of curved surface samples with sub millimeters internal defects is established. And then the laser ultrasound field is obtained through numerical simulation. At last the SAFT algorithm was performed to image the defects in the samples. The results show that laser ultrasonic SAFT technology can image curved surface samples with sub millimeters internal defects. The results provide a reference for the practical application of laser ultrasonic SAFT technology.

Synthetic Aperture Focusing (SAFT) is one of the methods to improve the spatial resolution in the traditional acoustics field. Its basic principle is to combine a series of small-aperture sensors to replace a large-aperture sensor in order to improve the detection lateral resolution. However, the practical detection results will be affected by noise. In this paper, the time-domain B-scan signal is obtained by establishing a physical model of a lead sample containing defects and computing with finite element method. Then, the influence of noise with different signal-tonoise ratio(SNR) on SAFT imaging results is studied. The results show that SAFT algorithm has better anti-noise performance, and can still obtain good results even when the SNR is low.