The three-dimensional defect distribution in material test specimens is a very important piece of information for us to understand the deformation and failure mechanism of materials. This distribution is sometimes complicated by the surface roughness of specimens in the defect detection of computed tomography data. In this paper, we proposed a new local differentiation algorithm to remove the s...

The accurate image segmentation of surface defects is challenging for modern convolutional neural networks (CNN)-based models. This paper identifies that loss imbalance a critical problem in accuracy improvement. includes: label imbalance, which impairs the on less represented classes; easy–hard example misleads focus optimization valuable examples; and boundary involves an unusually large valu...

On the basis of a rigorous, nonperturbative, purely numerical solution of the corresponding reduced Rayleigh equation for the scattering amplitudes we have studied the scattering of a surface plasmon polariton by a two dimensional dielectric defect on a planar metal surface. The profile of the defect is assumed to be an arbitrary single-valued function of the coordinates in the plane of the met...

In recent years, there has been an increased emphasis for quality control in the manufacturing sector. Many manufacturing processes have become fully automated resulting in high production volumes. However, this is not necessarily the case for inspection of aerospace surface defects. Volume measurement of defects is one of the key elements in quality assurance in order to determine the pass or ...

Steel surface defect detection is crucial for ensuring steel quality. The traditional algorithm has low probability. This paper proposes an improved based on the YOLOv5 model to enhance Firstly, deformable convolution introduced in backbone network, and a module replaced by convolution; secondly, CBAM attention mechanism added network; then, Focal EIOU used instead of CIOU loss function YOLOv5;...

Scanning tunneling spectroscopy images of Bi2Se3 doped with excess Bi reveal electronic defect states with a striking shape resembling clover leaves. With a simple tight-binding model, we show that the geometry of the defect states in Bi2Se3 can be directly related to the position of the originating impurities. Only the Bi defects at the Se sites five atomic layers below the surface are experim...