Surface defect detection for high-speed rails using an inverse P-M diffusion model

Abstract

Purpose – When using a machine vision inspection system for rail surface defect detection, many complex factors such as illumination changes, reflection inequality, shadows, stains and rust might inevitably deform the scanned rail surface image. This paper aims to reduce the influence of these factors, a pipeline of image processing algorithms for robust defect detection is developed. Design/methodology/approach – First, a new inverse Perona-Malik (P-M) diffusion model is presented for image enhancement, which takes the reciprocal of gradient as feature to adjust the diffusion coefficients, and a distinct nearest-neighbor difference scheme is introduced to select proper defect boundaries during discretized implementation. As a result, the defect regions are sufficiently smoothened, whereas the faultless background remains unchanged. Then, by subtracting the diffused image from the original image, the defect features will be highlighted in the difference image. Subsequently, an adaptive threshold binarization, followed by an attribute opening like filter, can easily eliminate the noisy interferences and find out the desired defects. Findings – Using data from our developed inspection apparatus, the experiments show that the proposed method can attain a detection and measurement precisions as high as 93.6 and 85.9 per cent, respectively, while the recovery accuracy remains 93 per cent. Additionally, the proposed method is computationally efficient and can perform robustly even under complex environments. Originality/value – A pipeline of algorithms for rail surface detection is proposed. Particularly, an inverse P-M diffusion model with a distinct discretization scheme is introduced to enhance the defect boundaries and suppress noises. The performance of the proposed method has been verified with real images from our own developed system.

Advances in Fault Diagnosis for High-Speed Railway: A Review

“…[27] summarized the NDE techniques used for rail track defects detection, among all the techniques surveyed, the automated visual inspection technique is popular for HSR systems, which can detect track corrugation, missing part and defective ballast. [28] developed an image processing method to detect track defects based on the scanned track surface image. In [29], an acoustic emission (AE) technology-based NDE method was proposed for HSR track defect detection, and the Kalman filter was applied to denoise the AE signals.…”

Block Sparse Low-rank Matrix Decomposition based Visual Defect Inspection of Rail Track Surfaces

“…The fine extractor can reduce most of the impacts of noise interferences by vertically fusing the context information, and horizontally fusing the prior information. In [37], a new inverse Perona-Malik (P-M) diffusion model was proposed for image enhancement. Then, an adaptive threshold binarization method was proposed for defect inspection.…”

Probing nonclassicality in an optically driven cavity with two atomic ensembles

“…An operational definition of steering was first provided in [59], wherein they proved that steerable states are a strict subset of the entangled states and a strict superset of the states that can exhibit Bell non-locality. In the context of field modes a and b, the EP R − steering entanglement is confirmed if it satisfies [60]…”