An automatic scheme for rail wear detection based on infrared image analysis

Detecting rail-wear status is critical to guarantee high-speed running safety, proper maintenance schedule, and low operating costs. An automatic scheme has been presented using near-infrared laser line projector, Charged Coupled Device (CCD) camera and image processing technology for rail wear detection. After obtaining original rail images, a DLT (Direct Linear Transformation) algorithm is analyzed and modified to correct the nonlinear lens distortion using a planar spot-grid. To analyze the shape of rail header, the corners (key points) on rail curve have been detected successfully. Compared with relevant points on standard rail curve, rail wear values are computed fast and accurately. It is testified that the whole system reflects the status of rail profiles wear authentically and dependably. Having high performance/cost ratio, the system is much suitable for Chinese context.