Research On Automatic Measurement Method And Corrosion Evolution Law Of Cable Wire Corrosion Pit Based On Image Processing

Most of my country’s land area belongs to the acid rain affected area.Acid rain will significantly accelerate the corrosion damage of the bridge cables and affect the safe service life of the bridge.In order to avoid serious safety accidents and major economic losses due to the corrosion fatigue fracture of the cable steel wire,regular inspections of the corrosion status of the cable steel wire of the bridge and systematic research on the corrosion development law of the cable steel wire are of great significance to engineering practice.The traditional manual detection of the corrosion status of the cable wire has problems such as time-consuming,difficult to measure corrosion pits,and difficult to ensure the accuracy of the measurement.This paper is based on digital image processing technology,through the digital photo image of the corrosion appearance of the cable wire Processing,an automatic processing method for extracting the pit shape and measuring the pit parameters is proposed,and then using this method to study the development law of artificial accelerated corrosion of cable steel wire,which provides an effective method for the research of cable steel wire corrosion.Test tools and data materials for reference.The main research content and results are as follows:(1)Take pictures of the corroded cable wire in the laboratory,and perform grayscale processing,image denoising,image sharpening,blur enhancement,and binarization on the corroded photos in sequence,and further morphological processing,taking into account the influence of the wire surface,An automatic measurement method for the corrosion morphology of cable steel wire is proposed,which can realize the automatic measurement of parameters such as the length,length,width,corrosion area and pit spacing of the long axis of the etch pit.The comparison and statistical analysis of the automatic measurement results and the manual measurement results show that the accuracy and efficiency of the automatic measurement method are significantly improved compared with the manual method,and the automatic measurement method effectively meets the engineering test accuracy requirements.(2)Aiming at the problem of image denoising,the influence of different filter window sizes is analyzed,and it is found that the smaller the filter window size,the clearer the processed image;the 3×3 window of cable wire corrosion photo denoising is more suitable;comparing different spatial filtering methods,It is found that the filtering effect is ranked from good to bad in order of median filtering,mean filtering,and Wiener filtering;comparing different frequency domain methods,the results show that the wavelet filtering has the best effect;the research results show that the cable wire corrosion image denoising median filtering The method combined with wavelet has the best effect.(3)The automatic measurement method was used to extract the corrosion morphology of the steel wire in the artificial accelerated corrosion test with different corrosion time,and the relationship between the pit density,pit spacing,pit size and corrosion area ratio over time was studied.The distribution statistics of the pit size and the function fitting of its distribution law show that the length and width of the pit are distributed according to the log-normal distribution.The length of the pit long axis conforms to the Weibull distribution.The change rule of the pit can be determined by the shape parameter.And the position parameter reflects.(4)Through the research on the corrosion grayscale pictures,it is found that the peak width of the grayscale histogram has a good linear relationship with the corrosion rate,and the peak width can be used to reflect the corrosion rate;the peak width and the corrosion area ratio are negatively correlated,the grayscale histogram The peak width reflects the degree of corrosion.The research results of corrosion parameters based on fractal theory show that the size of etch pits has good fractal characteristics.There is no obvious relationship between the corrosion rate and the fractal dimension.The relationship between the fractal dimension and the corrosion area ratio is an exponential change.The fractal dimension is consistent with the evolution of the cable wire corrosion process and can be used to characterize the degree of corrosion.