Research On Method And Application Of Aggregate Size Recognition Based On Image Processing Technology

The segregation of the material pile will lead to the segregation of the mixture.After paving,the void ratio of different areas changes greatly,the road performance is poor,and the service life is greatly reduced.Effective identification and control of material segregation has always been one of the important research contents in the field of highway engineering.Based on the image processing technology,this paper studies the aggregate particle size recognition method and applies it to the identification of the segregation degree of the material pile.Further,based on the purpose of avoiding excessive segregation of the material pile,the segregation control system of the material pile is studied.Finally,the quantitative relationship between milling material particle size and milling machine operation speed is studied,and a milling machine operation speed control scheme based on particle size identification method is proposed.In the study of aggregate particle size identification method,based on the traditional bimodal method,an automatic threshold bimodal method is designed to binarize the image,and then the average area of the aggregate image is obtained through image optimization,segmentation and other steps.The real average area of the aggregate is obtained by combining with the correlation ratio,and the equivalent circle diameter of the area is taken as the average particle size of the identified aggregate.In the application of particle size identification method,the particle size dispersion coefficient of the pile is used as the evaluation index of segregation degree.The average particle size of the aggregate is obtained by this method and substituted into the evaluation index to analyze the variation law of segregation degree of the pile with volume in three particle size ranges.Based on the purpose of segregation degree control,the four point rotation stacking function is designed for the unloading car,and the MATLAB segregation control program is simulated by using the system composed of Virtual PLC and Win CC.In order to explore the quantitative relationship between the milling material particle size and the milling machine speed,the energy transfer analysis,kinematics analysis and experimental research of milling process were carried out.The results show that the particle size identification method can identify the aggregate particle size and is feasible.The pile height and segregation degree of 10-25 mm,5-10 mm and 0-5 mm aggregates increase gradually with the increase of pile volume,and they all show a trend of rapid increase at first and slow increase later.For the same volume of pile,the higher the friction coefficient of aggregate,the higher the height of pile,and the smaller the segregation degree of pile,that is,the segregation degree of pile: 0-5mm>5-10mm>10-25 mm.With the stacking process,the segregation degree of the three kinds of aggregates is increasing.Limited by the threshold of dispersion coefficient,the allowable maximum stacking volume of 10-25 mm aggregate is much smaller than that of 0-5 mm aggregate,but due to the large friction coefficient,the allowable maximum stacking height of 10-25 mm aggregate is almost the same as that of 0-5 mm aggregate.The energy transfer and kinematics of the milling rotor are studied,and the conclusion is consistent with the milling test results.There is a quantitative relationship between the milling speed and the milling material particle size.It is suggested that the operation speed of milling machine should be controlled above 1.7m/min to reduce the sensitivity of milling material particle size to the change of operation speed and enhance the accuracy of milling material particle size identification.