Study On Evaluation For Surface Texture Of Asphalt Pavement Based On Digital Image Processing

The advantages of the asphalt concrete pavement with smooth pavement, low noise,driving comfort and no juncture make it be used broadly worldwide in the highwayconstruction. With the developing of the construction of asphalt concrete pavement, theskid-resistance of pavement becomes very important. The texture of the pavement have aclosely link with its skid-resistance, but the current evaluation indexes of the pavementtexture are very less and the evaluation methods are backward.Considering the disadvantages of measurements for asphalt pavement surface texture inspecification, a test system for surface texture is invented based on Digital Image Processingin this paper. Three red, green, blue images are obtained firstly. Gradient is figured up relyingon photometric stereo techniques. Altitude chart of asphalt pavement is obtained whichreconstructs by means of Global integration techniques. Results demonstrate that athree-Dimension RGB image for asphalt pavement surface texture is reconstructed preciselyaccording to this tester； The actual surface of ups and downs of pavement is describedaccurately from the RGB image.According to fractal theory and geometry, calculates the fractal dimension and fivegeometry characteristic parameters of three dimensional images separately, and analyses thecorrelation with the traditional evaluation methods. Results demonstrate that the microtextureof asphalt pavement surface can be characterized by fractal dimension, and the macrotaxturecan be characterized by the five geometry characteristic parameters.Combining the demand on asphalt pavement skid resistance condition of currentcriterion with the calculated results of this research, the paper commends different figures offractal dimension D and five geometry characteristic parameters: AC：D>2.74，θ_s>32.31，Z2s>1.34，R_s>1.25，T_s>1.25，0.9>K_a>0.7；SMA：D>2.81，θ_s>39.61，Z2s>2.35，R s>2.10，T_s>2.10，0.9>K_a>0.7；OGFC：D>2.85，θ_s>47.10，Z2s>3.0，R s>2.78，T_s>2.78，0.9>K_a>0.7，the test system for asphalt pavement surface texture based on Digital Image is completed.Finally, GUI is developed using MATLAB, Realizing the man-machine interactive processingof the test of asphalt pavement surface texture.