关键词: 道路工程, 数字图像处理技术, 沥青混合料, 离析, 图像预处理, 图像采集方法

Abstract: In order to study the influence of the acquisition method on the evaluation results of the digital image processing technology asphalt mixture evaluation method, a reasonable image acquisition condition was proposed. Digital image preprocessing was carried out on the AC-13 and AC20 grade type mixture images, the asphalt mixture images under different light intensity as well as images of different acquisition heights. Image uniformity was evaluated by four-sided static moment variation coefficient, and the results of variation coefficients were compared and analyzed. The research results show that the results of the static moment variation coefficient of 500 images of the AC-13 and AC25 asphalt mixture are concentrated in the range of 0 to 1.5%. The lower layer of AC-25 asphalt mixture is more prone to segregation than the upper layer of AC-13. In the case of sufficient light intensity, the uniformity evaluation result is not affected, but when the illumination is insufficient at night, the result will deviate, so it is necessary to compensate the illumination for the image acquisition. When the image acquisition height is 60cm, the aggregate particle surface ratio is consistent with the actual condition. As the height of the acquisition increases, the adhesion particles with large size in the preprocessed image increase, which affects the accuracy of uniformity evaluation.

Key words: highway engineering, digital image processing technology, asphalt mixture, segregation, image preprocessing, image acquisition method