Automatic detecting method of cement concrete pavement fault

In order to realize the automatic detection of cement concrete pavement fault, the active optical 3D shape measurement technique was analyzed, area array CCD camera was used to receive the measurement images, the detecting platform of fault was established based on the line laser 3D scanning, and mainly included the power subsystem, the acquisition subsystem of cement road surface image, the external trigger subsystem and the GPS positioning subsystem. The noise filtering threshold was determined according to the noise characteristics of 3Ddetecting data of cement concrete pavement, the open and corrosion operations were implemented for eliminating the isolated points in the data after the mean square deviation filtering. 3D data matrix was divided into homogeneous blocks according to its size, the blocks mean was used to eliminate the incline of data matrix, the inflection point matrix was obtained according to each row inflection point of 3Ddata matrix, and the faulting values were calculated. In order to verify the feasibility and validity of the method, parallel fault, trapezoid fault and cross fault weresimulated and respectively detected three times according to the fault sizes in the laboratory, and the detecting result was compared with the testing result of leveling instrument. The same fault was repeatedly measured 10 times by the leveling instrument and the 3D detecting method to verify the reproducibility of 3D detection method. Experimental result shows that 96% of absolute errors between the measuring values using the 3D detection method and the leveling instrument are less than 1mm, the standard deviation is about 7.8 times larger using the leveling instrument than using the 3Ddetection method, so the 3Ddetection method has higher accuracy, stability and reproducibility and can be used in the automatic detection of concrete joint fault.