Aiming at dealing with the problem of digital detection of flush and gap between aircraft skins

the measurement technology of detection method is studied based on the grating projection technology. Firstly

the dense point cloud data of surface to be measured is obtained using the technology of grating projection; Then

the seam area is positioned from the image

and the point cloud data of the seam area is obtained according to the correspondence between the point cloud and the image; After that

the point cloud data is analyzed and the joint on both sides of a straight line segment is determined. And based on them

the flush and gap are calculated. Compared to the structure line technology

the proposed method can obtain more data. Besides

we can analyze all seams during one measurement and thus

the detection efficiency is very high. The experimental results show that the mean error of the proposed method is less than 0.03mm and the maximum error is less than 0.05mm

which can meet the requirements of aircraft skin seam testing.