Research On Deformation Measurement Method Based On Camera Grou

In the process of development and in-service monitoring of large structures such as bridges,aircraft,large vehicles,ships,and spacecraft etc.,it is often necessary to measure the deformation of different positions on the structure at the same time.In response to this important demand,a distributed synchronous 3D deformation measurement system based on camera group was developed in this paper.The measurement accuracy and anti-disturbance characteristics of the system were discussed and the feasibility of the system used in engineering was verified.The main research contents of this paper are as follows:1.Through theoretical derivation and computer simulation,the relationship between different system parameters and 3D reconstruction errors of camera group and two-camera was studied comparatively.The results showed that the reconstruction error of the camera group system was about 20% lower than that of the two-camera system.2.A distributed multi-camera measurement system was developed based on Raspberry Pi.Under the wireless network,multiple cameras in the system can be arranged arbitrarily in a wide range,with the functions of remote control,synchronous shooting,image transmission,image processing and deformation analysis.3.Considering the heat flow disturbance is the main source of errors in long-distance optical measurement,the anti-interference ability of the camera group to the heat flow disturbance was studied.Through experiments,the measurement errors of the camera group and the two-camera system due to heat flow disturbances in the heating stage temperature of 60°,80° and 100° were compared.The experimental results showed that the measurement error of the camera group system was about 16% smaller than that of the two-camera system.4.Through the experiment of multi-point synchronous measurement of deflection of an elastic rod fixed at both ends,the error between the measurement result of the camera group and that of the displacement sensor was less than 5%,and the equipment was easy to install and operate,so it can be widely used in multi-point synchronous deformation measurement of large structures.