Research On The Method Of Single Camera Photogrammetry With A Small Number Of Coded Targets

Single camera digital close range photogrammetry is a non-contact measurement method which is widely used in large-scale manufacturing industry.It uses a digital camera to take photos of an object from different positions and angles,and calculates the three-dimensional coordinates of the marks on the object using digital image processing and photogrammetry principles.A new method of determining relative orientation with a small number of coded targets is proposed in this dissertation.With the aim of engineering application,a software of digital close range photogrammetry is developed.Based on the requirements for deformation test of large sized object,a measurement system is designed.Artificial marks used in close range photogrammetry are introduced.The advantages and disadvantages of different types of uncoded marks are compared considering the application scene of large sized object deformation test.The design principle,detection method and decoding method of the coded targets are analyzed in detail.A new method of determining relative orientation with a small number of coded targets is proposed.The corners in coded targets are used to determine relative orientation.The ordering rules of the corners are developed together with an effective method of corner detection.Experiments are conducted in order to find the minimum number of coded targets from which a satisfactory result of relative orientation can be drawn.The processes of solving three-dimensional point coordinates by single camera close range photogrammetry system are introduced,including determining relative orientation,matching uncoded targets using epilines twice,bundle adjustment and structure from motion.Based on the requirements for deformation test of large sized object,a measurement system is designed including a customized digital close range photogrammetry software.