Wide Range Coordinate Measurement Method Under Small Field Of View

Acquiring three-dimensional shape data of large-scale objects quickly and accurately is an important research direction in the development of modern mechanical industry and measurement industry.The use of computer vision for coordinate measurement technology is one of the hot spots.The current domestic research on coordinate measurement of visual coordinates has made some progress,but there is no breakthrough in solving the basic contradictions of measurement range and measurement resolution.The subject is proposes a large-scale visual coordinate measuring method and this measurement system is based on a small field of view of a coded target.With the holographic characteristics and image sensors of a digitally-encoded target,only the local coded information of the target needs to be obtained,and the spatial coordinate transformation and image information processing can be performed.Getting a wide range of information methods to achieve high-resolution,using a small-field images to achieve a wide range of three-dimensional coordinate measurement.It provides a new idea and new method to solve the conflict of large-scale and high-resolution of vision measurement,which has theoretical innovation significance and practical value.The main research work of this dissertation is as follows:(1)By analyzing the current status of visual coordinate measurement technology,a large-scale coordinate measurement method for small-field of view using coded targets is proposed,which breaks the contradiction between large-scale measurement and high resolution.(2)Studying the working principle of the measurement system and completed the overall structural design of the system.Based on the structure and measurement principle of the system,the mathematical model of coordinate measurement and the corresponding measurement equations were established.Simulated the parameters of the measurement system to determine the best system parameters.(3)Studying the centering algorithm of the light spot centered on the image of the coded target,used software programming for image processing,calculated the center of the light spot,and located the marker points in the measurement.Changed the state of the measured point(target tilt,etc.)to get the center of the spot in different environments.(4)Using the holographic nature of a digitally encoded target,a set of codes is decoded,and the global information of the measured point is found under the condition that only an arbitrary piece of spot information is obtained.(5)Completed the measurement software design of the system,and built an experimental platform,conducted fixed-point measurement experiments,repeatability experiments,and comparative experiments.