The Study Of Space Object Attitude Measurement Technology Based On Optics

In the field of precision manufacturing,aerospace,aviation,architecture and other fields,the relative three-dimensional attitude angle between devices is an important physical parameter that affects the transmission performance or machining accuracy of the system.Because optical measurement is non-contact and full field measurement,optical measurement technology has the advantages of simplicity,convenience,reliability and low cost compared with other measuring technologies such as sensor measurement.Based on the optical non-contact measurement method and based on image processing technology,we have studied the design of space object attitude measurement system,the attitude angle calculation method,the attitude measurement image processing,the test and verification of the measurement system and so on.Firstly,we design the attitude measurement system and the hardware and software platform.According to the principle of optical angle measurement,we design the overall structure of the optical attitude determination system,and use FPGA as the processor of the attitude measuring system.Firstly,the hardware system,including the embedded NiosII soft core,is built to replace the traditional FPGA+DSP structure.Secondly,we set up the software part,including the design of video acquisition and communication module.The former is used for image acquisition and real-time display,which is the basis for the implementation and verification of a series of image algorithms.The latter is used to communicate with PC.Secondly,the attitude angle calculation method is studied.According to the plane reflection theorem,a three dimensional small angle measurement method is designed by using a double reference light source.First,each coordinate system of the attitude measurement system is set up to complete the mathematical modeling of the attitude angle.Then we use the common coordinate system of camera to establish the transformation relationship between the image pixel and the actual size.Finally,we finish the solution of the pose angle through the optical angle measurement principle and the pinhole imaging model of the camera.Thirdly,the algorithm of attitude measurement image processing is studied.By analyzing the characteristics of laser spot and in order to effectively extract laser spot images,we first need to preprocess the collected images,so as to improve the image data and filter out the interference part.Second,the spot real-time detection and spot center coordinates are extracted,which can be prepared for the next step of attitude angle calculation.Finally,according to the real-time requirements of the optical attitude measurement system,the hardware implementation of the image processing algorithm is completed by using the advantages of FPGA design flexible and parallel processing.Finally,the test and verification of the measurement system are carried out.In order to calibrate and test the geometric parameters of the internal optical system and the external structure,the accuracy of the measurement system is ensured.First,the camera calibration method of plane template is used to calibrate the camera's internal and external parameters.Secondly,the grid calibration method is used to calibrate the measurement system.Finally,the error of the system measurement is analyzed,and it is verified that the attitude measurement system designed in this paper meets the requirement of the angle measurement accuracy.