| Attitude measurement was widely used in all fields of aviation, spaceflight, military industry as well as civil use, for different concrete application, description for attitude was also different, and there were mainly two modes. One was to describe with the angle of rotation that its longitudinal axis was relative to some reference coordinate system, which was the attitude on absolute meaning, the other was to describe with the set of attitude Eulerian angle that rotation transformation was performed with carrier coordinate system relative to reference coordinate system, which was the attitude on relative meaning. Attitude measurement was the measurement of attitude angle. Aimed at the contradiction between speed and precision mostly existing in traditional attitude measurement methods based on array image sensor, which was adverse to satisfying requirements of real-time measurement, a kind of attitude measurement method of multiple linear CCD was put forward.Combination of one-dimensional imaging units composed by three linear CCDs catching information of different direction and cylindrical lens can realize three-dimensional coordinate reconstruction for spatial point target, such system was called as point target three-dimensional coordinate reconstruction subsystem, three sets of point target three-dimensional coordinate reconstruction subsystems were used to individually catch three point cooperation targets on real time which were set on two end faces of objects to be measured, which can realize measurement of attitude angle on two kinds of different meaning. LEDs of different wave band within visible light were taken as point cooperation targets, which respectively corresponded to filters of corresponding wave bands in point target three-dimensional coordinate reconstruction subsystems, and interference problem when one-to-one correspondence between multiple cameras and multiple-point cooperation targets was solved. New optical frame was designed, which was favorable to improvement of measurement precision and had saved measurement space. Multiple DSP parallel processing and embedded hardware platform with ARM-Linux as main control unit were used, which was accessible for real-time treatment and at the same time was favorable to commercialization transformation. Mathematical models aimed at two kinds of attitude angle on different physical meaning were established, respectively, and placement rule of cooperation targets had been given out.Concerned technology research used for realizing three-dimensional coordinate positioning for spatial point target based on combination of one-dimensional imaging units composed by three linear CCDs catching information of different direction and cylindrical lens was called as three-linear array positioning technology. Aimed at some problems that still existed in current research findings, meticulous and thorough research had been carried out. As for cylindrical lens and combined cylindrical lens, there was no classical formula for reference aimed at their distortion expression like the classical formula based on spherical lens aberration theory, a new method of distortion expression of complicated (aspheric surface) lens with known structure was brought forward; as for its vertical into meridian plane and its imaging relationship with plate lens, there was no formula like Gauss formula describing object-image relationship of spherical lens for reference, relationship expression between its imaging distortion in horizontal meridian plane and ideal image point position through spherical lens with same focal length on viewing field and vertical direction of meridian plane had been determined.Two-step method that divided nonlinear distortion coefficient and camera parameter was introduced to perform calibration. Because position information of ideal image points obtained through spherical lens with same focal length on viewing field and vertical direction of linear array CCD was contained in nonlinear imaging model of one-dimensional imaging units composing point target three-dimensional coordinate reconstruction subsystem, therefore, linear DLT imaging model on this direction was constructed to realize correction for nonlinear distortion parameter during process of calibration and measurement. DLT equations of seven coefficients can determine 8 internal and external parameters of camera under reference coordinate system, among which a position component was random, therefore, when coordinate reconstruction was carried out, the nondeterminacy of this position sometimes may result in divergence of solution, when mutual position relationship among one-dimensional cameras of reconstruction subsystem, stable solution of three-dimensional coordinate reconstruction can be obtained. Unification of local calibration and overall calibration when measuring with multiple-vision sensor was realized by introducing DLT imaging model based nonlinear compensation. In view of imaging characteristics of cooperation targets on linear array CCD, positioning method of weighted centroid was used.With reference of similar products home and abroad, research was carried out on relationship between mutual placement position of three one-dimensional cameras in each coordinate reconstruction subsystem and measurement space as well as relationship between reconstructed point target under reference coordinate system in measurement space and its corresponding spatial resolution on each coordinate orientation, which provided basis for design and application. With reference of research findings about the effect of control point placement used for calibrating two-dimensional cameral DLT imaging model parameter on its coordinate reconstruction precision, effect of control point layout used for calibration on coordinate reconstruction precision of positioning model based on one-dimensional DLT imaging equation had been studied via simulation experiment. Experimental device had been constructed to verify correctness of key problems studied in this paper.
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