Research On Optical Deflection Angle Measuring System Based On Non-diffracting Beam And Dedicated Matching Algorithms

Space attitude positioning is a common engineering problem, in which the accurateattitude measurement in a long and narrow space is the research difficulty. For example,the shield guiding technology is used in the construction of the subway, railway tunnelexcavation and other practical engineering applications. Accurate measurement of theoptical deflection angle can ensure the accuracy of the shield guidance. In particular thebearings positioning in the rational alignment of propulsion shaft require the space attituderelative to the datum line of shafting. This paper aims to establish a measurement systemof optical deflection angle in the space attitude. And it also proposes a image matchingalgorithm to calculate the optical deflection angle in order to obtain the higher accuracyand stability of measurement. The main research work includes the followings:(1) It raises the overall program of optical deflection angle measuring method andsystem based on non-diffracting beam space straight line datum. And it expounds themeasuring principle of the optical deflection angle and the design principle of the imagingoptical path. It also plans the relative positions of the component parts and chooses theappropriate lens to increase the measuring ranges of the optical deflection angle.(2) It designs the probe’s structure of the measuring system. Then it selects theinternal component parts to determine the structure parameter. The ZEMAX software isused to simulate the optical path of the measuring structure. Through the simulation theoptical path is verified reliably and can ensure the best imaging effect. Atomizedexperiment is to meet the requirements of the optical imaging membrane.(3) This paper raised the image matching method based on the Bessel image featuretemplate to obtain the center of the Bessel image combined with the sectional images’characteristics of non-diffracting beam. Obtaining the sub-pixel accuracy centralcoordinate through the pixel level and sub-pixel level matching process. The appropriatecorrelation metric formula can make the matching algorithms fast, stable and effective.Select the bilinear interpolation method to construct a new pixel image in order to meetthe matching sub-pixel accuracy. Finally, experiments are carried out to achieve the image acquisition and matchingprocess. The measuring accuracy of the optical deflection angle is0.1mrad, whichbasically meets the design requirements.