The Research Of Testing Theory And Testing Methods Of Low-Level-Light Aiming Sight-Glass In Multi-Environmental Test

In this paper, the main research work is LLL(Low-Level-Light) aiming sight-glass zero displacement detection system design is done; Theoretical analysis on the testing of LLL aiming sight-glass in multiple circumstances is done and mathematical models under different tests are established; A zero displacement target detection and image processing method is achieved based on the characteristics of multi- environmental test circumstances dim light testing image; The vibration of aiming sight-glass and shock test modal identification method are studied.Analysis of multi-environmental testing on LLL aiming sight-glass is done. Its image features are studied. Optical imaging system is designed. Main component parameters are calculated. With the method that LLL aiming sight-glass axially loaded, the design of environmental testing detection system is finally completed.Using vibration theory to study the vibration test, it concludes that vibration system can be equivalent to a forced vibration system model with damping and without damping according to freedom and forced condition. Using shock theory to study the shock test, it concludes that shock system can be equivalent to a model that is shocked by transient half sine pulse. Using temperature impact theory, Aiming Sight Glass cylindrical shell thermal stress model is established. Under the thermal shock environment, radial, tangential, axial thermal stress varies with the thickness of the cylinder. Using thermal optical theory and finite elements analysis methods, Combined with the actual size of object lens and design parameters, a temperature impact main objective lens model is established. Then the obtained data is analyzed and simulated, the error caused thermally and optical properties MTF is achieved. That is meaningful to the guiding of the material choice of the main objective lens.Using structural mechanics and the theory of vibration, the vibration force of the division plate connections rotating screw is studied. The test shows that by the methods of adjusting thread friction coefficient, the equivalent friction angle and additional damper bound-by conditions to control zero displacement move of the sight glass. This provides a theoretical and analysis basis for the production of other straight sight optical devices. According to multi-environmental testing dim-light image noise characteristics, the calculation methods of geometric mean, median filtering and histogram equalization pretreatment are applied. Dim-light image threshold value segmentation uses the improved Daubechies wavelet algorithm. Low-light-level image target detection uses SSDA sequential similar algorithm and the improved one return algorithm that makes matching accuracy and matching time increase substantially.Combining the experimental model curve and theory model curve using optimal control theory, optimal error and modal parameters that show the actual system features are obtained. Based on frequency response functions modal identification to the first seven bands, it is found that at order 5, 6 and 7 modes, with frequency of between 75Hz to 95 Hz, the vibration load affects larger on the structure. During shock test modal identification to the first six orders, it is found that at 2 and 3-order mode, with frequency between 5.3326 Hz and 39.8205Hz, the shock load affects larger on the structure.