Evaluation And Measurement Method On Light Transmitting Capability Of Sights

The level of light transmitting capability of sights is directly related to its visual range. Photocell is usually used to measure light flux directly, or photomultiplier is usually used to indirectly measure the output illuminance of integrating sphere in traditional measurement methods of light transmitting capability. Reference inconsistent errors may arise from changes of input light geometry due to the differences of diopter between under-tested optical system of sights and standard sample supplied by National Department of Metrology when placing and then removing them.Traditional measurement methods of light transmitting capability cannot meet the overall evaluation and inspection requirement of light transmitting capability of sights in the process of developing,setting and producting.After consulting related domestic and international literature and information, this paper proceeds thorough research on evaluation method, testing theory and key technology. Meantime the test system of light transmitting capability is designed.After analyzing and summarizing present situation of measurement method of light transmitting capability and instruments at home and abroad, two concepts that light transmitting efficiency and relative distribution of light energy are proposed to give an overall description of sights,aiming to the one-sided evaluation on light transmitting capability of sight. Based on the concepts, measuring theories of light transmitting efficiency and relative distribution of light energy are deduced, and the relationship model between the output illumination of integrating sphere and the incident beam geometry is established. Simulation experiment has proved that why the present measurement method of light transmitting capability cannot unify planar system measurement with nonplannar system measurement is mainly that reference inconsistency of incident geometry may arise from the random variation of escaped light flux due to the changes from incident beam geometry. Aiming to the problem, an incident geometry controlling method of nonplanner system is proposed. It can make the geometry of measurement focus of nonplannar sample be consistent with the geometry of reference focus by keeping lambert screen and detector simultaneous and equidistant, so the reference inconsistent error due to the changes from incident beam geometry is eliminated.For the planner system, the method, which converts plannar sample measurement to nonplannar sample measurement by using additional lens, unifies the measurement reference of plannar system with nonplannar system. Base on above method, a test setup, which can measure light transmitting efficiency and relative distribution of light energy together, is designed.Research on implementation method of transmitting,receiving and information processing module of the setup is made,and its vibration characteristics is also analyzed by simulation experiment.Deep study on the interferenc problem from background light is made here, and correlation filtering method is proposed to conquer background light interference in order to meet the requirement of bright field test.To solve the problem that the distribution nonuniformity errors of light source, lambert screen, imaging lens and CCD camera will influence the measurement of relative distribution of light energy, the distribution surface of luminous intensity is fitted with least square method for constructing light source reference plane to therefore realize the united calibration of CCD area array.based on the fact that the nonuniformity of light source, lambert screen and imaging lens is deterministic and the inhomogeneity of CCD is random from spatial domain analysis,Experimental results indicate that the design, which can measure light transmitting efficiency and relative distribution of light energy together, unifies the measurement reference of light transmitting capability of plannar system with nonplannar system, and solves the problems that light transmitting capability can not be compared and transferred between planar system and nonplanar system.and its accuracy of light transmitting capability is 0.3%. It provides evidence for objective and overall evaluation on the light transmitting capability of sights and also has great significance in improving the visual range of visibility of sights and guaranteeing the attack efficacy of weapons.