Design Of Automatic Focus Meter Measurement And Control System Based On ARM

The automatic focal meter is an instrument used to measure the optical parameters of spectacle lenses or contact lenses,and it is one of the necessary instruments in the process of fitting lenses.It has the advantages of simple and convenient use,rapid and accurate measurement.As the current domestic automatic focus meter mainly relies on imported products from abroad,an ARM-based automatic focus meter measurement and control system is proposed for the problem of localization of the automatic focus meter.Based on the Hartmann diaphragm measurement principle,the paper calculates the calculation formulas of spherical lens power,cylindrical lens power,cylindrical lens axis position and prism power,analyzes the functional requirements and performance index requirements of the measurement system,and selects the one introduced by Allwinner the A33 ARM processor is used as the hardware and software carrier of the measurement and control system,and the Linux real-time operating system is used as the embedded system software platform to determine the overall plan based on the ARM+Linux measurement and control system is determined.When considering how to reduce the measurement error of the measurement and control system,the optimal aperture of the Hartmann diaphragm is optimized.The objective function model is established according to the arrangement of the circular holes on the Hartmann diaphragm,the variable model is determined by the theory of aperture diaphragm diffraction interference optics and Matlab simulation,and the enumeration method is used as the extreme value search method to obtain a certain measurement area.The best aperture of the Nei Hartmann diaphragm;an experimental platform is built,and the reliability of the best aperture value obtained by this method is verified by comparison,and the designed Hartmann diaphragm is applied to the measurement and control system in the article.The hardware part of the system determines the light source module,image acquisition module,WiFi transmission data module,LCD touch screen human-computer interaction module and printing function module according to the specific peripheral function requirements given,and designs the interface between them and the microprocessor;The software part builds a development platform based on the Linux operating system environment,compiles the program,and completes the software design of the peripheral module functions;completes the spherical degree,cylindrical degree,cylindrical lens axis and prism degree measurement program based on the calculation formula of the lens optical parameter Design: Programming through the C++ language of the application Qt software,designed the human-computer interaction measurement interface and the setting interface.Combining the measurement optical path,structure and main control hardware,an experimental prototype was built to verify the functions and performance indicators of the measurement and control system.The experimental results show that the system realizes the functional requirements of image acquisition,WiFi data transmission,LCD interface display and touch operation,and printing of measurement data results.In terms of performance indicators,the measurement data is also analyzed,showing that the expected performance indicators can be achieved.