Design And Implementation Of A New Generation Of Automatic Focimeter Measurement System

Auto focimeter is an essential measurement and inspection instrument of lensmanufacturing and spectacle fitting. The new generation auto-focimeter adopts multidots Hartmann diaphragm, with simple and sealed optical system, green LED lightmakes no longer Abbe compensation, with strong measurement Fault Tolerance, it canhave a better and stable measurement of astigmatism and low power lens, it has a bettersupport of the measurement of free-form progressive lens.Although China is a most country of lens production and consumption, however thecore technology of auto focimeter has controlled by Japanese factories for a long time,therefore it is extremely urgent to R&D a new generation auto focimeter with fullyindependent of the core technology; if this can be come true, we can provide the enduser a easy operate auto fociemeter with more faster, stable, accuracy measurement andcan participate market competition with high cost performance.This thesis is studying the Embedded Software System and implementationtechnique of measurement algorithm which researched and developed in the newgeneration auto-fociemeter.Define the measurement algorithm requirement and function basis of this EmbeddedSystem, confirm the three core technical problem have to solved and softwareperformance requirements have to achieved of software system.1）Diaphragm image magnifying power extraction algorithmThis algorithm gets the image magnifying power, calculate the spherical power,cylindrical lens power and axis by extracting interpolation, fitting extract facularhorizontal-to-vertical spacing and slope of diaphragm image.When moving the lens, it makes stable and accuracy lens measurement byarithmetic and median-value average of the multiframe centroid Dot Matrix and keydata during extracting, especially have a stable, sensitive and accuracy measurementof.low degree and low astigmatism lens.The two-dimensional image data are projected through the horizontal,vertical,45°,135°direction, it reduce the projection interference of astigmatismtilt, transform the two-dimensional data to a4vertical one-dimensional data and make asimplified processing, analyze the peak-to-trough topological relations, Primary define the image centre and basic parameter of facular spacing and offset at horizontaland vertical, then make3X3facular region search of the two-dimensional image, get theaccuracy image center and spacing slope, position the facular region of the wholeimage, the is alignment and segmentation difficulties of image large dynamic is solvedaptly2）High-speed implementation of measurement algorithmThe image receiving and utilizing the approximationof the table frame beamsearch positioning frame data; softwarearchitecture, wait-free task scheduling; Self-developed IP based fast GUI cooperateparts image processing algorithm implement the fastest measurement refresh rate in thisindustry.3）Vivid Graphical User InterfaceVivid Graphical User Interface can makes a fast display of measurement date andinteraction states, easy and convenience to operate, it can makes what you see is whatyou get.