| The optical data such as the diopter of the spectacle lens are obtained by the calculation of the power meter.Therefore,the power meter is an optical detecting instrument for ensuring the quality of the lens,and has high requirements for the accuracy and stability of the detection.From the development of the power meter,most of the auto power meter relies on the foreign market.Some domestic companies are also developing the automatic power meter,but the core technology of the test equipment does not meet the market demand.It is not possible to produce and manufacture in large quantities,so it is necessary to develop an advanced level autofocus meter with core competitiveness.In view of the current anti-interference ability of some lens diopter measurement systems on the market,the measurement accuracy is not high enough,and combined with the research status of automatic power meter,this topic is based on the patents of related autofocus meters at home and abroad and some related literatures.Based on the Raspberry Pi microcomputer as the control core,the Hartmann diaphragm 165 point area measuring glasses diopter automatic measuring system.The research content of this paper mainly includes the hardware architecture design of the system,image threshold segmentation and spot centroid extraction method,diopter measurement based on interpolation fitting and software design and measurement experiment of measurement system.Firstly,according to the working principle and scheme of the measurement system,the overall structure of the system is designed,and the electronic components used in this experiment are selected and combined with other hardware to build a complete visual measurement system.Then,based on the analysis of several commonly used spot image filtering algorithms and image threshold segmentation algorithms,the original Otsu threshold segmentation method is improved,and the performance of the improved method is better than the original method..The extraction of the centroid of the spot is also analyzed in detail.Finally,the centroid of the spot is calculated according to the experimental needs,and the experimental results of the method are verified by experiments.Then,the optical calculation formula of lens diopter is deduced,and the requirements of measurement system are analyzed from two aspects of function and performance.The diopter measurement method by calculating the spot spacing and interpolating is proposed.Finally,the software design of the diopter measurement system was completed and the measurement accuracy of the diopter measurement system was verified by experiments,which can meet the measurement accuracy and real-time requirements specified by the state. |
