A new design of imaging and image processing system for auto lensmeter was presented to improve the measuring accuracy of the equipment. Compared with the traditional design which has 4 imaging points

the new method increased 12 points.A mathematical model based on the 16 testing points was established.By dividing the 16 testing points into 4 groups

the final measurement result was the average of the 4 groups' testing values.According to the calculation method of the model

a measuring system based on ARM and CCD was designed

and the image binarization algorithm was realized.The experiment results show that the new design of auto lensmeter has been qualified to the related national standard.Furthermore

the results also imply that the new design is better than the old one on measurement accuracy and stability.