Automatic prismatic refractive power measuring instrument for eye-protector

Based on the BS EN167 standard, it usually needed two operators to perform the prismatic refractive power measuring because the distance between tested eye-protector and image plane is about 2m. Furthermore, the prismatic refractive power measuring instruments were usually performed by using human eyes and the larger uncertainty of measurement will be induced while observing the measuring patterns using human eyes. Therefore this study presents the development of automatic prismatic refractive power measuring instrument, which was integrating machine vision, image analysis and processing without human operation. The experimental results showed the automatic prismatic refractive power measuring instrument has the high accuracy and good repeatability.