The measuring method for actual total magnification of metallographic microscope — digital image method

摘要

In this paper, taking MM6 metallographic microscope 160x as an example, one kind of new method is studied on measuring actual total magnification of metallographic microscope by measuring digital images, the digital image is virtual image viewed through eyepiece of microscope and acquired by digital camera instead of eyes. Results show: 1) The digital images of 5/100 ocular micrometer and 1/100 stage micrometer in the eyepieces of microscope are acquired. The digital images of the 5 grade gauge block, which is 5mm length and is from camera 250 mm, are acquired in the same acquiring conditions. The lengths of the ocular micrometer and gauge block in the digital image are measured, and then the magnification of eyepieces is calculated. The lengths of the ocular micrometer and stage micrometer in the same digital image are measured, and then the magnification of objectives and tube factor is calculated. The actual total magnification of metallographic microscope is the product of magnification of eyepieces and magnification of objectives and tube factor; 2) For 160 x magnification of MM6 metallographic microscope, the measurement result of actual total magnification are stated as: 154.8 x, U=2.8x, k=2, and the actual relative deviation is-3.2%. 3)The digital image measuring method for actual total magnification of metallographic microscope can be a standardized method.