| 摘要 |
PURPOSE:To permit non-contact and high accurate measurement of an inner diameter with simple construction and measuring procedures by a method wherein a transparent tube to be measured is disposed in parallel light flux to focus the transmitted light on an image pickup system and there are measured a refractive index of the measured tube and a distance between two bright lines in dark images which are produced as shadows of the measured tube. CONSTITUTION:A glass tube 21 to be measured is vertically disposed and held by a support 22 in parallel light flux emitted from a parallel light source 23 which comprises a tungsten lamp and a lens system,thereby to focus the transmitted light on a vidicon camera 24 for image pickup. An image on a monitor 27 indicates two bright lines 54, 55 in shadows 51, 52 of the glass tube 21. On the basis of measured values of a distance of those two bright lines and a refractive index of the glass tube 21, an inner diameter of the glass tube 21 is calculated using a predetermined pertient formaula. By so doing, it becomes possible to make non-contact and high accurate measurement of an inner diameter with simple construction and measuring procedures. |
