Summary
Apart from pointing out to the necessity of a uniform nomenclature for the geometrical values like tube diameter, tube length, and direction of view, additional proposals are made for measuring other optical properties like field-angle, magnification, diameter of entrance and exit pupils, transmittance, and vignetting, all of them important features for describing the characteristics of endoscopes. It is further shown that the optical transfer function (OTF) offers a very good possibility for characterizing the image quality which is subject to aberrations and influences of diffraction. This is followed by the description of a measuring method for determining the “OTF” of endoscopes, illustrated by several curves of this particular function which has been applied to measure 4 different endospoce types. A table shows a number of measuring results obtained on 4 different endoscopes of those particular values as have been recommended for characterization.
Key-Words
Optical properties - characteristics of endoscopes - optical transfer function
