It is difficult to measure the circular arc radius for central angle less than 30 degrees. The existing measuring methods are of low efficiency and big error. Through designing the machine vision system and studying the image detecting method for measurement, It is obtained good results by using the new measurement for tracheal intubation's circular arc radius, Realized a rapid and accurate measurement of the circular arc radius, and expanded the application in the field of machine vision.
Humans ; Imaging, Three-Dimensional ; instrumentation ; Intubation ; Trachea

The product standards for medical devices' registration are important technical document for production and supervision. Up to now, some problems still exist in these product standards. This paper analyzes common issues according to the standard writing specifications.
Equipment Safety ; Equipment and Supplies ; standards