حمیدرضا جعفری

Thesis: Application of machine vision in profile projector instrument for automation and improvement of precision and quickness of holes measurement in objects

Abstract

Today, manual or semi-automatic systems are replaced with automatic systems to increase speed, accuracy and efficiency. To this end, the use of machine vision and image processing techniques are very useful. The aim of this project is to automate and increase the measurementaccuracy and speed of profile projectormachine. In this machine, the objectis placed on the table, then the light source emits directly into the object and the enlarged shadow of the object appears on the device screen with the aid of two magnifying lenses. The user commands the motors to change the position of table such that different points of holeshadow coincide with thecentral point of screen.Coordinates of these points is tranfered into the computer through digital rulers installed on the device.Using the coordinates of these points,the specification of the corresponding circle is calculated.In this project to avoid influence ofvisual error on measuring system, digital image processing techniques are used. So, theposition of the holes is given to the systemin two ways. In the first approach, the objectmap information is given directly to the designed software. In the second approach, the desired circles are selected using the imageof the object, taken by a camera. Inboth methods, "Hough circle detector algorithm"is employed to detect the initial location and radius of circles. After accomplishing the automated measurement of circles, some important specifications like diameter, center coordinates, and deviation from ideal circles is obtained automatically with high accuracy and speed. Many useful options such as determination of distances and angles between circles,is added to the programto assist the operator in his tasks and giving complementary results. Finally, the measurement has been done accurately.

Keywords:

Automation, Circle measurement, Profile projector, Machine Vision