Research On Image Detection Technology For The Profile Of Revolving Body

Digital image measuring method is a new photoelectric measuring technology based on the theory of computer vision, which can obtain the tested object's dimension parameter from its images photographed by the CCD. Using the method can increase productivity greatly by integrating the process of machining, detecting and controlling.A digital image measuring method is developed in this paper in order to measure the profile of the revolving body, and extracting the edge of workpiece is the key to this method. In the study of digital image process algorithm, integer-pixel edge detection algorithm is analyzed firstly, and the Robert operator is chose to detect the integer-pixel edge based on the edge characteristic of the revolving body. Then the sub-pixel edge detection algorithm is studied and a new algorithm named mixed algorithm is developed. The new algorithm is also compared with the other classical sub-pixel algorithms, the comparison results confirm the new algorithm and show that the mixed algorithm has higher detecting accuracy and faster computing speed.According to the principle of the digital image measuring method, a digital image measuring software is developed using the VC++ computer language, and a digital image measuring system is built, which is made up of the hardware and the software. The hardware includes the camera, lens, light sources and computer. The software is made up of some image process algorithms, such as, the image pre-process, integer-pixel edge detection and sub-pixel edge detection etc., it integrates some functions, such as, image histogram, batch process, filter process and edge detection etc. and this software is an opening system, operates facility, direct-viewing is strong, and is advantageous for developing to the system promotion.Based on the digital image measuring system, a bell and shaft are measured respectively. In the experiment, firstly, the rotating processes of the bell and shaft are recorded as images by the CCD camera, and all the images are saved to the hardware of computer, then these images are processed to obtain the dimension parameter of the bell and shaft by the edge detection algorithm. Based on the edge detection results, the profiles of bell and shaft are reconstructed. The measuring accuracy and speed are also analyzed.