The Design And Realization Of Aerogun Shell Defect Detection

An experimental device using CCD (Charge Coupled Device) matrix camera to detect aerogun shell defect was designed based on the deep investigation and study of existed surface detection technologies in this paper, and a new method for shell defects detection was invented. In this detection system, the hardware is simple, and the functions of software are flexible and abundant, and the plasticity is good, especially the image resolution and recognition speed and anti-interference do well. It has a bright application future in nondestructive detection on object surfaces. Meanwhile, it is outstanding characteristics, such as combinability and expandability; It also has extensive value in other product's nondestructive detection systems. It is of great practical importance, as to the security of the detection procedure, improvement of detection level, precision and productivity of detection, great reduction of people's labor intensity.Image processing is the core of the system. It consists of image pre-process-ing, treatment of rifling,image segmentation, feature pick-up,defects recognition.Image pre-processing aims to lessen the effect of noise.Analyzing the noise of all kinds of defects and comparing all kinds of processing methods, the system chooses Median Filtering Method. Image segmentation aims to separate the defects from the background.After the analysis of the gray scale of them, the binary method is used. The key point of the method lies in the selection of the threshold. So the selection of the optimizing threshold is an important portion in this dissertation. Defect recognition is the main destination where the research work falls. Besides, the dissertation lays stress on the analysis of the characteristics of defects in artillery bomb, and recognizes the defects making use of its area value and the ratio of short diameter and long diameter. The dissertation gives the standard thresholds after many experiments, The systerm realized by this method can effectivlly detect the main types of shells surface defect, and the detection rate overrun 97%. This detection method of this systerm is novel with simple equipment, which can meet precision requirement of shell defect detection and have a great potential to popularize it.