Visualization of macrodefects of dynamic periodic structures based on the moiré effect
In the introduction, it is described the object of research, which represents a class of dynamic periodic structures widely used in industry. The relevance of this method of visualization is substantiated. The aim of research is to develop a method for visualizing macrodefects of dynamic periodic structures, which is based on the moiré effect. In the main part, features of recording of a series of images of the investigated periodic structure are described and the mechanism of formation of moiré pattern is considered. It is shown that moiré stripes occur when pair of images is combined. The peculiarity of this method both the registration of images and the formation of moiré bands is the possibility of using incoherent light. To confirm the efficiency of this method of studying dynamic periodic structures, a periodic metallic mask is chosen as the object under investigation, the surface of which is subjected to mechanical deformation. Models of devices of registration of a series of pictures of the investigated mask and formation of moiré pictures are described. The moiré patterns obtained by using pairs of images of the studied metal mask, the surface of which was subjected to mechanical deformation, are presented. Moiré patterns show changes in the surface profile of the metal mask that occurred due to deformation of its surface over time, corresponding to the registration of a pair of selected images. In the conclusion, it is noted that this method of visualization of macrodefects of periodic structures does not require complex technical implementation of optical recording and optical processing schemes. The use of photosensitive materials in the registration of images of the periodic structure, whose spatial resolution exceeds the resolution of the receiving photosensitive matrices, can significantly expand the list of objects under study than in the digital registration. The resulting moiré patterns can be processed according to known algorithms of digital processing of interferograms.