Geometric signs of punched marker and their resistance to obstruction

Abstract

The field of application of perforation markers is shown - product quality management systems of industries that use raw materials of biological origin and mechanical, thermal and chemical processing of products, during which the outer layer of the material can be removed along with the marking, as well as the optical characteristics of the surface of the products can change significantly. A specific type of marker used in leather production is considered. The method of determining the orientation during recognition using geometric features is considered. Expressions for determining the geometric and moment features used during marker image recognition, namely the coordinates of the center of gravity and the value of the axial moments of inertia, were obtained. A computer experiment was conducted, as a result of which graphs of the distribution of the angle of rotation of the main central axis with the minimum moment of inertia relative to the base row of a marker of a specific appearance and graphs of the distribution of moments of the third order with respect to the main central axes of inertia were obtained. The analysis of the selected geometric and moment features showed that the influence of individual errors in determining the coordinates of the hole centers is leveled out and does not cause a significant impact on their values. The choice of geometric and moment features for determining the orientation of the marker is substantiated. In order to check the effect on the momentary signs of the errors of applying holes and the deformation of the marker matrix during the processing of the products, an experiment was performed using 958 marking images obtained on the prototype in real production conditions. Recognition and decoding of the markers was carried out, the coordinates of the centers of all holes were determined, and momentary characteristics were calculated for the displayed marker and for the same marker, but without distortions of the hole location grid. Histograms of the distribution of the distances between rows of holes and the normalized deviation of the centers of the holes from the grid nodes were constructed. A scatter table of the geometric characteristics of the markers was constructed based on the results of the experimental processing of the test batch. It is shown that the distribution of the deviation of holes from the nodes of the coordinate grid has a normal character.