Measurement of contamination concentration using an adjustable image contrast method

The results of an investigation that focused on the development of an adjustable image contrast method are presented. The method was designed to solve the applied problem of measuring the concentration of contamination of recoverable scrap with cutting fluid to enhance the accuracy of visual inspection methods. The currently used control method is based on visual assessment of the degree of contamination of a sheet of paper after its contact with a sample of contaminated material. The proposed method entails the use of a standard image scanner for digitizing visual information in the form of oil imprints on the paper and its subsequent processing by adjusting the image contrast, which makes it possible to obtain quantitative information on the object under investigation. The principal parameters of oil imprint scanning and subsequent processing of the obtained images were determined during the course of the study. Equations for calculating the values of reduction of cutting fluid content in the cleaned samples with respect to its initial concentration were obtained. The main concepts of the proposed method were formulated. Its main advantage is its simplicity and the use of commonly available, inexpensive control and measuring equipment. (C) 2021 Optica Publishing Group