Metal Surface Quality Characterization

Residue on kitchenware in a dishwasher influences the decision to continue using a brand of detergent. The objective of this project is to design a system to quantify this residue and provide a cleanliness grade that mirrors how a human would visually grade the kitchenware. The team focused on measuring spotting and film left on knives, because knives can be modeled as mirrors. The team measured and graded cleanliness using distinctness of image, a metric that uses contrast degeneration to determine image degradation. For example, perfect mirrors reflect black and white stripes in sharp contrast, but a surface with degraded reflective properties blurs the distinction between the same black and white stripes. The team projected a striped pattern onto the knives and measured the degradation of distinction between segments imaged, investigating the correlation between cleanliness and distinctness of image.