Scratch visibility of polymers measured using optical imaging

Abstract

As plastics replace metal in automotive and other applications, aesthetic concerns due to scratch or mar damage replace rust and corrosion issues. This paper presents a novel method to quantify the visibility of a scratch on a polymer surface. It is shown that the most important factor is the optical contrast between the damaged area and its surroundings. The critical optical parameters that affect a viewer's perception of scratch severity are identified as the size and roughness of the scratch, and the color and gloss of the surroundings. An optical imaging system and method for measuring the optical parameters that result in this contrast is described.

An integrated approach towards the study of scratch damage of polymer

“…Many attempts have been made to quantify scratch visibility by measuring the surface reflectivity of the scratch. [5][6][7][8][9][10] Due to the diverse techniques employed and the lack of systematic studies to correlate scratch features with visibility, 11 the results obtained from one set of experiments are often valid within a set of narrowly defined conditions. It remains to be seen which of these methods, if any, will prove to be the most useful in characterizing scratch visibility.…”

Polyester Wire Enamels ‐ Reliable Coatings in the Wire Industry from the Beginning to Nowadays

“…It also requires the use of copper wire of consistent quality and the same impurity profile, since the surface tension of copper substrate can change due to its constituents as well as because of inadvertent impurities sticking on the surface while drawing small diameter wires. Lot of effort in polymer physics has been directed in recent times to reducing the surface roughness and also in understanding, with the help of optical studies, what we perceive as a scratch on visual inspection 61–63. Instruments are nowadays used to check the uniformity of round coating during manufacturing 64.…”

Effect of color, gloss, and surface texture perception on scratch and mar visibility in polymers

“…Improving surface visibility resistance against scratch and mar damages is becoming more and more of an interest to industry and academia [14][15][16][17]. It was claimed that the hue-saturation-in tensity (HSI) space combination can be used to quantify scratch visibility resistance [16].…”

“…Instead, Rangarajan et al were able to successfully determine scratch visibility resistance using an optical imaging instrument. Their approach is based on the contrast between the damage and the background of the sample [14]. This approach was used later to evaluate scratch and mar visibility depending on the change of their contrast and specular gloss [17].…”