In order to obtain a rapid, accurate, repeatable and reproducible quality control protocol for the visual assessment of Universal Camouflage Pattern (UCP) substrates, various methodologies were examined. The role of parametric factors in repeatability and reproducibility of visual assessments was determined. Each of the colors within the pattern was measured spectrophotometrically and samples were then assessed by a panel of naïve subjects under various conditions. An acceptability tolerance volume for each color was obtained under simulated daylight illumination at 7500K (equivalent to illuminant D75) using eighteen subjects that repeated assessments six times on separate dates. Visual assessment techniques included a set of sixty woven camouflage samples, some of which contained a repeat pattern that we refer to as “key” and some that did not. Identical subjects repeated assessments under various viewing and surround conditions (e.g. placing samples side by side or juxtaposing samples). A total of 31,320 visual assessments were thus obtained. The role of viewing conditions on the level of inter- and intra-subject variability in pass/fail assessments, as well as color difference evaluation of individual colors, based on an AATCC Gray Scale evaluation method, was examined. STRESS was used to compare the degree of variability among subjects. Analysis of results indicates that subjects' agreement in determining pass/fail responses is improved when a visual reference (such as the print repeat pattern) is included as reference. In addition masking the surround improved subject consistency and repeatability in assessments.
Juan Lin, Renzo Shamey, "The Role of Parametric Factors on Visual Assessment of Camouflage Substrates" in Proc. IS&T 21st Color and Imaging Conf., 2013, pp 134 - 142, https://doi.org/10.2352/CIC.2013.21.1.art00024