Comparative study of the illumination effect on the appearances of woven fabrics composed of single and multiple colors of yarns

Color has been strategically used to attract consumers in the textile and clothing industry, and yarn color mixing is one of the most typical methods of imparting color to textile products. However, the fact that color appears different depending on the illumination has concerned textile designers and sellers at the point of color communication and sale. This study quantitatively analyzed how the color appearance of woven fabrics composed of single and multiple colors of yarns changes under a broad spectrum of illumination conditions. The lightness, chroma, and hue appearance values of 36 chromatic fabrics, in which red, yellow, green, and blue yarns were woven together, under 16 different illumination conditions were calculated. For the illumination conditions, correlated color temperatures (CCTs) of 2700, 4000, 5000, and 6500 K and luminance of 100, 1000, 4000, and 8000 cd/m2 were employed. The color appearance values of fabrics under the 16 light sources were compared with each other and also with their true physical colors. It was observed that the ranges of the varying lightness, chroma, and hue appearances of fabrics ranged up to 8.49, 16.24, and 27.04, respectively, indicating the huge effect of illumination on color appearance changes. In particular, the lower CCT of light sources induced the larger lightness appearance changes of fabrics from their actual physical colors. It was also found that the magnitudes of the color appearance changes of fabrics induced by light sources differed significantly according to the number of yarn colors and the overall colorimetric properties of the fabrics.

ILLUMINATION EFFECT ON RECOGNITION ABILITY OF MULTISENSOR MICROSYSTEMS BASED ON TIN OXIDE NANOWHISKERS

С помощью стандартных методов классификации данных показана возможность распознавания газовых смесей с помощью мультисенсорной микросистемы с газочувствительным слоем на основе нитевидных нанокристаллов. Проведенный статистический анализ экспериментальных результатов показал, что освещение светодиодом в ультрафиолетовом диапазоне газочувствительного слоя диоксида олова значительно увеличивает медианное расстояние Евклида-Махаланобиса между классами (распознавательная способность) различных газовых проб по сравнению с результатами измерений в темноте. Высказана гипотеза о том, что повышение распознавательной способности мультисенсорной микросистемы связано с селективным влиянием освещения на поверхностные химические реакции активных форм кислорода и частицами анализируемых газов. Using standard methods of data classification, the possibility of recognizing gas mixtures using a multisensor microsystem with a gas-sensitive layer based on whisker nanocrystals is shown. The statistical analysis of the experimental results showed that the illumination of a gas-sensitive layer of tin dioxide with a LED in the ultraviolet range significant increases the median Euclidean-Mahalanobis distance between the classes (recognition ability) of various gas samples compared to the results of measurements in the dark. Suggested that the increase in the recognition ability of a multisensor microsystem is associated with the selective effect of illumination on surface chemical reactions of oxygen species and particles of analyzed gases.

Appearance Reconstruction of Fluorescent Objects Based on Reference Geometric Factors

An approach is proposed for the reliable appearance reconstruction of fluorescent objects under arbitrary conditions of material and illuminant based on reference geometric factors. First, a large set of spectral images is acquired from a variety of scenes of fluorescent objects paired with a mutual illumination effect under different conditions. The target fluorescent object is constructed using a cube and a flat plate supporting it, and is subsequently illuminated using a directional light source. We produce many target objects of the same size with different fluorescent materials and observe them under different illumination conditions. The observed spectral images are subsequently decomposed into five components, combining the spectral functions and geometric factors. The reference geometric factors are independent of the material, illuminant, and illumination direction change; instead, they are only dependent on object geometries. A reliable estimation method of reference geometric factors is presented using the whole spectral images observed under various conditions. Further, we propose an algorithm for reconstructing a realistic appearance including mutual illumination effect under arbitrary conditions of material, illuminant, and illumination direction. Finally, the reliability of the proposed approach is examined experimentally.