Performance Evaluation of Color Descriptors under Illumination Variation

Color descriptors, which involve the extraction of color information that is robust to illumination variation, are indispensable for accessing reliable visual information as illumination variation is inevitable in many practical cases. There has been many color descriptors proposed in literature, but the performance of different color descriptors in different scenes under illumination variation and the influence of the surface characteristics have not been investigated. In this paper, we first systematically introduced the theoretical basis of color descriptors, categorized the existing color descriptors according to the theoretical basis, and then compared the performance of different color descriptors utilized for image recognition and image retrieval tasks on both the indoor and outdoor image datasets. We adopted the recognition rate and normalized average rank as the evaluation criteria to measure the performance of color descriptors. Experiment results show that the color moment invariants (CMI) provide the optimal balance between the performance and dimensions in most tests, and color descriptors derived from physical reflectance models are more suitable for object recognition and image retrieval. We also concluded the best color descriptors for each kind of scene and surface characteristics.

Misleading Tobacco Packaging: Moving Beyond Bans on "Light" and "Mild"

Objectives: In this paper, we assess compliance of cigarette packaging with policies in 9 countries that ban misleading descriptors, assess the presence of other packaging design elements that are misleading to consumers, and identify policy loopholes. Methods: Cigarette packages were systematically collected in 9 countries between 2015 and 2017 – Bangladesh, Brazil, China, India, Indonesia, Philippines, Russia, Thailand, and Vietnam. The packs were coded for banned misleading descriptors and other misleading packaging design elements. Descriptive analyses were conducted. Results: Overall, compliance with explicitly banned misleading descriptors is high across countries, with the exception of packs from Indonesia, where compliance is mod- erate. However, the use of other misleading packaging elements such as alternative descriptors (soft, smooth, mellow), select color descriptors (blue, gold, silver), and a slim pack shape are still widely used in packaging design across the 9 countries examined. Conclusions: Policies that include loopholes or allow for other misleading packaging design elements could weaken the impact of recommended misleading packaging and labeling regulations as laid out in the WHO Framework Convention on Tobacco Control. Stronger provisions are needed and countries should consider comprehensive plain packaging.

An Evaluation of the Variation in the Morphometric Parameters of Grain of Six Triticum Species with the Use of Digital Image Analysis

Kernel images of six wheat species were subjected to shape and color analyses to determine variations in the morphometric parameters of grain. The values of kernel shape descriptors (area, perimeter, Feret diameter, minimal Feret diameter, circularity, aspect ratio, roundness, solidity) and color descriptors (H, S, I and L*a*b*) were investigated. The influence of grain colonization by endophytic fungi on the color of the seed coat was also evaluated. Polish wheat grain was characterized by the highest intraspecific variation in shape and color. Bread wheat was most homogeneous in terms of the studied shape and color descriptors. An analysis of variations in wheat lines revealed greater differences in phenotypic traits of relict wheats, which have a larger gene pool. The grain of ancient wheat species was characterized by low roundness values and relatively low solidity. Shape and color descriptors were strongly discriminating components in the studied wheat species. Their discriminatory power was determined mainly by genotype. A method that supports rapid discrimination of cereal species and admixtures of other cereals in grain batches is required to guarantee the quality and safety of grain. The results of this study indicate that digital image analysis can be effectively used for this purpose.