The paper deals with the well-known problem of Erdős and Hajnal concerning colorings of uniform hypergraphs and some related questions. Let m(n, r) denote the minimum possible number of edges in an n-uniform non-r-colorable hypergraph. We show that for r > n, c1 n lnn m(n, r) rn C1 n lnn, where c1, C1 > 0 are some absolute constants.

Widely varying estimates of the number of discernible object colors have been made by using various methods over the past 100 years. To clarify the source of the discrepancies in the previous, inconsistent estimates, the number of discernible object colors is estimated over a wide range of color temperatures and illuminance levels using several chromatic adaptation models, color spaces, and col...

Reducing the number of colors in an image while preserving its quality, is of importance in many applications such as image analysis and compression. It also decreases memory and transmission bandwidth requirements. Moreover, classification of image colors is applicable in image segmentation and object detection and separation, as well as producing pseudo-color images. In this paper, the Kohene...

Background and aims: Color blindness is a disease that remains undiagnosed in some cases. Thediagnosis of the disease during schooling is necessary to take the required measures for the future lifeof adolescents. Therefore, the aim of this study was to determine the prevalence of color blindnessamong the students of secondary schools in Shahrekord.Methods: In this descri...

this study aimed to examine the relationship between pigments and seed fall rate of iranian castor genotypes and genetic diversity, specifically 28 castor genotypes (27 native and 1 modified), a randomized complete block design with three replications was conducted in 2014 and 2015 at the research farm of islamic azad university in damghan, northern iran. during the growth period, the following...

In this paper we investigate the relationship between matrixing methods, the number of filters adopted and the size of the color gamut of a digital camera. The color gamut is estimated using a method based on the inversion of the processing pipeline of the imaging device. Different matrixing methods are considered, including an original method developed by the authors. For the selection of a hy...