High Capacity Image Watermarking in the Joint Spatio-Frequency Domain

Watermarking techniques are proposed as a solution to copyright protection of digital media files. Watermarking algorithms are mainly concentrated on spatial or spectral domains. In this work, a robust and high capacity watermarking method that is based on spatio-frequency (SF) representations is presented. We use the Discrete Evolutionary Transform (DET) calculated by Gabor expansion to represent an image in the SF domain. A watermark is embedded onto selected coefficients in the joint SF domain. Hence by combining the advantages of spatial and spectral domain watermarking methods, a robust, invisible, secure and high capacity watermarking method is presented

A robust image watermarking based on time-frequency

Watermarking techniques are proposed as a solution to copyright protection of digital media files. In this work, a new and robust watermarking method that is based on time-frequency (TF) representations is presented. We use the discrete evolutionary transform to represent an image in the TF domain. A watermark is embedded onto selected cells in the joint TF domain. Hence by combining the advantages of spatial and spectral domain watermarking methods, a robust and perceptual watermarking algorithm is presented

HPLC Detection and Antioxidant Capacity Determination of Brown, Red and Green Algal Pigments in Seaweed Extracts

This study was carried out to determine the main pigments in some different selected seaweeds and to reveal their antioxidant potential regarding the ever-increasing demand for utilization of marine pigments in human health and nutrition. The individual amounts of algal pigments were found by reverse phase high-performance liquid chromatography (HPLC) and their total antioxidant capacities (TAC) by two spectrophotometric TAC assays, namely: CUPRAC (CUPric ion Reducing Antioxidant Capacity) and ABTS/TEAC (2,2'-azinobis [3-ethyl benzo thiazoline-6-sulfonate])/(trolox equivalent antioxidant capacity). These two tests gave the same rank order for TAC. The TAC of HPLC-quantified compounds accounted for a relatively much lower percentage of the observed CUPRAC capacities of seaweed extracts, namely ranging from 11 to 68% for brown, from 4 to 41% for red and from 3 to 100% for green species, i.e., some TAC originated from chromatographically unidentified compounds. Fucoxanthin, chlorophyll a, and pheophytin a compounds were major pigments in brown algae. The relative carotenoid contents in red marine algae were generally lower than those of chlorophylls. Overall total quantities were quite low compared with those of brown species. In general, chlorophyll a and chlorophyll b were chiefly present in green algae, but beta-carotene, violaxanthin and siphonaxanthin were also detected substantially higher in some species of green algae such as Caulerpa racemosa var. cylindracea and Codium fragile