Recently، digital image authentication technologies have gained much attention because of
their importance in many multimedia applications. In general digital images are
transmitted over unsaved media such as the internet and many types of computer
networks.
Applications may require a large amount of safety such as military applications and
medical applications. Therefore the digital images must be protected against any
modifications، which may lead to influence the decisions that associated with them.
In this paper، a general scheme based on Steganography & Perceptual Image Hashing
techniques was proposed to enhance the security of digital image transmission. In the final
test stage, we checked the accuracy of the proposed scheme against potential modifications
was studied, by applying different levels of compression and changing the contrast &
brightness level of the image. For analyzing the final results, we computed the matching
ratio between the original hash vector and the embedded hash vector. As a result، we
achieved a near perfect match ratio even after applying the image compression level or
changing its brightness level (approximately 99.9%), while the match ratio decreased
significantly with the increase of the contrast level of the image (approximately 94%).
This paper presents the development and evaluation of BroadBand Electrically Steerable
Parasitic Array Radiator antenna by using eight parasitic radiators BB-ESPAR-8 .
The antenna has a symmetrical structure that consists of: i- one active element as a broad band
shuttle antenna, ii- eight wideband parasitic radiators, iii- cylindrical ground plane, iv- set of
reactances.
