Search

Space target recognition is of great importance for maintaining aerospace safety and national security. When observing a space target, owing to the low spatial resolution of ground-based observation equipment, each pixel in a hyperspectral image might represent a mixture of several different materials. Hyperspectral unmixing is a process used to extract the endmembers and their corresponding abundances from hyperspectral data. Unfortunately, most existing methods cannot make full use of the available spatial information data. The paper proposes a new local manifold sparse regularized unmixing model based on similarity regularized nonnegative matrix factorization (SRNMF). To exploit the spatial information of the vis-NIR (approximately 400-2500 nm) hyperspectral image of a space target, image segmentation is introduced to generate similar local regions. These local regions are generated adaptively, and pixels within each region have similar abundance sparseness. Simulation experiments validated the high efficiency and precision of the proposed algorithm, which should also be suitable for other spectral analysis applications. [ABSTRACT FROM AUTHOR]

As vast channels for communication, such as the Internet, become more popular, the security of digital media becomes a greater concern. Steganography is one of the techniques used to make detecting the transmitted data over channels more difficult, as hiding a message will reduce the probability of detecting this message. In this paper we suggest a new algorithm of steganography for hiding a gray image in one another. The cover is divided into blocks of equal sizes. Each block size equals the size of the embedding image. The results drawn in this paper with the similarity equals 0.9717 are more improved and give the clear picture of the object. [ABSTRACT FROM AUTHOR]

This article describes a method for predicting improvements in stability and degradation of noise figure caused by resistive loading of low-noise and broadband amplifier input and output ports. High-performance transistor is required when designing an effective low-noise amplifier. However, suitable devices are potentially unstable at microwave frequencies that lead to oscillation. In this paper, a search algorithm was designed to identify resistor combinations that stabilize the transistor at all frequencies while providing a stability factor.