PCA-Based Advanced Local Octa-Directional Pattern (ALODP-PCA): A Texture Feature Descriptor for Image Retrieval

This paper presents a novel feature descriptor termed principal component analysis (PCA)-based Advanced Local Octa-Directional Pattern (ALODP-PCA) for content-based image retrieval. The conventional approaches compare each pixel of an image with certain neighboring pixels providing discrete image information. The descriptor proposed in this work utilizes the local intensity of pixels in all eight directions of its neighborhood. The local octa-directional pattern results in two patterns, i.e., magnitude and directional, and each is quantized into a 40-bin histogram. A joint histogram is created by concatenating directional and magnitude histograms. To measure similarities between images, the Manhattan distance is used. Moreover, to maintain the computational cost, PCA is applied, which reduces the dimensionality. The proposed methodology is tested on a subset of a Multi-PIE face dataset. The dataset contains almost 800,000 images of over 300 people. These images carries different poses and have a wide range of facial expressions. Results were compared with state-of-the-art local patterns, namely, the local tri-directional pattern (LTriDP), local tetra directional pattern (LTetDP), and local ternary pattern (LTP). The results of the proposed model supersede the work of previously defined work in terms of precision, accuracy, and recall.

Palmprint Recognition System Based on Multi-Block Local Line Directional Pattern and Feature Selection

In this paper, we deal with multimodal biometric systems based on palmprint recognition. In this regard, several palmprint-based approaches have been already proposed. Although these approaches show interesting results, they have some limitations in terms of recognition rate, running time and storage space. To fill this gap, we propose a novel multimodal biometric system combining left and right palmprints. For building this multimodal system, two compact local descriptors for feature extraction are proposed, fusion of left and right palmprints is performed at feature-level, and feature selection using evolutionary algorithms is introduced. To validate our proposal, we conduct intensive experiments related to performance and running time aspects. The obtained results show that our proposal shows significant improvements in terms of recognition rate, running time and storage space. Also, the comparison with other works shows that the proposed system outperforms some literature approaches and comparable with others.

Method for directional pattern adaptation of hydroacoustic antenna array to the current conditions of a non-stationary underwater communication channel

Гидроакустический канал связи отличается значительной и нестационарной многолучевостью, что делает разработку помехоустойчивой и высокоскоростной гидроакустической системы связи весьма нетривиальной задачей. В работе представлен авторский метод адаптации диаграмм направленности гидроакустических антенных решеток под текущие условия канала. Его новизна – в структуре пилот-сигнала, предназначенного для определения оптимального угла наклона передающей диаграммы направленности, и способе его приема и обработки. Приводятся результаты проведенных автором математического моделирования и экспериментальной оценки эффективности предлагаемого метода.

OBSERVATION CONTROL DEVICE FOR THE URAN-4 DECAMETER RADIO TELESCOPE

The URAN-4 radio telescope has been operating at the Odessa Radio Astronomy Observatory of the Radio Institute of the National Academy of Sciences of Ukraine since 1986. The telescope is an element of a decameter long-base interferometer – the radio telescopes which are located across the territory of Ukraine from west to east. The URAN-4 consists of antenna and upgraded radiometer. Antenna consists of 128–element with phased array with dimensions of 232.5 x 22.5 m. The telescope operates in the 10 – 30 MHz range. Its receiving equipment is capable of separating two polarization components of the received signal. The radiation pattern of the radio telescope is 2,7x22 degrees at 25 MHz. The resolution of 2 seconds is realized in the interferometer mode. The instrumental complex of the radio telescope includes the upgraded device for controlling its operation. This device is made in the form of a separate unit. The ATMEL AT90S8515 microcontroller with registers and a communication circuit between the unit and the computer are mounted in it. The discrete movement in space of the antenna's directional pattern and sets the required attenuation in the attenuator during calibration are carried out with the upgraded controlling device at a given time during the observation period. The controlling device also allows adjust the current time of the computer using GPS.

Analysis of the possibility of creating an acoustic velocity sensor using GaN epitaxial films

This paper results in results of analyzing the possibility of creating an acoustic velocity sensor using epitaxial GaN films. Technology for the fabrication of a microelectromechanical acoustic velocity sensor was developed and a prototype of the sensor was produced. The simulation of the characteristics of the obtained acoustic velocity sensors was carried out on the basis of the measured electrical characteristics, where the sensitivity and the directional pattern were determined.

A New Optimized Hybrid Local Lifting Wavelet Co-occurrence Texture Pattern for Content Based Medical Image Retrieval

<p class="0abstract">Medical image retrieval (MIR) is a hard task owing to the varied patterns and structures in the medical images. The feature descriptors have been used to describe the images in most MIR approaches. Based on the local relationship, several feature descriptors of neighbouring image pixels have been proposed for MIR so far, but their low performance scores make them unsuitable. In this paper, an efficient optimized hybrid local lifting wavelet co-occurrence texture pattern for content-based MIR is proposed. Initially, image resize and Adaptive histogram equalization technique is used to carried out for contrast enhancement. Then Local Lifting Wavelet Co-occurrence Texture Pattern is derived using Local tetra pattern, Gradient directional pattern, lifting wavelet transform and Gray level co-occurrence matrix. An Equilibrium optimization technique is employed to select the most important features of an image from the obtained feature vectors (FV). Finally, to match the query image with the database images, distance between their FV is computed and the minimum distance images are considered as retrieval outcome. Three benchmark medical databases of various modalities (CT and MRI) are used to test the efficiency of the proposed method: EXACT-09, TCIA-CT, and OASIS. The experimental results prove that the proposed approach outperforms existing descriptors in terms of APR and ARR.</p>

Face Recognition System Using Local Features Fusion for Multi-Masks

Face recognition is a relatively novel research field, and its application is closely related to numerous other areas. Moreover, it is emerging as a critical research theme due to its broad range of applications. Thus, many face recognition methods use a variety of feature extraction approaches. Nonetheless, the issue continues to be challenging, particularly identifying non-biological entities. This paper proposes an extended descriptor for local features of an effectual facial recognition system using a local directional pattern operator. This technique combines the Frei-Chen and Robinson masks’ strengths by fusion of the directional features of LDP for these two masks; this elicits a robust feature extraction method for distinguishing faces. Experimental results using the Yale database show that the extended descriptor considerably improved recognition rate and better performance than traditional local feature descriptors.

ACCOUNTING THE DIRECTIONAL DIAGRAM OF THE ON-BOARD ANTENNA IN ANALYSIS OF THE COMMUNICATION CHANNEL WITH THE AIRCRAFT

Синтез оптимальной с точки зрения дальности диаграммы направленности является одной из основных задач построения канала связи. Для многих приложений, таких как 2D вторичный локатор, канал связи с БЛА, оптимальной является косекансная диаграмма направленности. В первом приближении антенна, установленная на борту, обладает практически постоянным коэффициентом усиления в направлении на стационарную антенну. Характеристики бортовой антенны получаются из решения задачи в свободном пространстве. Учёт рассеивающих свойств объектов сложной геометрической формы с размерами в десятки длин волн является актуальной, но сложной задачей. При перемещении по поверхности носителя диаграмма направленности бортовой антенны может меняться существенным образом. Современные системы автоматизированного проектирования на основе приближённых численных методов электродинамики позволяют получать характеристики антенн, размещённых на реальных объектах. Ввиду увеличения количества полезных нагрузок на борту не всегда удаётся разместить бортовую антенну в таком месте, которое позволяет пренебречь влиянием геометрии носителя. В результате в диаграмме направленности бортовой антенны появятся интерференционные провалы или минимумы. Дальность работы будет зависеть от перемещения носителя. Рассматривается метод учета характеристик ДН бортовой антенны, позволяющий минимизировать запас на замирания The synthesis of the optimal, in terms of range, directional pattern is one of the main tasks of building a communication channel. For many applications, such as a 2D secondary locator, a communication channel with a UAV, the cosecant radiation pattern is optimal. As a first approximation, the on-board antenna has an almost constant gain towards the stationary antenna. The characteristics of the onboard antenna are obtained by solving the problem in free space. Taking into account the scattering properties of objects of complex geometric shapes with dimensions of tens of wavelengths is an urgent but difficult task. When moving over the surface of the carrier, the radiation pattern of the onboard antenna can change significantly. Modern computer-aided design systems based on approximate numerical methods of electrodynamics make it possible to obtain the characteristics of antennas placed on real objects. Due to the increase in the number of payloads on board, it is not always possible to place the onboard antenna in such a place that makes it possible to neglect the influence of the carrier geometry. As a result, interference dips or minima will appear in the directional pattern of the onboard antenna. The operating range will depend on the movement of the media. We considered a method for taking into account the characteristics of the antenna pattern of an airborne antenna, which allows minimizing the margin for fading

A Study on Antenna of Low-Probability of Intercept for LOS Datalink System

In this paper, an array antenna for LOS datalink for mounting UAV(Unmanned Aerial Vehicle) of low-probability of intercept is presented. For low RCS, radome was designed by conformal form, and other components were inserted into the UAV. The antenna of the transmitter and receiver are each composed of 12×12 array antennas, and include a beam steering function by controlling the phase of the unit element for the Uni-directional pattern and the Bi-directional pattern. As a result of the measurement of the manufactured antenna, it was confirmed that all the required specifications were met, and the installing possibility of the UAV platform on low-probability of intercept in the future was confirmed.