This paper reports a polarization controllable and angle-insensitive perfect metamaterial absorber (PMA). The proposed PMA consists of periodically arranged asymmetric omega-shaped resonators made of ...metallic copper. The absorptivity was analyzed considering the microwave C-band from 4 GHz to 8 GHz. The proposed PMA shows an absorption peak with almost 100% absorptivity at 6.2 GHz. Also, wideband negative index of refraction is observed. Further, the absorber is inspected for the different rotation angles of the top metasurface (omega-shaped ring) along the optical axis, and obliquity of incidence angle for both TE and TM polarized waves. Moreover, surface electric field and surface current distribution were analyzed to understand the absorption mechanism. It was noticed that at resonance (considering 6.2 GHz) electric field maximally remains concentrated on the omega-shaped rings. Furthermore, the simulation and measured results show a good agreement. It is inferred that the proposed PMA would be useful candidate for the sensing and filtering applications in the C-band of the microwave regime.
Object tracking in a video sequence is usually achieved by tracking the bounding box over the object or the object's boundary, each of which has somewhat different applications. In this paper, we ...present a new open-contour tracking algorithm based on a Bayesian framework in which the contour is a part of the object's boundary. We first propose a new state-space model for the representation of contours, which can handle the rigid and nonrigid motions of contours independently. This model enables us to focus on the nonrigid motions during the training, and the model works for challenging rigid motion scenarios. In addition, for the robust tracking of contours, we propose a measurement function that considers the contrast on object boundaries, target appearance, and temporal coherence. We applied the proposed method to two kinds of open-contours targets, and the experimental results show that the proposed method achieves superior performance to the conventional contour tracking methods. The proposed method is also compared with recent bounding box tracking methods for the object tracking purposes, and the comparison shows that the proposed method works robustly to fast motions and yields a more accurate estimate of an object's location than the conventional bounding box tracking methods.
A new compact broadband and high gain antenna by using the slotted inverted omega shaped ground plane and circular disc loaded radiator is presented. The designed antenna prototype is engraved on low ...cost thick substrate with compact electrical size of (0.201
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×
0.16
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0.01001
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mm
3
at 2 GHz frequency. Several prototypes have been designed and investigated to achieve the proper matching. The parametric study is conducted to attain an optimized prototype of antenna. The novelty lies in proposed antenna’s simple structure with compact dimensions of radiator. It exhibits the peak realized gain of 9.93 dBi at 19.9 GHz, broadband fractional impedance bandwidth of 142.6% at 10 dB return loss, and stable radiation pattern across all the frequency sweeps. The antenna have been simulated, fabricated and tested. Moreover, frequency and time domain performance have been analyzed to validate the antenna design. Finally the comparison analysis with the state of the art existing work has been conducted. The simulated and tested results are in good agreement hence make the antenna suitable for UWB (3.1–10.6 GHz), WiMAX (3.5–5.8 GHz), C (4–8 GHz), H (6–8 GHz), X (8–12 GHz), Ku (12–18 GHz), Ka (18–26 GHz) and future wireless communication applications.
Region-based Fully ConvNet (R-FCN) designed for general object detection is difficult to be directly applied for pedestrian detection, due to being with large human pose and scale changes, and even ...with partial occlusion in surveillance scenarios. This paper presents a rapid pedestrian detection method with partial occlusion handling, which builds on the framework of R-FCN. We introduce a deep Omega-shape feature learning and multi-paths detection to make our detector be robust to human pose and scale changes. A novel predicted boxes fusion strategy is proposed to reduce the number of false negatives caused by partial occlusion in crowded environment. Our end-to-end approach achieved 95.35% mAP on the Caltech dataset, 96.22% mAP on DukeMTMC dataset and 97.43% mAP on Bronze dataset at a test-time speed of approximate 86 ms per image.
This study proposes a new omega-shaped tag antenna with inductively-coupled feeding (ICF) using U-shaped stepped- impedance resonators (SIRs). It aims at improving the performance of the tag antennas ...for Radio Frequency Identification (RFID) applications. The radiating body of the antenna is fed using two mirroring symmetrical U-shaped SIRs. This antenna is a simpler alternative for the existing antennas that match the impedance of the antenna to the chip impedance effectively applying varied reinforcement of the equivalent inductance of the radiating structure. In addition to the use of an omega-shaped structure, the proposed feeding technique boosts performance of the antenna impedance, dimensions, and peak gain. The measured size of the antenna was 50×55.55×1.6 mm3. It attains a peak gain of 1.8 dBi and radiation efficiency higher than 85% at its operating frequency. The experimental results revealed that this tag antenna has the characteristic of good impedance matching within the frequency range of 900-940 MHz, corresponding to a better power reflection coefficient of -3 dB. Comparison between the measured and simulated results verified that the proposed feeding method is capable to improve overall performance of RFID tag antennas.
A novel octahedron frequency reconfigurable multiband antenna for microwave sensing-based Internet of things (IoT) applications is proposed in this work. This reconfigurable antenna operates over the ...bands 1.57-2.15 GHz, 2.13-3.0 GHz, 3.17-3.43 GHz, 5.2-5.8 GHz, 6.3-6.78 GHz, 8.31-8.90 GHz, 9.04-9.58 GHz, and 12.03-13.14 GHz, which can be used for wireless sensing, space, and IoT applications. By using omega shape slot in the radiating structure and with PIN diodes switching to change the current direction, the desired resonant frequencies are achieved. The PIN diodes are controlled by using an IoT device NodeMcu. As per the software programmed, the NodeMcu switches the PIN diodes into on and off conditions. We can change the program and monitor through the World Wide Web. The S-parameter characteristics and the radiation patterns have been measured, and good compatibility between simulated and measured results has been identified. The designed model is tested with center for development of advanced computing (CDAC) Cmote device and controlled through IoT for data transmission and reception at desired operating bands.
Region-based Fully ConvNet (R-FCN) designed for general object detection is difficult to be directly applied for pedestrian detection, due to being with large human pose and scale changes, and even ...with partial occlusion in surveillance scenarios. This paper presents a real time pedestrian detection method with partial occlusion handling, which builds on the framework of Region-based Fully ConvNet. We introduce a deep Omega-shape feature learning and multi-paths detection to make our detector being robust to human pose and scale changes. A novel predicted boxes fusion strategy is proposed to reduce the number of false negatives caused by partial occlusion in crowded environment. Our end-to-end approach achieved 95.35% mAP on the Caltech dataset and 97.43% on Bronze dataset at a test-time speed of 86ms second per image.
Head detection in images and videos plays an important role in a wide range of computer vision and surveillance applications. Aiming to detect heads with arbitrarily occluded faces and head pose, in ...this paper, we propose a novel Gaussian energy function based algorithm for elliptical head contour detection. Starting with the localization of head and shoulder by an improved Gaussian Mixture Model (GMM) approach, the precise head contour is obtained by making use of the Omega shape formed from the head and shoulder. Experimental results on several benchmark datasets demonstrate the superiority of the proposed idea over the state-of-the-art in both detection accuracy and processing speed, even though there are various types of severe occlusions in faces.
This paper proposes a vision-based human arm gesture recognition method for human–robot interaction, particularly at a long distance where speech information is not available. We define four ...meaningful arm gestures for a long-range interaction. The proposed method is capable of recognizing the defined gestures only with 320×240 pixel-sized low-resolution input images captured from a single camera at a long distance, approximately five meters from the camera. In addition, the system differentiates the target gestures from the users’ normal actions that occur in daily life without any constraints. For human detection at a long distance, the proposed approach combines results from mean-shift color tracking, short- and long-range face detection, and omega shape detection. The system then detects arm blocks using a background subtraction method with a background updating module and recognizes the target gestures based on information about the region, periodical motion, and shape of the arm blocks. From experiments using a large realistic database, a recognition rate of 97.235% is achieved, which is a sufficiently practical level for various pervasive and ubiquitous applications based on human gestures.
Dehiscence of the bony canal of the facial nerve is relatively common in the human adult. The highest incidence occurs in the tympanic segment, near the region of the oval window. However, extreme ...dehiscence and protrusion of the facial nerve are rare. We present a case of a 34-year-old man suffering intermittent left-sided middle ear discharge for several years. During the operation, we found the trunk of the facial nerve which looked like Greek alphabet letter “omega”. It protruded from the fallopian canal within the middle ear space between the first and second genu. The mucosa which covered the whole protruded facial nerve seemed healthy. The medial part of the cavum tympani was not affected. In this report, we described an extreme protrudion of the facial nerve inside the space of the cavum tympani. The dehiscence of the Fallopian canal was not associated with inflammation and bone resoption.
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