The model's approach, emphasizing spatial correlation over spatiotemporal correlation, reintroduces the previously reconstructed time series of defective sensors into the input data. The inherent spatial correlations guarantee the proposed method's production of precise and robust results, irrespective of the RNN model's hyperparameter values. The performance of simple RNN, LSTM, and GRU models was assessed by training them on acceleration data acquired from laboratory-tested three- and six-story shear building frames, in order to verify the proposed method.
This paper aimed to develop a method for assessing GNSS user spoofing detection capabilities, focusing on clock bias behavior. Spoofing interference, a longstanding concern particularly within military Global Navigation Satellite Systems (GNSS), presents a novel hurdle for civilian GNSS applications, given its burgeoning integration into numerous commonplace technologies. This is why the topic continues to be important, particularly for recipients having access only to high-level information—specifically PVT and CN0. Investigating the receiver clock polarization calculation procedure, a very basic MATLAB model was designed to emulate a spoofing attack at the computational level. Our examination of the clock bias using this model revealed the attack's influence. However, the sway of this disturbance is predicated upon two factors: the remoteness of the spoofing source from the target, and the alignment between the clock producing the deceptive signal and the constellation's governing clock. This observation was validated through the application of roughly synchronized spoofing attacks on a static commercial GNSS receiver. These attacks leveraged GNSS signal simulators, and a moving object as a source. Therefore, we propose a technique for assessing the capacity of detecting spoofing attacks, analyzing clock bias tendencies. This method's application is demonstrated on two commercial receivers, manufactured by the same company but from different production runs.
A concerning upsurge in vehicle accidents involving pedestrians, cyclists, road workers, and, notably, scooter riders has taken place in urban areas over the past years. This study investigates the practicality of boosting the identification of these users through the use of CW radar, given their low radar cross-section. The typically sluggish pace of these users can make them appear indistinguishable from obstructions caused by the presence of bulky objects. read more This paper pioneers a method of spread-spectrum radio communication between vulnerable road users and automotive radars, achieved by modulating a backscatter tag on the user. It is also compatible with inexpensive radars that employ various waveforms, including CW, FSK, and FMCW, without the need for any hardware modifications. The prototype, constructed from a commercial monolithic microwave integrated circuit (MMIC) amplifier positioned between two antennas, is modulated by adjusting its bias. Data from scooter experiments, both static and dynamic, are shown using a low-power Doppler radar functioning in the 24 GHz band, making it compatible with existing blind spot radar systems.
This work seeks to prove the suitability of integrated single-photon avalanche diode (SPAD)-based indirect time-of-flight (iTOF) for sub-100 m precision depth sensing, utilizing a correlation approach with GHz modulation frequencies. A 0.35-micron CMOS process was utilized to create and characterize a prototype pixel. This pixel included an integrated SPAD, quenching circuit, and two independent correlator circuits. The system demonstrated a precision of 70 meters and a nonlinearity of less than 200 meters, thanks to a received signal power that remained under 100 picowatts. With a signal power of under 200 femtowatts, sub-mm precision was realized. These results, in conjunction with the straightforwardness of our correlation methodology, underscores the immense potential of SPAD-based iTOF for future depth sensing applications.
A fundamental problem in computer vision has consistently been the process of extracting information pertaining to circles from images. read more Circle detection algorithms in widespread use frequently struggle with noise interference and slow computational performance. We introduce, in this document, a fast circle detection algorithm that effectively mitigates noise interference. We enhance the anti-noise capability of the algorithm by first performing curve thinning and connection on the image following edge extraction. Next, we mitigate noise interference from the irregular edges of noise. Finally, we extract circular arcs using directional filtering. To mitigate erroneous fits and accelerate execution, we introduce a five-quadrant circle-fitting algorithm, enhancing efficiency via a divide-and-conquer approach. The algorithm's performance is evaluated in comparison to RCD, CACD, WANG, and AS, employing two publicly available datasets. Our algorithm maintains a rapid pace while achieving the best performance metrics in the presence of noise.
Data augmentation is central to the multi-view stereo vision patchmatch algorithm presented in this paper. Through a cleverly designed cascading of modules, this algorithm surpasses other approaches in optimizing runtime and conserving memory, thereby enabling the processing of higher-resolution images. Compared to algorithms leveraging 3D cost volume regularization, this algorithm functions effectively on platforms with constrained resources. This study applies a data augmentation module to an end-to-end multi-scale patchmatch algorithm, employing adaptive evaluation propagation to reduce the substantial memory consumption that typically plagues traditional region matching algorithms. Comprehensive trials of the algorithm on the DTU and Tanks and Temples datasets confirm its substantial competitiveness concerning completeness, speed, and memory requirements.
The quality of hyperspectral remote sensing data is compromised due to the presence of optical noise, electrical noise, and compression errors, which severely limits its application potential. read more Hence, the enhancement of hyperspectral imaging data quality is of paramount significance. To preserve spectral accuracy in data processing of hyperspectral data, band-wise algorithms prove inadequate. This research proposes a quality-enhancement algorithm leveraging texture search and histogram redistribution, augmented by denoising and contrast enhancement. For improved denoising accuracy, a texture-based search algorithm is crafted to enhance the sparsity characteristics of 4D block matching clustering. The combination of histogram redistribution and Poisson fusion enhances spatial contrast, whilst safeguarding spectral details. The proposed algorithm is quantitatively evaluated using synthesized noising data sourced from public hyperspectral datasets, and the experimental results are subsequently analyzed using multiple criteria. To assess the quality of the enhanced dataset, classification tasks were used concurrently. The results support the conclusion that the proposed algorithm is suitable for enhancing the quality of hyperspectral data.
Neutrinos' interaction with matter is so feeble that detection proves challenging, thus making their characteristics amongst the least understood. The liquid scintillator (LS), with its optical properties, influences the performance of the neutrino detector. Tracking alterations in LS characteristics offers an understanding of how the detector's output varies with time. The characteristics of the neutrino detector were investigated in this study using a detector filled with liquid scintillator. We devised a method to distinguish the concentrations of PPO and bis-MSB, which are fluorescent markers added to LS, by using a photomultiplier tube (PMT) as an optical sensor. Determining the level of flour dissolved in LS is usually quite intricate and challenging. Our procedure involved the data from the PMT, the pulse shape characteristics, and the use of a short-pass filter. A measurement using this experimental setup has not, until now, been documented in any published literature. The pulse's morphology exhibited variations contingent upon the quantity of PPO present. Likewise, a drop in the light output of the PMT, featuring a short-pass filter, was seen as the concentration of bis-MSB was heightened. These results support the feasibility of real-time monitoring of LS properties, directly linked to fluor concentration, through a PMT, thereby eliminating the necessity of extracting LS samples from the detector during the data acquisition.
Utilizing both theoretical and experimental approaches, this study explored the measurement characteristics of speckles, particularly regarding the photoinduced electromotive force (photo-emf) effect in high-frequency, small-amplitude, in-plane vibrations. Relevant theoretical models were put to use. To explore the influence of vibrational parameters, imaging system magnification, and speckle size on the induced photocurrent's first harmonic, a GaAs crystal was employed as the photo-emf detector for experimental research. The supplemented theoretical model's accuracy was established, underpinning the viability of using GaAs to measure in-plane vibrations with nanoscale amplitudes through a combination of theoretical and experimental approaches.
Modern depth sensors, unfortunately, often exhibit low spatial resolution, a significant impediment to real-world use. Nevertheless, a high-resolution color image frequently accompanies the depth map in diverse situations. Because of this, depth map super-resolution, guided by learning-based methods, has been widely used. A guided super-resolution approach uses a high-resolution color image to infer high-resolution depth maps, derived from their low-resolution counterparts. Due to the problematic guidance from color images, these techniques unfortunately suffer from ongoing texture replication issues.