Capture Distance Research Articles

DESIGN OF IMAGE PROCESSING APPLICATION FOR FOREIGN OBJECT INSPECTION USING DRONE ON AIRCRAFT RUNWAYS

Flight safety is a crucial aspect of the aviation industry, heavily reliant on optimal runway conditions for successful takeoffs and landings. Foreign Object Debris (FOD) such as stones and potholes on the runway pose significant threats, necessitating preventive measures to avoid operational failures and aircraft damage. This research focuses on designing an image processing application for drone usage to enhance runway inspections. The Research and Development (R&D) method is employed from application design to field testing. Image processing utilizes the You Only Look Once (YOLO) method for swift and accurate FOD detection, maximizing drone effectiveness in identifying risks. Findings indicate that object size and image capture distance significantly affect detection performance. This analysis provides a basis for model optimization through improved data augmentation techniques and parameter adjustments to address challenges in detecting objects of various sizes.

Passive particles driven by self-propelled particle: The wake effect

This work focuses on numerically studying hydrodynamic interaction between a passive particle and a self-propelled particle, termed a squirmer, by using a two-dimensional lattice Boltzmann method (LBM). It is found that the squirmer can capture a passive particle and propel it simultaneously, provided the passive particle is situated within the squirmer’s wake. Our research shows that the critical capture distance, which determines whether the particle is captured, primarily depends on the intensity of the squirmer’s dipolarity. The stronger dipolarity of squirmer results in an increased critical capture distance. Conversely, the Reynolds number is found to have minimal influence on this interaction. Interestingly, the passive particle, when driven by the squirmer’s wake, contributes to a reduction in the squirmer’s drag. This results in a mutual acceleration for both particles. Our findings can provide valuable perspectives for formulating the principles of reducing the drag of micro-swimmers and help to achieve the goal of using micro-swimmers to transport goods without physical tethers.

Pulsed field ablation and ventricular capture: assessing the need for R-wave gated therapy

Abstract Background Pulsed field ablation (PFA) is a therapy that disrupts cellular homeostasis by applying high intensity and short duration electrical pulses to cardiac tissue, ultimately resulting in cell death. Such stimuli have the potential to initiate ventricular arrhythmias if the therapy is not synchronized with the beginning of ventricular systole (R-wave gating). For the treatment of cardiac arrhythmias, it is important that the candidate therapy locations in the left atrium (e.g., pulmonary veins) are a sufficient distance away from ventricular tissue to avoid ventricular capture. Objective data exploring the need for R wave gating in the context of PFA therapy for pulmonary vein isolation is currently lacking. Purpose To study the effect of electrode distance of the 12-electrode loop catheter from the epicardium on likelihood of ventricular capture. Methods A sternotomy was performed on swine to expose the heart. An incision was then made in the pericardial sac and the edges were lifted and sutured to the surrounding chest cavity to create a cradle. The function of the cradle was to hold a ∼37C saline solution (tuned to match the electrical conductivity of blood) while PFA treatments were performed. Two left ventricular sites (apex and lateral aspect) were selected for treatment, taking care to avoid proximity to the coronary artery. For each PFA therapy trial, the catheter loop was positioned 10mm above the surface of the epicardium and then advanced in 1mm increments until capture was achieved; spacers were used to assure fixed spacing during cardiac activity. For each trial, the maximum distance between the catheter and the epicardium at which the IRE therapy captured the ventricle was recorded. Additionally, CT scans (N=20 human patients) were analyzed to understand distances of interest to ventricular tissue. Results N=12 trials were conducted at each target in each animal (N=48 total ablations). For all trials, the minimum capture distance was found to be 6-8mm (4/48 at 6mm, 28/48 at 7mm and 16/48 at 8mm), with a mean capture distance of 7.25±0.60mm. The mean capture distances for the left ventricular apex and lateral aspect were 7.29±0.55mm and 7.21±0.66mm, respectively (p=0.636). For the CT scan analysis, the minimum distance from pulmonary vein ostia to left ventricular tissue ("nominal case") were 10.6mm and 12.8mm for the left superior and inferior veins, respectively. Considering the use ("worst case") where the catheter is placed just distal to the ostia, the distances to ventricular tissue were 1.6mm and 5.8mm, respectively; 4/20 patients had a vein less than 10mm from ventricular myocardium. Conclusions This study was successful in establishing the distance of ventricular capture via PFA therapy (6-8mm for the considered therapy). Given the described use and CT analysis, there is potential risk in triggering ventricular arrhythmia via PFA therapy unless R-wave triggering is implemented.

Drone Photogrammetry for Accurate and Efficient Rock Joint Roughness Assessment on Steep and Inaccessible Slopes

The roughness of rock joints exerts a substantial influence on the mechanical behavior of rock masses. In order to identify potential failure mechanisms and to design effective protection measures, the accurate measurement of joint roughness is essential. Traditional methods, such as contact profilometry, laser scanning, and close-range photogrammetry, encounter difficulties when assessing steep and inaccessible slopes, thus hindering the safety and precision of data collection. This study aims to assess the feasibility of utilizing drone photogrammetry to quantify the roughness of rock joints on steep and inaccessible slopes. Field experiments were conducted, and the results were compared to those of 3D laser scanning in order to validate the approach’s procedural details, applicability, and measurement accuracy. Under a 3 m image capture distance using drone photogrammetry, the root mean square error of the multiscale model-to-model cloud comparison (M3C2) distance and the average roughness measurement error were less than 0.5 mm and 10%, respectively. The results demonstrate the feasibility and potential of drone photogrammetry for joint roughness measurement challenges, providing a useful tool for practitioners and researchers pursuing innovative solutions for assessing rock joint roughness on precipitous and hazardous slopes.

The tailless gecko gets the worm: prey type alters the effects of caudal autotomy on prey capture and subjugation kinematics.

Prey capture and subjugation are complex behaviors affected by many factors including physiological and behavioral traits of both the predator and the prey. The western banded gecko (Coleonyx variegatus) is a small generalist predator that consumes both evasive prey items, such as spiders, wasps, and orthopterans, and non-evasive prey items, including larvae, pupae, and isopterans. When consuming certain prey (e.g., scorpions), banded geckos will capture and then rapidly oscillate, or shake, their head and anterior part of their body. Banded geckos also have large, active tails that can account for over 20% of their body weight and can be voluntarily severed through the process of caudal autotomy. However, how autotomy influences prey capture behavior in geckos is poorly understood. Using high-speed 3D videography, we studied the effects of both prey type (mealworms and crickets) and tail autotomy on prey capture and subjugation performance in banded geckos. Performance metrics included maximum velocity and distance of prey capture, as well as velocity and frequency of post-capture shaking. Maximum velocity and distance of prey capture were lower for mealworms than crickets regardless of tail state. However, after autotomy, maximum velocity increased for strikes on mealworms but significantly decreased for crickets. After capture, geckos always shook mealworms, but never crickets. The frequency of shaking mealworms decreased after autotomy and additional qualitative differences were observed. Our results highlight the complex and interactive effects of prey type and caudal autotomy on prey capture biomechanics.

Optimization of Image Capture Distance for Facial Thermograms in Dentistry

Thermography has not yet been validated for the screening of oral disorders and no clear guidelines or methodology for this purpose have been defined in the literature. The current pilot study was aimed as an initial step to evaluate the influence of shooting distances on the detection of the temperature asymmetries on the face for the purpose of dental thermography. Facial thermograms were taken in three views at three shooting distances for each participant. The mean temperature of the overall image and at the region of interest (ROI) were measured from the analysis software. Thirty adult volunteers participated in this study [n = 30, mean age: 25.8 ± 6.0]. The differences between the mean temperature values at the ROI for all different shooting distances within each profile view were statistically significant [Front: H(2) = 80.176, p < 0.001; Left: H(2) = 21.399, p < 0.001; Right: H(2) = 49.451, p < 0.001]. The mean ROI temperature was influenced by personal effects (p < 0.001), medications (p < 0.001), undergoing dental treatments (p < 0.001) as well as the consumption of food (p < 0.001). This study concludes that the detection of temperature asymmetries on the face in adult volunteers are affected by the capture distance as well as factors such as medication, oral-care, and alimentation. Therefore, it is advised that personal as well as medical histories are obtained in detail prior to making the facial thermograms.

Optimized Modulation and Coding for Dual Modulated QR Codes.

We present optimized modulation and coding for the recently introduced dual modulated QR (DMQR) codes that extend traditional QR codes to carry additional secondary data in the orientation of elliptical dots that replace black modules in the barcode images. By dynamically adjusting the dot size, we realize gains in embedding strength for both the intensity modulation and the orientation modulation that carry the primary and secondary data, respectively. Furthermore, we develop a model for the coding channel for the secondary data that enables soft-decoding via 5G NR (new radio) codes already supported by mobile devices. The performance gains for the proposed optimized designs are characterized via theoretical analysis, simulations, and actual experiments using smartphone devices. The theoretical analysis and simulations inform our design choices for the modulation and coding, and the experiments characterize the overall improvement in performance for the optimized design over the prior unoptimized designs. Importantly, the optimized designs significantly increase usability of DMQR codes with commonly used QR code beautification that cannibalizes a portion of the barcode image area for the insertion of a logo or image. In experiments with a capture distance of 15 inches, the optimized designs increase the decoding success rates between 10% and 32% for the secondary data while also providing gains for primary data decoding at larger capture distances. When used with beautification in typical settings, the secondary message is decoded with a high success rate for the proposed optimized designs, whereas it invariably fails for the prior unoptimized designs.

Calibration of UAV Flight Parameters to Inspect the Deterioration of Heritage Façades Using Orthogonal Arrays

Heritage façades are relevant to the historical preservation and identity of a city. Their deterioration can cause the devaluation of the urban environment, together with accidents caused by possible detachment of their different elements; therefore, maintaining them is crucial. It is important to have early warning systems in place, systems which would indicate potential damage and deterioration of such façades, which can be caused by factors such as humidity, earthquakes, the passage of time, or even people. This is often done through visual inspection; however, visual inspection is often affected by external factors, such as the financing of the on-site inspection and the availability of experts. Unmanned aircraft vehicles (UAVs) are a practical and economical tool that has facilitated and improved imaging by regulating parameters such as camera angle, capture distance and image overlap, thus allowing improvements in photogrammetry techniques for virtual reconstruction processes. Although the implementation of this technology has been studied in recent years, research has focused primarily on horizontal structures, such as roads. In the case of vertical structures, flight parameters are traditionally defined by trial and error, without any methodological procedure. Therefore, this paper proposes a methodology to calibrate UAV flight parameters to build a photogrammetric 3D model of a vertical structure. This proposal is based on the development of a series of experiments configured through Taguchi orthogonal arrays, which is a method that significantly reduces the number of experiments required. This methodology is applied to a case study of a façade with architectural heritage features. The results obtained offer a flight plan and the optimal parameters to achieve efficiency in the capture of images in an inspection of heritage façades, thus achieving the optimisation of resources and time.

Comparison of Capture Power of Wajanbolic Antenna with Parabolic Directional Antenna to the Distance of Capture Wireless LAN Signal 2.4 GHz

The wokbolic antenna is used to capture the 2.4 GHz wireless LAN signal. The reflector is made of a frying pan. Focus on using a foil-lined paralon pipe. At the focus is given a USB adapter to capture the signal reflected by the reflector. To see the feasibility of a tool needs to be compared with equipment that has a standard data sheet. So a research was conducted by comparing the capture power of the wokbolic antenna with a directional parabolic antenna. The research method used is a real experimental method, namely an experimental signal strength measurement of both antennas at the same location, altitude under LOS conditions. From the results of experiments conducted at five distances: at a radius of 50 meters, 73 meters, 120 meters, 150 meters, and 290 meters. The farther the capture distance, the smaller the received signal, this happens to both antennas. After the data is obtained in the form of signal strength, then the antenna gain is calculated. The results of the antenna gain calculation show the difference between the gain of the wokbolic antenna and the directional satellite dish. To see if the difference in antenna gain is significant, it is analyzed by t-test. From the t test, it turns out that t count is greater than t table, it can be concluded that the difference in antenna gain is not significant.

Analysis of the Quality of Natural Dyes in Weaving Exposed to Sunlight Using MSE and PSNR Parameters

It is widely assumed that natural dyes in weaving degrade in quality when exposed to sunlight for an extended period. This indication is visible to the naked eye. There is currently no standard for evaluating the quality of natural dyes. The Boti tribe's weaving on Timor Island, East Nusa Tenggara Province, is one type of weaving that uses natural dyes. The dye is made from corn flour and a combination of "nobah" leaves and the bark of the "bauk ulu" tree (from the local language). White (from corn flour) and blue-black are the colors produced by dyeing the yarn. The purpose of this research is to examine the image quality of the Boti tribe's woven fabric. The parameters used were Means Square Error (MSE), Peak Signal to Noise (PSNR), and RGB values. The image of the weaving used as a reference is compared to the image of the sun-dried weaving. The image capture distance was 30 cm, and the cropped RGB image size was 423x623x3. The experimental method was used in the research. The drying time was one hour, and it was repeated every hour between 10:00 and 15:00 local time. The sun-dried images were photographed, and parameter comparisons were performed for analysis. The results demonstrated that the MSE and PSNR methods were effective in measuring the image quality of weaving dyed with natural dyes. The average value has changed by 8.42% for the R-value, 8.58% for the G value, and 9.68% for the B value. The average PSNR for RGB images is 9.44288 dB, and the MSE is 7477.52. For grayscale images, the average PSNR is 10.52 dB and the average MSE is 5832.06.

Capture capability of different intrinsic structures for helium bubbles in micro-nano composite 304L steels

• Micro-nano composite 304L stainless steel (MN304-La) is implanted with He + and annealed at 900 °C. • Nano-precipitates, grain boundaries, and dislocation are three intrinsic structures coexisting in MN304-La. • Three intrinsic structures have competing processes for capturing helium bubbles. • Nano-precipitates exhibit the strongest strength in capturing helium bubbles compared to grain boundaries and dislocations. The formation and migration of helium bubbles lead to performance degradation of structural materials in nuclear reactors. Intrinsic structures in nuclear materials can significantly influence the behavior and distribution of these helium bubbles under irradiation. Micro-nano composite 304L stainless steel (MN304-La) possesses three main kinds of intrinsic structures: grain boundaries (GBs), dislocations, and La-rich nano-precipitates (NPs). In this study, the helium bubbles on different intrinsic structures in MN304-La after He + ions implantation were characterized and analyzed. We compared the capabilities of different intrinsic structures in capturing helium bubbles and confirmed that NPs exhibit the strongest strength in capturing helium bubbles among the three kinds of intrinsic structures. We found that the competition of intrinsic structures for capturing helium bubbles depends on both the capture strength of the intrinsic structures and the capture distance to the helium bubbles.

PointpartNet: 3D point-cloud registration via deep part-based feature extraction

This paper proposes a deep learning model for point cloud registrations of different sizes. 3D point clouds play a very important role in various fields. They have been widely studied, and recently deep learning has also started to deal with point clouds. PointNet was the first deep learning model for point cloud classification and semantic segmentation. Since then, methods based on PointNet for tasks like point cloud registration have also been proposed. However, these methods are only suitable for identical or nearly identical point clouds. However, in practice, the sizes of point clouds vary depending on the capture distance, sensor type, the environment, and many other factors. Therefore, it is often the case that point clouds that need to be registered are of very different sizes. For example, point clouds captured in the same environment by an omnidirectional LiDAR and an RGB-D camera will have very different sizes. Conventional methods cannot cope with such situations. In this paper, we propose ‘PointpartNet', a new deep neural network based on partial feature extraction. This network enables feature extraction of partial point clouds by partitioning the point clouds. It uses the features of partial point clouds to search for matching regions between point clouds of different sizes. This makes it capable of registering point clouds of different sizes. In qualitative experiments, we demonstrate its high robustness and accuracy for point cloud registration of different sizes in comparison to previous research.

Efficient removal of Congo red from wastewater by gas-assisted low-gradient magnetic separation

Gas-assisted low-gradient magnetic separation (GAMS) was proposed for removing Congo red (CR) from wastewater. GAMS included the adsorption removal process of nanoparticles for CR and GAMS recovery process for CR-loaded nanoparticles from wastewater. Polyethylene glycol (PEG) modified Fe3O4 (Fe3O4/PEG) nanoparticles showed maximum saturated adsorption capacity of 133.3 mg/g. The results indicated that the adsorption process conditions changed the loading amounts of CR on Fe3O4/PEG nanoparticles, showing indirect effect on the separation efficiency of GAMS. And the separation performance of GAMS could be significantly improved by changing gas flow rate, ionic strength, pH, and dyes loading amounts on nanoparticles. The comparison results of MS and GAMS suggested that the limitation of magnetic force on the capture distance could be overcome and the separation efficiency of MS could be significantly improved by the bubbles. These made it feasible to rapidly recover dyes-loaded nanoparticles from large volume wastewater. GAMS combined the efficient removal of dyes by magnetic nanoparticles with rapid recovery of dyes-loaded nanoparticles from large volume wastewater, showing great potential for wastewater treatment.

Dual-attention-based optical terminal guidance for the recovery of unmanned surface vehicles

With the outstanding performance of unmanned surface vehicles (USVs) in maritime missions with scientific and commercial applications, increasing numbers of ships have begun to carry USVs to perform tasks. For the autonomous recovery of a USV along a preset trajectory to the docking station under various sea conditions, we propose a new navigation strategy with dual-attention-based optical terminal guidance. Monocular vision systems with creatively designed identification light sources are mounted on the docking station and USV, respectively. Thus, the azimuth angle, heading angle and relative distance between the docking station and the USV can be accurately measured. This method achieves centimeter-level homing accuracy and a 0.1-degree angle measurement error. A tracking control algorithm based on a line-of-sight method is suggested , and the control quantity of the USV is directly generated. Sea trials were conducted under various weather conditions to validate the proposed algorithm. This method provides reliable USV guidance to the docking station with a stern ramp from the maximum capture distance of approximately 100 meters. The proposed dual-attention method provides convenient implementation and transplantation to various unmanned platforms.

CONSTRUCTION OF A PHYSICAL AND MATHEMATICAL MODEL OF THE GRAVITATIONAL FIELD

The problem of gravitational field physics is to identify the relationship between the gravitational field and the expansion of the space-time continuum. Therefore, the creation of models, the study of which makes it possible to identify these relationships and express them in formulas, is relevant. In the modern theory of the gravitational field, small quantities appear, which are neglected in the derivation of formulas of practical application. This paper presents a model of the gravitational field that combines quantum properties with the expansion of the space-time continuum. Also, using a simplified model of the coordinate system, the gravitational field of a stationary centrally symmetric object is studied and the limiting distance of the test particle capture by the gravitational field is calculated. Calculations made without neglecting small quantities gave interesting results: the limiting radius of capture by the gravitational field of the test particle; the formula for the mass defect of the black hole Schwarzschild; relations expressing the dependence of the quantities of quantum physics on the Hubble constant.

Anisotropic interaction between self-interstitial atoms and 1/2<111> dislocation loops in tungsten

We investigate the interaction between self-interstitial atoms (SIAs) and 1/2 self-interstitial dislocation loops in tungsten (W) via atomistic simulations. We explore the variation of the anisotropic distribution of binding energies with the shapes and sizes of the 1/2[111] loop and the nonequivalent configurations of SIAs. For an arbitrarily shaped loop, SIA can be more easily trapped in the concave region of the loop than the convex region, which forms a loop whose curvature is closer to that of a circular loop. The direction of SIAs can largely affect the interaction behaviors with the loop. The capture distance of an SIA by the edge of a circular-shaped 1/2[111] loop is clearly elongated along the direction of the SIA; however, it weakly depends on the size of the loop. Then, we analyze the slanted ring-like capture volume of SIAs formed by the circular loop based on their generated anisotropic stress fields. Furthermore, the binding energies obtained from the elastic theory and atomistic simulations are compared. The results provide a reasonable interpretation of the growth mechanism of the loop and the anisotropic interaction that induces irregular-shaped capture volume, affording an insight into the numerical and Object Kinetic Monte Carlo simulations to evaluate the long-term and large-scale microstructural evolution and mechanical properties of W.

Capture characteristics of graded-index fiber optical tweezer based on ultraviolet glue cavity

In the process of fiber optic tweezer manipulating cells, an adjustable and long working distance is very important for cell capture. To address this issue, a graded-index fiber (GIF) optical tweezer based on a UV glue cavity is proposed in this paper, and its ability to capture yeast cells was characterized. The initial air cavity between the single-mode fiber (SMF) and the GIF cone is filled with ultraviolet glue. By adjusting the length of the ultraviolet glue cavity and the laser power, the manipulation distance of the cells can be controlled. The light field distribution of the UV glue cavity is numerically investigated, which is compared with that of the GIF optical tweezers based on conventional air cavity. The contrastive result proved that the UV glue filled between the SMF and the GIF has a longer working distance than the original air cavity. The experimental results indicate that the fiber optical tweezer has a good capture distance controllability. The fiber optical tweezer also has the advantages of simple structure and convenient operation.

Dual Modulated QR Codes for Proximal Privacy and Security.

The ubiquitous presence of surveillance cameras severely compromises the security of private information (e.g. passwords) entered via a conventional keyboard interface in public places. We address this problem by proposing dual modulated QR (DMQR) codes, a novel QR code extension via which users can securely communicate private information in public places using their smartphones and a camera interface. Dual modulated QR codes use the same synchronization patterns and module geometry as conventional monochrome QR codes. Within each module, primary data is embedded using intensity modulation compatible with conventional QR code decoding. Specifically, depending on the bit to be embedded, a module is either left white or an elliptical black dot is placed within it. Additionally, for each module containing an elliptical dot, secondary data is embedded by orientation modulation; that is, by using different orientations for the elliptical dots. Because the orientation of the elliptical dots can only be reliably assessed when the barcodes are captured from a close distance, the secondary data provides "proximal privacy" and can be effectively used to communicate private information securely in public settings. Tests conducted using several alternative parameter settings demonstrate that the proposed DMQR codes are effective in meeting their objective- the secondary data can be accurately decoded for short capture distances (6 in.) but cannot be recovered from images captured over long distances (>12 in.). Furthermore, the proximal privacy can be adapted to application needs by varying the eccentricity of the elliptical dots used.

Monitoring of Corroded and Loosened Bolts in Steel Structures via Deep Learning and Hough Transforms.

In this study, a regional convolutional neural network (RCNN)-based deep learning and Hough line transform (HLT) algorithm are applied to monitor corroded and loosened bolts in steel structures. The monitoring goals are to detect rusted bolts distinguished from non-corroded ones and also to estimate bolt-loosening angles of the identified bolts. The following approaches are performed to achieve the goals. Firstly, a RCNN-based autonomous bolt detection scheme is designed to identify corroded and clean bolts in a captured image. Secondly, a HLT-based image processing algorithm is designed to estimate rotational angles (i.e., bolt-loosening) of cropped bolts. Finally, the accuracy of the proposed framework is experimentally evaluated under various capture distances, perspective distortions, and light intensities. The lab-scale monitoring results indicate that the suggested method accurately acquires rusted bolts for images captured under perspective distortion angles less than 15° and light intensities larger than 63 lux.

Gas-assisted low-field magnetic separation for efficient recovery of contaminants-loaded magnetic nanoparticles from large volume water solution

Gas-assisted low-field magnetic separation (GAMS) was proposed for efficient recovery of contaminants-loaded magnetic nanoparticles from the large volume of water solution. Pb2+ loaded magnetic nanoparticles (Fe3O4/HA) were selected as separation model of GAMS. It was demonstrated under the condition of no surfactant as flotation agent that bubbles could overcome the limitation of magnetic force on the capture distance and improve significantly the separation efficiency in low-field magnetic separation (MS). The greater improvement could be further obtained by adjusting some nonmagnetic factors such as gas flow rate, ionic strength, pH, and heavy metals loading amount. The enhancement mechanism of some factors on GAMS was disclosed by the electrostatic forces and hydrophobic forces, which was characterized by Zeta potential and contact angle. Compared with MS, GAMS had the advantages of good distant recovery, improved separation efficiency by nonmagnetic factors, low cost and high separation performance for diluted nanoparticles solution (about 10 times rate of MS).