Relative Distance Change Research Articles

Influence of relative distance between fault and tunnel on dynamic response of tunnel: An experimental and numerical investigation

The effect of earthquakes on deep tunnels near faults has always been a significant issue in underground engineering research. The presence of fault fracture zones tends to intensify the seismic response of tunnels. On the basis of the Xianglushan tunnel project, the influence of relative distance between fault and tunnel on the dynamic response of tunnel was investigated utilizing laboratory test, shaking table test, and numerical simulation. The results indicated that as the relative distance between the fault and the tunnel increased, the peak acceleration and peak strain of the tunnel first increased and then decreased. The results of numerical simulations and experimental tests demonstrated that changes in relative distance had a significant influence on the dynamic response of the tunnel. Since the Xianglushan tunnel is located near the fault, the superposition of seismic load and the residual tensile and compressive stress led to the appearance of through-type cracks, which eventually resulted in large deformation or even failure. The left arch springing and left spandrel of the tunnel closer to the fault were prone to failure first. This study provides a reference for the seismic dynamic response and failure mechanism of near-fault tunnels.

Mixbiotic society measures: Assessment of community well-going as living system.

Social isolation and fragmentation represent global challenges, with the former stemming from a lack of interaction and the latter from exclusive mobs-both rooted in communication issues. Addressing these challenges, the philosophical realm introduces the concept of the "mixbiotic society." In this framework, individuals with diverse freedoms and values mix together in physical proximity with diverse mingling, recognizing their respective "fundamental incapacities" and uniting in solidarity. This study aims to provide novel measures to balance freedom and solidarity, specifically the intermediate between isolation and mobbing, within a mixbiotic society. To achieve this, we introduce simplified measures to evaluate dynamic communication patterns. These measures complement traditional social network analysis of static structures and conventional entropy-based assessments of dynamic patterns. Our specific hypothesis posits that the measures corresponding to four distinct phases are established by representing communication patterns as multidimensional vectors. These measures include the mean of Euclidean distance to quantify "mobism" for fragmentation, the relative distance change for "atomism" indicating isolation, and a composite measure derived from multiplying the mean and variance of cosine similarity for "mixism," reflecting the well-going state of a mixbiotic society. Additionally, nearly negligible measures correspond to "nihilism." Through the evaluation of seven real-society datasets (high school, primary school, workplace, village, conference, online community, and email), we demonstrate the utility of the "mixism" measure in assessing freedom and solidarity in society. These measures can be employed to typify communities on a radar chart and a communication trajectory graph. The superiority of the measures lies in their ability to evaluate dynamic patterns, ease of calculation, and easily interpretable meanings compared to conventional analyses. As a future development, alongside additional validation using diverse datasets, the mixbiotic society measures will be employed to analyze social issues and applied in the fields of digital democracy and platform cooperativism.

Safety-critical control of planar quadcopters under dynamic event-triggered mechanism

This paper aims to solve the problem of safety-critical control, i.e., safe flight of planar quadcopters in complex environments. By introducing input-to-state safe barrier function (ISSf-BF), the attitude, position, speed, and other key parameters of planar quadcopters are fully considered to realize safety-critical control. Also, a dynamic event-triggered mechanism (DETM) is constructed, and Zeno phenomenon is ruled out based on the constructed DETM. By monitoring the relative distance and speed changes between planar quadcopters and the boundary of the safe zone, the control action is triggered only when the control strategy needs to be adjusted, which effectively reduces the unnecessary waste of computation and communication resources. Finally, a series of simulation experiments are demonstrated to verify the feasibility of the proposed method.

Sensor noise in LISA Pathfinder : Laser frequency noise and its coupling to the optical test mass readout

The (LPF) mission successfully demonstrated the feasibility of the technology needed for the future space borne gravitational wave observatory LISA. A key subsystem under study was the laser interferometer, which measured the changes in relative distance in between two test masses (TMs). It achieved a sensitivity of 32.0−1.7+2.4 fm/Hz, which was significantly better than the prelaunch tests. This improved performance allowed direct observation of the influence of laser frequency noise in the readout. The differences in optical path lengths between the measurement and reference beams in the individual interferometers of our setup determined the level of this undesired readout noise. Here, we discuss the dedicated experiments performed on LPF to measure these differences with high precision. We reached differences in path length difference between (368±5) μm and (329.6±0.9) μm which are significantly below the required level of 1 mm or 1000 μm. These results are an important contribution to our understanding of the overall sensor performance. Moreover, we observed varying levels of laser frequency noise over the course of the mission. We provide evidence that these do not originate from the laser frequency stabilization scheme which worked as expected. Therefore, this frequency stabilization would be applicable to other missions with similar laser frequency stability requirements. Published by the American Physical Society 2024

Relationship between prior statin therapy and radiological features and clinical outcomes of intracerebral hemorrhage

ObjectivesA post-hoc analysis of the ICH Deferoxamine (i-DEF) trial was performed to examine any associations pre-ICH statin use may have with ICH volume, PHE volume, and clinical outcomes. Materials and methodsBaseline characteristics were assessed. Various ICH and PHE parameters were measured via a quantitative, semi-automated method at baseline and follow-up CT scans 72–96 h later. A multivariable logistic regression model was created, adjusting for the variables that were significantly different on univariable analyses (p < 0.05), to assess any associations between pre-ICH statin use and measures of ICH and PHE, as well as good clinical outcome (mRS ≤2), at 90 and 180 days. Results262 of 291 i-DEF participants had complete data available for analysis. 69 (26.3 %) used statins prior to ICH onset. Pre-ICH statin users had higher prevalences of hypertension, diabetes, and prior ischemic stroke; higher concomitant use of antihypertensives and antiplatelets; and higher blood glucose level at baseline. On univariable analyses, pre-ICH statin users had smaller baseline ICH volume and PHE volume on repeat scan, as well as smaller changes in relative PHE (rPHE) volume and edema extension distance (EED) between the baseline and repeat scans. In the multivariable analysis, none of the ICH and PHE measures or good clinical outcome was significantly associated with pre-ICH statin use. ConclusionPre-ICH statin use was not associated with measures of ICH or PHE, their growth, or clinical outcomes. These findings do not lend support to either overall protective or deleterious effects from statin use before or after ICH.

Influencing Pedestrians’ Route Choice Using Route Shape Simplification

Pedestrians’ route choice is critical for several purposes, while deliberately changing map representations can influence map users’ route choice. Simplifying routes’ geometric shapes is one way to achieve this. However, the other geometric characteristics of routes (e.g., the relative distance of different routes, differences in initial orientation, the number of intersections, and the direction changes) also influence pedestrians’ route choice, per relevant research. Hence, this study conducted an experimental investigation to examine the influence of route shape simplification on pedestrians’ route choice, under various geometric characteristics conditions. The results of the statistical tests and correlation analyses showed that (1) route shape simplification has a significant influence on route choice; (2) larger relative distance and direction changes reduce shape simplification’s influence, while the number of intersections and differences in initial orientation have weak effects; (3) 1.3 times the relative distance may be the threshold for the selection of recommended routes, and the improvement of visual continuity at route nodes may prove more influential. The results of this study can support the applicability of shape simplification to influence route choice.

The Prognostic Roles of Perihematomal Edema and Ventricular Size in Patients with Intracerebral Hemorrhage.

Conflicting data exist regarding the association of perihematomal edema (PHE) with outcomes after intracerebral hemorrhage (ICH). We performed a post hoc analysis of the ICH Deferoxamine trial to examine whether an early change in ventricular size (VS), as a composite measure of PHE growth and mass effect, intraventricular hemorrhage, and hydrocephalus, is a more accurate predictor of outcome than PHE measures alone. Computerized tomography scans were performed at baseline and after 72-96h. We evaluated measures of PHE and change in VS as predictors of outcome, assessed by a dichotomized modified Rankin Scale score (0-2 versus 3-6), primarily at 90days and secondarily at 30days. A multivariable logistic regression model was fitted for each predictor, with adjustment for the same confounders. A total of 248 participants were included after we excluded those requiring external ventricular drains. On univariate analyses, older age, female sex, lower Glasgow Coma Scale score and baseline temperature, greater ICH volume, absolute PHE volume, edema extension distance at presentation, lesser changes in relative PHE volume and edema extension distance, and an increase in VS were associated with poor outcome. In multivariable analyses, only the increase in VS was associated with lower odds of modified Rankin Scale scores 0-2 at 90days (odds ratio 0.927, 95% confidence interval 0.866-0.970, p = 0.001) and 30days (odds ratio 0.931, 95% confidence interval 0.888-0.975, p = 0.003). Within the context of a randomized controlled trial with standardized imaging and functional assessments, we did not find significant associations between measures of PHE and outcome but documented an independent association between early increase in VS and lower odds of good clinical outcome.

An analysis of the impact of economic context of selected determinants of cross-border mergers and acquisitions in the EU

Cross-border mergers and acquisitions represent a significant global phenomenon that allows businesses to generate business synergies, procure assets, generate tax optimisations, gain access to new technologies and markets, increase competitiveness and market value and differentiate and diversify business activities. In this study, we analyse the impact of economic determinants which influence the year to year increase in the average volume of cross-border mergers and acquisitions (M&A) directed from the source country to the target country. We run binary logistic regression on the data which contains observation of selected indicators in EU countries (including the UK) within 1998–2015. Our data have nature of panel data. We study impact of selected indicators on the year to year increase of merges and acquisitions in the European Union. We document that market capitalisation growth has a positive influence on the year-on-year increase in the volume of M&A. We also provide proof that changes in relative distance between source and target country affects the volume of M&A and that existence of a common border between the source and target country induce an increase in M&A. Our study contributes to better understanding of the cross-border mergers and acquisitions phenomena and is complementary to already conducted research.

Hybrid of Angular and Distance Protection for Coexistence of 5G Base Stations and Satellite Earth Stations

In this study, we investigated the coexistence of the 5G communication network with a fixed-satellite service (FSS) in the 3.5 GHz and 26 GHz frequency bands. We analyzed an angular protection scheme for the FSS Earth station (ES) and 5G base stations (BSs). In addition, we defined the fixed BS-ES relative location, relative distance, and angular changes. The angular protection was integrated into the exclusion and restricted zones proposed by the distance protection scheme for simulation analysis to develop a transmit power control scheme based on the Citizens Broadband Radio Service. Its performances were extensively analyzed through simulations. The proposed scheme was evaluated in practical scenarios: rural macrocells, urban macrocells, and urban microcells, as defined by the 3rd Generation Partnership Project (3GPP). The influence of antenna type was also researched, and BSs with 4 × 4, 8 × 8 and 16 × 16 antenna arrays, as specified by 3GPP, were considered for 5G networks. Finally, the results prove that the angular protection solution can solve the coexistence of the 5G system and the FSS. In addition, when angular protection and distance protection are used simultaneously, the coexistence effect of the two systems can be strengthened. Moreover, this work provides a quantitative perception for selecting system parameters, including an interference margin for the different scenarios and antenna types, the exclusion size, and the reduction area.

Effect of an anti-adhesion agent on vision-based assessment of cervical adhesions after thyroid surgery: randomized, placebo-controlled trial

Many patients experience cervical adhesions after thyroid surgery. To date, however, no studies have objectively measured the effects of anti-adhesion agents on cervical adhesion symptoms. This study evaluated the effects of an anti-adhesion agent on cervical adhesions after thyroid surgery, as determined using a system that measures the extent of marker movement objectively. One hundred patients were randomized in a 1:1 ratio to undergo thyroid surgery with or without the anti-adhesion agent Collabarrier. Using specially manufactured recording equipment, the position of the marker on neck skin was measured before surgery, and 2 weeks, 3 months, and 9 months after surgery. Relative change in marker distance, calculated by subtracting the marker position before surgery from the marker positions 2 weeks, 3 months, and 9 months after surgery, differed significantly in the groups of patients who underwent thyroid surgery with and without the anti-adhesion agent (P < 0.05). A novel measuring system can objectively evaluate the effectiveness of a thyroid anti-adhesion agent. The anti-adhesion agent used significantly reduced adhesions compared with the control group. The trial is registered at www.cris.nih.go.kr (KCT0005745; date of registration, 08/01/2021).

Pimples reduce and dimples enhance flat dielectric surface image repulsion.

In solid-liquid, or liquid-liquid, interfaces with dielectric contrast, charged particles interact with the induced polarization charge of the interface. These interactions contribute to an effective self-energy of the bulk ions and mediate ion-ion interactions. For flat interfaces, the self-energy and the mediated interactions are neatly constructed by the image charge method. For other geometries, explicit results are scarce and the problem must be treated via approximations or direct computation. The case of interfaces with roughness is of great practical importance. This article provides analytical results, valid to first-order in perturbation theory, for the self-energy of particles near rough substrates. Explicit formulas are provided for the case of a sinusoidal deformation of a flat surface. Generic deformations can be treated by superposition. In addition to results for the self-energy, the surface polarization charge is presented as a quadrature. The interaction between an ion and the deformed surface is modified by the change in relative distance as well as by the local curvature of the surface. Solid walls, with a lower dielectric constant than the liquid, repel all ions. We show that the repulsion is reduced by local convexity and enhanced by concavity; dimples are more repulsive than pimples.

Research on Vehicle Adaptive Cruise Control Method Based on Fuzzy Model Predictive Control

Under complex working conditions, vehicle adaptive cruise control (ACC) systems with fixed weight coefficients cannot guarantee good car following performance under all conditions. In order to improve the tracking and comfort of vehicles in different modes, a fuzzy model predictive control (Fuzzy-MPC) algorithm is proposed. Based on the comprehensive consideration of safety, comfort, fuel economy and vehicle limitations, the objective function and constraints are designed. A relaxation factor vector is introduced to soften the hard constraint boundary in order to solve this problem, for which there was previously no feasible solution. In order to maintain driving stability under complex conditions, a multi-objective optimization method, which can update the weight coefficient online, is proposed. In the numerical simulation, the values of velocity, relative distance, acceleration and acceleration change rate under different conditions are compared, and the results show that the proposed algorithm has better tracking and stability than the traditional algorithm. The effectiveness and reliability of the Fuzzy-MPC algorithm are verified by co-simulation with the designed PID lower layer control algorithm with front feedforward and feedback.

Validation of Relative Motion Measurement Method of Lateral Compression Pelvic Fractures During Examination Under Anesthesia.

To determine if the relative distance between the acetabular teardrops on unstressed and lateral compressive stress examination under anesthesia (EUA) pelvic fluoroscopic images is reproducible between independent reviewers. Retrospective database review. Level 1 trauma center. Fifty-eight patients with a lateral compression type 1 pelvic ring injury who underwent EUA. Validation of EUA objective measurements between blinded, independent reviewers using interclass and intraclass correlation coefficients. There was excellent interobserver and intraobserver reliability between all reviewers. Values for each intraclass correlation coefficients (including 95% confidence intervals) were between 0.96 (0.95-0.098) and 0.99 (0.99-0.99) for all measurements. P values were <0.0001 for all measured parameters. The relative change in distance between the acetabular tear drops during lateral compressive EUA of lateral compression type 1 pelvic injuries is reliable between independent reviewers. This allows for accurate, objective measurement of pelvic motion independent of patient size or body habitus. Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

A UHF RFID-Based Dynamic Object Following Method for a Mobile Robot Using Phase Difference Information

Dynamic object following is an essential ability for mobile robots in various application scenarios such as auxiliary cargo transportation, disabled assistant caring, and multirobot formation. A dynamic object following method for a mobile robot based on ultrahigh-frequency (UHF) radio frequency identification (RFID), which uses a phase difference information-based dynamic following model, is presented in this article. Through this method, a mobile robot equipped with an RFID reader can follow a dynamic target object attached with a passive RFID tag. A cost function is constructed to indicate the changes in relative distance and bearing between the target object and the following robot, allowing the real-time calculation of the translational and rotational velocities of the following robot using an algorithm base on proportional integral differential (PID)-based controllers. Compared with the existing RFID-based following methods, the proposed method can achieve a satisfactory distance and bearing following accuracy by using RFID phase difference information without any tedious and time-consuming phase drift or antenna installation calibration. Real experiments were conducted using commercial off-the-shelf (COTS) UHF RFID, and results show that the proposed method is effective and robust, the respective average distance and bearing following errors were approximately 1.65 cm and 4.94° during the robot-following tests and 4.45 cm and 6.03° during the human-following tests. The proposed method has promising applications in mobile robot following of dynamic object to provide service or assistance in large storage and manufacturing industries.

Analysis of Correlation Between Breast Surface Position and Internal Organ Deformation Using Deep-Inspiration Breath Holding for Left-Sided Breast Irradiation

An increased risk of cardiac toxicity and radiation pneumonitis is related to the mean dose of radiation to the heart and lungs during left-sided breast irradiation. The deep-inspiration breath holding (DIBH) technique was investigated with focus on reducing the radiation dose to the heart and its substructures, such as the left anterior descending coronary artery (LAD). Three-dimensional surface-imaging systems have been used to facilitate image-guided breast radiotherapy. However, internal organ position during DIBH depends on the compliance of the patient. Previous research has shown that relative craniocaudal distance changes during inspiration and expiration normalized to the mean distance in quiet breathing was maximum 44.3% ± 4% and minimum 4% ± 5%. We investigated positional correlations between limited breast surface position and internal organs and evaluated the effect of doses in left-sided breast irradiation with the DIBH technique. In this study, breast surface position was measured using an infrared range finder and the heart position was retrospectively measured using CT data. Five patients who had undergone left-sided lumpectomy practiced DIBH during CT. Simultaneously, breast surface distance (BSD) was monitored by a range finder continually during CT acquisition. The range finder was attached to the CT couch and measured the distance from one point of the breast surface to the scanner. CT with voluntary DIBH and free breathing in the treatment position was performed three times in each patient. To measure heart distances (HD), the maximum distance from the LAD to the chest wall (lateral edge of the lung) was calculated in each CT image and associated with the location to the corresponding BSD. Each free-breathing CT image was deformed to each DIBH CT image, and the deformation vector field (DVF), which was associated with the HD and the BSD, was calculated. Moreover, we evaluated dosimetric effects of variations of internal organ deformation by the voluntary DIBH. Compared with the mean BSD during free breathing, mean BSD during DIBH was reduced by 12 mm and the reproducibility was shown to be stable at approximately ± 0.2～3.9 mm. The mean HD was increased by 5.4 ± 2.4 mm. The correlation coefficient between BSD and HD during DIBH was 0.23, which indicated a weak positive correlation. According to the results of DVF, the heart and diaphragm positions moved forward toward the front caudal side; however, the variation in HD and internal organ motion depended on the characteristics of each patient. Moreover, in cases of abdominal breathing, breast surface motion was significantly small and no correlation between BSD and HD was observed. However, dosimetric errors of target and normal tissue were small, suggesting that DIBH irradiation while monitoring BSD is feasible. Correlations among BSD, HD, and internal organ motion were weak and depended on patient characteristics and respiratory method.

Joint Support Technology and Its Engineering Application to Deep Soft Rock Tunnel with Strong Creep

Deformation control of soft rock in deep roadways has always been a challenge in coal mining. The strain softening and rheological properties of high-stress soft rock not only cause large deformation of the surrounding rocks, but also lead to a long duration of deformation. Based on previous research results obtained here in China as well as abroad, this study focused on the S2S2 mining roadway in the Xiaokang Coal Mine of Liaoning Province in China for research and studied the characteristics and damage of its surrounding rock deformation. Furthermore, the sectional form that should be used in roadway construction, as well as the support structure types and parameters were proposed to control the excessive deformation of the surrounding rock. It is suggested that a circular section should be adopted as the mining roadway section, and the high-strength rock should be bolted together, employing the combination of the anchor cable support method. Industrial tests have verified that the circular roadway under the new support mode can enable relative distance changes between the roadway walls, make the roof and floor relatively flat, and reduce the convergence speed to a value lesser than that of the original support mode. The most important advantage is that under this joint support mode, the deformation and damage of the circular roadway would be less affected by mining activity, so the deformation and damage of the mining roadway can be controlled effectively. Therefore, the research results of this study can provide a reference value for similar engineering projects.

Part-based visual tracking via structural support correlation filter

To better deal with the partial occlusion issue and improve their efficiency of part-based and support vector machines (SVM) based trackers, we propose a novel part-based structural support correlation filter tracking method, which absorbs the strong discriminative ability from SVM and the excellent property of part-based tracking methods which is less sensitive to partial occlusion. Then, our proposed model can learn the support correlation filter of each part jointly by a star structure model, which preserves the spatial layout structure among parts and tolerates outliers of parts. In addition, our model introduces inter-frame consistencies of local parts to mitigate the drift problem. Finally, our model can accurately estimate the scale changes of object by the relative distance change among reliable parts. The extensive empirical evaluations on three benchmark datasets: OTB2015, TempleColor128 and VOT2015 demonstrate that the proposed method achieves comparable performance against several state-of-the-art trackers and runs in real time.

Modern methodology for the development of parametric models for determining the cost of transporting freights for tariff setting purposes

One of the key problems of organizing an effective The article considers problems of the influence of technical transportation process is an adequate reflection of the current and technological parameters of freight transportation by rail on pricing factors in the tariff system. This can be done on the basis of the cost price for tariff purposes, the distribution of the cost of the the development of appropriate models for determining the cost initial-final operation between loaded and empty cars, determinaof transportation. Modeling the cost of transporting freights by rail tion of coefficients taking into account the length of cars and the for tariff purposes is based on determining and assessing the rela-distance of transportation, as well as the methodology for the distionship between transportation costs and work indexes. tribution of costs between the initial-final and motion operations. Proposed updated methodology for constructing parametric models for determining the cost of transportation of freights for tariff setting purposes includes: method of itemized distribution of expenditures between non-commercial organizations and affiliated subsidiaries in terms of infrastructure and traction; procedure for allocating the costs, attributed to affiliated subsidiaries, to the indexes “ton-kilometer gross” and “car-kilometer”; system of itemized distribution of freight costs for the indexes of the transportation operation, as well as the system for calculating the aggregate expenditure rates (AER) used in parametric models of the cost price; actualized assessment of the influence of the length of the car on the cost value for tariff setting purposes; procedure for allocating the cost of initial-final operations between loaded and empty cars. The developed parametric models for calculating the cost of transportation for tariff purposes for transportation by the locomotive of the JSC “Russian Railways” take into account such factors as the distance of transportation, the weight of the container and the length of the car, its loading, the type of shipment. Within the framework of creating new parametric models, the following factors have been updated: coefficients that take into account the length of the car; coefficients that take into account the effect on the cost of production up to the distance of transportation in connection with the change in the relative distance of carriage of the car as part of mixed and transfer-and-export trains; coefficients depending on the type of shipment.

Concurrent Validity of a Rugby-Specific Yo-Yo Intermittent Recovery Test (Level 1) for Assessing Match-Related Running Performance.

Dobbin, N, Highton, J, Moss, SL, Hunwicks, R, and Twist, C. Concurrent validity of a rugby-specific Yo-Yo intermittent recovery test (level 1) for assessing match-related running performance. J Strength Cond Res 35(1): 176-182, 2021-This study investigated the concurrent validity of a rugby-specific high-intensity intermittent running test against the internal, external, and perceptual responses to simulated match play. Thirty-six rugby league players (age 18.5 ± 1.8 years; stature 181.4 ± 7.6 cm; body mass 83.5 ± 9.8 kg) completed the prone Yo-Yo Intermittent Recovery Test (Yo-Yo IR1), of which 16 also completed the Yo-Yo IR1, and 2 × ∼20 minute bouts of a simulated match play (rugby league match simulation protocol for interchange players [RLMSP-i]). Most likely reductions in relative total, low-speed and high-speed distance, mean speed, and time above 20 W·kg-1 (high metabolic power [HMP]) were observed between bouts of the RLMSP-i. Likewise, rating of perceived exertion (RPE) and percentage of peak heart rate (%HRpeak) were very likely and likely higher during the second bout. Pearson's correlations revealed a large relationship for the change in relative distance (r = 0.57-0.61) between bouts with both Yo-Yo IR1 tests. The prone Yo-Yo IR1 was more strongly related to the RLMSP-i for change in repeated sprint speed (r = 0.78 cf. 0.56), mean speed (r = 0.64 cf. 0.36), HMP (r = 0.48 cf. 0.25), fatigue index (r = 0.71 cf. 0.63), %HRpeak (r = -0.56 cf. -0.35), RPEbout1 (r = -0.44 cf. -0.14), and RPEbout2 (r = -0.68 cf. -0.41) than the Yo-Yo IR1, but not for blood lactate concentration (r = -0.20 to -0.28 cf. -0.35 to -0.49). The relationships between prone Yo-Yo IR1 distance and measures of load during the RLMSP-i suggest that it possesses concurrent validity and is more strongly associated with measures of training or match load than the Yo-Yo IR1 using rugby league players.

Cross-device hand vein recognition based on improved SIFT

The recognition rate of SIFT algorithm in single hand vein database has been as high as 99.5%. But with the development of Internet-plus technology, the demand for distributed systems becomes more and more significant. However, the problem of picture quality caused by cross-device makes the intraclass variations larger. For example, when gathering the dorsal hand vein images, subtle changes in relative distance and orientation among the imaging camera, the illumination LED arrays and the different location of users’ hand, as well as shielding by the external housing box from ambient light sources and so on, these will make large difference to one person’s hand images. So, including the contrast, the lightness, the shifting, the angle of rotation, the size and so on, these differences make it possible to use some traditional methods to recognize dorsal hand vein with a low recognition rate of less than 50%. Therefore, based on the traditional SIFT, this paper optimized the scale factor [Formula: see text], extreme searching neighborhood structure and matching threshold [Formula: see text]. It can be seen that the cross-device hand vein feature is more robust, and the recognition rate reached an average of 88.5%.