Finger Shape Research Articles

A digital signature system based on hand geometry - Survey

In recent years large number of emerging automated applications faces the need to have recognition abilities of persons using their own self biometrics, before they can access the applications services. Nowadays, Biometric recognition is used, it can be used as automatic identification or automatic verification of persons based on their physiological or behavioral characteristics. There are no perfect biometric measurements; each biometry has its advantages and limitations. Each biometry requires specific vital identity to answer the identification or verification question. The suitability of a particular biometry for a particular application depends on many factors. Hand geometry/shape is a very simple biometric technology that uses the measurements of human hand to verify the identity of the individuals. The measurements include the distance between certain mark points, shape and width of fingers and size of palm. The biometric systems that employing hand geometry become widely used since they have high public acceptance. This article aims to survey several articles found in literature about hand based biometric system, and to compare different methods of biometric recognition that based on hand geometry.

Endowing rotation invariance for 3D finger shape and vein verification

Endowing rotation invariance for 3D finger shape and vein verification

Static hand gesture recognition based on hierarchical decision and classification of finger features.

AbstractConsidering that the distinctions among static hand gestures are the difference between fingers sticking out, a method of grouping and classifying hand gestures step by step by using the information of the quantity, direction, position and shape of the outstretched fingers was proposed this paper. Firstly, the gesture region was segmented by using the skin color information of the hand, and the gesture direction was normalized by using the direction information of the gesture contour lines. Secondly, the finger was segmented one by one by using convex decomposition in the hand gesture image based on the convex characteristic of the gesture shape. Thirdly, the features of quantity, direction, position and shape of the segmented fingers were extracted. Lastly, a hierarchical decision classifier embedded with deep sparse autoencoders was constructed. The quantity of fingers was used to divide the gesture images into groups first, then the direction, position and shape features of the fingers were used to subdivide and recognize gestures within each group. The experimental results show that the proposed method is robust as lighting, direction and scale changes and significantly superior to the traditional method both in the recognition rate and the recognition stability.

Covariation of proximal finger and toe phalanges in Homo sapiens: A novel approach to assess covariation of serially corresponding structures.

As hands and feet are serially repeated corresponding structures in tetrapods, the morphology of fingers and toes is expected to covary due to a shared developmental origin. The present study focuses on the covariation of the shape of proximal finger and toe phalanges of adult Homo sapiens to determine whether covariation is different in the first ray relative to the others, as its morphology is also different. Proximal phalanges of 76 individuals of unknown sex (Muséum national d'Histoire naturelle, Paris, and the Natural History Museum, London) were digitized using a surface scanner. Landmarks were positioned on 3D surface models of the phalanges. Generalized Procrustes analysis and two-block partial least squares (PLS) analyses were conducted. A novel landmark-based geometric morphometric approach focusing on covariation is based on a PCoA of the angles between PLS axes in morphospace. The results can be statistically evaluated. The difference in PCo scores between the first and the other rays indicates that the integration between the thumb and the big toe is different from that between the lateral rays of the hand and foot. We speculate that the results are possibly the evolutionary consequence of differential selection pressure on the big toe relative to the other toes related to the rise of bipedalism, which is proposed to have emerged very early in the hominin clade. In contrast, thumb morphology and its precision grip never ceased undergoing changes, suggesting less acute selection pressures related to the evolution of the precision grip.

Classification of Leaves Based on the Shape of Leaves Using Convolutional Neural Network Methods

One part of the tree, namely the leaves, which grow on the branches, has several types of leaves consisting of 4 shapes, ranging from circular shapes, elongated shapes, and some even have a finger shape. Often we mistake the shapes of these leaves. This study discusses the classification of leaves based the shape of the leaf bones using the Convolutional Neural Network, which is used to classify data that has been labeled using one of the methods, namely supervised learning. The purpose of this method is to classify a variable into the variables that have been listed. The goal is to classify leaves based on leaf shape to implement a Convolutional Neural Network algorithm model for leaf classification based on bone shape, which will produce an accuracy value. Accuracy values are obtained from conducting experiments at the training and trial stages. So it can be concluded using the epochs parameter of 30 and a batch size of 128, using ReLU and Softmax activations. The results obtained for the accuracy value for training are 98.52%, while the validation is 89.06%.

Insights from molecular dynamics on CO2 diffusion coefficient in saline water over a wide range of temperatures, pressures, and salinity: CO2 geological storage implications

Successful design and execution of CO2 sequestration in saline aquifers requires a comprehensive understanding of CO2 transport properties. CO2 diffusion coefficient affects CO2 dissolution behavior in water/brine and controls phenomena such as shape of viscous fingers and onset of instabilities. Experimental determination of CO2 diffusion coefficient is a technically and economically challenging task. In this research work, we used Molecular Dynamics (MD) simulation to compute CO2 diffusion coefficient in various NaCl saline water concentrations (1–6 mol NaCl/kg water) under a broad range of temperatures (294–423 K) and pressures (10–30 MPa) to acquire a data set for CO2 diffusion coefficient in different conditions. According to the results, NaCl concentration increase gives rise to a decrease in CO2 diffusion coefficient by 15%, 29%, 49%, and 64% at 1 M, 2 M, 4 M, and 6 M solutions, respectively, compared to pure water. Presence of more cations due to salinity increase forms further hydration shells act as a barrier for CO2 diffusion. In addition, the rise in CO2 diffusion at elevated temperatures can be explained by the cation's hydration shell size reduction with temperature increment due to intensifying repulsive forces among water molecules. We proposed a new precise correlation for estimation of CO2 diffusion coefficients over temperatures and salinity ranges of this study. Regarding the pressure variation effects, no tangible changes were observed with pressure increase, validating a negligible influence on diffusion coefficient. Furthermore, the CO2 diffusion coefficient variability in presence of other salts, namely MgCl2, CaCl2, KCl, and Na2SO4, were computed separately. Comparing the influence of various salts, CaCl2 and KCl have the highest and lowest effect on the CO2 diffusion coefficient, respectively. Finally, a set of direct numerical simulations were conducted to study the impact of CO2 diffusion coefficient on CO2 dissolution process. The results obtained from this research work shed light on the importance of CO2 diffusion coefficient changes in saline water for prediction of dissolution process behavior.

A Soft Robotic Gripper With an Active Palm and Reconfigurable Fingers for Fully Dexterous In-Hand Manipulation

This study is focused on developing a new dexterous soft robotic gripper with three fingers and an active palm capable of performing in-hand manipulation purposes. This innovative design meets all the dexterous manipulation requirements without any increase in mechanical complexity. In each finger, the bending position can be modified and controlled by moving a stiff rod inserted inside the center hole of the finger. In this way, the effective length of the manipulation can be changed. As a result, these reconfigurable fingers provide a more accessible workspace than conventional soft grippers. Besides, a large diversity of the finger's shape configurations results in more dexterity and in-hand manipulation capability. Workspace analysis is accomplished to characterize the advantages of the proposed design. The effectiveness of this soft robotic gripper is validated by different in-hand manipulation experimental tests, including rotation, regrasping, and rolling. The results suggest a promising solution to bridge the design gap between hard and soft robots for dexterous manipulation tasks. The hybrid design carries advantages of these two classes, such as reconfigurability, position, and shape control from hard robots, with large degrees of freedom (DOFs), complex deformations, and lightweight from soft robots. Like human manipulation, the palm plays a major role in stable grasping, especially for enhancing the in-hand manipulation capability. Therefore, we also investigate two types of vacuum palms (suction cup and granular particles) to guarantee a wide range of object manipulation tasks that cannot be completely performed by previously suggested soft grippers.

Sinuous bar fingers of digitate shallow‐water deltas: Insights into their formative processes and deposits from integrating morphological and sedimentological studies with mathematical modelling

AbstractThis paper helps to address the growing need to resolve the severe loss of deltaic lands by providing a new understanding for shallow‐water digitate delta growth. The integration of satellite image analysis of modern deltas, field studies of the Ganjiang Delta in the Poyang Lake and ‘Delft3D’ simulations further results in improved facies models for shallow‐water digitate deltas. These analyses show that shallow‐water digitate delta bar fingers are sinuous in contrast to the straight deep‐water digitate delta bar fingers. These differences are assigned to the effect of water depth on outflow hydraulics, where friction‐dominated shallow‐water delta effluents promote mouth bar deposition that then divert flow around the mouth bar, resulting in the formation of sinuous bar fingers. These effects are further strengthened by the meandering of the shallow‐water jet that increases lateral sediment transport, and by the higher flow resistance and lower gradient of the shallow‐water outflows. Our data and analyses further show differences in the morphology and deposits of the shallow‐water sinuous bar fingers, where some bar fingers develop sinuous and others meandering (with point bars) distributary channels. Lateral channel migration and point bar formation (meandering) occur as a secondary process that does not change the shape or width of the bar fingers themselves, and is suggested to be a function of slight initial differences in channel sinuosity. These differences in distributary channel morphology have a strong effect on bar finger facies distribution. Sediment cohesion is another important control on bar finger bending processes, because high cohesion promotes formation of enclosed bays, where their bank strength exceeds the centrifugal force of water flow. Lower sediment cohesion results in sinuous bar fingers without formation of enclosed bays. This work provides insights into natural and artificial shallow‐water digitate delta growth and provides new quantitative facies models for shallow‐water digitate deltas.

Numerical simulation of the solidification phenomena of single molten droplets impinging on non-isothermal flat plate using explicit moving particle simulation method

In jet engines and gas turbines, the deposition phenomenon is attributed to the adhesion of molten droplets on walls. In this study, numerical simulations of the deposition phenomena on a substrate were performed using the explicit moving particle simulation (E-MPS) method. We adopted a non-isothermal condition for the substrate using a coupling method including wall particles and a regular grid to estimate the heat conduction to and within the substrate for enhanced numerical accuracy. This coupling method was validated by comparing the theoretical values of the one-dimensional unsteady heat conduction. Simulations were performed to study the solidification phenomena of a single molten stannum (Sn) droplet impinging and solidifying on a vertical substrate. The droplet behavior from impingement to solidification shows reasonable agreement with experimental results in terms of spread factor, taking into account the heat exchange between the droplet and substrate, including the substrate temperature change. Although temperature change in the substrate is limited to areas near the impinging droplet, temperature distributions on the interface differ between the early and later stages. The high-temperature region appears near the impinging center except near the stagnation point for the former stage, while it is near the center for the latter stage. The finger and bump shapes around the impinging droplet are explained via Rayleigh–Taylor and Plateau–Rayleigh instabilities, respectively, using the actual expanding acceleration of the liquid film.

Multi-Link Magnet Device with Electromagnetic Manipulation System for Assisting Finger Movements with Wireless Operation

We introduce a new mechanism and control system for wireless assistive finger training. The proposed mechanism and control system can provide natural finger flexion and extension via magnetic force and torque between a driving coil and a multi-link magnetic assist device placed on the fingers. The proposed mechanism is designed to allow normal movement while maintaining a natural finger shape, even when multiple magnets are applied to the fingers. Anatomical features were considered in the design to accommodate the angular changes between the fingers during hand extension and flexion. The magnetic force between the control system and the device on the hand allows extension and flexion of the fingers without the use of wires and electrical motors. The performance of the driving system and the magnetic device were verified through various simulations and experiments. A control program with motion tracking is also developed using LabView software. Hence, a wireless assistive finger training system is successfully realized.

Exploiting In-Hand Knowledge in Hybrid Joint-Cartesian Mapping for Anthropomorphic Robotic Hands

Replication of human hand motions on anthropomorphic robotic hands is typically treated in literature as the combination of two sub-problems: the measurement of human hand motions, and the mapping of such motions on the robotic hand. In this letter we focus on the second one. Different approaches have been proposed to deal with this problem, but none of them preserves both master finger shapes and fingertip positions on the robotic hand, i.e. ensuring predictability and natural motion for the teleoperator. In this article, we propose a novel hybrid approach that combines both joint and Cartesian mappings in a single solution. In particular, we exploit the a priori, in-hand information related to the areas of the workspace in which thumb and finger fingertips can get in contact. This allows to define, for each finger, a zone of transition from joint to Cartesian mapping. As a consequence, both hand shape during volar grasps and correctness of the fingertip positions for precision grasps are preserved, despite the master-slave kinematic dissimilarities. The proposed hybrid mapping is presented and experimentally evaluated both in simulation and with a real slave anthropomorphic robotic hand.

Diffusion coefficients of CO2–SO2–water and CO2–N2–water systems and their impact on the CO2 sequestration process: Molecular dynamics and dissolution process simulations

AbstractThe high cost of the CO2 sequestration in saline aquifers is a barrier to the implementation of them. However, a large portion of the cost is invested to purify and transport the CO2 from the flue gas stream of the emission sources. Therefore, the possibility of injecting impure CO2 will reduce the costs strongly. The diffusion coefficient is an important factor that plays a significant role in different aspects of the process. In spite of its importance, it is got less attention due to complex experimental procedures and low range of temperature and pressure applicability in the experimental conditions. To shed light on the effects of the impurity on the diffusion coefficient of CO2‐water systems, two types of impurities (SO2 and N2) in two levels are considered in this study through the molecular dynamics simulation approach. Simulations are done on a wide range of pressure and temperature conditions to cover a wide range of operational conditions for CO2 sequestration projects. The outcomes of these simulations were used in the direct numerical simulations to analyze the effect of the diffusion coefficient matrix changes on the CO2 dissolution process such as dissolution flux, the motion and shape of convective fingers, and their patterns. Results indicate that impurity has a great impact on the diffusion coefficient, and consequently on the CO2 dissolution behavior. We hope that reported results will pave the way for future studies regarding impure CO2 sequestration in saline aquifers. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd.

Development of handshape tuina-cupping instrument based on pulsating airflow technology

A new type of handshape tuina-cupping instrument is developed to overcome the shortcomings of traditional cupping therapy, such as indentation and pain, and simulates the tuina manipulation, so as to realize the combination of cupping therapy and tuina manipulation. The handshape tuina-cupping instrument has a trumpet-shaped, silica gel edge. At the same time, the finger-belly shape is added at the cupping edge to simulate the shape of fingers during tuina. Under the action of air suction and deflation of pulsating airflow, the purpose of simulating tuina manipulation is achieved, and the indentation and pain caused by the handshape tuina-cupping instrument is significantly less than that of the traditional cupping instrument.

Activation of Prefrontal Cortex in Process of Oral and Finger Shape Discrimination: fNIRS Study.

BackgroundThe differences in the brain activities of the insular and the visual association cortices have been reported between oral and manual stereognosis. However, these results were not conclusive because of the inherent differences in the task performance-related motor sequence conditions. We hypothesized that the involvement of the prefrontal cortex may be different between finger and oral shape discrimination. This study was conducted to clarify temporal changes in prefrontal activities occurring in the processes of oral and finger tactual shape discrimination using prefrontal functional near-infrared spectroscopy (fNIRS).MethodsSix healthy right-handed males [aged 30.8 ± 8.2 years (mean ± SD)] were enrolled. Measurements of prefrontal activities were performed using a 22-channel fNIRS device (ETG-100, Hitachi Medical Co., Chiba, Japan) during experimental blocks that included resting state (REST), nonsense shape discrimination (SHAM), and shape discrimination (SHAPE).ResultsNo significant difference was presented with regard to the number of correct answers during trials between oral and finger SHAPE discrimination. Additionally, a statistical difference for the prefrontal fNIRS activity between oral and finger shape discrimination was noted in CH 1. Finger SHAPE, as compared with SHAM, presented a temporally shifting onset and burst in the prefrontal activities from the frontopolar area (FPA) to the orbitofrontal cortex (OFC). In contrast, oral SHAPE as compared with SHAM was shown to be temporally overlapped in the onset and burst of the prefrontal activities in the dorsolateral prefrontal cortex (DLPFC)/FPA/OFC.ConclusionThe prefrontal activities temporally shifting from the FPA to the OFC during SHAPE as compared with SHAM may suggest the segregated serial prefrontal processing from the manipulation of a target image to the decision making during the process of finger shape discrimination. In contrast, the temporally overlapped prefrontal activities of the DLPFC/FPA/OFC in the oral SHAPE block may suggest the parallel procession of the repetitive involvement of generation, manipulation, and decision making in order to form a reliable representation of target objects.

Rt-me-fMRI: a task and resting state dataset for real-time, multi-echo fMRI methods development and validation

A multi-echo fMRI dataset (N=28 healthy participants) with four task-based and two resting state runs was collected, curated and made available to the community. Its main purpose is to advance the development of methods for real-time multi-echo functional magnetic resonance imaging (rt-me-fMRI) analysis with applications in neurofeedback, real-time quality control, and adaptive paradigms, although the variety of experimental task paradigms supports a multitude of use cases. Tasks include finger tapping, emotional face and shape matching, imagined finger tapping and imagined emotion processing. This work provides a detailed description of the full dataset; methods to collect, prepare, standardize and preprocess it; quality control measures; and data validation measures. A web-based application is provided as a supplementary tool with which to interactively explore, visualize and understand the data and its derivative measures:https://rt-me-fmri.herokuapp.com/. The dataset itself can be accessed via a data use agreement on DataverseNL athttps://dataverse.nl/dataverse/rt-me-fmri. Supporting information and code for reproducibility can be accessed athttps://github.com/jsheunis/rt-me-fMRI.

Authenticating user while Performing Transaction at ATM/POS using Hand Gestures

This electronic document defines the use of Vision-based technology for authentication at ATM/POS while performing a transaction. It makes use of Hand Gestures which are conveyed through finger position and shape of a palm, which helps in entering the ATM pin through gestures of the hand. The hand gestures are being detected using OpenCV, python 3.7. A High-uality camera and well-lit background are required for proper detection of hand position. This Paper will propose to develop a hand gesture recognition system for safely performing a transaction at ATM/POS.

Numerical investigation of immiscible Liquid-Liquid displacement in Hele-Shaw cell

In the present work, a numerical simulation has been performed on the immiscible liquid–liquid displacement flow in two- dimensional rectilinear Hele-Shaw cell (HSC) by using ANSYS FLUENT commercial software. The volume of fluid (VOF) model has been used to track the interface of immiscible liquids in the displacement flow process. A finger shape instability records at the oil–water interface when a large viscous liquid oil is displaced by lower viscous liquid water from the oil-saturated Hele-Shaw cell. This finger shape interfacial instability is called viscous fingering. The viscosity ratio (ratio of the viscosity of displacing and displaced liquids) of two-phase flow is less than unity then unstable displacement occurs and results in finger shape instability appears at the interface. The numerical simulation of two-phase flow has been performed by using the pressure base solver and transient model. The present work aims to capture the propagation of a finger shape instability at the oil–water interface and calculate the sweep efficiency by image processing. We observed that water displaces approximately 72.42% of oil from the entire oil-saturated HSC and sweep efficiency gradually increases with time in the displacement process.

Investigation of waterflood front digitations during immiscible displacements in porous media

In this work, unstable displacements were conducted using special equipment designed to run in-situ CT-scanner experiments. All the displacements were conducted on a homogeneous Bentheimer sandstone plug, of 10 cm in diameter and 40 cm in length. Digitations (or fingering) have been observed under varying conditions of injection flowrate, displaced fluid viscosity, and core wettability. They have been characterized at both the core scale, using the core average oil saturation and the water breakthrough; and at the local scale, using the local saturations and had-hoc image processing analysis. It was found that the effect of the different flowing conditions on the front digitations could not be interpreted independently. The oil recovery at brine breakthrough showed a good correlation with the viscous fingering number for the water-wet case. However, a different scaling was observed for the oil-wet case. The interplay of the different flowing conditions mitigates the possibility of constructing a unique scaling number to account for all experimental condition. The local saturation monitoring has provided a new insight to characterize the finger shapes and analyze the production mechanisms. It allowed to distinguish two independent contributions to early breakthrough: viscous dominated digitations and capillary dominated digitations. A two-phases diagram has been constructed to plot and compare these contributions for all flowing conditions. Their evolutions show the main production mechanisms during the flooding. We observed that the viscous digitations were not causing phase trapping at core scale: the core is completely swept after breakthrough. For the water-wet case, we found that the local oil recovery of swept zone remained constant before and after breakthrough while for the oil-wet case it is improving during all the water flooding process.

CFD analysis of viscous fingering in Hele-Shaw cell for air-glycerin system

In this research paper, a numerical study has been done on the viscous fingering instability for the air-glycerin system in the 2D horizontal Hele-Shaw cell. The air and glycerin are immiscible fluids and the viscosity of glycerin is too much higher than air and viscous fingering strongly depends upon the viscosity differences of fluids pairs so that the air-glycerin system is taken. In this work, an immiscible fluid–fluid displacement flow process occurs and a low viscous fluid air displaces another high viscous fluid glycerin in the rectangular Hele-Shaw cell then due to unstable displacement of glycerin by air a single finger shape instability appears at the air-glycerin interface. This phenomenon is called viscous fingering. The viscous fingering has got importance in many natural and industrial applications such as geologic carbon dioxide sequestration, oil recovery, water infiltration into the soil, mixing of fluids at low Reynolds numbers in microfluidic devices, and many more. This numerical simulation is based on the transient solver. Volume of fluid (VOF) model has been accounted for tracking of the air- glycerin interface. The Geo-reconstruct scheme has been selected for precise interface tracking. The PISO (Pressure Implicit with Splitting of Operators) scheme has been adopted because it has improved the calculation efficiency. The objectives of this paper are to track the growth of a single finger at the air-glycerin interface and calculate the displacement efficiency by image processing. We found that air displaces only 74.15% of glycerin from the entire cell. We have also shown the distribution of pressure and velocity in the entire cell domain.

On-Body RF Sensor Toward Tremor Detection in Parkinson's Disease

This article presents a conformal and on-body RF sensor with reduced wiring complexity for tremor detection in Parkinson's disease evaluation. RF sensor aids in detecting and extracting continuous finger movement that makes exact and repeated estimation of tremor feasible. The shift in frequency during finger motion is investigated to monitor tremor. The sensor is developed on a finger cap in such a way that it conforms to the shape of a human finger. The realized sensor can detect relative angle changes with an accuracy of 0.57o. The fabricated sensor is tested in real-time with variations in finger length, diameter, and skin thickness. The influence of these variations on the frequency shift is investigated using analysis of the variance and fuzzy method. The correlation value of 98% between experimental and predicted values is obtained using the fuzzy logic.