Fascinating Rhythms Played on Fingertips

Zhao Cong, a young pipa (four-stringedChinese lute) performer with the China CentralTraditional Music Ensemble, was born into a familyof musicians. She developed an extraordinaryinterest in this ancient Chinese instrument in herchildhood. When her parents asked

Affine transformation of virtual 3D object using 2D localization of fingertips

Background Interactions with virtual 3D objects in the virtual reality(VR)environment using the gesture of fingers captured in a wearable 2D camera have emerging applications in real-life.Method This paper presents an approach of a two-stage convolutional neural network,one for the detection of hand and another for the fingertips.One purpose of VR environments is to transform a virtual 3D object with affine parameters by using the gesture of thumb and index fingers.Results To evaluate the performance of the proposed system,one existing,and another developed egocentric fingertip databases are employed so that learning involves large variations that are common in real-life.Experimental results show that the proposed fingertip detection system outperforms the existing systems in terms of the precision of detection.Conclusion The interaction performance of the proposed system in the VR environment is higher than that of the existing systems in terms of estimation error and correlation between the ground truth and estimated affine parameters.

Evaluation of sensory function and recovery after replantation of fingertips at ZoneⅠin children

Sensory function is the most significant criterion when evaluating the prognosis of replanted fingers. Current clinical research has focused on surgical techniques and indications for finger replantation; however, few studies have focused on recovery of finger sensory function af- ter replantation. This study retrospectively assessed data of eight patients who had undergone nine Zone I replantations of the fingertips in the First Affiliated Hospital of Sun Yat-sen University of China from July 2014 to January 2016. Variations in the extent of damage, with the residual vessels or nerves in some fingers being too short or even missing, prevented tension-free suture repair in some patients. Thus, re- pair of four of the nine fingertips included arteriovenous anastomosis, the remaining five undergoing arterial anastomosis during replanta- tion of the amputated fingers. Three patients underwent nerve repair, whereas the remaining six cases did not. Fingertip replantations were successful in all eight patients. Compared with the patients without vascular anastomosis, no obvious atrophy was visible in the fingertips of patients who did undergo vascular anastomosis during replantation and their sensory function did recover. Fingertip replantation pro- vides good sensory function and cosmetic outcomes when good artery and vein anastomoses have been created, even when digital nerves have not been repaired.

RESEARCH ON BEHAVIORS OF ELECTRORHEOLOGICAL FLUID-BASED SEMIACTIVE ROBOT FINGERTIPS

A new design of robot gripper with electrorheological fluid (ERF) semiactive tips is described. There are two remarkable properties using this fingertip. One is the higher lifting capability at little grasp force, which can realize stable grasp. Another is the damping controllable which can be used for controlling contact forces. A viscoelastic plastic model for normal direction of the fingertip is proposed to explore the contact behavior. The electric field strength is induced into the dynamic model of contact transition for simulations. The simulation results and conclusions are given.

At Your Fingertips

Biometric technology is helping to streng then China’s banking security you are at the ATM machine.You have your credit card ready,but can’t remember the password.You have several credit cards,and it is

Epidemiology of Fingertip Injuries at South Central Hospital Petróleos Mexicanos “Pemex” with a Review of the Literature

Background: The hand is an essential component for performing our daily tasks;as a result, injuries to the fingertip are frequently seen. Accurate evaluation and treatment of fingertip injuries are essential to avoiding long-term disability, job loss and psychological issues. No matter the injury classification system, maintaining finger length, regaining sensation, and improving appearance are the three main objectives of treatment. The objective of this research was to outline the epidemiology of fingertip injuries treated between 2021 and 2022 at a highly specialized referral hospital in Mexico City. Methodology: This investigation is cross-sectional, retrospective, and observational. From January 2021 to December 2022, 60 patients with a diagnosis of fingertip injury from the South Central Hospital “Pemex” were included. The descriptive statistical analysis was performed using SPSS29. Results: 60 patients were included, 27 (45%) were women and 33 (55%) were men. Allen’s classification was able to classify only 19 patients, of which 18 (94.7%) had a type 1 classification and one (5.26%) had a type 2 classification. 10% of patients experienced complications, which included 2 patients with surgical site infections (3.3%), 3 patients with persistent pain (5%), and 1 patient (1.6%) with graft rejection. Conclusions: There are currently insufficient epidemiological data on hand and wrist injuries and its effects on labor in Mexico. Fingertip injuries require particular care in order to prevent complications and long-term damage. The creation of national registries could help with the creation of reference manuals for the care of hand and wrist injuries in our nation.

Supermicrosurgery in fingertip defects-split tibial flap of the second toe to reconstruct multiple fingertip defects: A case report

BACKGROUND Injuries to multiple fingertips pose a significant treatment dilemma.Numerous reconstructive options exist,all with the ultimate goal of restoring function and sensibility to the injured fingertips.CASE SUMMARY A 24-year-old male suffered injury to multiple fingertips of the right hand,resulting in exposed distal phalanges of the middle,ring,and small fingers.The amputated distal stumps were not possible for replantation.Free flap coverage was selected in order to achieve better functional outcome.The fingertip defects were covered by performing a right second toe split tibial flap using local anesthesia at the harvest site and brachial plexus nerve block for the right upper extremity.At 6-month follow-up,all three of the reconstructed fingertips had some preserved nail growth,Semmes-Weinstein Monofilaments testing was equal to the contralateral side and the Static Two-Point Discrimination were comparable to the contralateral side.CONCLUSION This report provides a novel reconstructive option for the management of multiple fingertip injuries and demonstrates the utility of supermicrosurgery in management of these injuries.

A Vision-Based Fingertip-Writing Character Recognition System

This paper presents a vision-based fingertip-writing character recognition system. The overall system is implemented through a CMOS image camera on a FPGA chip. A blue cover is mounted on the top of a finger to simplify fingertip detection and to enhance recognition accuracy. For each character stroke, 8 sample points (including start and end points) are recorded. 7 tangent angles between consecutive sampled points are also recorded as features. In addition, 3 features angles are extracted: angles of the triangle consisting of the start point, end point and average point of all (8 total) sampled points. According to these key feature angles, a simple template matching K-nearest-neighbor classifier is applied to distinguish each character stroke. Experimental result showed that the system can successfully recognize fingertip-writing character strokes of digits and small lower case letter alphabets with an accuracy of almost 100%. Overall, the proposed finger-tip-writing recognition system provides an easy-to-use and accurate visual character input method.

A Hand Gesture Recognition Method Based on SVM

A hand gesture recognition method is presented for human-computer interaction, which is based on fingertip localization. First, hand gesture is segmented from the background based on skin color characteristics. Second, feature vectors are selected with equal intervals on the boundary of the gesture, and then gestures＇ length normalization is accomplished. Third, the fingertip positions are determined by the feature vectors＇ parameters, and angles of feature vectors are normalized. Finally the gestures are classified by support vector machine. The experimental results demonstrate that the proposed method can recognize 9 gestures with an accuracy of 94.1%.

Converting a Display Screen into a Touchscreen

A method is presented to convert any display screen into a touchscreen by using a pair of cameras. Most state of art touchscreens make use of special touch-sensitive hardware or depend on infrared sensors in various configurations. We describe a novel computer-vision-based method that can robustly identify fingertips and detect touch with a precision of a few millimeters above the screen. In our system, the two cameras capture the display screen image simultaneously. Users can interact with a computer by the fingertip on the display screen. We have two important contributions： first, we develop a simple and robust hand detection method based on predicted images. Second, we determine whether a physical touch takes places by the homography of the two cameras. In this system, the appearance of the display screen in camera images is inherently predictable from the computer output images. Therefore, we can compute the predicted images and extract human hand precisely by simply subtracting the predicted images from captured images.

Fingertip skin models for analysis of the haptic perception of textiles

This paper presents finite element models of the fingertip skin which have been created to simulate the contact of textile objects with the skin to gain a better understanding of the perception of textiles through the skin, the so-called hand of textiles. Many objective and subjective techniques have already been developed for analysing the hand of textiles;however, none of them provide exact overall information concerning the sensation of textiles through the skin. As the human skin is a complex heterogeneous hyperelastic body composed of many particles, some simplifications had to be made at the early stage of building the models;however, their utilitarian value was maintained. The models relate only to mechanical loading of the skin. They predict a low deformation of the fingertip skin under the pressure of virtual heterogeneous material: acrylic, coarse wool, and steel.

A 3D Spectroscopic Vision-based Control Technique for Bilateral Systems

Visual servoing is an active and popular area of research among roboticists.Eventhough visual servoing techniques enhance the perfomance,the associated systems still use traditional methods for their input control.Many research activities and applications have been carried out to implement effective and precise controlling of bilateral systems.This paper presents a 3D spresctroscope-based control technique for bilateral systems.The effectiveness of the available master side designs are evaluated against gesture-based techniques.Joystick control,Electromyography(EMG),Voice control,Haptic control,Exoskeleton control,Gesture and Brain Control Interface(BCI)are identified in the litreature as available bilateral inputs.In the present technnique,Leap Motion Controller(LMC)has been introduced(LMC)to extract the human hand gestures and their parameters.Then these parameters are convereted into respective joint sapce angles using the presented mathematical model.The mathematical models for fingertip mapping,inverse kinematics,dynamics and trajectory generation are implemented and studied.Wolfman Mathematica 10 and MATLAB simulation framework are used to validate the mathematical models,simulations and developed control algorithms.The developed system has sucesfully imitated the fingertip motion.In particular,the system has been able to imitate the figretip motion with a deviation of 6.7%in X axis,5.5%in Y axis and7.9%in Z axis with respect to the expected position.

Acute Fingertip Injuries in Sudanese Patients: Patterns and Clinical Presentation

Background: Acute fingertip injuries are common and may lead to functional and aesthetic complications if not treated properly. Different types of trauma result in injuries with variable severity and affect certain risk groups. Objectives: To study the high-risk groups affected by fingertip injuries, their etiological factors, clinical features, and wound patterns, and the influence of hand dominance. Study Design: A descriptive study of 103 consecutive patients with 144 acutely injured fingertips. Data Collection/Analysis: We obtained demographic data, occupation, hand dominance, time and cause of trauma, and the presenting symptoms. Further, clinical examination, radiological, and laboratory studies were performed. Wound characteristics were classified according to the pulp, nailbed and bone (PNB) classification. The data were analyzed with the Fisher’s exact test and Chi-square test. Results: A total of 103 patients (88 males, 15 females) presented with 144 injured fingertips. The male to female ratio was 5.8:1, and the mean age was 27.5 years. The age group affected most commonly was 16 - 20 years. There was a strong association between hand dominance and fingertip injuries, as in 65% of the cases, the dominant hand was injured more frequently than the non-dominant (p = 0.01). The sharp and blunt injuries observed involved the left hand more than the right and were often the result of machinery-related trauma (p = 0.04). Approximately 68% of the injuries were related to work, while 26% were attributable to domestic accidents. In 22% of the cases, seasonal workers were the category affected most often, followed by factory workers. Nearly half of the injuries were related to working with machines, while door-trapping was the most frequent cause of injury in children under 5. The index finger was injured most frequently (31.9%), followed by the middle finger (27.9%), while the thumb and little fingers were involved least (11% for each). Pulp injuries were seen in 97% of cases, commonly with lacerations (39.6%, n = 139) while complete pulp loss was seen in 12.6% of cases. 87% of the cases were nail bed injuries, often with nail bed lacerations (28.6%, n = 126), while complete nail bed loss was observed in 9.5% of cases. Tuft fractures were the commonest bone injuries (26%), while complete bone loss was seen in 7.7% of the injured bones (n = 104). Conservative management was carried out on 9% of fingers, while the others required various methods of surgical repair. Nail bed repair was performed in 48.8% of cases (n = 126), while bone fixation was required in 20.2% (n = 104). Conclusions: Fingertip injuries are highly common in practice. In our study, the age, gender, mechanism of trauma and hand dominance had their influence on the pattern of injury. Finally, wound characteristics determine the type of management required.

Perception of Static and Dynamic Forces with a Bio-inspired Tactile Fingertip

With the aid of different types of mechanoreceptors,human is capable of perceiving stimuli from surrounding environments and manipulating various objects dexterously.In this paper,a bio-inspired tactile fingertip is designed mimicking human fingertip in both structures and functionalities.Two pairs of strain gages and(Polyvinylidene Fluoride)PVDF films are perpendicularly arranged to simulate the Fast-Adapting(FA)and Slowly Adapting(SA)type mechanoreceptors in human hands,while silicones,Polymethyl Methacrylate(PMMA),and electronic wires are applied to mimic the skin,bone and nerve fibers.Both static and dynamic forces can be perceived sensitively.A preprocessing electric circuit is further designed to transform the resistor changes into voltages,and then filter and amplify the four-channel signals.In addition to strong robustness due to the embedded structure,the developed fingertip is found sensitive to deformations via a force test experiment.Finally,two robotic experiments explore its recognition ability of contact status and object surface.Excellent performance is found with high accuracy of 99.72%achieved in discriminating six surfaces that are ubiquitous in daily life,which demonstrates the effectiveness of our designed tactile sensor.

CVD growth of fingerprint-like patterned 3D graphene film for an ultrasensitive pressure sensor

With the rapid development of wearable devices, flexible pressure sensors with high sensitivity and wide workable range are highly desired. In nature, there are many well-adapted structures developed through natural selection, which inspired us for the design of biomimetic materials or devices. Particularl3 human fingertip skin, where many epidermal ridges amplify external stimulations, might be a good example to imitate for highly sensitive sensors. In this work, based on unique chemical vapor depositions （CVD）-grown three-dimensional （3D） graphene films that mimic the morphology of fingertip skin, we fabricated flexible pressure sensing membranes, which simultaneously showed a high sensitivity of 110 （kPa）-1 for 0-0.2 kPa and wide workable pressure range （up to 75 kPa）. Hierarchical structured polydimethylsiloxane （PDMS） films molded from natural leaves were used as the supporting elastic films for the graphene films, which also contribute to the superior performance of the pressure sensors. The pressure sensor showed a low detection limit （0.2 Pa）, fast response （〈 30 ms）, and excellent stability for more than 10,000 loading/unloading cycles. Based on these features, we demonstrated its applications in detecting tiny objects, sound, and human physiological signals, showing its potential in wearable electronics for health monitoring and human/machine interfaces.

Aesthetic fingertip reconstruction with partial second toe transfer

Background Fingertip defect significantly affects the appearance of the hand. The aim of this research was to evaluate the clinical effect of aesthetic fingertip reconstruction with partial second toe transfer.Methods Between July 2005 and December 2008, 17 patients underwent aesthetic fingertip reconstruction with partial second toe transfer. The mean size of fingertip defects was 0.7 cm （ranging from 0.5-1.1 cm）. Anastomosis was performed between one dominant plantar digital artery and one proper digital artery, between two dorsal digital veins of the toe and two dorsal digital veins of the finger, respectively, for the reconstruction of blood supply to the reconstructed finger. Two plantar digital nerves of the toe were then sutured to two proper digital nerves of the finger for the restoration of fingertip sensation.Results All reconstructed fingers survived completely. The follow-up period ranged from 6 to 24 months, and the appearance of the reconstructed fingertip was similar to that of the normal fingertip. Two-point discrimination of the reconstructed fingertip was （7.8±1.3） mm. The recovered pinch strength of the reconstructed finger was about （89.0±5.1）% of that of the normal finger. Donor site healed well without complications.Conclusions Partial second toe transfer is an ideal aesthetic reconstruction method for fingertip defects; it can not only achieve a satisfactory appearance of the fingertip, but can also obtain excellent sensory and motor functions.