Realistic Human Body Models Research Articles

Application of 3D Motion Graphic Design Technology of Object Simulation Human Body in Sports Teaching

In the current era, the rapid development of computer technology has brought unprecedented opportunities for innovation in physical education teaching. The introduction of computer technology not only improves the efficiency of physical education teaching but also provides more accurate and scientific means for sports training. In response to this trend, this paper proposes an innovative human body model design method and explores in detail the key implementation techniques of computer simulation of 3D motion maps, aiming to further optimize and improve the quality of physical education teaching. The design of human body models plays a crucial role in physical education teaching and training, as it can help students and teachers better understand the mechanisms and principles of human movement. By introducing computer technology, this paper can construct a more precise, dynamic, and realistic human body model that conforms to the actual motion situation. This model can simulate various movement states of the human body, providing students with an intuitive and vivid learning experience. In the classroom, teachers can use projection or virtual reality devices to display 3D motion models, allowing students to intuitively see the details and changes of motion movements, deepening their understanding of the essentials of the movements. Teachers can demonstrate different movements in real time by operating models, and explain the technical points and precautions of each movement. Students can observe the motion trajectory and posture changes of the model from multiple perspectives to improve learning efficiency. The system generates personalized feedback reports based on students’ movement data, pointing out the problems and improvement directions that students have during the exercise process. Teachers can provide more accurate guidance to students based on these feedbacks, helping them correct incorrect movements and improve their skill levels.

Understanding Head Injury Risks During Car-to-Pedestrian Collisions Using Realistic Vehicle and Detailed Human Body Models.

Traumatic brain injury (TBI) is the leading cause of death and long-term disability in road traffic accidents (RTAs). Researchers have examined the effect of vehicle front shape and pedestrian body size on the risk of pedestrian head injury. On the other hand, the relationship between vehicle front shape parameters and pedestrian TBI risks involving a diverse population with varying body sizes has yet to be investigated. Thus, the purpose of this study was to comprehensively study the effect of vehicle front shape parameters and various pedestrian bodies ranging from 95th percentile male (AM95) to 6 years old (YO) child on the dynamic response of the head and the risk of TBIs during primary (vehicle) impact. At three different collision speeds (30, 40, and 50 km/h), a total of 36 car-to-pedestrian collisions (CPCs) were reconstructed using three different vehicle types (Subcompact passenger sedan, mid-sedan, and sports utility vehicle (SUV)) and four distinct THUMS pedestrian finite element (FE) models (AM50, AM95, AF05, and 6YO). We assessed skull stress and brain strains besides head linear and rotational kinematics. Our findings indicate that vehicle shape parameters especially bonnet leading edge height (BLEH), when being divided by the height of the Center of Gravity of the human body, correlated positively to head kinematics. The data from this study using realistic vehicle structures and detailed human body models showed that smaller BLEH/CG ratios reduced head injury criteria (HIC) and brain injury criteria (BrIC) values for the car center to mid-stance walking pedestrian impacts but with low-to-moderate R squared values between 0.2 to 0.5. Smaller BLEH/CG reduced head lateral bending velocities with R squared values of 0.57 to 0.63 for all impact velocities, and reduced HIC with R squared value of 0.62 for 50 km/h cases. In the future, simulations with realistic car structures and detailed human body models will be further used to simulate impacts at different locations and with various body shapes/postures.

A Compact Dual-Band Implantable Antenna for Wireless Biotelemetry in Arteriovenous Grafts

Arteriovenous grafts (AVGs) are indispensable life-saving implants for chronic kidney disease (CKD) patients undergoing hemodialysis. However, AVGs will often fail due to postoperative complications such as cellular accumulation termed restenosis, blood clots, and infections, which are dominant causes of morbidity and mortality. A new generation of hemodialysis implants equipped with biosensors and multi-band antennas for wireless power and telemetry systems that can detect specific pathological parameters and report AVGs’ patency would be transformative for CKD. Our study proposes a compact dual-band implantable antenna for hemodialysis monitoring applications. It operates in 1.4 GHz and 2.45 GHz for wireless power transfer and biotelemetry purposes. The miniaturized antenna with a current size of 5 × 5 × 0.635 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> exhibits wide bandwidth (300 MHz at 1.4 GHz band and 380 MHz at 2.45 GHz band), along with good impedance matching at two resonance frequencies. In addition, simulations are performed separately in a three-layer homogenous phantom and a realistic human body model. Measurements of the proposed antenna are evaluated in minced pork. The measured results of the fabricated antenna prototype are closely harmonized with the simulation ones, and the effect of different proportions of fat tissue in pork mince was analyzed, to verify the sensitivity of the antenna to the contacting medium. The specific absorption rate (SAR) and link budget calculation are also analyzed. Finally, the wireless biotelemetry function of the proposed antenna is realized and visualized by adopting a pair of nRF24L01 wireless transceivers, and sustainable and stable wireless data transmission characteristics are shown at a high data rate of 2 Mbps with up to 20 cm transmission distance.

Modeling the Correlation of Human Vertebral Body Volumes*

Anatomical parameters of the human body strongly correlate with each other. Modelling these dependencies enables the creation of a realistic anatomical human body model that can be parameterized. Such a model can be used for several diagnostic processes to identify abnormalities or even give guidance in surgical interventions. This paper proposes a probabilistic model describing the dependencies between the vertebral body volumes of humans from the Caucasian human race. As demonstrated, the proposed model can accurately describe the relationship between the vertebral body volumes and is used for the prediction of an unknown vertebral volume based on a known one. The probabilistic model is created by using the CT segmentation of 37 patients.

Assessment of virtual thermal manikins for thermal comfort numerical studies. Verification and validation

In turbulent flows as in HVAC applications, the fluctuation of air speed can affect the sensation of thermal comfort. This study is a part of a larger experimental and numerical campaign intended to evaluate the influence of the turbulence intensity at the inlet of air distribution systems on the local draft sensation and thermal discomfort for different ventilation cases using numerical simulations. For five different imposed values of turbulence intensity (0%, 3%, 10%, 30%, 50%) the local heat loss for different body parts was quantified CFD simulations were performed using a realistic model of human body along with an experimental validation with a humanoid thermal manikin. The CFD model was further exploited for several cases to evaluate the influence of turbulence intensity on the comfort indicators and local heat loss. The recorded velocity, turbulence and temperature fields allowed us to estimate the distributions of DR, PPD and PMV indexes which showed no significant changes, but correlations were found for the imposed turbulence intensity and local heat loss on different body parts, indicating the influence on thermal perception.

An X-Band Dielectric Rod Antenna for Subdermal Tumor Heating to Assist Electroporation-Mediated DNA Delivery

An end-fire dielectric rod antenna is proposed as a heating device for integration with an array of electroporation electrodes in order to enable efficient delivery of DNA into the cells that comprise subcutaneous tumors. A 5-7 °C temperature elevation of tumors that are located near the fat-muscle boundary and 3-7 mm below the skin surface can be achieved in a short period of time without damaging surrounding tissues. This capability is demonstrated through a combination of a directional antenna applicator operating at 8 GHz, and utilization of forced air cooling of the outer surface (skin layer). The directionality of the antenna is improved by cladding its high permittivity core with 3D printed, low permittivity dielectric material. Experimental data using a pork skin-fat-muscle tissue show that the desired temperature elevation at the tumor location is obtained after 2.5 W RF illumination for 3 minutes, which is in good agreement with electro-thermal simulations. With the addition of realistic human body model parameters to the same simulation setup, the results indicate that tumors can be uniformly heated with 3 minutes of illumination at 2.5 W input power while keeping the surrounding healthy tissues at a safe temperature.

MRSaiFE: An AI-based Approach Towards the Real-Time Prediction of Specific Absorption Rate.

The purpose of this study is to investigate feasibility of estimating the specific absorption rate (SAR) in MRI in real time. To this goal, SAR maps are predicted from 3T- and 7T-simulated magnetic resonance (MR) images in 10 realistic human body models via a convolutional neural network. Two-dimensional (2-D) U-Net architectures with varying contraction layers and different convolutional filters were designed to estimate the SAR distribution in realistic body models. Sim4Life (ZMT, Switzerland) was used to create simulated anatomical images and SAR maps at 3T and 7T imaging frequencies for Duke, Ella, Charlie, and Pregnant Women (at 3, 7, and 9 month gestational stages) body models. Mean squared error (MSE) was used as the cost function and the structural similarity index (SSIM) was reported. A 2-D U-Net with 4 contracting (and 4 expanding) layers and 64 convolutional filters at the initial stage showed the best compromise to estimate SAR distributions. Adam optimizer outperformed stochastic gradient descent (SGD) for all cases with an average SSIM of 90.5∓3.6 % and an average MSE of 0.7∓0.6% for head images at 7T, and an SSIM of >85.1∓6.2 % and an MSE of 0.4∓0.4% for 3T body imaging. Algorithms estimated the SAR maps for 224×224 slices under 30 ms. The proposed methodology shows promise to predict real-time SAR in clinical imaging settings without using extra mapping techniques or patient-specific calibrations.

A Fast Volume Integral Equation Solver With Linear Basis Functions for the Accurate Computation of EM Fields in MRI

A stable volume integral equation (VIE) solver based on polarization/magnetization currents is presented, for the accurate and efficient computation of the electromagnetic (EM) scattering from highly inhomogeneous and high contrast objects. We employ the Galerkin method of moments to discretize the formulation with discontinuous piecewise linear basis functions on uniform voxelized grids, allowing for the acceleration of the associated matrix-vector products in an iterative solver, with the help of FFT. Numerical results illustrate the superior accuracy and more stable convergence properties of the proposed framework, when compared against standard low-order (piecewise constant) discretization schemes and a more conventional VIE formulation based on electric flux densities. Finally, the developed solver is applied to analyze complex geometries, including realistic human body models, typically used in modeling the interactions between EM waves and biological tissue.

Simultaneous identification of human body model parameters and gait trajectory from 3D motion capture data

The analysis of human movements rests on a realistic human body model. Deducing model parameters from anthropomorphic data is challenging since these are inherently imprecise. An approach to improve model accuracy is the parameter adaptation based on motion data. 3D motion capture data are already being used for generating the trajectories of a human body model, so combining motion tracking and parameter identification seems most natural. This paper introduces a holistic approach to simultaneously identify the geometric parameters of a kinematic human lower limb model and the parameters defining a (cyclic) gait trajectory, based on 3D marker positions. The result is a time-continuous description of a physiologically compatible lower extremity movement along with optimal model parameters so to best reproduce the captured motion. The method takes into account restrictions such as the range of motion of human body joints and is robust against missing data due to marker occlusions or failures of the measurement system. Considering multiple gait cycles of a movement trial, we derive the characteristic motion pattern (CMP) of a specific subject walking at a specific speed. Our method further allows for motion analysis and assessment, but also for motion synthesis with arbitrary time span and time resolution and can thus be used for simulations and trajectory planning of rehabilitation and movement assistance systems, such as exoskeletons.

Reduction of Human Interaction with Wireless Power Transfer System Using Shielded Loop Coil

The impedance variation of wireless power transfer (WPT) coils owing to the presence of the human body may result in mismatches, resulting in a decrease of the transmission efficiency. In addition, one of the decisive factors of the permissible transfer power in WPT systems is a compliance assessment with the guidelines/standards for human protection from electromagnetic fields. In our previous study, we reported that a shielded loop coil can potentially reduce human interaction with WPT coils. In this study, first, the rationale for this reduction is investigated with equivalent circuit models for a WPT system using a shielded loop coil operated in close proximity to the human body. We then conducted an equivalent circuit analysis considering the capacitance between the inner and outer conductors of the shielded loop coil, suggesting the stability of the impedance matching. From computational results, the mitigation capability of the shielded loop coil on impedance matching and transmission efficiency owing to the presence of the human body was verified for 6.78 MHz wireless power transfer. Additionally, the reduction of the specific absorption rate (SAR) with coils comprised of the shielded loop structure was confirmed in the presence of anatomically realistic human body models. The maximum transferable power was increased from 1.5 kW to 2.1 kW for the restrictions of the local SAR limit prescribed in the international safety guidelines/standard.

In vivo human head MRI at 10.5T: A radiofrequency safety study and preliminary imaging results.

The purpose of this study is to safely acquire the first human head images at 10.5T. To ensure safety of subjects, we validated the electromagnetic simulation model of our coil. We obtained quantitative agreement between simulated and experimental and specific absorption rate (SAR). Using the validated coil model, we calculated radiofrequency power levels to safely image human subjects. We conducted all experiments and imaging sessions in a controlled radiofrequency safety lab and the whole-body 10.5T scanner in the Center for Magnetic Resonance Research. Quantitative agreement between the simulated and experimental results was obtained including S-parameters, maps, and SAR. We calculated peak 10 g average SAR using 4 different realistic human body models for a quadrature excitation and demonstrated that the peak 10 g SAR variation between subjects was less than 30%. We calculated safe power limits based on this set and used those limits to acquire T2 - and -weighted images of human subjects at 10.5T. In this study, we acquired the first in vivo human head images at 10.5T using an 8-channel transmit/receive coil. We implemented and expanded a previously proposed workflow to validate the electromagnetic simulation model of the 8-channel transmit/receive coil. Using the validated coil model, we calculated radiofrequency power levels to safely image human subjects.

Assessment of virtual thermal manikins for thermal comfort numerical studies. Verification and validation

This study is a part of a larger experimental and numerical campaign intended to evaluate the influence of the turbulence intensity at the inlet of the terminal air distribution systems on the local draft sensation and thermal discomfort of ventilation users. In this paper we present preliminary results of CFD simulations using a realistic model of human body along with an experimental validation. The model is further used in a piston distribution scheme to evaluate the influence of turbulence intensity on the comfort indicators. The recorded velocity, turbulence and temperature fields allowed us to estimate the distributions of DR, PPD and PMV indexes. For the investigated case, the results indicated a direct correlation.

2D 이미지 기반 형상 변형을 이용한 개인 맞춤형 인체 하반신 모델링

A realistic and accurate human body model is being used as a powerful tool for designing for a human-centered product as an international trend in ergonomics, game industry, and automobile industry. In this respect, there have been many efforts and studies to obtain the realistic and accurate human body model. But there are limitations on each type of data required to make this model. Therefore, this study proposes a novel method for creating a personalized human body models using two 2D images and a human template model. When the template model is determined through simple individual information such as the user’s height and weight, the personalized human body model is created by the following four steps; i) Image processing and silhouette extraction, ii) Defining characteristic points and creating key-sections, iii) Width deformation through matching with body silhouette, and iv) Creating a sweep-based human body model. Unlike existing methods of generating the human body models through 3D scan data, the proposed method can provide convenience to the user by requesting simple information. In addition, the method can improve accuracy of the model through deforming the width by matching with the body silhouette. Finally, the study demonstrated the validity of the method by comparing the result model generated by the purposed method with the model created through the 3D scan data.

A mixed human body modeling method based on 3D body scanning for clothing industry

PurposeThe purpose of this paper is to propose a relatively simple and rapid method to create a digital human model (DHM) to serve clothing industry.Design/methodology/approachHuman body’s point cloud is divided into hands, foots, head and torso. Then forward modeling method is used to model hands and foots, photo modeling method is used to model head and reverse modeling method is used to model torso. After that, hands, foots, head and torso are integrated together to get a static avatar. Next, virtual skeleton is bound to the avatar. Finally, a lifelike digital human body model is created by the mixed modeling method (MMM).FindingsIn allusion to the defect of the three-dimension original data of human body, this paper presented an MMM, with which we can get a realistic digital human body model with accurate body dimensions. The DHM can well meet the needs of fashion industry.Practical implicationsThe DHM, which is got by the MMM, can be well applied in the field of virtual try on, virtual fashion design, virtual fashion show and so on.Originality/valueThe originality of the paper lies in the integration of forward modeling, reverse modeling and photo modeling to present a novel method of human body modeling.

A Wideband Circularly Polarized Conformal Endoscopic Antenna System for High-Speed Data Transfer

In this paper, a conformal wideband circularly polarized (CP) antenna is presented for endoscopic capsule application over the 915-MHz Industrial, Scientific, and Medical (902–928 MHz) band. The thickness of the antenna is only 0.2 mm, which can be wrapped inside a capsule’s inner wall. By cutting meandered slots on the patch, using open-end slots on the ground, and utilizing two long arms, the proposed antenna obtains a significant size reduction. In the conformal form, the antenna volume measures only 66.7 mm3. A single-layer homogeneous muscle phantom box is used for the initial design and optimization with parametric studies. The effect of the internal components inside a capsule is discussed in analyzing the antenna’s performance and to realize a more practical scenario. In addition, a realistic human body model in a Remcom XFdtd simulation environment is considered to evaluate the antenna characteristics and CP purity, and to specify the specific absorption rate limit in different organs along the gastrointestinal tract. The performance of the proposed antenna is experimentally validated by using a minced pork muscle phantom and by using an American Society for Testing and Materials phantom immersed in a liquid solution. For measurements, a new technique applying a printed 3-D capsule is devised. From simulations and measurements, we found that the impedance bandwidth of the proposed antenna is more than 20% and with a maximum simulated axial ratio bandwidth of around 29.2% in homogeneous tissue. Finally, a wireless communication link at a data rate of 78 Mb/s is calculated by employing link-budget analysis.

In-to-out body path loss for wireless radio frequency capsule endoscopy in a human body.

Physical-layer characterization is important for design of in-to-out body communication for wireless body area networks (WBANs). This paper numerically investigates the path loss of an in-to-out body radio frequency (RF) wireless link between an endoscopy capsule and a receiver outside the body using a 3D electromagnetic solver. A spiral antenna in the endoscopy capsule is tuned to operate in the Medical Implant Communication Service (MICS) band at 402 MHz, accounting for the properties of the human body. The influence of misalignment, rotation of the capsule, and human body model are investigated. Semi-empirical path loss models for various homogeneous tissues and 3D realistic human body models are provided for manufacturers to evaluate the performance of in-to-out-body WBAN systems.

Wireless Power Transfer Charging System for AIMDs and Pacemakers

This paper deals with the electric and magnetic field (EMF) safety aspects of a wireless power transfer (WPT) system based on magnetic resonant coupling between two coils. The primary coil is assumed to be on-body, while the secondary coil is assumed to be inside the human body and connected to a battery recharge system of an active implantable medical device such as a pacemaker. This study allows us to identify a good preliminary solution of the WPT coil configuration, compensation capacitor topology, and operational frequency. Demonstrative WPT systems operating at two different frequencies are proposed in order to verify the WPT performances. The EMF safety has been finally assessed by numerical dosimetry studies using anatomically realistic human body models revealing no particular concerns about this application.

Fast Electromagnetic Analysis of MRI Transmit RF Coils Based on Accelerated Integral Equation Methods.

A fast frequency domain full-wave electromagnetic simulation method is introduced for the analysis of MRI coils loaded with the realistic human body models. The approach is based on integral equation methods decomposed into two domains: 1) the RF coil array and shield, and 2) the human body region where the load is placed. The analysis of multiple coil designs is accelerated by introducing the precomputed magnetic resonance Green functions (MRGFs), which describe how the particular body model used responds to the incident fields from external sources. These MRGFs, which are precomputed once for a given body model, can be combined with any integral equation solver and reused for the analysis of many coil designs. This approach provides a fast, yet comprehensive, analysis of coil designs, including the port S-parameters and the electromagnetic field distribution within the inhomogeneous body. The method solves the full-wave electromagnetic problem for a head array in few minutes, achieving a speed up of over 150 folds with root mean square errors in the electromagnetic field maps smaller than 0.4% when compared to the unaccelerated integral equation-based solver. This enables the characterization of a large number of RF coil designs in a reasonable time, which is a first step toward an automatic optimization of multiple parameters in the design of transmit arrays, as illustrated in this paper, but also receive arrays.

Assessment of human exposure to electromagnetic fields from wireless power transfer system in the 1.8 MHz

ABSTRACTIn this study, we discuss human exposure to electromagnetic fields from magnetically coupled resonance wireless power transfer system operating at 1.8 MHz. A two‐step method that is composed of the finite element method (FEM) and finite‐difference time domain method are proposed. The applicability of the proposed two‐step method for a localized exposure within this frequency band is discussed by comparing the specific absorption rate (SAR) in a homogenous human‐body model computed using the FEM. From the computational results, the difference between the peaks 10‐g averaged SAR is below 10 %. These suggest results that the proposed method is applicable for evaluating compliance in realistic anatomical human body models from a wireless power transfer system. With proposed two‐step methods, the SAR in the anatomical human body model is computed for the different exposure scenarios under isolated and grounded conditions. The peak 10‐g averaged SAR in grounded human is larger than that in an isolated human. In the worst case, the peak 10‐g averaged SAR for isolated and grounded condition are 50.6 and 60.7 mW/kg, respectively. The peak 10‐g averaged SAR limits are generally reached when the input powers are 33 W for the worst‐exposure condition. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1125–1129, 2015

Predicting Realistic and Precise Human Body Models Under Clothing Based on Orthogonal-view Photos

Accurate and realistic digital human body models are required by many research applications, for example in the areas of ergonomics, clothing technology, and computer graphics. The already difficult research problem becomes more challenging if the individual subjects to be modelled are dressed in normal or loose-fit clothing. In this study, we present an intelligent two-phase method to customize 3D digital human body models based on two orthogonal-view photos of the customers. It integrates both image-based and example-based modelling techniques to create human body models for individual customers with precise body measurements and realistic appearance. It fills up the research gap of human model customization; without the need of taking body scan, any customers can create their 3D digital body models only based on their orthogonal-view photos in normal or loose-fit clothing. Experimental results have shown that the proposed method can efficiently and accurately customize human models of diverse shapes, meeting the specific needs of the clothing industry.