Development of a mobile, cost-effective and easy to use inertial motion capture system for monitoring in rehabilitation applications

Abstract Many people are familiar with the feeling of instability, pain, or subsidence in the knee joint after a knee injury. There are many different methods for examining the knee, such as the drawer test or the Lachman test [1], before and after surgery. While these tests can be used in short term and provide useful results, motion capture systems can be used as an alternative measurement method, almost as a substitute in longer term. These include marker-based or mechanica l systems, which achieve good measurement results but are expensive and inflexible. For this reason, this paper presents a mobile, easy-to-use motion and easy expandable capture system using a low-cost IMU-based development system. The modular design of the system allows it to be adapted to each body region with simple adjustments. However, the present work focuses on applications for capturing human motion sequences and deriving three joint angles of the lower extremities to detect malposition.

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A Textile Sensor for Long Durations of Human Motion Capture

Sensors ◽

10.3390/s19102369 ◽

2019 ◽

Vol 19 (10) ◽

pp. 2369 ◽

Cited By ~ 5

Author(s):

Sufeng Hu ◽

Miaoding Dai ◽

Tianyun Dong ◽

Tao Liu

Keyword(s):

Knee Joint ◽

Motion Capture ◽

Sports Medicine ◽

Low Cost ◽

Movement Analysis ◽

Human Motion ◽

Joint Movement ◽

Human Motion Capture ◽

Knee Joint Motion ◽

Textile Sensor

Human posture and movement analysis is important in the areas of rehabilitation, sports medicine, and virtual training. However, the development of sensors with good accuracy, low cost, light weight, and suitability for long durations of human motion capture is still an ongoing issue. In this paper, a new flexible textile sensor for knee joint movement measurements was developed by using ordinary fabrics and conductive yarns. An electrogoniometer was adopted as a standard reference to calibrate the proposed sensor and validate its accuracy. The knee movements of different daily activities were performed to evaluate the performance of the sensor. The results show that the proposed sensor could be used to monitor knee joint motion in everyday life with acceptable accuracy.

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Gait Analysis in the Assessment of Patients Undergoing a Total Hip Replacement

Volume 14: Design, Systems, and Complexity ◽

10.1115/imece2019-10491 ◽

2019 ◽

Author(s):

Daniele Regazzoni ◽

Andrea Vitali ◽

Filippo Colombo Zefinetti ◽

Caterina Rizzi

Keyword(s):

Motion Capture ◽

Hip Replacement ◽

Motion Tracking ◽

Low Cost ◽

Quantitative Measure ◽

Clinical Information ◽

Human Motion ◽

Technical Solution ◽

Specific Context ◽

Main Challenge

Abstract Nowadays, healthcare centers are not familiar with quantitative approaches for patients’ gait evaluation. There is a clear need for methods to obtain objective figures characterizing patients’ performance. Actually, there are no diffused methods for comparing the pre- and post-operative conditions of the same patient, integrating clinical information and representing a measure of the efficiency of functional recovery, especially in the short-term distance of the surgical intervention. To this aim, human motion tracking for medical analysis is creating new frontiers for potential clinical and home applications. Motion Capture (Mocap) systems are used to allow detecting and tracking human body movements, such as gait or any other gesture or posture in a specific context. In particular, low-cost portable systems can be adopted for the tracking of patients’ movements. The pipeline going from tracking the scene to the creation of performance scores and indicators has its main challenge in the data elaboration, which depends on the specific context and to the detailed performance to be evaluated. The main objective of this research is to investigate whether the evaluation of the patient’s gait through markerless optical motion capture technology can be added to clinical evaluations scores and if it is able to provide a quantitative measure of recovery in the short postoperative period. A system has been conceived, including commercial sensors and a way to elaborate data captured according to caregivers’ requirements. This allows transforming the real gait of a patient right before and/or after the surgical procedure into a set of scores of medical relevance for his/her evaluation. The technical solution developed in this research will be the base for a large acquisition and data elaboration campaign performed in collaboration with an orthopedic team of surgeons specialized in hip arthroplasty. This will also allow assessing and comparing the short run results obtained by adopting different state-of-the-art surgical approach for the hip replacement.

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Before-and-After Empirical Bayes Evaluation of Citywide Installation of Driver Feedback Signs

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198120912243 ◽

2020 ◽

Vol 2674 (4) ◽

pp. 419-427

Author(s):

Mingjian Wu ◽

Karim El-Basyouny ◽

Tae J. Kwon

Keyword(s):

Traffic Safety ◽

Spatial Data ◽

Empirical Bayes ◽

Large Scale ◽

Low Cost ◽

Cost Effective ◽

Before And After ◽

Feedback Sign ◽

Driver Feedback ◽

Road Segments

Speeding is a leading factor that contributes to approximately one-third of all fatal collisions. Over the past decades, various passive/active countermeasures have been adopted to improve drivers’ compliance to posted speed limits to improve traffic safety. The driver feedback sign (DFS) is considered a low-cost innovative intervention that is being widely used, in growing numbers, in urban cities to provide positive guidance for motorists. Despite their documented effectiveness in reducing speeds, limited literature exists on their impact on reducing collisions. This study addresses this gap by designing a before-and-after study using the empirical Bayes method for a large sample of urban road segments. Safety performance functions and yearly calibration factors are developed to quantify the sole effectiveness of DFS using large-scale spatial data and a set of reference road segments within the city of Edmonton, Alberta, Canada. Likewise, the study followed a detailed economic analysis based on three collision-costing criteria to investigate if DFS was indeed a cost-effective intervention. The results showed significant collision reductions that ranged from 32.5% to 44.9%, with the highest reductions observed for severe speed-related collisions. The results further attested that the benefit–cost ratios, combining severe and property-damage-only collisions, ranged from 8.2 to 20.2 indicating that DFS can be an extremely economical countermeasure. The findings from this study can provide transportation agencies in need of implementing cost-efficient countermeasures with a tool they need to design a long-term strategic deployment plan to ensure the safety of traveling public.

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Human Arm Motion Tracking by Orientation-Based Fusion of Inertial Sensors and Kinect Using Unscented Kalman Filter

Journal of Biomechanical Engineering ◽

10.1115/1.4034170 ◽

2016 ◽

Vol 138 (9) ◽

Cited By ~ 19

Author(s):

Arash Atrsaei ◽

Hassan Salarieh ◽

Aria Alasty

Keyword(s):

Kalman Filter ◽

Motion Capture ◽

Motion Tracking ◽

Inertial Sensors ◽

Unscented Kalman Filter ◽

Low Cost ◽

Human Motion ◽

Home Based ◽

Human Arm ◽

Arm Motion

Due to various applications of human motion capture techniques, developing low-cost methods that would be applicable in nonlaboratory environments is under consideration. MEMS inertial sensors and Kinect are two low-cost devices that can be utilized in home-based motion capture systems, e.g., home-based rehabilitation. In this work, an unscented Kalman filter approach was developed based on the complementary properties of Kinect and the inertial sensors to fuse the orientation data of these two devices for human arm motion tracking during both stationary shoulder joint position and human body movement. A new measurement model of the fusion algorithm was obtained that can compensate for the inertial sensors drift problem in high dynamic motions and also joints occlusion in Kinect. The efficiency of the proposed algorithm was evaluated by an optical motion tracker system. The errors were reduced by almost 50% compared to cases when either inertial sensor or Kinect measurements were utilized.

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A Low-Cost Instrumented Spatial Linkage Accurately Determines ASIS Position during Cycle Ergometry

Journal of Applied Biomechanics ◽

10.1123/jab.23.3.224 ◽

2007 ◽

Vol 23 (3) ◽

pp. 224-229 ◽

Cited By ~ 11

Author(s):

James C. Martin ◽

Steven J. Elmer ◽

Robert D. Horscroft ◽

Nicholas A.T. Brown ◽

Barry B. Shultz

Keyword(s):

Motion Capture ◽

Low Cost ◽

Cost Effective ◽

Cycle Ergometry ◽

Two Dimensional ◽

Motion Capture System ◽

Valid Measure ◽

Kinematic Data ◽

Vertical Error ◽

Parasagittal Plane

The purpose of this study was to develop and evaluate an alternative method for determining the position of the anterior superior iliac spine (ASIS) during cycling. The approach used in this study employed an instrumented spatial linkage (ISL) system to determine the position of the ASIS in the parasagittal plane. A two-segment ISL constructed using aluminum segments, bearings, and digital encoders was tested statically against a calibration plate and dynamically against a video-based motion capture system. Four well-trained cyclists provided data at three pedaling rates. Statically, the ISL had a mean horizontal error of 0.03 ± 0.21 mm and a mean vertical error of −0.13 ± 0.59 mm. Compared with the video-based motion capture system, the agreement of the location of the ASIS had a mean error of 0.30 ± 0.55 mm for the horizontal dimension and −0.27 ± 0.60 mm for the vertical dimension. The ISL system is a cost-effective, accurate, and valid measure for two-dimensional kinematic data within a range of motion typical for cycling.

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Reliability of Passive UHF RFID Copper Tags on Plywood Substrate in High Humidity Conditions

Additional Conferences (Device Packaging HiTEC HiTEN & CICMT) ◽

10.4071/2016-nor-sipila ◽

2016 ◽

Vol 2016 (NOR) ◽

pp. 12-16 ◽

Cited By ~ 1

Author(s):

Erja Sipilä ◽

Johanna Virkki ◽

Lauri Sydänheimo ◽

Leena Ukkonen

Keyword(s):

Moisture Absorption ◽

Low Cost ◽

Cost Effective ◽

High Volume ◽

High Humidity ◽

Uhf Rfid ◽

Passive Uhf Rfid ◽

Before And After ◽

Moist Environment ◽

Read Range

The growth of the wireless world, especially the increasing popularity of the Internet of Things, has created a need for cost-effective and environmentally friendly electronics. Great potential lies especially in versatile applications of passive UHF RFID components. However, the reliability of these components is a major issue to be addressed. This paper presents a preliminary reliability study of glue-coated and non-coated brush-painted copper tags on a plywood substrate in high humidity conditions. The passive UHF RFID components presented in this paper are fabricated using brush-painting and photonic sintering of cost-effective copper oxide ink directly on a plywood substrate. The performance of the glue-coated and non-coated tags is evaluated through wireless tag measurements before and after high humidity testing. The measurement results show that the copper tags on plywood substrate initially achieve peak read ranges of 7–8 meters and the applied coating does not affect to the read range. Moisture does not prevent the coated tags from working in a tolerable way, although the tag performance slightly temporarily decreases due to the moisture absorption. However, when the moisture exposure is long, the performance degradation comes irreversible. The absorbed moisture decreases the read range of the non-coated tags and the performance does not return back to normal after drying. Hence, the coating improves the reliability of the tags in a moist environment compared to the non-coated tags. Based on our results, the plywood material and the used manufacturing methods are very potential for low-cost, high-volume green electronics manufacturing.

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Advanced Substrate Applied Fluxing Underfill for Bonding of Fine Pitch Solder Capped Cu Pillars to Oxidized Cu Substrates

Additional Conferences (Device Packaging HiTEC HiTEN & CICMT) ◽

10.4071/2012dpc-tp21 ◽

2012 ◽

Vol 2012 (DPC) ◽

pp. 000924-000943

Author(s):

Russell Stapleton ◽

Jim Greig

Keyword(s):

Cross Sections ◽

Flip Chip ◽

Low Cost ◽

Cost Effective ◽

Filler Loading ◽

Thermal Compression ◽

Transparent Substrate ◽

Fine Pitch ◽

Before And After ◽

Cu Substrates

Underfill solutions for fine pitch flip chip assemblies is an active area of development. Non-conductive films (NCF) and pastes (NCP) have shown great potential in bridging the gap between no-flow and capillary underfills for improving the reliability of fine pitched devices. But NCFs and NCPs require costly passivated pad finishes (e.g. Au, Sn, Ni, OSP) or careful substrate handling for proper solder joint formation. In this paper, we will describe a new class of underfill material that benefits from the growing trend of using thermal compression bonding as a cost effective alternative to mass reflow based underfilling processes (e.g. capillary and no-flow). This material is a fluxing NCP that is useful for a wide variety of fine pitch substrates, including low cost Cu. The material we will demonstrate contains many advanced features: high filler loading, strong flux activity, long work life, off-tool pre-dispense, low stress, high Tg, high modulus and rapid cure. The all-in-one underfill demonstrated in this paper is applied by using a screen printing process, where the material is applied to all of the chip sites in one step achieving excellent application efficiency and wetting/conformity to the substrate. The substrate is glass, containing a 4x4 array of die sites. Each of the die sites are 5x5mm in size with a full area array of 2501 Cu pads (50um pads on 100um pitch) that are pre-oxidized for 1h at 175C in air prior to printing (to simulate a dehydration bake). This transparent substrate was chosen to show the robust nature of the underfill for fluxing, stability and void-free placement/cure. Images of the substrate, before and after chip bonding will be given, along with cross sections. Details of the material properties will also be discussed.

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Real-Time Motion Capture for a Human Body using Accelerometers

Robotica ◽

10.1017/s0263574701003319 ◽

2001 ◽

Vol 19 (6) ◽

pp. 601-610 ◽

Cited By ~ 25

Author(s):

Jihong Lee ◽

Insoo Ha

Keyword(s):

Real Time ◽

Motion Capture ◽

Human Body ◽

Degrees Of Freedom ◽

Low Cost ◽

Human Motion ◽

The Body ◽

Sensor Data ◽

Time Motion ◽

Gravity Acceleration

In this paper we propose a set of techniques for a real-time motion capture of a human body. The proposed motion capture system is based on low cost accelerometers, and is capable of identifying the body configuration by extracting gravity-related terms from the sensor data. One sensor unit is composed of 3 accelerometers arranged orthogonally to each other, and is capable of identifying 2 rotating angles of joints with 2 degrees of freedom. A geometric fusion technique is applied to cope with the uncertainty of sensor data. A practical calibration technique is also proposed to handle errors in aligning the sensing axis to the coordination axis. In the case where motion acceleration is not negligible compared with gravity acceleration, a compensation technique to extract gravity acceleration from the sensor data is proposed. Experimental results not only for individual techniques but also for human motion capturing with graphics are included.

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Leading Pedestrian Intervals

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/2620-09 ◽

2017 ◽

Vol 2620 (1) ◽

pp. 96-104 ◽

Cited By ~ 1

Author(s):

Anuj Sharma ◽

Edward Smaglik ◽

Sirisha Kothuri ◽

Oliver Smith ◽

Peter Koonce ◽

...

Keyword(s):

Low Cost ◽

Cost Effective ◽

Signalized Intersections ◽

Crash Data ◽

Trade Offs ◽

Quantitative Metrics ◽

Traffic Conflicts ◽

Before And After ◽

Economic Analyses ◽

Benefit Cost

To improve the safety of people walking at particular signalized intersections, traffic signal engineers may implement leading pedestrian intervals (LPIs) to provide pedestrians with a walk signal for a few seconds before the parallel vehicular green indication. Previous before-and-after studies and simple economic analyses have indicated that LPIs are low-cost tools that can reduce vehicle–pedestrian conflicts and crashes at some signalized intersections. Despite this evidence, municipalities have little guidance for when to implement LPIs. A marginal benefit–cost framework is developed with quantitative metrics and extends the concept of traffic conflicts and marginal safety–delay trade-offs to analyze the appropriateness of implementing an LPI at specific signalized intersections. The method provides guidance to help quantify the probability of a conflict occurring and direction on whether to implement an LPI at a given location from macroscopic-level inputs, including number of turning movements, crash data, and geometry. A case study with sample data indicated that an LPI was cost-effective for the scenario presented.

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