Fig 8 - available via license: Creative Commons Attribution 4.0 International
Content may be subject to copyright.
Marker placement. A diagram illustrating marker placement on the subject. As shown, 16 points were taken into consideration with 2 markers per joint for shoulders, elbows, wrists, and hips 3 markers per joint for the knees, and ankles, and a single marker for the head, trunk and left and right feet. Also shown are the joint angles, illustrated in the right part of the diagram; angles are named according to the joint at the vertex. https://doi.org/10.1371/journal.pone.0186443.g008
Source publication
The three dimensional (3D) reconstruction of movement from videos is widely utilized as a method for spatial analysis of movement. Several approaches exist for a 3D reconstruction of movement using 2D video projection, most of them require the use of at least two cameras as well as the application of relatively complex algorithms. While a few appro...
Citations
... Ďalšou nevýhodou uvedených systémov je ekonomický aspekt z pohľadu finančných nákladov na prístrojové vybavenie a odbornosť obslužného personálu. Mimo klinický význam monitorovania chôdze patrí aj monitorovanie pohybových aktivít zdravej časti populácie, a to najmä ako prevencia pred civilizačnými ochoreniami (obezita a kardiovaskulárne ochorenia) [4][5]. V dnešnej dobre je čo raz populárnejšie monitorovanie pohybových aktivít prostredníctvom rôznych druhov nositeľnej elektroniky vo forme smartfónov alebo smart-hodiniek, kde základný senzorický prvok meracieho reťazca predstavuje akcelerometer (primárne pre výpočet dominantnej harmonickej frekvencie a z nej odhad počtu krokov), prípadne GPS rádiokomunikačný modul (doplnková informácia pre presnejší odhad počtu krokov a urazenej vzdialenosti). ...
... Tracker software was chosen for measurement of RWD and SWS due to its consistent and accurate 2D tracking methods which have been used in past studies [35,36]. Waves were only tracked for 15 frames after impact due to decreased visual identification of the wave's edge as wave amplitude decreased and contrast between the wave's edge and background became indiscernible about 1 ms after impact. ...
Secondary blast injuries may result from high-velocity projectile fragments which ultimately increase medical costs, reduce active work time, and decrease quality of life. The role of skin penetration requires more investigation in energy absorption and surface mechanics for implementation in computational ballistic models. High-speed ballistic penetration studies have not considered penetrating and non-penetrating biomechanical properties of the skin, including radial wave displacement, resultant surface wave speed, or projectile material influence. A helium-pressurized launcher was used to accelerate 3/8″ (9.525 mm) diameter spherical projectiles toward seventeen whole porcine legs from seven pigs (39.53 ± 7.28 kg) at projectile velocities below and above V50. Projectiles included a mix of materials: stainless steel (n = 26), Si3N4 (n = 24), and acetal plastic (n = 24). Tracker video analysis software was used to determine projectile velocity at impact from the perpendicular view and motion of the tissue displacement wave from the in-line view. Average radial wave displacement and surface wave speed were calculated for each projectile material and categorized by penetrating or non-penetrating impacts. Two-sample t-tests determined that non-penetrating projectiles resulted in significantly faster surface wave speeds in porcine skin for stainless steel (p = 0.002), plastic (p = 0.004), and Si3N4 ball bearings (p = 0.014), while ANOVA determined significant differences in radial wave displacement and surface wave speed between projectile materials. Surface wave speed was used to quantify mechanical properties of the skin including elastic modulus, shear modulus, and bulk modulus during ballistic impact, which may be implemented to simulate accurate deformation behavior in computational impact models.
... According to the DMS method [13], a single camera setup with multiple markers on joints and head could reconstruct 3D coordinates with maximum linear displacement error of 77mm, with averages from 4 to 33 mm. Inferred joint angles maximum error is 38 o , with averages from 2.4 to 11.6 o . ...
Scientific gait analysis methods aim to offer objective measurements, to assist physicians towards an accurate diagnosis or pre-diagnosis of ailments before they actually manifest through noticeable symptoms. This paper reviews selected gait analysis system technologies, trends, applications and discusses errors and precision in spatial and angular readings. Furthermore, we propose a novel test and calibration method using a biomimetic rig. To illustrate this, we conduct three tests on an optical single-camera gait analysis system based on a mobile android smart-phone with specially developed software.
... According to the DMS method [13], a single camera setup with multiple markers on joints and head could reconstruct 3D coordinates with maximum linear displacement error of 77mm, with averages from 4 to 33 mm. Inferred joint angles maximum error is 38 o , with averages from 2.4 to 11.6 o . ...
... Several movement analysis devices are available to assist objective and accurate kinematic measurements varying from simple video cameras to complex optical motion capture systems (e.g., [16][17][18][19]). Such evaluation systems generally demand highly expensive equipment, well-skilled personnel for operational procedure, as well as dedicated spaces, which is not realistically suitable for clinical settings in hospital or space-limited environments. ...
Residual motion of upper limbs in individuals who experienced cervical spinal cord injury (CSCI) is vital to achieve functional independence. Several interventions were developed to restore shoulder range of motion (ROM) in CSCI patients. However, shoulder ROM assessment in clinical practice is commonly limited to use of a simple goniometer. Conventional goniometric measurements are operator-dependent and require significant time and effort. Therefore, innovative technology for supporting medical personnel in objectively and reliably measuring the efficacy of treatments for shoulder ROM in CSCI patients would be extremely desirable. This study evaluated the validity of a customized wireless wearable sensors (Inertial Measurement Units—IMUs) system for shoulder ROM assessment in CSCI patients in clinical setting. Eight CSCI patients and eight healthy controls performed four shoulder movements (forward flexion, abduction, and internal and external rotation) with dominant arm. Every movement was evaluated with a goniometer by different testers and with the IMU system at the same time. Validity was evaluated by comparing IMUs and goniometer measurements using Intraclass Correlation Coefficient (ICC) and Limits of Agreement (LOA). inter-tester reliability of IMUs and goniometer measurements was also investigated. Preliminary results provide essential information on the accuracy of the proposed wireless wearable sensors system in acquiring objective measurements of the shoulder movements in CSCI patients.
... The results of such research allow for rational and beneficial therapeutic decisions. Modern, objective diagnostic methods of spatial motion analysis [13,14,15,16] are particularly useful for such assessments. These methods include computerized measurements of spine mobility in diagnostics of patients with musculoskeletal disorders. ...
... Studies on the functional assessment with the Wiva® system meet all basic scientific criteria: they are valid due to the existence of an external standard, and they are repeatable and reliable, which means that the variability of the observer and device is kept to a minimum [8,9,10]. Wiva® system also helps evaluate the progress of patient's rehabilitation, as well as patient's condition after treatment [14,15]. ...
An assessment of patients’ functional state, performed in accordance with rehabilitation results objectivization methods, supports the diagnosis of patients’ health and allows to plan and implement the most effective therapeutic strategy, as well as to monitor progress of the rehabilitation process, which increases patients’ chances for recovery. Objectivization of functional diagnostics is also carried out through the selection of appropriate research methods and tools. Intensive development of rehabilitation requires the use of modern, objective diagnostic methods. The aim of this paper is to assess the usefulness of a computerized functional diagnostics system with the Wiva® science sensor in the diagnostics and assessment of rehabilitation effects in patients with spinal pain syndromes. The method of measuring spine mobility described in this article has a great potential, due to the use of the Wiva® science sensor computerized functional diagnosis system. The system, combined with Biomech software, may be used for objective and precise functional analysis of joints and spine in active and passive exams. It may also be used in physiotherapy, orthopedics and neurology, in the activation process, as well as in multidirectional and objective assessment of motor performance in children, adolescents, the elderly, and athletes. It is an excellent aid in developing rehabilitation programs. It is also an appropriate tool for widespread clinical applications, as well as other uncontrolled environments. The Wiva® Joint Mobility protocol is a simple, fast, accurate and reliable tool used to monitor progress of treatment/rehabilitation of patients with joint or spine mobility disorders; hence, its usefulness in clinical practice is high. The development of objective diagnostic methods used in monitoring the progress of treatment will undoubtedly contribute to further improvements and higher effectiveness of the implemented therapeutic programs.
O objetivo do projeto foi desenvolver um protótipo de sistema de análise do movimento humano em 3D utilizando dois Raspberry Pi (com de câmeras infravermelho acopladas). A interface do sistema foi desenvolvida em Django (com Bootstrap). A partir da captura de marcadores reflexivos, fixados no corpo humano, o sistema deve reconstruir o movimento humano em modelo virtual mecânico 3D. Os algoritmos de rastreamento dos marcadores reflexivos foram desenvolvidos com uso da biblioteca OpenCV. O desenvolvimento do sistema de calibração e reconstrução 3D ainda não foi finalizado por completo. Nas pŕoximas etapas do projeto o protótipo deve ser finalizado e testado.
