The understanding of body measurements and body shapes in and between populations is important and has many applications in medicine, surveying, the fashion industry, fitness, and entertainment. Body ...measurement using 3D surface scanning technologies is faster and more convenient than measurement with more traditional methods and at the same time provides much more data, which requires automatic processing. A multitude of 3D scanning methods and processing pipelines have been described in the literature, and the advent of deep learning-based processing methods has generated an increased interest in the topic. Also, over the last decade, larger public 3D human scanning datasets have been released. This paper gives a comprehensive survey of body measurement techniques, with an emphasis on 3D scanning technologies and automatic data processing pipelines. An introduction to the three most common 3D scanning technologies for body measurement, passive stereo, structured light, and time-of-flight, is provided, and their merits w.r.t. body measurement are discussed. Methods described in the literature are discussed within the newly proposed framework of five common processing stages: preparation, scanning, feature extraction, model fitting, and measurement extraction. Synthesizing the analyzed prior works, recommendations on specific 3D body scanning technologies and the accompanying processing pipelines for the most common applications are given. Finally, an overview of about 80 currently available 3D scanners manufactured by about 50 companies, as well as their taxonomy regarding several key characteristics, is provided in the Appendix.
Purpose A 128‐channel receive‐only array for brain imaging at 7 T was simulated, designed, constructed, and tested within a high‐performance head gradient designed for high‐resolution functional ...imaging. Methods The coil used a tight‐fitting helmet geometry populated with 128 loop elements and preamplifiers to fit into a 39 cm diameter space inside a built‐in gradient. The signal‐to‐noise ratio (SNR) and parallel imaging performance (1/g) were measured in vivo and simulated using electromagnetic modeling. The histogram of 1/g factors was analyzed to assess the range of performance. The array's performance was compared to the industry‐standard 32‐channel receive array and a 64‐channel research array. Results It was possible to construct the 128‐channel array with body noise–dominated loops producing an average noise correlation of 5.4%. Measurements showed increased sensitivity compared with the 32‐channel and 64‐channel array through a combination of higher intrinsic SNR and g‐factor improvements. For unaccelerated imaging, the 128‐channel array showed SNR gains of 17.6% and 9.3% compared to the 32‐channel and 64‐channel array, respectively, at the center of the brain and 42% and 18% higher SNR in the peripheral brain regions including the cortex. For R = 5 accelerated imaging, these gains were 44.2% and 24.3% at the brain center and 86.7% and 48.7% in the cortex. The 1/g‐factor histograms show both an improved mean and a tighter distribution by increasing the channel count, with both effects becoming more pronounced at higher accelerations. Conclusion The experimental results confirm that increasing the channel count to 128 channels is beneficial for 7T brain imaging, both for increasing SNR in peripheral brain regions and for accelerated imaging.
Purpose: To determine if integrated area provides better specificity than average thickness for measurements of minimal cross‐section of the nerve fibre layer at the optic nerve head (ONH).
Methods: ...In each of 40 non glaucomatous subjects aged 20–69 years, male/female ratio 1, the ONH was captured in 3D with Topcon OCT‐Triton with a raster scan. Subjects were recruited stratified to provide even age distribution. The ONH volumes were exported and the minimal cross‐section of the nerve fibre layer at the ONH was segmented fully automated with a custom algorithm. The minimal cross‐section around the circumference of the ONH was for half the sample estimated as average thickness (μm), PIMD‐2Pi, and for the other half as integrated area, PIMA‐2Pi (mm2). For each sample, the dependence on the estimates on age was fitted to a straight line with linear regression, providing the quantity at average age and the age loss for each quantity. Then, for each quantity, the specificity for level at average age and age loss was estimated numerically as a 95% confidence interval considering a threshold for not pathological of 0.1 of the estimated mean above the mean. Further, the difference in specificity between the two quantities was numerically estimated as a 95% confidence interval for the difference between specificities for the two quantities.
Results: The specificity for not pathological was for; PIMD‐2π:average age, 0.67;0.80, PIMA‐2π:average age, 0.68; 0.82 (d.f. = 18), difference average at age, −0.09; 0.11 (d.f. = 36), PIMD‐2π: thickness·year−1, 0.39; 0.45, PIMA‐2π: area·year−1, 0.36; 0.43 (d.f = 18), difference year−1, −0.07; 0.03 (d.f = 36).
Conclusions: When comparing subjects, there is no advantage of estimating the minimal cross‐section of the nerve fibre layer over the circumference of the ONH as integrated area as compared to average thickness, with regard to differentiating pathological from not pathological.
Ecuaciones de predicción de pliegues cutáneos en escolares Buendía-Lozada, E.R.P; Cruz-Gómez, M A; Flores-Chico, B ...
Revista internacional de medicina y ciencias de la actividad física y del deporte,
03/2017, Volume:
17, Issue:
65
Journal Article
Open access
El objetivo de este trabajo es crear ecuaciones que estimen las medidas de los pliegues cutáneos para escolares de 6 a 13 años de edad. Como resultado se obtuvieron catorce ecuaciones que estiman ...algunos pliegues cutáneos. Las ecuaciones se validaron con muestras aleatorias de 479 niñas y 541 niños del estado de Puebla y otras 2 muestras aleatorias del estado de Veracruz con 155 niñas y 146 niños respectivamente; las mediciones directas se realizaron con la metodología y unidades ISAK (International Society for the Advancement of Kinanthropometry).
Running movements are parametrised using a wide variety of devices. Misleading interpretations can be avoided if the interdependencies and redundancies between biomechanical parameters are taken into ...account. In this synthetic review, commonly measured running parameters are discussed in relation to each other, culminating in a concise, yet comprehensive description of the full spectrum of running styles. Since the goal of running movements is to transport the body centre of mass (BCoM), and the BCoM trajectory can be derived from spatiotemporal parameters, we anticipate that different running styles are reflected in those spatiotemporal parameters. To this end, this review focuses on spatiotemporal parameters and their relationships with speed, ground reaction force and whole-body kinematics. Based on this evaluation, we submit that the full spectrum of running styles can be described by only two parameters, namely the step frequency and the duty factor (the ratio of stance time and stride time) as assessed at a given speed. These key parameters led to the conceptualisation of a so-called Dual-axis framework. This framework allows categorisation of distinctive running styles (coined 'Stick', 'Bounce', 'Push', 'Hop', and 'Sit') and provides a practical overview to guide future measurement and interpretation of running biomechanics.
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