Application of Moire Profilometry in Three-Dimensional Profile Reconstruction of Key Parts in Railway.

Moire profilometry (MP) is one of the three-dimensional (3D) topography measurement methods of structured light, which has the advantages of single frame reconstruction, high speed, no contact and high precision, and is suitable for dynamic measurement scenes. In this article, the digital MP is applied to the wheel tread measurement, the virtual grating is generated by computer to project to the object surface, the moire fringe pattern of the object is obtained by filtering, and finally the continuous phase pattern is obtained by phase unwrapping. The 3D shape reconstruction of the wheel tread is realized, and a new method of wheel tread detection is provided. At the same time, in this paper, the results of using different filters are compared, and the significance of the frequency domain filtering to MP is proved. It is necessary to choose a suitable filtering method according to different environmental conditions. At present, digital MP can be used in industrial static detection, and it can be extended to the dynamic detection of rolling wheels in the future, so as to improve the detection efficiency and realize the automatic detection of trains.

Moiré topography as a screening and diagnostic tool-A systematic review.

Diagnostic investigation can be carried out using non-radiological and non-contact methods. Moiré topography (MT) seems to be a viable alternative to radiographic research in evaluating the spine and/or trunk deviations. The aim of this systematic review was to analyze the current knowledge regarding the reliability and validity of Moiré topography as a screening and diagnostic tool. The systematic review was performed from 2010 until March 2021 in the PubMed, EBSCO, Web of Science, and Scopus databases, according to the eligibility criteria. This review fulfilled the following criteria according to the PICO system: population (children and adolescents), intervention (MT measurement), comparison (repeated MT measurements, MT compared to Cobb angle or scoliometer), outcome (reliability and validity of MT). Eight studies fulfilled the inclusion criteria for further analysis. All the studies were assessed to be of high quality. Included studies found that MT had high repeatability and high intraobserver and interobserver correlation, and correlation between MT parameters and radiographic Cobb angle ranged from moderate to high. The authors reported difficulty in defining the cut-off values for MT parameter (Surface Trunk Rotation-STR), and unsatisfactory sensitivity and specificity of MT examination. The studies did not reveal the advantage of MT as a screening method in the detection of idiopathic scoliosis in comparison to radiograph. Based on the evidence from eight studies, the results indicated moderate evidence for reliability and validity of Moiré topography as a screening and diagnostic tool. There is still no strong evidence for the accuracy of MT.

3D enamel profilometry reveals faster growth but similar stress severity in Neanderthal versus Homo sapiens teeth.

Early life stress disrupts growth and creates horizontal grooves on the tooth surface in humans and other mammals, yet there is no consensus for their quantitative analysis. Linear defects are considered to be nonspecific stress indicators, but evidence suggests that intermittent, severe stressors create deeper defects than chronic, low-level stressors. However, species-specific growth patterns also influence defect morphology, with faster-growing teeth having shallower defects at the population level. Here we describe a method to measure the depth of linear enamel defects and normal growth increments (i.e., perikymata) from high-resolution 3D topographies using confocal profilometry and apply it to a diverse sample of Homo neanderthalensis and H. sapiens anterior teeth. Debate surrounds whether Neanderthals exhibited modern human-like growth patterns in their teeth and other systems, with some researchers suggesting that they experienced more severe childhood stress. Our results suggest that Neanderthals have shallower features than H. sapiens from the Upper Paleolithic, Neolithic, and medieval eras, mirroring the faster growth rates in Neanderthal anterior teeth. However, when defect depth is scaled by perikymata depth to assess their severity, Neolithic humans have less severe defects, while Neanderthals and the other H. sapiens groups show evidence of more severe early life growth disruptions.

Surface topography assessment of body shape after surgical correction in adolescent idiopathic scoliosis.

HYPOTHESIS: Body surface topography (ST) improvements are associated with surgical correction in adolescent idiopathic scoliosis (AIS) and correlate with radiographic imaging. DESIGN: Prospective observational study. INTRODUCTION: Patients undergoing correction of AIS are most affected by body image. Radiographs have been the standard assessment tool but do not assess body shape features. ST, a validated, radiation-free assessment tool, directly represents the patient's deformity. We set out to assess ST improvements associated with surgical correction in AIS. METHODS: Twenty-three consecutive operative AIS patients were enrolled and had radiographs and posterior ST obtained pre- and postoperatively (PO). ST changes were compared using paired t test, and correlations of ST with radiograph measurements were evaluated by linear regression. RESULTS: Mean age at surgery was 15.0 ± 2 years, 82.6% female with mean follow-up of 1.0 year. Major Cobb angle improved from 56.91° ± 15.57° to 13.70° ± 4.89°. ST scoliosis angle corrected from 41.43° ± 11.52° to 11.78° ± 7.84° (p < .0001). Trunk length increased from 401.22 ± 32.43 to 422.30 ± 25.77 mm (Δ21.08 mm; p = .0004). Pelvic obliquity (waist asymmetry) trended toward improvement (6.0 ± 4.3 vs. 5.3 ± 7.1 mm; p = .06). Surface rotation was corrected from 17.35 ± 6.73 to 11.8 ± 4.12 mm (p < .0001), highly correlated with clinical trunk rotation (T p = .002 and TL p = .02). ST highly correlated with radiographic parameters. Sagittal balance correlated with improved function (p = .02). CONCLUSION: ST, a radiation-free body shape assessment tool, improved with surgical correction of AIS and was highly correlated with radiographic outcomes.

High-resolution imaging of organic pharmaceutical crystals by transmission electron microscopy and scanning moiré fringes.

Formulation processing of organic crystalline compounds can have a significant effect on drug properties, such as dissolution rate or tablet strength/hardness. Transmission electron microscopy (TEM) has the potential to resolve the atomic lattice of these crystalline compounds and, for example, identify the defect density on a particular crystal face, provided that the sensitivity of these crystals to irradiation by high-energy electrons can be overcome. Here, we acquire high-resolution (HR) lattice images of the compound furosemide using two different methods: low-dose HRTEM and bright-field (BF) scanning TEM (STEM) scanning moiré fringes (SMFs). Before acquiring HRTEM images of furosemide, a model system of crocidolite (asbestos) was used to determine the electron flux/fluence limits of low-dose HR imaging for our scintillator-based, complementary metal-oxide semiconductor (CMOS) electron camera by testing a variety of electron flux and total electron fluence regimes. An electron flux of 10 e- /(Å2 s) and total fluence of 10 e- /Å2 was shown to provide sufficient contrast and signal-to-noise ratio to resolve 0.30 nm lattice spacings in crocidolite at 300 kV. These parameters were then used to image furosemide which has a critical electron fluence for damage of ≥10 e- /Å2 at 300 kV. The resulting HRTEM image of a furosemide crystal shows only a small portion of the total crystal exhibiting lattice fringes, likely due to irradiation damage during acquisition close to the compound's critical fluence. BF-STEM SMF images of furosemide were acquired at a lower electron fluence (1.8 e- /Å2 ), while still indirectly resolving HR details of the (001) lattice. Several different SMFs were observed with minor variations in the size and angle, suggesting strain due to defects within the crystal. Overall BF-STEM SMFs appear to be more useful than BF-STEM or HRTEM (with a CMOS camera) for imaging the crystal lattice of very beam-sensitive materials since a lower electron fluence is required to reveal the lattice. BF-STEM SMFs may thus prove useful in improving the understanding of crystallization pathways in organic compounds, degradation in pharmaceutical formulations and the effect of defects on the dissolution rate of different crystal faces. Further work is, however, required to quantitatively determine properties such as the defect density or the amount of relative strain from a BF-STEM SMF image.

Evaluating the role of surface topography in the surveillance of scoliosis.

STUDY DESIGN: Literature review. OBJECTIVE: To review the history, modern uses, limitations, and future direction of surface topography (ST) in surveillance of scoliosis. Spinal deformities, including scoliosis, can be characterized using measurements such as the Cobb angle, lateral curvature, and vertebral rotation. The gold standard for diagnosis and surveillance of such deformities utilizes radiographic images. To minimize repeated radiation exposure, many systems have been developed utilizing ST. ST measures local deviations of a surface from a flat plane. Applying this concept to spinal deformities, ST can non-radiographically study the 3-dimensional shape of the back. One ST system, rasterstereography, projects parallel white light lines onto a patient's back and analyzes line distortion with a camera. While radiography has long been considered the primary diagnostic tool for scoliosis, rasterstereography may possess alternative or complementary benefits in monitoring scoliosis and other diseases. METHODS: A comprehensive literature review was performed on the history, development, and validity of ST. The advantages and limitations of this technique were compared to those of radiography. RESULTS: While the initial goal of ST, designing a system to accurately reproduce the Cobb angle, was not successful, research efforts over the last 40 years have attempted to improve this correlation. ST technologies, including rasterstereography and the Formetric ST System, currently play important roles in scoliosis surveillance, research, and minimizing radiation exposure in longitudinal care of patients. Such technologies are also useful as an adjunct to X-rays for monitoring disease progression, especially in Parkinson's disease. CONCLUSION: Despite its limitations, ST has proven useful across multiple fields of medicine. It is a safe and cost-effective tool for long-term surveillance of scoliosis and early detection of progressive disease. With technological improvements, the Formetric System will become a critical alternative in dynamic spinal motion and gait analysis. LEVEL OF EVIDENCE: N/A.

Emerging Techniques in Diagnostic Imaging for Idiopathic Scoliosis in Children and Adolescents: A Review of the Literature.

Traditionally, full spine standing radiographs have been the reference standard for diagnostic imaging in adolescent idiopathic scoliosis (AIS). However, recent advances in diagnostic imaging have the potential to reduce radiation exposure and preserve the image quality and utility. Recent advances in diagnostic imaging for AIS include the EOS imaging system, the DIERS formetric scanner, and ultrasonography. Moderate to strong evidence is available to support the interobserver reliability and validity of each of these modalities, even compared with the reference standard imaging techniques. As such, these emerging techniques might prove beneficial in diagnosing and monitoring AIS and its progression, without high levels of continued radiation exposure. To understand the historical perspective and current state of advanced imaging techniques for AIS, a search of PubMed electronic database was conducted to identify studies that had examined these new techniques in the diagnosis of idiopathic scoliosis in children and adolescents.

Pressure-impedance analysis: Assist the diagnosis and classification of ineffective esophageal motility disorder.

BACKGROUND AND AIM: We elucidated the clinical significance of distal contractile integral-to-esophageal impedance integral (EII) ratio (DCIIR) in ineffective esophageal motility (IEM) adult patients. METHODS: We recruited 101 patients with IEM (48.38 ± 1.58 years) and 42 matched healthy volunteers (44.28 ± 1.85 years) in this case-control study. All subjects underwent esophageal high-resolution impedance manometry from October 2014 to May 2018. The diagnosis of IEM was based on the Chicago Classification version 3.0. The EII, EII ratio, and DCIIR were analyzed by matlab software. RESULTS: The EII, EII ratio, and DCIIR calculated at an impedance threshold of 1500 Ω (EII1500, EII ratio1500, and DCIIR1500, respectively) were significantly lower in the IEM group than in healthy controls (P < 0.0001, < 0.0001, and < 0.0001, respectively). Receiver operating characteristic analysis showed that DCIIR1500 < 0.008 mmHg/Ω, EII1500 > 71 000 Ω.s.cm, and EII ratio1500 > 0.43 were all predictive of IEM. Only DCIIR1500 < 0.008 mmHg/Ω remained significant in diagnosing IEM in the multivariate logistic regression analysis (odds ratio = 72.13, P < 0.001). The DCIIR1500 is negatively correlated with Eckardt score and the Reflux Disease Questionnaire (correlation coefficient = -0.2844 and -0.3136; P = 0.0006 and 0.0002, respectively). Receiver operating characteristic analysis further showed that a DCIIR1500 cut-off of 0.002 mmHg/Ω achieved the best differentiation between the IEM-alternans and IEM-persistens subtypes among IEM patients (P < 0.001). CONCLUSIONS: The novel pressure-impedance parameter of high-resolution impedance manometry, DCIIR1500, may assist in the diagnosis and classification of IEM and correlated with clinical symptoms.

Percutaneous MR-guided interventions using an optical Moiré Phase tracking system: Initial results.

The aim of this study was the development and evaluation of a real-time guidance support using optical Moiré Phase Tracking (MPT) for magnetic resonance (MR) guided percutaneous interventions. A gradient echo sequence, capable of real-time position updates by the MPT system, was modified to enable needle guidance based on four rigidly attached MPT markers at the back of a needle. Two perpendicular imaging planes were automatically aligned along the calibrated needle and centered at its tip. For user guidance, additional information about the needle trajectory and the tip to target distance were added as image overlay. Both, images and guiding information were displayed on the in-room monitor to facilitate MR guided interventions. The guidance support was evaluated by four experienced interventional radiologists and four novices targeting rubber O-rings embedded in a custom-made phantom on a 3T wide-bore MRI system (80 punctures). The skin to target time, user error, system error and total error were analyzed. The mean skin to target time was 146s±68s with no statistically significant difference between experts and novices. A low mean user error (0.91mm±0.43mm), system error (0.53mm±0.27mm) and total error (0.99mm±0.47mm) was reached in all directions. No statistically significant difference in user error, system error and total error could be found between experts and novices. The presented tracking and image guidance system combined with the user interface offers continuous and interactive control of the imaging plane while puncturing in the magnet enabling accurate real-time feedback for both, experienced and non-experienced users.

School scoliosis screening by Moiré topography - Overview for 33 years in Miyazaki Japan.

BACKGROUND: Since 1981, we have performed school scoliosis screening (SSS) using Moiré topography in Miyazaki, Japan and attained a certain result in detecting scoliosis. However, this screening system was discontinued due to cessation of repair and production of Moiré topographic equipment. The purpose of this study was to make clear both the results and the problems of SSS by Moiré topography on the basis of our past 33 years' experiences. METHODS: The subjects were 689,293 students (5th grade boys in 200,329, 5th grade girls in 191,919, 8th grade boys in 151,351, and 8th grade girls in 145,694) who were screened by Moiré topography between 1981 and 2013. The number of students received SSS, the positive rate of Moiré topography, the discovery rate of scoliosis greater than 20°, the reference rate to the second screening, and the positive predictive value of Moiré topography to detect scoliosis greater than 20° were investigated. RESULTS: The number of students received SSS achieved a peak in 1992. The positive rate of Moiré topography and the discovery rate of scoliosis were highest in 8th grade girls. The reference rates to the second screening were 49.8% in 5th grade students and 41.4% in 8th grade students. The positive predictive values were 2.1% in 5th grade students and 7.6% in 8th grade students. CONCLUSION: SSS by Moiré topography seemed to be effective in detecting scoliosis although both the positive predictive value and the reference rate to the second screening were low.

Micro/Nano-scale Strain Distribution Measurement from Sampling Moiré Fringes.

This work describes the measurement procedure and principles of a sampling moiré technique for full-field micro/nano-scale deformation measurements. The developed technique can be performed in two ways: using the reconstructed multiplication moiré method or the spatial phase-shifting sampling moiré method. When the specimen grid pitch is around 2 pixels, 2-pixel sampling moiré fringes are generated to reconstruct a multiplication moiré pattern for a deformation measurement. Both the displacement and strain sensitivities are twice as high as in the traditional scanning moiré method in the same wide field of view. When the specimen grid pitch is around or greater than 3 pixels, multi-pixel sampling moiré fringes are generated, and a spatial phase-shifting technique is combined for a full-field deformation measurement. The strain measurement accuracy is significantly improved, and automatic batch measurement is easily achievable. Both methods can measure the two-dimensional (2D) strain distributions from a single-shot grid image without rotating the specimen or scanning lines, as in traditional moiré techniques. As examples, the 2D displacement and strain distributions, including the shear strains of two carbon fiber-reinforced plastic specimens, were measured in three-point bending tests. The proposed technique is expected to play an important role in the non-destructive quantitative evaluations of mechanical properties, crack occurrences, and residual stresses of a variety of materials.

Digital holographic moiré for the direct and simultaneous estimation of strain and slope fields.

A novel method is proposed for the direct and simultaneous estimation of multiple phase derivatives corresponding to strain and slope fields from a single moiré fringe pattern in digital holographic moiré. The interference field in a given row/column is a multicomponent complex exponential signal and is represented as a spatially-varying autoregressive (SVAR) process. The spatially-varying coefficients of the SVAR model are computed by approximating them as the linear combination of linearly independent basis functions. Further, the spatially varying poles of the transfer function corresponding to the SVAR model are computed which provide the accurate estimation of the multiple phase derivatives. The simulation and experimental results are provided to substantiate the effectiveness of the proposed method.

Comparison of the accuracy of digital stereophotogrammetry and projection moiré profilometry for three-dimensional imaging of the face.

The aim of this study was to compare the three-dimensional (3D) imaging accuracy between a digital stereophotogrammetry device and a projection moiré profilometry setup using anatomical models in conjunction with surface matching software. Twenty-two 3D surface models of the middle third of the face derived from computed tomography (CT) scans were used to fabricate photopolymer models by rapid prototyping. These were digitized using digital stereophotogrammetry and projection moiré profilometry. The 3D surface models acquired were compared for shape differences with the original CT models using surface matching software. Global registration between each pair of corresponding models was carried out using an iterative closest point algorithm. The mean surface deviations following registration were used to calculate Bland-Altman limits of agreement between the two methods. The distributions of measured surface differences were used to calculate L-moments. Paired t-tests were carried out for hypothesis testing. Correlation between difference and mean was -0.3, and 95% limits of agreement were -0.084mm and 0.064mm. No statistically significant differences in mean measurement error (L1 moments) were observed (P=0.1882). The experimental moiré profilometry setup employed produced 3D models of facial anatomy of comparable accuracy to a widely used commercialized digital stereophotogrammetry device.

Lentes progressivas: análise da potência do astigmatismo induzido / Progressive addition lenses: analysis of the power of induced astigmatism

OBJETIVO: Avaliar a potência do astigmatismo induzido nas lentes progressivas em um deflexômetro. MÉTODOS: Foram incluídas onze lentes progressivas com poder longe de +1,00D e adição 2,00D para perto. Avaliou-se o astigmatismo induzido em doze pontos do campo intermediário, sendo seis de cada lado do corredor progressivo no deflexômetro. RESULTADOS: Existem diferenças significativas entre as somas dos astigmatismos induzidos de cada lado do corredor progressivo e no total geral nestas lentes estudadas, com coeficiente de variação com forte dispersão (CV 10 a 13%). CONCLUSÃO: Existe uma variação importante das potências dos astigmatismos induzidos nas lentes progressivas...

OBJECTIVE: Evaluate induced astigmatism in progressive addition lenses into deflectometer measurements. METHODS: Eleven progressive addition lenses were included with power away from +1.00D and addition 2.00D. Induced astigmatism was assessed twelve points in the zone intermediate, with six on each side of the progressive corridor in deflectometer. RESULTS: There are significant differences between the sums of induced astigmatism on each side of the corridor and in the general in progressive addition lenses studied, with coefficient of variation with strong dispersion (CV 10-13%). CONCLUSION: There is an important variation of the power of induced astigmatism in progressive addition lenses...

Measurements of 3D relative locations of particles by Fourier Interferometry Imaging (FII).

In a large number of physical systems formed of discrete particles, a key parameter is the relative distance between the objects, as for example in studies of spray evaporation or droplets micro-explosion. This paper is devoted to the presentation of an approach where the relative 3D location of particles in the control volume is accurately extracted from the interference patterns recorded at two different angles. No reference beam is used and only ten (2 + 8) 2D-FFT have to be computed.

Combining moiré patterns and high resolution transmission electron microscopy for in-plane thin films thickness determination.

This paper reports the coupling of HRTEM and moiré pattern observations, allowing the determination of the thickness ratio of two superimposed crystals. Pseudo-lattice fringes are observed using identical TEM experimental conditions as for observing moiré patterns. The pseudo-lattice spacing is first calculated in the dynamical theory framework in two beam conditions. This approach shows a linear behavior of the spacing as a function of the thickness ratio of the two crystals. The roles of sample crystallographic orientation and sample thickness on the thickness ratio determination are discussed from multi-beam simulations. Finally, the method is applied on a bimetallic CuAg core-shell nanoparticle of a known structure. It is demonstrated that for this particle, the thickness ratio of Cu and Ag can be determined with an error that results in a precision less than 0.75 nm on the Cu and Ag thicknesses. The advantages of the technique are the use of an in-plane sample configuration and a single HRTEM image.

Moiré topography: characteristics and clinical application.

Since 1970, the Moiré phenomenon has been employed as a method of clinical diagnosis in topographical analyses of the human body. The objective of this study was to review the literature on the main characteristics of the Moiré phenomenon and its use as a topographical method for clinical applications, particularly those related to postural deviations. A systematic search for papers written in English between 1966 and 2010 was performed according to pre-established selection criteria and the selected studies underwent a content analysis. The results showed an evolution in the method of Moiré topography (MT), which reflect an increasing effort to improve the accuracy and precision of the method, as well as to facilitate the interpretation of topograms using specific software. The Shadow and Projection Moiré techniques have more frequently been used in comparison with other techniques. On the other hand, the methodological procedures of MT are apparently not well defined in the literature. Although MT was shown to be useful in the detection of spinal deformities, there is still a lack of research in clinical settings, especially in the elderly. For the most part, the studies involve the tracking of scoliosis in school age children. Japan appears to be the most advanced country in terms of the application of MT.

[High-resolution fluorescence microscopy of retinal pigment epithelium using structured illumination]. / Hochauflösende Fluoreszenzmikroskopie des retinalen Pigmentepithels mittels strukturierter Beleuchtung.

BACKGROUND: The accumulation of autofluorescent bodies in retinal pigment epithelium (RPE) cells has an impact on the pathogenesis of retinal diseases, including age-related macular degeneration. While current in vivo fluorescence microscopy allows a lateral resolution of fluorophores in a micrometer range, with ex vivo microscopy a lateral resolution down to 200 nm is possible. For the first time, we used structured illumination microscopy for ex vivo high-resolution fluorescence microscopy of RPE cells. METHODS: Histological sections were prepared from a 68-year-old patient. With epifluorescence microscopy, fluorescent RPE cells were detectable. Structured illumination uses inhomogeneous illumination for resolution of previously nonresolvable structures, similar to the Moiré effect. Images were taken from RPE cells at different excitation wavelengths (488, 568, and 647 nm) and were reconstructed with special software. The different excitation patterns of the fluorescent granules in the RPE cells were colour-coded and analysed. RESULTS: With structured illumination microscopy, autofluorescence signals of RPE cells were detectable, and a lateral resolution of 110 nm could be achieved. Using varying wavelengths, different pigments were excitable. Lipofuscin gave the highest signals, at 488 and 568 nm. The improved resolution showed inhomogeneous intragranular fluorophore patterns. CONCLUSION: Structured illumination microscopy enabled us to generate images of fluorescent structures in RPE cells ex vivo with a lateral resolution of 110 nm. With the use of different excitation wavelengths, intracellular fluorescence patterns in single cell compartments are visible and allow further differentiation.

A study of labial groove-textures of upper central incisors by Shadow Moiré technology.

The labial groove-textures of upper central incisors were defined and explored to imitate the elaborate groove-textures for aesthetic restorations. In the current study, 158 upper central incisors were selected from 79 volunteers aged from 19 to 24 and recruited from Sichuan University in Chengdu of China. The length, width, depth, combination and distribution of the horizontal and vertical grooves on the labial surface were investigated by an optical measurement method, based on the Shadow Moiré technology and Temporal Fourier analysis. Vertical grooves were confirmed to be present in 94% of the samples and horizontal grooves in 77%. Perfect symmetry was shown in the vertical grooves of the same tooth, as well as in the homonymous teeth. The majority of horizontal grooves were distributed in the proximity of the cervical fourth and the middle of the crown. Based on the combination and distribution of the grooves, eight basic labial groove-texture types of maxillary central incisors were classified. The subtle morphological characters of natural teeth could be recorded by the new method, and it could also provide the minute groove-texture for dentists and technicians to achieve an aesthetic appearance for a restoration.

Measurement of scapular kinematics with the moiré fringe projection technique.

The aim of this study was to investigate the applicability of the moiré fringe projection technique (MFPT) to quantify the scapular motions relative to the thorax. This system was composed of a LCD projector, a digital photographic camera, and a microcomputer. To automatically obtain the scapular profiles, the phase shifting method was combined with the MFPT. Four fringes were projected on the scapula and four on the reference planes. By the simple subtraction of the reference values from the scapular phase maps, the map due to the moiré fringes could be digitally obtained. After the phase decoding, the tridimensional (3D) profiles were obtained without prior information about the samples and the calculations of the scapular kinematics were carried out using dedicated software. On average, the movements of lateral rotation ranged from -1.8+/-6.1 degrees to -26.5+/-3.5 degrees; the protraction from 28.4+/-4.7 degrees to 27.7+/-6.8 degrees, and the posterior tilt from -6.4+/-7.8 degrees to -21.7+/-6.1 degrees, during the arm elevation in the scapular plane performed by six healthy subjects. For the test-retest reliability, the intra-class correlation coefficients ranged from 0.92 to 0.997 and the maximum estimated error was 0.8%. The MFPT allowed the scapular 3D measurements to be obtained in a digital and non-invasive manner. The main advantages compared with other existing systems were its ease in implementation, the use of standard optical components, and its possible clinical applications.