Shape Measurement Research Articles

Effects of underweight, overweight, and obesity on the body growth of preschoolers

ObjectiveThis study aimed to investigate the impact of underweight, overweight, and obesity on the growth and development of preschoolers by comparing body shape characteristics across different weight statuses.MethodsA total of 729 preschoolers (5.2 ± 0.83 years, 53.8% boys) from three kindergartens were assessed for 11 different body shape measurements. Two-way ANOVA was employed to examine BMI variations across different ages and sexes. Discriminant analysis was utilized to identify body shape measurements correlated with BMI, and one-way ANOVA was conducted to compare the body shape differences among preschoolers with varying BMI.Results(1) There was no significant interaction effect of gender and age on BMI (F = 1.602, p = 0.173). Additionally, neither the main effect of age (F = 1.461, p = 0.228) nor the main effect of sex (F = 0.905, p = 0.345) was significant. (2) The results of the stepwise discriminant analysis showed that chest circumference, calf length, calf circumference, foot length, and width between greater trochanters entered the discriminant model, with the three discriminant functions explaining 95.8, 3.1, and 1.1% of variance, respectively. (3) Compared to their normal-weight counterparts, obese preschoolers displayed significantly larger measurements in chest circumference, width between greater trochanters, calf circumference, calf length, and foot length (p < 0.05). Overweight preschoolers also exhibited larger chest and calf circumferences, and width between greater trochanters (p < 0.05), while underweight children showed lagging development in various body shape measurements (p < 0.05).ConclusionVariations in BMI were significantly correlated with preschoolers’ body shape which included chest circumference, calf length, calf circumference, foot length, and the distance between the greater trochanters. Overweight and obese preschoolers experienced faster body growth; conversely, underweight preschoolers often showed delayed growth. This underscores that the underweight group also merits attention and concern.

Distortion correction algorithm based on absolute phase image in structured light 3D reconstruction

Abstract This paper proposes a distortion correction algorithm based on absolute phase maps for a dual-projector, single-camera structured light 3D shape measurement system. Distortion correction is performed separately for the projector-camera pairs on the left and right. By projecting a ninth-order complementary Gray code combined with the eight-step phase-shifting method onto a white board, absolute phase maps are obtained, solving the impact of radial and tangential lens distortion. A sub-pixel level distortion error lookup table is introduced to address the influence of residual error after distortion correction on measurement accuracy, improving the overall precision by at least 95.7%. Experiments demonstrate that the dual-projector, single-camera structured light 3D shape measurement system expands the system’s measurement range while reducing shadowing issues caused by single-projector illumination. The proposed distortion correction and error compensation algorithms effectively enhance the overall measurement accuracy of the system and significantly improve issues like warping caused by distortion.

Investigation on coupling vibration characteristics of asymmetric rails with variable cross-sections based on modal separation

In railway turnouts, asymmetric switch rails with variable cross-sections are designed for wheel load transitions. However, the dynamic characteristics of these specially shaped switch rails are not yet fully understood. This paper investigates the vibration characteristics of switch rails through theoretical simulations, on-site admittance tests, and operational deflection shape (ODS) measurements. The study reveals that the modes of the switch rail involve multi-directional coupling vibrations, making the mode types indiscernible through direct observation. To address this, a modal separation method is proposed, based on the calculation of modal mass. The vertical vibration of the switch rail can be categorized into three types: torsional mode, vertical bending mode, and reverse torsion mode of the rail head and base above 600 Hz. As the position approaches the switch rail point, the degree of cross-sectional asymmetry increases, which consequently intensifies torsional vibration. Cross-sectional asymmetry is identified as the primary factor causing the coupling of bending-torsional vibrations, while variable cross-sections contribute to mode shape asymmetry and the gradual alteration of natural frequency along the rail.

Weak Lensing Analysis of A2390 Using Short Exposures

We present a weak lensing analysis of the galaxy cluster A2390 at z = 0.23 using second moment shape measurements made in 411 short 60 s exposures. The exposures are obtained in three broadband photometric filters (g, r, and i) using WIYN-ODI. Shape measurement in individual exposures is done using a moment-matching algorithm. Forced measurement is used when the moment-matching algorithm fails to converge at low signal-to-noise ratio. The measurements made in individual images are combined using inverse error weighting to obtain accurate shapes for the sources and hence recover shear. We use PhoSim simulations to validate the shear measurements recovered by our pipeline. We find the mass of A2390 is in agreement with previously published results. We also find the E-mode maps show filamentary structures consistent with baryonic structures and recover most clusters/groups of galaxies found using optical and X-ray data. Thus, we demonstrate the feasibility of using weak lensing to map large-scale structure of the Universe. We also find the central portion of the cluster has a bimodal mass distribution and the relative orientation of the peaks is similar to X-ray. We discuss earlier research on this galaxy cluster, and show that a late-stage merger accounts for all the observed data.

3-D Shape Measurement Method Based on Phase Shifting Fringe Multiplexing

3-D Shape Measurement Method Based on Phase Shifting Fringe Multiplexing

Distance deviation sensitivity on null test of convex hyperboloid mirrors with large relative aperture

In the shape measurement of convex hyperboloid mirrors with large relative apertures, alignment deviations can significantly affect the accuracy of null test results owing to their sensitivity, resulting in inaccurate results. This paper introduces autocollimation and compensation methods. Subsequently, a shape detection experiment of a large relative aperture convex hyperboloid mirror with a diameter of 15 mm was conducted using the aforementioned methods. Further, a detailed simulation analysis was performed to address the inconsistencies between the two test results. The results suggested that the Hindle sphere method was highly sensitive to distance deviation. Furthermore, the distances in the optical path exerted a complementary effect, which easily obscured the true surface shape of the measured part. The computer-generated hologram (CGH) method could accurately determine the true surface shape deviation based on the alignment judgment provided by the aligned CGH part. These studies provide scientific guidance for more accurately obtaining the true surface shape error of the hyperboloid mirror under test, and have significant engineering application value.

Phase-shifting profilometry for 3D shape measurement of moving objects on production lines

It is challenging for phase-shifting profilometry to measure objects in motion on production lines due to two main issues. Firstly, the movement of the object causes a mismatch in its position across different fringe patterns. Additionally, there is a violation of the ideal phase shift between these fringe patterns. To address these problems, we propose a method that takes advantage of the known moving direction of objects on production lines. By aligning the isophase direction of fringe patterns with the known direction of the moving objects, our method essentially solves the well-known phase error problem caused by object motion. Furthermore, we have developed a projection and imaging technique to track the measured object that is covered with different fringe patterns. Both of the previously listed issues have been resolved in this manner. The proposed method is validated by comparisons with state-of-the-art methods, proving its simplicity, broader applicability, and improved measurement accuracy.

Shape Measurement of Single Gold Nanorods in Water Using Open-Access Optical Microcavities.

Shape measurement of single nanoparticles in fluids is an outstanding challenge with applications in characterizing synthetic functional nanoparticles and in early warning detection of rod-shaped pathogens in water supplies. Here we introduce a novel technique to measure the aspect ratio of rod-shaped particles by analyzing changes in the polarization state of a laser beam transmitted through an optical microcavity through which the particle diffuses. The resolution in aspect ratio measurement is found to be around 1%. Our work opens the new possibility of in situ and single-particle shape measurement, which has promising applications in nanoparticle characterization, water monitoring, and beyond.

The microlayer and force balance of bubbles growing on solid in nucleate boiling

This study uses interface-resolved computational fluid dynamics simulations to investigate the dynamics of bubble growth on a horizontal solid surface, with a focus on the characteristics of the microlayer and the forces involved in the process. The simulations exclude phase change effects to concentrate on hydrodynamics and employ an external mass source for controlled bubble inflation. This mass source follows a time-dependent bubble radius growth law, R(t)∝t1/2, which is typical for heat-transfer-controlled growth of a vapour bubble during nucleate boiling of water at atmospheric pressure. The numerical framework is validated against recent experimental measurements of bubble shape and microlayer profile. The results of this work indicate that the rate of bubble growth significantly influences microlayer formation. Faster growth rates produce a near-hemispherical bubble shape with an extended radial microlayer on the solid, while slower rates yield a taller, more spherical bubble with a shorter microlayer. All microlayer profiles exhibit an outwardly-curved shape, with a maximum microlayer thickness increasing with the growth rate. The study also examines the force balance on the bubble, revealing that the net vertical force of the bubble does not equal zero even when the bubble remains attached to the solid surface. Our analysis of the bubble motion demonstrates that previous force balance models used for determining bubble detachment lack robustness. The microlayer profile obtained in this work is important for boiling heat transfer studies as the microlayer contributes significantly to local heat transfer. The force balance analysis shows the need for a new approach to determine bubble detachment behaviour, which is vital for predicting flow boiling rates.

Muscularity-oriented disordered eating: investigating body image concerns and the moderating role of emotion dysregulation in cyclists

A lean muscular body of low weight is often associated with performance for cyclists and can be difficult to achieve. Disordered eating for some cyclists may develop in the pursuit of lean muscularity which is perceived to be beneficial to performance. Further, emotion dysregulation may exacerbate negative feelings about body image, increasing the risk of developing disordered eating as a means of controlling weight and shape. While research in athlete populations has been substantial, disordered eating in cyclists is relatively under-explored. The current study examined whether shape and weight concern and drive for leanness were associated with muscularity-oriented disordered eating and whether these relationships were moderated by emotion dysregulation. Interactions between these factors were also investigated. Participants were 139 Australian competitive cyclists (112 males, 27 females, aged 18–68 years) who completed a self-report questionnaire comprised of measures of shape and weight concern, drive for leanness, muscularity-oriented eating and emotion dysregulation variables. Both shape and weight concern and drive for leanness had a unique association with muscularity-oriented disordered eating. Emotion dysregulation was found to have a unique association with muscularity-oriented disordered eating when controlling for drive for leanness, but not when shape and weight concern was controlled. Additionally, emotion dysregulation moderated the association between shape and weight concern and muscularity-oriented disordered eating, whereby the relationship was intensified at higher levels of emotion dysregulation. Our study has extended the literature by indicating that cyclists’ desire to attain a lean body is associated with muscularity-oriented disordered eating. Further, emotion dysregulation moderated this link, suggesting it could be a maintaining factor worth addressing.

17O NMR relaxation measurements for investigation of molecular dynamics in static solids using sodium nitrate as a model compound

17O NMR methods are emerging as a powerful tool for determination of structure and dynamics in materials and biological solids. We present experimental and theoretical frameworks for measurements of 17O NMR relaxation times in static solids focusing on the excitation of the central transition of the 17O spin 5/2 system. We employ 17O-enriched NaNO3 as a model compound, in which the nitrate oxygen atoms undergo 3-fold jumps. Rotating frame (T1ρ), transverse (T2) and longitudinal (T1) relaxation times as well as line shapes were measured for the central transition in the 280 to 195 K temperature range at 14.1 and 18.8 T field strengths. We conduct experimental and theoretical comparison between different relaxation methods and demonstrate the advantage of combining data from multiple relaxation time and line shape measurements to obtain a more accurate determination of the dynamics as compared to either of the techniques alone. The computational framework for relaxation of spin 5/2 nuclei is developed using the numerical integration of the Liouville − von Neumann equation.

Triple-Phase Computed Tomography and Sonoelastographic Evaluation in Focal Hepatic Lesions

ABSTRACT Background: The liver plays a crucial role in metabolism and has a complex vascular structure, making the accurate characterization of hepatic lesions essential for diagnosis and treatment. This study explores the effectiveness of triple-phase computed tomography (CT) and sonoelastography in evaluating focal hepatic lesions. Methodology: A cross-sectional study was conducted on 50 patients with liver lesions who underwent triple-phase CT and elastographic ultrasound evaluations. The study analyzed various lesion characteristics, such as echogenicity, shape, and stiffness measurements, obtained through elastography. Results: Ultrasonography findings varied significantly between benign and malignant lesions. Elastography values were higher in malignant lesions, and triple-phase CT provided detailed insights into lesion characteristics, confirming the effectiveness of these imaging techniques in distinguishing between benign and malignant lesions. Conclusions: The integration of triple-phase CT and sonoelastography offers a comprehensive approach to evaluating focal hepatic lesions, enhancing diagnostic accuracy, particularly in differentiating benign from malignant lesions.

Curvature Analysis of Seed Silhouettes in the Euphorbiaceae

The Euphorbiaceae is a large, diverse, and cosmopolitan family of monoecious or dioecious trees, shrubs, herbs, and lianas. Their name comes from Euphorbia, one of the largest genera in the Angiosperms, with close to 2000 species and a complex taxonomy. Many of their members have an economic interest in multiple applications, including pharmaceutical, nutritional, and others. The seeds of the Euphorbiaceae develop in schizocarps and have a diversity of shapes that have proven useful for species identification and classification. Nevertheless, analytical quantitative methods can be the subject of further development for the application of seed morphology in the taxonomy of this family. With this objective, measurements of size (area, perimeter, length, and width) and shape (circularity, aspect ratio, roundness, and solidity) in seed images of 230 species representative of the main taxonomic groups of Euphorbiaceae are presented, and curvature analysis is applied to 19 species. Seed images corresponding to many species of this family present a tetragonal pattern with a curvature peak in the apical pole and three in the basal pole. The results of the curvature analysis are discussed in relation to other morphological properties, revealing new aspects of seed morphology of taxonomic application.

The prognostic importance of glioblastoma size and shape

PurposeExtent of resection, MGMT promoter methylation status, age, functional level, and residual tumor volume are established prognostic factors for overall survival in glioblastoma patients. Preoperative tumor volume has also been investigated, but the results have been inconclusive. We hypothesized that the surface area and the shape were more representative of the tumor’s infiltrative capacities, and thus, the purpose of this study was to assess the prognostic value of tumor size and shape in patients with glioblastoma.MethodsIn total, 271 patients with primary, unifocal glioblastoma were included from two centers in Norway and Sweden, respectively. All tumors were automatically segmented on preoperative MRI scans and manually validated. Tumor volume was used as a measurement of size, whereas sphericity index and area-to-volume ratio defined the shape complexity of the tumor. Contact surface area of the tumor was considered a measurement of both size and shape. Multivariable Cox proportional hazards models were used to assess the prognostic value of the respective tumor measurements, with previously established prognostic factors as covariates.ResultsThere were no associations between preoperative tumor volume and overall survival. Contact surface area (HR = 1.013, p = 0.002) and sphericity index (HR = 2.223, p = 0.001) were both significant independent prognostic factors for survival in the multivariable Cox models. Contact surface area was also associated with MGMT promoter methylation (p = 0.039) and extent of resection (p = 0.017).ConclusionTumor shape complexity appears to be an independent prognostic factor in glioblastoma patients and may also be associated with MGMT promoter methylation status and extent of surgical resection.

Motion-induced phase shift for dynamic structured light measurement.

Structured light 3D shape measurement is extensively utilized in semiconductor inspection, smart manufacturing, and biomedical imaging due to its rapid measurement speed, high precision, and versatile applicability to different objects. However, the traditional implementations of this method often require that the object remains static while recording the phase-shifting structured light images, which limits the adaptability of dynamic measurement. Here, we propose a dynamic 3D shape measurement using structured light based on a motion-induced phase shift (MIPS). As the object moves, the surface features distort the fringe pattern, resulting in a phase-shifting effect. By employing the MIPS method, we can determine the phase even in the situations where the knowledge of phase-shifting conditions is not accurate. This enables the acquisition of the 3D topography of the object surface with a high level of precision. Experimental results demonstrate that the MIPS method can accurately measure the 3D shape of objects moving as fast as 100 mm/s, with a relative discrepancy of less than 0.23%.

Study on the Correlation Between Mechanical Properties, Water Absorption, and Bulk Density of PVA Fiber-Reinforced Cement Matrix Composites

Fiber-reinforced cement matrix composites (CMCs) have gained significant attention due to their ability to enhance material properties for use in demanding environments. This study investigated the workability and mechanical properties of polyvinyl alcohol (PVA) fiber-reinforced CMCs, focusing on compressive strength, split tensile strength, and flexural strength. It also assessed water absorption capacity through immersive water absorption tests using cubes and capillary water absorption tests using cylinders, alongside bulk density measurements for both shapes. The results indicated that the dosage of PVA fibers significantly influences the workability of CMCs, while the water-to-binder ratio has a minimal effect. Increasing the dosage of PVA fibers in CMCs from 0.5 vol.% to 1 vol.% led to a decrease in several properties: compressive strength decreased by 13.38%, split tensile strength by 21.05%, flexural strength by 9.23%, bulk density of cube samples by 4.14%, and bulk density of cylindrical sample by 6.36%. Conversely, both immersive water absorption and capillary water absorption increased, rising by 10.87% and 77.71%, respectively. Compressive strength was found to increase with the bulk density of the cubes and to decrease with rising immersive water absorption. Similarly, split tensile strength increased with the bulk density of the cylinders and decreased as capillary water absorption increased. Strong correlations were observed among three key pairwise combinations: the bulk density of cubes and immersive water absorption (R2 = 94%), compressive strength and bulk density of cubes (R2 = 96%), and compressive strength and immersive water absorption (R2 = 92%). Furthermore, the analysis and comparison of carbon fiber-reinforced and PVA fiber-reinforced CMCs will provide important references for the field, especially in cases where material availability or cost varies.

NIMG-53. MRI-BASED RADIOMICS FOR DIFFERENTIATION BETWEEN PERIFOCAL EDEMA AND NON-CONTRAST-ENHANCING GLIOBLASTOMA FOCI

Abstract OBJECTIVE Various intracranial tumors can lead to the development of perifocal edema. Differentiating edema from tumor on MRI might be easy in metastases and meningiomas but can be challenging in patients with glioblastoma. We set out to compare and characterize perifocal edema and non-contrast-enhancing glioblastoma foci by means of radiomic feature analysis. METHODS In this single-center, retrospective study, patients with intracranial tumors and perifocal edema on preoperative T2/FLAIR-sequences were included. Patients diagnosed with brain metastasis, meningioma or glioblastoma were eligible. Tumor and edema volumes were semi-automatically segmented and extracted. After image registration, contrast-enhancing tumor and necrosis on T1-weighted sequences were subtracted from T2/FLAIR-hyperintense tumor and perifocal edema. Radiomic features were computed. Distribution of radiomic features were tested using the Shapiro-Wilk test. ANOVA or Kruskal-Wallis tests were applied to compare the features. Significant features were identified based on p-values (<0.05) and post-hoc Tukey’s Honest Significant Difference (HSD) tests were conducted. RESULTS The cohort comprised n=60 patients and was split in three groups according to histopathology (metastases, meningioma, glioblastoma). Each subgroup comprised n=20 patients (33.3%). 107 radiomic features of the T2-hyperintensity, after subtraction of contrast-enhancing tumor and necrosis, were tested for each patient. 18 radiomic features (17%) that mainly comprised measures of shape, texture and intensity distribution, e.g., sphericity (p<0.01), surface/volume (p<0.01), entropy (p<0.01), skewness (p<0.01) and kurtosis (p<0.01), showed no significant difference between metastases and meningiomas but differed significantly from the T2-hyperintensity of glioblastoma. The textual complexity of glioblastoma was significantly higher (p<0.01). CONCLUSION Radiomic feature analysis unraveled many features that might be helpful in differentiating perifocal edema from tumor infiltration. Future studies should aim at validating our results and further exploring the T2-hyperintensity of glioblastoma patients, e.g., suspected edema versus suspected tumor infiltration zone.

High-Precision Measurement Method for Small Angles Based on the Defect Spot Mode of the Position-Sensitive Detector.

The paper proposes and verifies a small-angle measurement method based on the defect spot mode of the position-sensitive detector (PSD). With the output characteristics of the PSD in the defect spot mode and the size transformation properties of a focused beam, the measurement sensitivity can be significantly improved. Calibration experiments with the piezoelectric transducer (PZT) indicate that compared with the current PSD-based autocollimation method, the proposed method can improve the sensitivity of small-angle measurement by 57 times, and the measurement sensitivity of the proposed method can be further improved by optimizing the system parameters, while the proposed method has the advantages of a simple system and high real-time performance. Therefore, the proposed method is expected to be used in high-precision motion error detection, as well as in shape and position measurement.

Stroboscopic sampling moiré microscope (SSMM) for investigating full field in-plane vibration of MEMS mechanical transducers

Precise analysis of the full-field in-plane vibration of microelectromechanical system (MEMS) transducers is crucial for assessing their device functionality and performance. As an example, in the context of frequency/amplitude modulation of Quartz Tuning Fork (QTF)-based atomic force microscopy (AFM) systems, understanding QTF’s in-plane vibration can significantly enhance accurate evaluation of tip-sample forces. Current methods, such as analytical and numerical approaches, have limitations when it comes to providing accurate measurements. To address these limitations, we proposed an experimental approach that combines stroboscopic and sampling moiré (SM) techniques. This method focuses on investigating the in-plane vibration of a QTF and utilizes the obtained results to measure the sensor’s dynamic properties such as vibration mode shape, resonance frequency (f0), and quality factor (Q). Nanometer-scale light pulses, generated using a custom-designed stroboscope, are synchronized with the QTF’s excitation voltage to freeze the vibration effectively, enabling imaging using a standard CCD camera. Subsequently, SM analysis is employed to extract the surface vibration profile, facilitating the measurement of vibration mode shape, f0, and Q. This technique shows promise for analyzing the dynamic behavior of various micro-devices compatible with the sample preparation process.

3-D Shape Measurement for Complex Reflective Surface Based on UAOM Device

3-D Shape Measurement for Complex Reflective Surface Based on UAOM Device