Systematic Errors Research Articles

Subaperture moving strategy and related systematic errors in stitching interferometry of X-ray mirrors

For high-precision metrology of X-ray mirrors, the subaperture moving strategy significantly impacts the accuracy of stitching interferometry. In this work, we investigated the systematic errors associated with various subaperture moving strategies of rotational stitching (RS), rotational displacement stitching (RDS), and displacement stitching (DS) in measuring X-ray mirrors. The effects of stitching strategies on a flat mirror and a spherical mirror with a radius of curvature (RoC) of 180 m and 60 m were compared. For the mirror with RoC of 60 m, the DS strategy showed the smallest height error of 3.3 nm (RMS) between algorithm-based stitching and the Nanometer Optical component Measuring machine (NOM), while RS showed a large error of 37.4 nm (RMS). The different regions of the interferometer aperture have different amplitudes of retrace errors, defocusing errors, and lateral distortion, which can lead to accumulations of systematic errors using the RS strategy. By reducing the pixel size from 0.268 mm/pixel to 0.089 mm/pixel, the measurement accuracy using the same RDS strategy improved from 7.4 nm (RMS) to 4.4 nm (RMS). Based on the optimal stitching strategy, the measurement accuracy of residual figure error of the X-ray mirror with a radius of curvature of 30 m reaches 0.2 nm (RMS).

Distant two-qubit gates in atomic array with Rydberg interaction using geometric quantum control

Connectivity between qubits plays an irreplaceable role in quantum computation. An urgent task of quantum computation based on atomic arrays is to generate effective coupling between two distant qubits, thereby enhancing connectivity. In this paper, we investigate the realization of two-qubit gates utilizing buffer-atomic configuration, where the non-coding atoms serve as quantum buses to connect the computational qubits. Geometric control is achieved through globally-shined laser pulses in the Rydberg blockade region. It is found that acceleration based on shortcut to adiabaticity can be realized by reshaping the original control waveforms. The proposed distant two-qubit gate demonstrates robustness against systematic errors and random noise. Further numerical simulations indicate that high-fidelity control is maintained even when considering next-nearest-neighbor coupling among the atoms. Thus, our proposal provides a fast and experimentally feasible method for realizing distant two-qubit gates in atomic arrays, which may contribute to improving the scalability of quantum computations.

Reliability, biological variability, and accuracy of multi-frequency bioelectrical impedance analysis for measuring body composition components

IntroductionBioelectrical impedance analysis (BIA) systems are gaining popularity for use in research and fitness assessments as the technology improves and becomes more affordable and easier to use. Multifrequency BIA (MF-BIA) may improve accuracy and precision using octopolar contacts for segmental analyses.PurposeEvaluate reliability, biological variability, and accuracy of component measures (total body water, mass, and composition) of commercially available MF-BIA system (InBody 770, Cerritos, California, USA).MethodsFourteen healthy military-age adults were assessed by MF-BIA in duplicate on five laboratory visits across 3 weeks (10 measures each). Participants were evaluated at the same time of day after refraining from strenuous exercise (> 48 h), alcohol consumption (> 24 h), and caffeine, nicotine, and food (> 10 h). Systematic error (test–retest reliability) and biological variability (day-to-day reliability) were summarized by intraclass correlation coefficient (ICC) values determined for body mass (fat, fat-free, total) and body water (extracellular, intracellular, total). Body composition measurements derived from BIA on the second visit were also tested for accuracy compared to dual-energy x-ray absorptiometry (DXA).ResultsTest–retest reliability was very high for all measurements of whole-body water and mass (ICC ≥ 0.999) and high for regional body water and mass (ICC 0.973–1.000). Biological variability was observable with very minor differences between tests (same day) for total and regional body water (0.0–0.2 L) and total and regional body mass measurements (0.0–0.2 kg); while between day differences were slightly higher (0.0–0.5 L and 0.1–0.7 kg). Compared to DXA, the MF-BIA whole-body measures showed an offset in %BF (Bias −4.0 ± 2.8%; Standard error of the estimate (SEE), 2.6%), an overprediction for total body fat-free mass (Bias 2.8 ± 2.1 kg; SEE 2.2 kg) and an underprediction of total body fat mass (Bias −2.9 ± 2.0 kg; SEE 1.9 kg).ConclusionUnder controlled conditions with fit and healthy men and women, this MF-BIA system has high methodological reliability and demonstrates stable day-to-day measurements of major body composition components. Previously reported ~3% body fat offset compared to criterion methods was again confirmed. Precision of the InBody 770 shows consistency and supports further testing of this specific device as a new military standards method and suitability across a wider range of %BF.

Comparative analysis of smartphone colorimeter apps and spectrophotometry for measuring forehead skin color in maxillofacial prosthesis fabrication.

This study aimed to evaluate the accuracy and precision of two smartphone colorimeter apps, Color Grab, and Color Picker, in measuring forehead skin color and to compare their readings with those from a spectrophotometer. Fifty participants (26 males, 24 females; median age 23 years, range 21-45) were included. Using a smartphone camera, images of forehead skin were captured, and CIELAB color values were reported by both apps. Measurements from a reference spectrophotometer (MiniScan EZ 4500L, 45°/0° geometry) served as the gold standard. Trueness and precision were assessed using CIELAB and CIEDE2000 formulas. Statistical analyses included one-way ANOVA and Mann-Whitney tests, with significance at p<0.05. Both apps showed comparable accuracy in capturing skin color, with absolute trueness (ΔEAbs) for Color Grab at 7.59 (CIEDE2000) and Color Picker at 7.65. Relative trueness (ΔERel) was 3.79 for Color Grab and 3.70 for Color Picker. Precision (MCDM) demonstrated significant differences between the apps: Color Grab at 1.34 (CIEDE2000) compared to Color Picker at 0.96 (p<0.0001). While smartphone apps may not match the accuracy of spectrophotometers, they offer valuable alternatives for color matching in maxillofacial prostheses. Future studies should focus on minimizing systematic errors related to environmental factors and camera settings to enhance measurement accuracy.

Potential of light-cone sum rules without semiglobal quark-hadron duality

This work addresses the calculation of local form factors involved in the theoretical predictions of semileptonic B-meson decays at low q2. We present a new approach to the method of QCD light-cone sum rule with B-meson light-cone distribution amplitudes. In our strategy, we bypass the semiglobal quark-hadron duality (QHD) approximation which usually contributes an unknown and potentially large systematic error to the prediction of form factors. We trade this improvement for an increased reliance on higher-order contributions in perturbation theory. Unlike the systematic error from semiglobal QHD, truncation errors are assessable and systematically improvable, hence allowing robust predictions of form factors. For the transitions B→π,ρ,K(*), our predictions agree with the literature for all form factors at q2=0. Published by the American Physical Society 2024

Feasibility of position emission tomography derived endocardial wall strain: direct comparison with magnetic resonance using hybrid 13N ammonia PETMR system.

We aimed to evaluate the feasibility of positron emission tomography feature tracking (PETFT) for assessing endocardial wall strain by comparing it with cardiac magnetic resonance (CMR)-derived feature tracking (CMRFT). We enrolled 83 consecutive patients with coronary artery disease who underwent rest-pharmacologic stress 13N-ammonia PETMR (67 males, mean age 66years). PETFT and CMRFT were obtained through simultaneous acquisition with electrocardiography-gated PET and cine-CMR. Global longitudinal and circumferential strain (GLS and GCS) were calculated. Correlations and Bland-Altman plots were employed to evaluate associations, bias, and 95% limit of agreement (LOA) between PETFT and CMRFT. PETFT and CMRFT showed significant correlations (R = 0.57 [95% CI 0.41-0.70], R = 0.71 [95% CI 0.58-0.80], R = 0.59 [95% CI 0.43-0.71], and R = 0.69 [95% CI 0.56-0.79] for rest GLS, rest GCS, stress GLS, and stress GCS, respectively; p < 0.001 for all). Bland-Altman plot showed good agreements, while a systematic error was observed (LOA -10.2-8.8, -8.7-10.7, -10.5-8.5, and -9.4-12.0; bias -0.7, 1.0, -1.0, and 1.3; for rest GLS, rest GCS, stress GLS, and stress GCS; respectively). PETFT has been identified as a feasible technique compared to CMRFT, highlighting its potential as a novel tool for assessing wall strain in routine clinical settings.

Image-based finite element model stiffness and vBMD by single and dual energy CT reconstruction kernel

Single-energy quantitative computed tomography (SEQCT) provides volumetric bone mineral density (vBMD) measures for bone analysis and input to image-based finite element models (FEMs). Dual-energy CT (DECT) improves vBMD by accounting for voxel-specific material variations utilizing scans at multiple x-ray energies. vBMD is also altered by reconstruction kernel that cannot be accounted for using calibration phantoms. This study compared vBMD and FEM stiffness derived from SEQCT and DECT images reconstructed with two common kernels. SEQCT and DECT images of cadaveric shoulders (n = 10) were collected using standard (STD) and boneplus (BONE) kernels. Hounsfield Units were converted to vBMD using specimen-specific calibrations. DECT STD and BONE images were generated using an established material decomposition method with 40 and 90 keV simulated monochromatic images. A proximal humerus bone section below the anatomic neck was used for vBMD analysis and FEM generation. FEMs were loaded to 1 % apparent strain for stiffness measurements.Between STD and BONE kernel images, average vBMD differed 0.9 mgK2HPO4/cc and 4.1 mg K2HPO4/cc, in SEQCT and DECT images, respectively. Significant differences occurred in DECT images (p = 0.001). BONE reconstructed images produced higher vBMD measures across both SEQCT and DECT images. The difference between STD and BONE in both SEQCT- and DECT-based FEMs persisted, with larger estimated stiffness in BONE models. For six of the models DECT-based had higher stiffness than SEQCT-based models using the same kernel, although these models differed between STD and BONE kernels. Differences in stiffness between STD and BONE derived models were similar across image types (DECT: 17.5 kN/mm; SEQCT: 19.0 kN/mm). Stiffness values were significantly different within SECT kernels and between SEQCT BONE and DECT STD models. This study shows important differences in vBMD and FEM stiffness that occur due to CT-based imaging parameters alone. These results indicate that consistent imaging parameters should be used for vBMD analysis and FEM input to avoid systematic measurement errors.

Comment on Lone et al. Phylogenetic Relationships in Earthworm Megascolex Species (Oligochaeta: Megascolecidae) with Addition of Two New Species. Diversity 2022, 14, 1006

Currently, on a global scale, integrated taxonomical works, by incorporating the molecular approach and traditional taxonomic methods have gained acceptance. Recently, Lone et al. (Diversity 2022, Phylogenetic Relationships in Earthworm Megascolex Species (Oligochaeta: Megascolecidae) with Addition of Two New Species) studied eleven Megascolex species (including two new species) from the Western Ghats biodiversity hotspot region of the Kerala state, India, by incorporating the integrated methods. The analysis of the results provided in Lone et al. indicated several discrepancies and shortcomings. They have overlooked or incorrectly described many key characters used in the Megascolex species identification and provided faulty figures. Apart from these, the paper had many factual as well as systematic errors. In this comment, based on the data provided by Lone et al., we critically reviewed their work, citing the errors and defects so as to help them to avoid similar issues in their future works and to obviate further confusions in the field of earthworm taxonomy.

A novel wall interference correction method for airfoil

Corrections for wind tunnel experimental results are crucial when accounting for tunnel wall interference. This study introduces a new method, the non-uniform wall pressure signature method (NUWPSM), which is designed to address tunnel wall interference in airfoil. The improved wall pressure signature method (WPSM), an enhanced version of the WPSM, is developed to address the velocity disparities and systematic errors in pressure measurements between with and without model conditions. Furthermore, the NUWPSM considers the non-uniformity of the flow induced by the limited far-field effect in wind tunnel experiments. Utilizing experimental data from three different scaled models of the WA210 airfoil, the efficacy of both the Improved WPSM and NUWPSM is verified. Results indicate that the Improved WPSM exhibits superior capabilities in simulating the distribution of axial induced velocity along the wall compared to the traditional WPSM. Additionally, both the Improved WPSM and NUWPSM demonstrate comparable abilities in correcting tunnel wall interference, achieving precise corrections within an angle of attack range of −180° to +180°. Notably, the NUWPSM effectively captures the velocity non-uniformity induced by the limited far-field effect, thereby extending its applicability to a broader range of scenarios. Furthermore, the NUWPSM showcases enhanced robustness by eliminating human intervention in the singularity quantity and distribution.

Assessing the Validity of a Wearable Shoulder Motion Tracking System Through Comparison with Dartfish in Patients Undergoing Shoulder Joint Replacement Surgery.

Objective assessments of shoulder motion are paramount for effective rehabilitation and evaluation of surgical outcomes. Inertial Measurement Units (IMU) have demonstrated promise in providing unbiased movement data. This study is dedicated to evaluating the concurrent construct validity and accuracy of a wearable IMU-based sensor system, called "Motion Shirt", for the assessment of shoulder motion arcs in patients awaiting shoulder replacement surgery. This evaluation was conducted by comparing Motion Shirt data with the Dartfish Motion Analyzer software during the Functional Impairment Test-Hand and Neck/Shoulder/Arm (FIT-HaNSA) test.&#xD;Thirteen patients (age>50), who were awaiting shoulder replacement surgery, were recruited. The Motion Shirt was employed to measure angular shoulder movements in two planes during the FIT-HaNSA test. Simultaneously, two cameras recorded the participants' movements to provide reference data. Bland-Altman plots were generated to visualize agreement between the Motion Shirt and the reference data obtained from the Dartfish Motion Analyzer software. &#xD;The data analysis on Bland-Altman plots revealed a substantial level of agreement between the Motion Shirt and Dartfish analysis in measuring shoulder motion. In Task-1, no significant systematic errors were exhibited, with only 3.27% and 2.18% of points exceeding the limits of agreement (LOA) in both elevation and the Plane of Elevation (POE), signifying a high level of concordance. In Task-2, a high level of agreement was also observed in Elevation, with only 3.8% of points exceeding the LOA. However, 5.98% of points exceeded LOA in POE for Task-2. In Task-3, focused on sustained overhead activity, the Motion Shirt showed strong agreement with Dartfish in Elevation (2.44% points exceeded LOA), but in POE, 7.32% points exceeded LOA.&#xD;The Motion Shirt demonstrated a robust concordance with Dartfish Motion Analyzer system in assessing shoulder motion during the FIT-HaNSA test. These results affirm the Motion Shirt's suitability for objective motion analysis in patients awaiting shoulder replacement surgery.&#xD.

Encoding quantum bits in bound electronic states of a graphene nanotorus

We propose to use the quantum states of an electron trapped on the inner surface of a graphene nanotorus to realize as a new kind of physical quantum bit, which can be used to encode quantum information. Fundamental tasks for quantum information processing, such as the qubit initialization and the implementation of arbitrary single qubit gates, can then be performed using external magnetic and electric fields. We also analyze the robustness of the device again systematic errors, which can be suppressed by a suitable choice of the external control fields. These findings open new prospects for the development an alternative platform for quantum computing, the scalability of which remains to be determined.

An adaptive continuous threshold wavelet denoising method for LiDAR echo signal

Atmospheric aerosols are the primary contributors to environmental pollution. As such aerosols are micro-to nanosized particles invisible to the naked eye, it is necessary to utilize LiDAR technology for their detection. The laser radar echo signal is vulnerable to background light and electronic thermal noise. While single-photon LiDAR can effectively reduce background light interference, electronic thermal noise remains a significant challenge, especially at long distances and in environments with a low signal-to-noise ratio (SNR). However, conventional denoising methods cannot achieve satisfactory results in this case. In this paper, a novel adaptive continuous threshold wavelet denoising algorithm is proposed to filter out the noise. The algorithm features an adaptive threshold and a continuous threshold function. The adaptive threshold is dynamically adjusted according to the wavelet decomposition level, and the continuous threshold function ensures continuity with lower constant error, thus optimizing the denoising process. Simulation results show that the proposed algorithm has excellent performance in improving SNR and reducing root mean square error (RMSE) compared with other algorithms. Experimental results show that denoising of an actual LiDAR echo signal results in a 4.37 dB improvement in SNR and a 39.5% reduction in RMSE. The proposed method significantly enhances the ability of single-photon LiDAR to detect weak signals.

Forward-Scattering and Multiple-Scattering Sources of Errors in UV-Visible Spectroscopy of Microspheres.

Conventional UV-visible spectroscopy instruments measure the extinction spectrum of solutions in a transmission configuration. Because of the finite (nonzero) acceptance angle in detection, errors due to forward scattering and multiple scattering can be introduced when measuring scattering samples. We here experimentally quantify these errors using polystyrene spheres of different sizes for two representative analytical/research UV-visible instruments, one based on a single-beam diode array and the other on a double-beam scanning configuration. The measured spectra for particles larger than 1 μm are shown to differ between the two instruments, even at low concentrations, and also vary with concentration (in contradiction with the Beer-Lambert law). We show that systematic errors in the range of 10-40% are common in such measurements. We propose a model accounting for both forward- and multiple-scattering errors and demonstrate its agreement with our experimental results. This model could reduce systematic errors in measurements of scattering samples by up to 40%.

Analysis of the Impact of High Temporal Resolution Tropospheric Parameters on GNSS Station Coordinate and Troposphere Estimation

Abstract Troposphere modeling accuracy can seriously influence the performances of precise Global Navigation Satellite System (GNSS) positioning. The temporal interpolation accuracies of troposphere parameters become important with the improvement in troposphere modeling, especially during the periods of severe weather changes. In this study, a one-month experiment was conducted for 10 EUREF Permanent GNSS Network (EPN) stations to analyze the temporal interpolation errors of numerical weather model (NWM) derived troposphere parameters and their influences on GNSS station coordinate and troposphere estimation. The root mean square (RMS) of the differences between the 1- and 6-hourly European Centre for Medium-Range Weather Forecasts (ECMWF) Reanalysis v5 (ERA5)-derived troposphere parameters are 0.72/11.52 mm for the zenith hydrostatic/wet delay (ZHD/ZWD), while are 7.09/91.84 mm for the slant hydrostatic/wet delay (SHD/SWD) at a 3^° elevation angle. The corresponding influences on the estimated up component and ZWD are 1.28 and 0.79 mm, respectively, in the daily static Precise Point Positioning (PPP) ambiguity resolution (AR) solutions. However, the accuracy improvements are insignificant in the daily static solutions, mainly due to the drop of temporal interpolation errors with increasing elevation angles and the influences of other unmodeled systematic errors. In the 4-hourly static solutions, the accuracies of the up component improve 0.51 mm (5.9% in relative) and 0.29 mm (3.5% in relative) during the severe and stable period, respectively. The impacts cannot be ignored in some GNSS subdaily applications, for example, monitoring non-tidal ocean loading effect, bedrock and monument thermal elastic effect, etc.

Calculated ionization energies, orbital eigenvalues (HOMO), and related QSAR descriptors of organic molecules: a set of 61 experimental values enables elimination of systematic errors and provides realistic error estimates.

Ionization energies (IEs) of organic compounds come in different forms-adiabatic, vertical, as electrode potentials, or as orbital eigenvalues via Koopmans' theorem. They have been linked to the reactivity towards electrophiles and have been used to quantitatively describe electron transfer processes. The de novo prediction of IEs is only meaningful when an estimate of the prediction's uncertainty is included. Pulsed-field ionization (PFI) experiments have quantified adiabatic IEs with unprecedented precision. In this work, a new set of PFI-derived IEs is compiled from the literature as a benchmark for prediction methods. This set includes many common functional groups, a size range from diatomics to two aromatic rings, and IEs between 7 and 14 eV. The first-principles CCSD(T)/CBS protocol presently used reproduces these values within 0.05 eV. For adiabatic IEs and vertical IEs/orbital eigenvalues predicted using approximate density functional theory (DFT), linear regression models are proposed, so that IEs calculated using different methods can be directly compared on a physical scale. This elimination of systematic errors improves the error statistics and allows the performance of predicted IEs to be evaluated if used in quantitative structure-property or -activity relationships, as the latter implicitly correct a descriptor's bias. Owing to the structural scope of the test set, the minimum and maximum deviations from experiment should correspond to those expected for common organic molecules. Deviations from reference values found for orbital eigenvalues but also for IEs calculated explicitly with HF or semi-empirical MO methods were as large as 0.5 eV to 2.0 eV. Such large errors could also propagate into quantitative structure-property models, as shown in illustrative examples of oxidation rate constants in solution.

Comparison of Implant Precision with Robots, Navigation, or Static Guides

Comparison of Implant Precision with Robots, Navigation, or Static Guides

Assessment of Setup-errors in 3Dd-Conformal Radiotherapy for Head and Neck Cancer Patients Using an Electronic Portal Imaging Device

Patient setup is crucial in radiotherapy since treatment is delivered as fractionated treatment over a period of time. Using own institutional margins by considering the setup errors will provide better radiotherapy outcome. Therefore, this study aims to assess set up errors for head and neck cancer patients using an electronic portal imaging device at Apeksha Hospital, Maharagama, Sri Lanka. A total of 101 head and neck cancer patients who were immobilized with thermoplastic mask were selected in this study. Stored data from July 2021 to July 2022 were obtained from ARIA patient management system in the Varian 2300CD Unit at Apeksha Hospital. In order to calculate systematic and random errors, translational errors in all directions were collected utilizing 303 pairs of orthogonal portal images. Moreover, three different algorithms were used to obtain the margin of clinical target volume (CTV) to planning target volume (PTV). The estimated systematic and random errors in the directions of antero-posterior, superior-inferior and medio-lateral are 0.13 cm, 0.10 cm and 0.08 cm, and 0.22 cm, 0.21 cm, and 0.19 cm respectively. Less than 0.5 cm margin were obtained by applying three different algorithms. This study indicates that using a 0.5 cm margin for head and neck cancer patients treating in 2300CD Varian Unit at Apeksha Hospital is safe. Further, this study recommends to developing institutional CTV to PTV margin for all sites of cancer to reduce unnecessary radiation to the surrounding normal healthy tissues.

Dual virtual non-contrast imaging: a Bayesian quantitative approach to determine radiotherapy quantities from contrast-enhanced DECT images.

Contrast agents in CT scans can compromise the accuracy of dose calculations in radiation therapy planning, especially for particle therapy. This often requires an additional non-contrast CT scan, increasing radiation exposure and introducing potential registration errors. Our goal is to resolve these issues by accurately estimating radiotherapy parameters from dual virtual non-contrast (dual-VNC) images generated by contrast-enhanced dual-energy CT (DECT) scans, while accounting for noise and variability in tissue composition.&#xD;Approach: A new Bayesian model is introduced to estimate dual-VNC Hounsfield units from contrast-enhanced DECT data. The model defines a prior distribution that describes tissue variations in terms of elemental compositions and mass densities. Multiple reference tissues are used to estimate variations across human tissues. A likelihood distribution is also defined to model the noise contained in CT data. The model is thoroughly validated in a simulated environment including 12 virtual patients under low and high iodine uptake scenarios, while incorporating noise and beam hardening effects. The eigentissue decomposition (ETD) technique is used to derive elemental compositions and parameters critical for radiotherapy from the dual-VNC images, such as electron density (ρe), particle stopping power (SPR), and photon energy absorption coefficient (EAC)&#xD;Main results: The proposed method yields accurate voxelwise estimations for ρe, SPR, and EAC, with root mean square errors of 3.09%, 3.14%, and 1.34% for highly-enhanced tissues, compared to 5.93%, 6.39%, and 17.11% when the presence of contrast agent is ignored. It also demonstrates robustness to systematic shifts in tissue composition and bandwidth variations in the prior distribution, resulting in overall uncertainties down to 1.13%, 1.33%, and 0.86% for ρe, SPR, and EAC in soft tissues; 1.17%, 1.32%, and 1.34% in enhanced soft tissues; and 4.34%, 4.00%, and 2.50% in bone.&#xD;Significance: The proposed method accurately derives radiotherapy parameters from contrast-enhanced DECT data and demonstrates robustness against systematic errors in reference data, highlighting its potential for clinical use.

Characterizing coherent errors using matrix-element amplification

Repeating a gate sequence multiple times amplifies systematic errors coherently, making it a useful tool for characterizing quantum gates. However, the precision of such an approach is limited by low-frequency noise, while its efficiency is hindered by time-consuming scans required to match up the phases of the off-diagonal matrix elements being amplified. Here, we overcome both challenges by interleaving the gate of interest with dynamical decoupling sequences in a protocol we call Matrix-Element Amplification using Dynamical Decoupling (MEADD). Using frequency-tunable superconducting qubits from a Google Sycamore quantum processor, we experimentally demonstrate that MEADD surpasses the accuracy and precision of existing characterization protocols for estimating systematic errors in single- and two-qubit gates. We use MEADD to estimate coherent parameters of CZ gates with 5 to 10 times the precision of existing methods and to characterize previously undetectable coherent crosstalk, reaching a precision below one milliradian.

METHODOLOGY FOR THE APPLICATION OF THE DIGITAL IMAGE CORRELATION (DIC) FOR INVESTIGATING RC BEAMS

The article discusses the improvement of the digital image correlation (DIC) method for analyzing deformations in RC beams, specifically focusing on the importance of zero-strain verification. This step is critical for ensuring high measurement accuracy, as it helps identify and minimize systematic and random errors. Before starting the research, system calibration is conducted, which includes the assessment of background noise and stability that influence the results. The study shows that proper sample preparation, pattern creation, and control of external factors allow for obtaining reliable data. The application of DIC enables remote monitoring of cracks and evaluation of the stress-strain state of structures. It has been established that this method is useful not only for scientific experiments but also in practical engineering, contributing to the increased reliability of structures.