Efficient Correction Method Research Articles

A model-based and efficient parameters correction method for low-cost MEMS IMU

A model-based and efficient parameters correction method for low-cost MEMS IMU

Efficient infrared nonuniform correction method considering optical attenuator and integration time

With the increasing number of optical attenuators and integration times in infrared imaging systems, this paper proposes an efficient nonuniform correction method that addresses drawbacks of complex operations and coefficient storage with traditional two-point nonuniform correction methods. First, the efficient nonuniform correction model was derived through the response model of the infrared imaging system with variable attenuators and integration times, which can achieve nonuniform correction of all attenuators and integration times using a correction equation. Based on the model, the efficient nonuniformity correction algorithm using a small number blackbody images was proposed. Finally, the experimental results show that the method has excellent nonuniformity correction performance. Compared with the two-point correction method, the maximum nonuniformity is reduced from 3.7% for the two-point method to 2.2% for the proposed method. In the meantime, the proposed method can greatly reduce the correction time and the number of blackbody temperature sampling points. Moreover, for the infrared imaging system with five integral times and three attenuators in this paper, the two-point method requires 30 correction coefficients, while the proposed method only requires eight correction coefficients. It reduces the required correction coefficients by about three times, achieving efficient and fast nonuniform correction.

58‐1: A Novel On‐line, Fast Color Correction by Machine Learnings

A new efficient color correction method, utilizing neural network models, is proposed by this study for OLED panels in production, offering a transformative approach to achieve accurate and rapid color calibration. Utilizing transfer learning with a limited dataset, it creates color conversion matrices for AI‐driven color correction. The process involves selecting a similar baseline model from prior batches with a ΔE00 below 1, then refining it using a representative dataset. This model corrects white point and overall color, achieving a ΔE00 less than 2. It corrects 300 data points in less than 4 seconds, demonstrating both speed and accuracy.

Nonlinear high-order harmonics correction for phase measuring profilometry

Gamma nonlinearity severely affects the accuracy of phase measuring profilometry (PMP). Through averaging two phase maps with inverse errors, conventional methods including double phase-shifting (DPS) and Hilbert transform (HT) only compensate the fundamental harmonic while leaving high-order harmonics. To address this issue, this paper presents an efficient high-order harmonics correction (HHC) method. The averaged phase is encoded into factitious fringes on the computer. Then we directly apply HT on these factitious fringes to generate transformed fringes, while the addition of the ideal phase and residual harmonics is converted to multiplication. Finally, the residual high-order harmonics are suppressed, and the corrected phase is calculated using the phase-shifting algorithm. In comparison to conventional DPS and HT methods, the proposed HHC method can efficiently correct the residual high-order harmonics, thereby enhancing the measuring accuracy.

An efficient method for transcranial ultrasound focus correction based on the coupling of boundary integrals and finite elements

Transcranial focused ultrasound is a novel technique for the noninvasive treatment of brain diseases. The success of the treatment greatly depends on achieving precise and efficient intraoperative focus. However, compensating for aberrated ultrasound waves caused by the skull through numerical simulation-based phase corrections is a challenging task due to the significant computational burden involved in solving the acoustic wave equation. In this article, we propose a promising strategy using the coupling of the boundary integral equation method (BIEM) and the finite element method (FEM) to overcome the above limitation. Specifically, we adopt the BIEM to obtain the Robin-to-Dirichlet maps on the boundaries of the skull and then couple the maps to the FEM matrices via a dual interpolation technique, resulting in a computational domain including only the skull. Three simulation experiments were conducted to evaluate the effectiveness of the proposed method, including a convergence test and two skull-induced aberration corrections in 2D and 3D ultrasound. The results show that the method’s convergence is guaranteed as the element size decreases, leading to a decrease in pressure error. The computation times for simulating a 500 kHz ultrasound field on a regular desktop computer were found to be 0.47 ± 0.01 s in the 2D case and 43.72 ± 1.49 s in the 3D case, provided that lower–upper decomposition (approximately 13 s in 2D and 2.5 h in 3D) was implemented in advance. We also demonstrated that more accurate transcranial focusing can be achieved by phase correction compared to the noncorrected results (with errors of 1.02 mm vs. 6.45 mm in 2D and 0.28 mm vs. 3.07 mm in 3D). The proposed strategy is valuable for enabling online ultrasound simulations during treatment, facilitating real-time adjustments and interventions.

An efficient correction method in Riemann SPH for the simulation of general free surface flows

In this paper, a new efficient weighted correction method for weakly-compressible smoothed particle hydrodynamics is proposed and successfully implemented in the simulation of violent free-surface flow exhibiting breaking and impact events for the first time. It is well known that the original kernel gradient correction (KGC) encounters numerical instability resulting from matrix inversion. The present method remedies this issue by introducing a weighted average of the KGC matrix and the identity matrix, other than directly applying the KGC matrix, to achieve numerical stability meanwhile decrease numerical dissipation. To ensure momentum conservation, the correction is implemented in a particle-average pattern by rewriting the pressure term of the Riemann solution. Furthermore, the proposed weighted KGC scheme is incorporated into the dual-criteria time-stepping framework developed by Zhang et al. (2020) to achieve optimized computational efficiency. A set of numerical examples in both two- and three-dimensions are investigated to demonstrate that the present method can significantly reduce numerical dissipation meanwhile exhibit a smooth pressure field for general free-surface flows.

Generic and Model-Based Calibration Method for Spatial Frequency Domain Imaging with Parameterized Frequency and Intensity Correction.

Spatial frequency domain imaging (SFDI) is well established in biology and medicine for non-contact, wide-field imaging of optical properties and 3D topography. Especially for turbid media with displaced, tilted or irregularly shaped surfaces, the reliable quantitative measurement of diffuse reflectance requires efficient calibration and correction methods. In this work, we present the implementation of a generic and hardware independent calibration routine for SFDI setups based on the so-called pinhole camera model for both projection and detection. Using a two-step geometric and intensity calibration, we obtain an imaging model that efficiently and accurately determines 3D topography and diffuse reflectance for subsequently measured samples, taking into account their relative distance and orientation to the camera and projector, as well as the distortions of the optical system. Derived correction procedures for position- and orientation-dependent changes in spatial frequency and intensity allow the determination of the effective scattering coefficient μs' and the absorption coefficient μa when measuring a spherical optical phantom at three different measurement positions and at nine wavelengths with an average error of 5% and 12%, respectively. Model-based calibration allows the characterization of the imaging properties of the entire SFDI system without prior knowledge, enabling the future development of a digital twin for synthetic data generation or more robust evaluation methods.

An Efficient Bias Correction Method for Large Planar Polarimetric Phased Array Radar

For a large planar polarimetric phased array radar, a bias correction matrix obtained from array pattern measurements needs to be applied when the beam is pointed off broadside. To avoid measuring all possible beam directions while ensuring the correction accuracy, an efficient bias correction method using polynomial surface fitting is proposed. After dividing the entire scan area into several subregions, merely dozens of beam directions are measured in each subregion. Through the polynomial surface model, the correction matrices of unmeasured beam directions can be well predicted. The simulated results show that the proposed method can effectively achieve accurate bias correction in two-dimension <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm 45^{\circ }$</tex-math></inline-formula> scanning. Under the same relative error level for antenna pattern measurement, the results of Monte Carlo simulations verify that the proposed method has a more stable performance than directly beam-by-beam measurement due to its least square process.

An improved system for long-term monitoring of full-bridge traffic load distribution on long-span bridges

Vision-based traffic load monitoring has attracted considerable attention in recent years due to its promise to enable continuous identification of full-bridge traffic load (FBTL). However, previous FBTL monitoring approaches have limits in small object detection and occluded object tracking, and have never been implemented in the whole range of long-span bridges. This paper proposes a long-term oriented FBTL monitoring system by introducing three improvements in vehicle detection, tracking and position correction to the existing framework that is based on the information fusion of weigh-in-motion (WIM) systems and multiple cameras. In the new system, vehicle detection is achieved by a YOLO-v4-based model, while vehicle tracking is realised by a dual-metric strategy combining vehicle motion and its appearance features. In addition, an efficient correction method for transverse vehicle position is derived from projective geometry, enabling the system to process a large number of vehicles at the same time. As the first complete implementation of FBTL monitoring on long-span bridges, the proposed system has been applied and verified on a cable-stayed bridge. The results suggest the proposed system is expected to provide long-term FBTL distribution, accompanied by faster calculation speed, higher small object detection accuracy, and better capacity to cope with the occlusion problem.

Acute Correction of Femoral Malrotation After Intramedullary Nailing Using an Intraoperative Digital Protractor.

The goal of the study is to diagnose and accurately correct malrotation of femur fractures after intramedullary (IM) nailing. An institutional review board (IRB) approved prospective study that was performed at a U.S. level 1 trauma center. After IMnailingof comminuted femur fractures, a computed tomography (CT) scanogram was routinely performed to detect the difference in the postoperative femoral version.Patients with malalignment greater than 15 degrees compared to the contralateral side were informed about the discrepancy and offered to have it acutely corrected.A four-pin technique was used: two Schanz pins were used for measuring angles and two different pins were used to turn and correct the malalignment.The pin in the distal fragment is placed directly under the nail to prevent shortening in comminuted fractures.The nail was unlocked either proximally for retrograde nails or distally for antegrade nails. The Bonesetter Angle application was used as a digital protractor to intraoperatively measure the two reference pins and correct the malrotation.Alternate holes were used for relocking the nail. All patients received a CT scanogram after correction. 19/128 patients with comminuted femoral fractures over five years with malrotations between 18 and 47 degrees were included in the study with anaverage malrotation of24.7 + 8 degrees.All patients were corrected to an average of 4.0 +/- 2.1 degrees difference, as compared to the contralateral side (range 0-8).No patients required further surgeries to correct malrotation. Comminuted fractures with malrotation >15 degrees after femoral nailing have an incidence of 15% at our institution.This technique provides an efficient and accurate correction method with the use of an intraoperative digital protractor, avoiding the need for revision IM nailing or osteotomies.

Measurement Accuracy Analysis of Distributed Fiber Optic Sensors for Asphalt Mixture Based on the DEM-FDM Coupled Method

Distributed fiber optic sensors (DFOSs) have been effectively used for pavement health monitoring. However, the inhomogeneity of the asphalt mixture and the characteristics of the sensor affect the measurement accuracy, which in turn affects the performance evaluation of asphalt pavement. In this study, the strain of nonembedded DFOS specimens was used as a reference and compared with the strain of embedded DFOS specimens to analyze the accuracy of DFOS based on the four-point bending test. To further improve accuracy, a numerical simulation model was established by coupling the discrete element method (DEM) and the finite difference method (FDM), and feasibility of the model was verified by comparing it with the load-displacement curves obtained from laboratory tests. The results of the laboratory tests and numerical simulations showed a linear relationship between the reference strain and the DFOS strain. Therefore, a strain correction method was proposed for the DFOS based on the DEM-FDM method, and the strain correction coefficient was used as the evaluation index. In addition, an orthogonal test was performed to analyze the influence of design parameters, including elastic modulus, section height, and section width, on the accuracy of the DFOS. Through variance and range analysis, it was found that elastic modulus has a significant effect on the strain measurement accuracy, followed by the section height and the section width. In summary, this study proposed an efficient strain correction method suitable for the application of DFOS in pavements considering the material characteristics of the asphalt mixture and the embedded sensor.

Efficient Method for Error Detection and Correction in In‐Memory Computing Based on Reliable Ex‐Logic Gates

In‐memory computing using memristor‐based stateful logic reveals high efficiency in the computing paradigm where the memory and computation are colocated. Still, variations in the memristor induce reliability issues for practical applications. Previous error detection and correction modules in the inmemory logic gates can handle the errors but only account for nonswitching errors of the output memristor, while the highly probable switching error of the output memristor is neglected, reducing overall efficiency. Moreover, the module operations use other added stateful logic gates, which may add errors. Herein, modules to handle both nonswitching and switching error cases within the three average steps using reliable logic gates consisting of five memristors are proposed. Detecting both error cases allows logic gates to be still operated in the optimized region for high‐energy efficiency and stability. In addition, combining two different logic families of stateful and sequential logic gates provides the reliability of the stateful logic gates and a possible solution to the peripheral complexity of cascading sequential logic gates. Although detection and correction are demonstrated in NOR and NAND logic gates with the memristor model, the other logic gates can be applied with the same algorithm with the appropriate module‐enable signal and input‐checker bits.

Practical Saccade Prediction for Head-Mounted Displays: Towards a Comprehensive Model

Eye-tracking technology has started to become an integral component of new display devices such as virtual and augmented reality headsets. Applications of gaze information range from new interaction techniques that exploit eye patterns to gaze-contingent digital content creation. However, system latency is still a significant issue in many of these applications because it breaks the synchronization between the current and measured gaze positions. Consequently, it may lead to unwanted visual artifacts and degradation of the user experience. In this work, we focus on foveated rendering applications where the quality of an image is reduced towards the periphery for computational savings. In foveated rendering, the presence of system latency leads to delayed updates to the rendered frame, making the quality degradation visible to the user. To address this issue and to combat system latency, recent work proposes using saccade landing position prediction to extrapolate gaze information from delayed eye tracking samples. Although the benefits of such a strategy have already been demonstrated, the solutions range from simple and efficient ones, which make several assumptions about the saccadic eye movements, to more complex and costly ones, which use machine learning techniques. However, it is unclear to what extent the prediction can benefit from accounting for additional factors and how more complex predictions can be performed efficiently to respect the latency requirements. This paper presents a series of experiments investigating the importance of different factors for saccades prediction in common virtual and augmented reality applications. In particular, we investigate the effects of saccade orientation in 3D space and smooth pursuit eye-motion (SPEM) and how their influence compares to the variability across users. We also present a simple, yet efficient post-hoc correction method that adapts existing saccade prediction methods to handle these factors without performing extensive data collection. Furthermore, our investigation and the correction technique may also help future developments of machine-learning-based techniques by limiting the required amount of training data.

Improved high-resolution EBSD analyses by correcting radial distortion of electron diffraction patterns

• An integrated DIC method is proposed to measure the radial optical distortion of electron diffraction cameras. • The method has a comparable accuracy with previous studies using chessboard samples. • Various high-resolution EBSD analyses benefit from the radial distortion corrections. Registering experimental and simulated electron diffraction patterns is increasingly used for advanced electron backscatter diffraction indexation (EBSD) analysis, yet the accuracy of registration is limited by several effects not accounted for in pattern simulation, such as the Kikuchi band (K-band) asymmetry, gray level reversal and (mainly radial) optical distortion. Radial distortion parameters have previously been measured with chessboard-type standard samples. Simulated patterns have been adopted to demonstrate the necessity of optical distortion removal in EBSD analyses. However there still lacks an efficient and precise radial distortion assessment and correction method. Here a simple radial distortion model, including barrel and pincushion distortions, is proposed to rectify the diffraction patterns during EBSD analyses. The correlation between experimental pattern and the simulated master pattern permits to index the diffraction pattern and assess the radial distortion simultaneously. The method is applied to three high-definition experimental electron diffraction datasets acquired with different cameras. The radial distortion parameter is identified with a relative uncertainty below 4%. The consideration of radial distortion improves the correlation between experimental and simulated patterns. Gray level profiles of the K-bands are analyzed to verify the correctness of image registration. The current method provides a fast, economic yet precise correction of the radial distortion for advanced EBSD analyses.

Economic-environmental dispatch for the integrated energy system considering off-design conditions

The integrated energy system (IES) is recognized as a promising energy utilization approach enabled to both improve the energy efficiency and reduce pollutant emissions. Although the economic-environmental dispatch (EED) problem of the IES has been widely studied, the fact that the IES is operated under off-design conditions, having a significant influence on the efficiency of energy devices, is neglected usually, resulting in the scheduled operations, for the IES could not be accurate enough in many actual situations. This study investigates the EED problem of the IES under off-design conditions. Technically, by integrating an efficiency correction process into the traditional energy hub (EH) model, a dynamic energy hub (DEH) model is first formulated for adapting itself to variable energy conversion efficiencies. Then, a deep neural network (DNN)-based efficiency correction method is proposed to predict and correct the time-varying efficiency of energy devices based on three main off-design conditions including the load rate, air temperature, and pressure. A multi-objective EED model is finally formulated for the IES, with the framework of the DEH model, aiming at establishing a trade-off between operational cost and emitted pollutants. Case studies show that the proposed approach helps in enhancing the accuracy of IES dispatch while having a good performance in both the operational cost and pollutant emission reduction.

Generic saturation-induced phase error correction for structured light 3D shape measurement.

Intensity saturation is a challenging problem in structured light 3D shape measurement. Most of the existing methods achieve high dynamic range (HDR) measurement by sacrificing measurement speed, making them limited in high-speed dynamic applications. This Letter proposes a generic efficient saturation-induced phase error correction method for HDR measurement without increasing any fringe patterns. We first theoretically analyze the saturated signal model and deduce the periodic characteristic of saturation-induced phase error. Based on this, we specially design a saturation-induced phase error correction method by joint Fourier analysis and Hilbert transform. Furthermore, the relationship among phase error, saturation degree, and number of phase-shifting steps is established by numerical simulation. Since the proposed method requires no extra captured images or complicated intensity calibration, it is extremely convenient in implementation and is applicable to performing high-speed 3D shape measurements. Simulations and experiments verify the feasibility of the proposed method.

A simple stress correction method for explicit integration algorithm of elastoplastic constitutive models and its application to advanced anisotropic S-CLAY1 model

The stress correction, which prevents stresses drifting from the yield surface, is a key step in the explicit scheme for integrating elastoplastic constitutive models in finite element analyses. In this paper, a simple, robust, and efficient stress correction method is proposed for improving the well-established explicit modified Euler scheme of Sloan et al. (2001). The method subtly proposes a single correction coefficient assuming that the stress components are proportional to the corrected stress components on the yield surface. The expression of the correction coefficient can be explicitly determined with the current stress state and the yield function, which allows the correction procedure to be easily and conveniently accomplished through multiplying the stress components by a single coefficient without resorting to the Newton iteration algorithm. The proposed method is applied to develop a user defined material (UMAT) subroutine for the advanced anisotropic elastoplastic model S-CLAY1 (Wheeler et al. 2003), which is subsequently used to simulate triaxial tests, the collapse of a rigid smooth square footing and a natural ground under embankment loading. The comparisons with other stress correction methods, the exact results from MATLAB, and the field measured values demonstrate the stability, robust, efficiency and validity of the proposed method.

An improved numerical method for variational image registration model with intensity correction

In this paper, we propose an efficient numerical method for registration and intensity correction of images. We first introduced a variational image registration model in our previous work. The variational minimization of the functional in the model is solved by using an alternating minimization method. In this work, we improve the numerical solution of the minimization problem by applying the Split Bregman method together with the alternating minimization method. As expected, our numerical experiments show that the proposed method converges rapidly and is significantly more accurate than the method used in our previous work.

Effect of non-uniform efficiency on higher-order cumulants in heavy-ion collisions * *Supported by National Key Research and Development Program of China (2018YFE0205200, 2018YFE0104700, 2020YFE0202002), Natural Science Foundation of China (11890711, 11890712, 12122505, 11828501, 11861131009), Anhui Provincial Natural Science Foundation (1808085J02) and Innovation Fund of Key Laboratory of Quark and Lepton Physics (QLPL2020P01)

We perform a systematic study on the effect of non-uniform track efficiency correction in higher-order cumulant analysis in heavy-ion collisions. Through analytical derivation, we find that the true values of cumulants can be successfully reproduced by the efficiency correction with an average of the realistic detector efficiency for particles with the same charges within each single phase space. The theoretical conclusions are supported by a toy model simulation by tuning the non-uniformity of the efficiency employed in the track-by-track efficiency correction method. The valid averaged efficiency is found to suppress the statistical uncertainties of the reproduced cumulants dramatically. Thus, usage of the averaged efficiency requires a careful study of phase space dependence. This study is important for carrying out precision measurements of higher-order cumulants in heavy-ion collision experiments at present and in future.

A Simple and Efficient Method for Correction of Basin-Scale Evapotranspiration on the Tibetan Plateau

Evapotranspiration (ET) is one of the important components of the global hydrologic cycle, energy exchange, and carbon cycle. However, basin scale actual ET (hereafter ETa) is difficult to estimate accurately. We present an evaluation of four actual ET products (hereafter ETp) in seven sub-basins in the Tibetan Plateau. The actual ET calculated by the water balance method (hereafter ETref) was used as the reference for correction of the different ETp. The ETref and ETp show obvious seasonal cycles, but the ETp overestimated or underestimated the ET of the sub-basins in the Tibetan Plateau. A simple and effective method was proposed to correct the basin-scale ETp. The method was referred to as ratio bias correction, and it can effectively remove nearly all biases of the ETp. The proposed method is simpler and more effective in correcting the four ETp compared with the gamma distribution bias correction method. The reliability of the ETp is significantly increased after the ratio bias correction. The ratio bias correction method was used to correct the ETp in the seven sub-basins in the Tibetan Plateau, and regional ET was significantly improved. The results may help improve estimation of the ET of the Tibetan Plateau and thereby contribute to a better understanding of the hydrologic cycle of the plateau.