Journal articles: 'Calibration robustness'

1

Wortel, V. A. L., W. G. Hansen, and S. C. C. Wiedemann. "Optimising Multivariate Calibration by Robustness Criteria." Journal of Near Infrared Spectroscopy 9, no. 2 (March 2001): 141–51. http://dx.doi.org/10.1255/jnirs.301.

Full text

Abstract:

Regular maintenance of (multivariate) near infrared (NIR) calibration models is a crucial but time-consuming step to ensure a successful NIR application in industry. Naturally, robustness of these models is essential to minimise both maintenance time and cost. In this paper, a method combining Taguchi philosophy, experimental design and artificially-derived spectra, is proposed to evaluate and improve the robustness of NIR calibrations. This approach is based upon a typical industrial NIR application, the determination of hydroxyl value of ester products. Experiments have been designed to investigate which parameters (control and signal) influence the performance of the calibration. Two calibration models have been selected for the robustness investigation. One benchmark model was based on general criteria applied for NIR calibration and another based on Taguchi's criteria. Artificially-derived spectra were produced by adding severe fluctuations of simulated wavelength shifts into original spectra for both models, then, the models' performance was evaluated six months after the calibration. The model selected based on Taguchi's criteria, is clearly more tolerant to wavelength shifts and less sensitive for overfitting in comparison with the “benchmark” model.

APA, Harvard, Vancouver, ISO, and other styles

2

Guthrie, John, Brett Wedding, and Kerry Walsh. "Robustness of NIR Calibrations for Soluble Solids in Intact Melon and Pineapple." Journal of Near Infrared Spectroscopy 6, no. 1 (January 1998): 259–65. http://dx.doi.org/10.1255/jnirs.145.

Full text

Abstract:

The soluble solids content of intact fruit can be measured non-invasively by near infrared spectroscopy, allowing “sweetness” grading of individual fruit. However, little information is available in the literature with respect to the robustness of such calibrations. We developed calibrations based on a restricted wavelength range (700–1100 nm), suitable for use with low-cost silicon detector systems, using a stepwise multiple linear regression routine. Calibrations for total soluble solids (°Brix) in intact pineapple fruit were not transferable between summer and winter growing seasons. A combined calibration (data of three harvest dates) validated reasonably well against a population set drawn from all harvest dates ( r2 = 0.72, SEP = 1.84 °Brix). Calibrations for Brix in melon were transferable between two of the three varieties examined. However, a lack of robustness of calibration was indicated by poor validation within populations of fruit harvested at different times. Further work is planned to investigate the robustness of calibration across varieties, growing districts and seasons.

APA, Harvard, Vancouver, ISO, and other styles

3

Xia, Dan, De Hua Li, and Sheng Yong Xu. "Efficient and Accurate Camera Calibration Based on Planar Pattern." Advanced Materials Research 204-210 (February 2011): 1258–61. http://dx.doi.org/10.4028/www.scientific.net/amr.204-210.1258.

Full text

Abstract:

We describe an effective method for calibrating cameras by using planar calibration patterns. The calibration pattern control points are localized by Harris detector incorporating the gradient histogram. The accuracy of the calibration control points location consequently improves the accuracy of the camera calibration. Additionally, optimization computation is carried out for increasing the accuracy of camera calibration results. Experiments using real images verified the effectiveness and robustness of the proposed method.

APA, Harvard, Vancouver, ISO, and other styles

4

Stevens, Garrison, Kendra Van Buren, Elizabeth Wheeler, and Sez Atamturktur. "Evaluating the fidelity and robustness of calibrated numerical model predictions." Engineering Computations 32, no. 3 (May 5, 2015): 621–42. http://dx.doi.org/10.1108/ec-09-2013-0217.

Full text

Abstract:

Purpose – Numerical models are being increasingly relied upon to evaluate wind turbine performance by simulating phenomena that are infeasible to measure experimentally. These numerical models, however, require a large number of input parameters that often need to be calibrated against available experiments. Owing to the unavoidable scarcity of experiments and inherent uncertainties in measurements, this calibration process may yield non-unique solutions, i.e. multiple sets of parameters may reproduce the available experiments with similar fidelity. The purpose of this paper is to study the trade-off between fidelity to measurements and the robustness of this fidelity to uncertainty in calibrated input parameters. Design/methodology/approach – Here, fidelity is defined as the ability of the model to reproduce measurements and robustness is defined as the allowable variation in the input parameters with which the model maintains a predefined level of threshold fidelity. These two vital attributes of model predictiveness are evaluated in the development of a simplified finite element beam model of the CX-100 wind turbine blade. Findings – Findings of this study show that calibrating the input parameters of a numerical model with the sole objective of improving fidelity to available measurements degrades the robustness of model predictions at both tested and untested settings. A more optimal model may be obtained by calibration methods considering both fidelity and robustness. Multi-criteria Decision Making further confirms the conclusion that the optimal model performance is achieved by maintaining a balance between fidelity and robustness during calibration. Originality/value – Current methods for model calibration focus solely on fidelity while the authors focus on the trade-off between fidelity and robustness.

APA, Harvard, Vancouver, ISO, and other styles

5

Melfsen, Andreas, Eberhard Hartung, and Angelika Haeussermann. "Robustness of near-infrared calibration models for the prediction of milk constituents during the milking process." Journal of Dairy Research 80, no. 1 (November 27, 2012): 103–12. http://dx.doi.org/10.1017/s0022029912000672.

Full text

Abstract:

The robustness of in-line raw milk analysis with near-infrared spectroscopy (NIRS) was tested with respect to the prediction of the raw milk contents fat, protein and lactose. Near-infrared (NIR) spectra of raw milk (n = 3119) were acquired on three different farms during the milking process of 354 milkings over a period of six months. Calibration models were calculated for: a random data set of each farm (fully random internal calibration); first two thirds of the visits per farm (internal calibration); whole datasets of two of the three farms (external calibration), and combinations of external and internal datasets. Validation was done either on the remaining data set per farm (internal validation) or on data of the remaining farms (external validation). Excellent calibration results were obtained when fully randomised internal calibration sets were used for milk analysis. In this case, RPD values of around ten, five and three for the prediction of fat, protein and lactose content, respectively, were achieved. Farm internal calibrations achieved much poorer prediction results especially for the prediction of protein and lactose with RPD values of around two and one respectively. The prediction accuracy improved when validation was done on spectra of an external farm, mainly due to the higher sample variation in external calibration sets in terms of feeding diets and individual cow effects. The results showed that further improvements were achieved when additional farm information was added to the calibration set. One of the main requirements towards a robust calibration model is the ability to predict milk constituents in unknown future milk samples. The robustness and quality of prediction increases with increasing variation of, e.g., feeding and cow individual milk composition in the calibration model.

APA, Harvard, Vancouver, ISO, and other styles

6

Huang, J., D. Brennan, L. Sattler, J. Alderman, B. Lane, and C. O'Mathuna. "A comparison of calibration methods based on calibration data size and robustness." Chemometrics and Intelligent Laboratory Systems 62, no. 1 (April 2002): 25–35. http://dx.doi.org/10.1016/s0169-7439(01)00211-8.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Guerra, Maria Letizia, and Laerte Sorini. "Testing robustness in calibration of stochastic volatility models." European Journal of Operational Research 163, no. 1 (May 2005): 145–53. http://dx.doi.org/10.1016/j.ejor.2004.01.004.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Chesi, Graziano, and Koichi Hashimoto. "Configuration and Robustness in Visual Servo." Journal of Robotics and Mechatronics 16, no. 2 (April 20, 2004): 178–85. http://dx.doi.org/10.20965/jrm.2004.p0178.

Full text

Abstract:

Effects of camera calibration errors on the point-to-point task are investigated in static-eye and hand-eye visual servoing realized with position-based and image-based control laws. For these four configurations, the effect of uncertainty on the extrinsic parameters is analyzed. The results show local stability for all configurations under small calibration errors. However, a steady state error is found in the hand-eye position-based configuration. Simulations have been done to confirm the theoretical results and evaluate the effects of the uncertainty in terms of stability region. Another contribution of the paper consists of providing a method for estimating the stability region robust against uncertainty directions for the static-eye position-based case with uncertainty on the camera centers.

APA, Harvard, Vancouver, ISO, and other styles

9

Buchanan, B. R., D. E. Honigs, Cynthia J. Lee, and William Roth. "Detection of Ethanol in Wines Using Optical-Fiber Measurements and Near-Infrared Analysis." Applied Spectroscopy 42, no. 6 (August 1988): 1106–11. http://dx.doi.org/10.1366/0003702884430245.

Full text

Abstract:

Optical-fiber measurements coupled with near-infrared analysis is used to predict the ethanol content of wine samples to within ±0.33 volume percent. Because telecommunications-grade optical fibers are used, the wavelength range is limited and the signal-to-noise ratio is an order of magnitude less than that for conventional near-infrared measurements. These features prompted the use of partial least-squares (PLS) as the calibration algorithm. PLS provides robust calibrations that are based upon the entire spectrum. The problem of extreme samples not being represented in the calibration model is discussed and illustrated. Also, the robustness of the PLS calibration is demonstrated. Spectral reconstruction is used to help assign the bands in the wavelength range used.

APA, Harvard, Vancouver, ISO, and other styles

10

Coron, L., V. Andréassian, C. Perrin, M. Bourqui, and F. Hendrickx. "On the lack of robustness of hydrologic models regarding water balance simulation: a diagnostic approach applied to three models of increasing complexity on 20 mountainous catchments." Hydrology and Earth System Sciences 18, no. 2 (February 21, 2014): 727–46. http://dx.doi.org/10.5194/hess-18-727-2014.

Full text

Abstract:

Abstract. This paper investigates the robustness of rainfall–runoff models when their parameters are transferred in time. More specifically, we propose an approach to diagnose their ability to simulate water balance on periods with different hydroclimatic characteristics. The testing procedure consists in a series of parameter calibrations over 10 yr periods and the systematic analysis of mean flow volume errors on long records. This procedure was applied to three conceptual models of increasing structural complexity over 20 mountainous catchments in southern France. The results showed that robustness problems are common. Errors on 10 yr mean flow volume were significant for all calibration periods and model structures. Various graphical and numerical tools were used to investigate these errors and unexpectedly strong similarities were found in the temporal evolutions of these volume errors. We indeed showed that relative changes in simulated mean flow between 10 yr periods can remain similar, regardless of the calibration period or the conceptual model used. Surprisingly, using longer records for parameters optimisation or using a semi-distributed 19-parameter daily model instead of a simple 1-parameter annual formula did not provide significant improvements regarding these simulation errors on flow volumes. While the actual causes for these robustness problems can be manifold and are difficult to identify in each case, this work highlights that the transferability of water balance adjustments made during calibration can be poor, with potentially huge impacts in the case of studies in non-stationary conditions.

APA, Harvard, Vancouver, ISO, and other styles

11

Kettner, Jan-Eric. "ROBUSTNESS OF NTC-ALGORITHM FOR MISFITS IN CASE OF AIRFLOW CALIBRATION." International Journal of Engineering Applied Sciences and Technology 7, no. 3 (July 1, 2022): 316–20. http://dx.doi.org/10.33564/ijeast.2022.v07i03.044.

Full text

Abstract:

Study with comparison of three-point airflowauto calibration algorithm for NTC-thermistors. The results show that Hoge-5 is the best implementation of the NTC as well as the most robust to unavoidable calibration errors.

APA, Harvard, Vancouver, ISO, and other styles

12

Lumetti, Stefano, Perla Malagò, Dietmar Spitzer, Sigmund Zaruba, and Michael Ortner. "Computationally Efficient Magnetic Position System Calibration." Engineering Proceedings 2, no. 1 (November 14, 2020): 72. http://dx.doi.org/10.3390/ecsa-7-08219.

Full text

Abstract:

Properties such as high resolution, contactless (and thus wear-free) measurement, low power consumption, robustness against temperature and contamination as well as low cost make magnetic position and orientation systems appealing for a large number of industrial applications. Nevertheless, one major practical challenge is their sensitivity to fabrication tolerances. In this work, we propose a novel method for magnetic position system calibration based on the analytical computation of the magnetic field and on the application of an evolutionary optimization algorithm. This scheme enables the calibration of more than 10 degrees of freedom within a few seconds on standard quad-core ×86 processors, and is demonstrated by calibrating a highly cost-efficient 3D-printed 3-axis magnetic joystick.

APA, Harvard, Vancouver, ISO, and other styles

13

Kay, N. J., N. L. Oo, M. S. Gill, P. J. Richards, and R. N. Sharma. "Robustness of the digital filter to differing calibration flows." Journal of Wind Engineering and Industrial Aerodynamics 197 (February 2020): 104061. http://dx.doi.org/10.1016/j.jweia.2019.104061.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Zeaiter, M., J. M. Roger, V. Bellon-Maurel, and D. N. Rutledge. "Robustness of models developed by multivariate calibration. Part I." TrAC Trends in Analytical Chemistry 23, no. 2 (February 2004): 157–70. http://dx.doi.org/10.1016/s0165-9936(04)00307-3.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Yu, Guang, Bo Yang Yu, Shu Cai Yang, Li Wen, Wen Fei Dong, and Hui Wang. "The Projector Calibration Based on ZHANG’s Self-Calibration Method." Advanced Materials Research 981 (July 2014): 364–67. http://dx.doi.org/10.4028/www.scientific.net/amr.981.364.

Full text

Abstract:

Projector calibration can be seen as a special case of the camera calibration. It can establish the relationship of the three dimensional space coordinates for points and projector image coordinates for points DMD by using a projector to project coding pattern. In camera calibration, ZHANG’s self-calibration was conducted in the maximum likelihood linear refinement. Operation process takes the lens distortion factors into account finding out the camera internal and external parameters finally. Using this algorithm to the projector calibration can solve the traditional linear calibration algorithm which is complex and poor robustness. Otherwise, it can improve the practicability of calibration method. This method can both calibrate the internal and external parameters of projector, which can solve the problem of independently inside or outside calibration.

APA, Harvard, Vancouver, ISO, and other styles

16

Chen, Hua-Zhou, Kai Shi, Ken Cai, Li-Li Xu, and Quan-Xi Feng. "Investigation of sample partitioning in quantitative near-infrared analysis of soil organic carbon based on parametric LS-SVR modeling." RSC Advances 5, no. 98 (2015): 80612–19. http://dx.doi.org/10.1039/c5ra12468a.

Full text

Abstract:

A framework for sample partitioning is proposed to take into account the tunable ratio of numbers of calibration and prediction samples, in consideration with the randomness, stability and robustness of calibration models.

APA, Harvard, Vancouver, ISO, and other styles

17

Lin, Wenwei, Peidong Liang, Guantai Luo, Ziyang Zhao, and Chentao Zhang. "Research of Online Hand–Eye Calibration Method Based on ChArUco Board." Sensors 22, no. 10 (May 17, 2022): 3805. http://dx.doi.org/10.3390/s22103805.

Full text

Abstract:

To solve the problem of inflexibility of offline hand–eye calibration in “eye-in-hand” modes, an online hand–eye calibration method based on the ChArUco board is proposed in this paper. Firstly, a hand–eye calibration model based on the ChArUco board is established, by analyzing the mathematical model of hand–eye calibration, and the image features of the ChArUco board. According to the advantages of the ChArUco board, with both the checkerboard and the ArUco marker, an online hand–eye calibration algorithm based on the ChArUco board is designed. Then, the online hand–eye calibration algorithm, based on the ChArUco board, is used to realize the dynamic adjustment of the hand–eye position relationship. Finally, the hand–eye calibration experiment is carried out to verify the accuracy of the hand–eye calibration based on the ChArUco board. The robustness and accuracy of the proposed method are verified by online hand–eye calibration experiments. The experimental results show that the accuracy of the online hand–eye calibration method proposed in this paper is between 0.4 mm and 0.6 mm, which is almost the same as the offline hand–eye calibration accuracy. The method in this paper utilizes the advantages of the ChArUco board to realize online hand–eye calibration, which improves the flexibility and robustness of hand–eye calibration.

APA, Harvard, Vancouver, ISO, and other styles

18

Küderle, Arne, Sebastian Becker, and Catherine Disselhorst-Klug. "Increasing the Robustness of the automatic IMU calibration for lower Extremity Motion Analysis." Current Directions in Biomedical Engineering 4, no. 1 (September 1, 2018): 439–42. http://dx.doi.org/10.1515/cdbme-2018-0104.

Full text

Abstract:

AbstractWith the advances of IMU-based human motion tracking, joint angle tracking in an home environment has become a realistic goal. Achieving it, could enable novel applications in rehabilitation and sports medicine. However, in existing systems the process of aligning the mounted sensors with the body coordinate system is either not robust enough or to complicated for fully unsupervised usage. In this publication the performance of a promising existing algorithm is evaluated with a range of different calibration motions. Further, an extension to this implementation is proposed, aiming to improve its stability when only non-ideal calibration data is available. It could be validated that the modification of the algorithm can increase the stability and reduce the dependency of the calibration on specific calibration motions. Based on these results, we recommend the proposed extension of the algorithm as a drop-in replacement for the existing implementation.

APA, Harvard, Vancouver, ISO, and other styles

19

Guthrie, J. A., D. J. Reid, and K. B. Walsh. "Assessment of internal quality attributes of mandarin fruit. 2. NIR calibration model robustness." Australian Journal of Agricultural Research 56, no. 4 (2005): 417. http://dx.doi.org/10.1071/ar04299.

Full text

Abstract:

The robustness of multivariate calibration models, based on near infrared spectroscopy, for the assessment of total soluble solids (TSS) and dry matter (DM) of intact mandarin fruit (Citrus reticulata cv. Imperial) was assessed. TSS calibration model performance was validated in terms of prediction of populations of fruit not in the original population (different harvest days from a single tree, different harvest localities, different harvest seasons). Of these, calibration performance was most affected by validation across seasons (signal to noise statistic on root mean squared error of prediction of 3.8, compared with 20 and 13 for locality and harvest day, respectively). Procedures for sample selection from the validation population for addition to the calibration population (‘model updating’) were considered for both TSS and DM models. Random selection from the validation group worked as well as more sophisticated selection procedures, with approximately 20 samples required. Models that were developed using samples at a range of temperatures were robust in validation for TSS and DM.

APA, Harvard, Vancouver, ISO, and other styles

20

Dou, Jianyu, Chong Pan, and Jianhua Liu. "Robustness of neural network calibration model for accurate spatial positioning." Optics Express 29, no. 21 (September 27, 2021): 32922. http://dx.doi.org/10.1364/oe.438539.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Reynolds, J. E., S. Halldin, J. Seibert, C. Y. Xu, and T. Grabs. "Robustness of flood-model calibration using single and multiple events." Hydrological Sciences Journal 65, no. 5 (May 17, 2019): 842–53. http://dx.doi.org/10.1080/02626667.2019.1609682.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Aalerud, Atle, Joacim Dybedal, and Geir Hovland. "Automatic Calibration of an Industrial RGB-D Camera Network Using Retroreflective Fiducial Markers." Sensors 19, no. 7 (March 31, 2019): 1561. http://dx.doi.org/10.3390/s19071561.

Full text

Abstract:

This paper describes a non-invasive, automatic, and robust method for calibrating a scalable RGB-D sensor network based on retroreflective ArUco markers and the iterative closest point (ICP) scheme. We demonstrate the system by calibrating a sensor network comprised of six sensor nodes positioned in a relatively large industrial robot cell with an approximate size of 10 m × 10 m × 4 m. Here, the automatic calibration achieved an average Euclidean error of 3 cm at distances up to 9.45 m. To achieve robustness, we apply several innovative techniques: Firstly, we mitigate the ambiguity problem that occurs when detecting a marker at long range or low resolution by comparing the camera projection with depth data. Secondly, we use retroreflective fiducial markers in the RGB-D calibration for improved accuracy and detectability. Finally, the repeating ICP refinement uses an exact region of interest such that we employ the precise depth measurements of the retroreflective surfaces only. The complete calibration software and a recorded dataset are publically available and open source.

APA, Harvard, Vancouver, ISO, and other styles

23

Zhang, Qiang, Banyong Sun, Yaxiong Cheng, and Xijie Li. "Residual Self-Calibration and Self-Attention Aggregation Network for Crop Disease Recognition." International Journal of Environmental Research and Public Health 18, no. 16 (August 9, 2021): 8404. http://dx.doi.org/10.3390/ijerph18168404.

Full text

Abstract:

The correct diagnosis and recognition of crop diseases play an important role in ensuring crop yields and preventing food safety. The existing methods for crop disease recognition mainly focus on accuracy while ignoring the algorithm’s robustness. In practice, the acquired images are often accompanied by various noises. These noises lead to a huge challenge for improving the robustness and accuracy of the recognition algorithm. In order to solve this problem, this paper proposes a residual self-calibration and self-attention aggregation network (RCAA-Net) for crop disease recognition in actual scenarios. The proposed RCAA-Net is composed of three main modules: (1) multi-scale residual module, (2) feedback self-calibration module, and (3) self-attention aggregation module. Specifically, the multi-scale residual module is designed to learn multi-scale features and provide both global and local information for the appearance of the disease to improve the performance of the model. The feedback self-calibration is proposed to improve the robustness of the model by suppressing the background noise in the original deep features. The self-attention aggregation module is introduced to further improve the robustness and accuracy of the model by capturing multi-scale information in different semantic spaces. The experimental results on the challenging 2018ai_challenger crop disease recognition dataset show that the proposed RCAA-Net achieves state-of-the-art performance on robustness and accuracy for crop disease recognition in actual scenarios.

APA, Harvard, Vancouver, ISO, and other styles

24

Erke, Shang, Dai Bin, Nie Yiming, Xiao Liang, and Zhu Qi. "A fast calibration approach for onboard LiDAR-camera systems." International Journal of Advanced Robotic Systems 17, no. 2 (March 1, 2020): 172988142090960. http://dx.doi.org/10.1177/1729881420909606.

Full text

Abstract:

Outdoor surveillance and security robots have a wide range of industrial, military, and civilian applications. In order to achieve autonomous navigation, the LiDAR-camera system is widely applied by outdoor surveillance and security robots. The calibration of the LiDAR-camera system is essential and important for robots to correctly acquire the scene information. This article proposes a fast calibration approach that is different from traditional calibration algorithms. The proposed approach combines two independent calibration processes, which are the calibration of LiDAR and the camera to robot platform, so as to address the relationship between LiDAR sensor and camera sensor. A novel approach to calibrate LiDAR to robot platform is applied to improve accuracy and robustness. A series of indoor experiments are carried out and the results show that the proposed approach is effective and efficient. At last, it is applied to our own outdoor security robot platform to detect both positive and negative obstacles in a field environment, in which two Velodyne-HDL-32 LiDARs and a color camera are employed. The real application illustrates the robustness performance of the proposed approach.

APA, Harvard, Vancouver, ISO, and other styles

25

Hindle, P. H., and C. R. R. Smith. "A Comparison of Calibration Robustness Relating to Different Data Treatments of a Standard Set of Spectra." Journal of Near Infrared Spectroscopy 4, no. 1 (January 1996): 119–28. http://dx.doi.org/10.1255/jnirs.83.

Full text

Abstract:

Several different data treatments are currently in use for calibrating near infrared instruments of diverse designs. It is practically impossible to assess the relative performances of these methods, for example with a set of standard samples, because of inaccuracies in laboratory estimates of concentrations, sample presentation difficulties and sample stability. This paper presents the first results of calibrations derived from computer synthesised spectra as an attempt to circumvent sample problems.

APA, Harvard, Vancouver, ISO, and other styles

26

Gaborit, Étienne, Simon Ricard, Simon Lachance-Cloutier, François Anctil, and Richard Turcotte. "Comparing global and local calibration schemes from a differential split-sample test perspective." Canadian Journal of Earth Sciences 52, no. 11 (November 2015): 990–99. http://dx.doi.org/10.1139/cjes-2015-0015.

Full text

Abstract:

This work explores the performances of the hydrologic model Hydrotel, applied to 36 catchments located in the Province of Quebec, Canada. A local calibration (each catchment taken individually) scheme and a global calibration (a single parameter set sought for all catchments) scheme are compared in a differential split-sample test perspective. Such a methodology is useful to gain insights on a model’s skills under different climatic conditions, in view of its use for climate change impact studies. The model was calibrated using both schemes on five non-continuous dry and cold years and then evaluated on five dissimilar humid and warm years. Results indicate that, as expected, local calibration leads to better performances than the global one. However, global calibration achieves satisfactory simulations while producing a better temporal robustness (i.e., model transposability to periods with different climatic conditions). Global calibration, in opposition to local calibration, thus imposes spatial consistency to the calibrated parameter values, while locally adjusted parameter sets can significantly vary from one catchment to another due to equifinality. It is hence stated that a global calibration scheme represents a good trade-off between local performance, temporal robustness, and the spatial consistency of parameter values, which is, for example, of interest in the context of ungauged catchments’ simulation, climate change impact studies, or even simply large-scale modeling.

APA, Harvard, Vancouver, ISO, and other styles

27

De Vito, Saverio, Elena Esposito, Nuria Castell, Philipp Schneider, and A. Bartonova. "On the robustness of field calibration for smart air quality monitors." Sensors and Actuators B: Chemical 310 (May 2020): 127869. http://dx.doi.org/10.1016/j.snb.2020.127869.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Zeaiter, Magida, Éric Latrille, Pascal Gras, Jean-Philippe Steyer, Véronique Bellon-Maurel, and Jean-Michel Roger. "Improvements in the Robustness of Mid-Infrared Spectroscopy Models against Chemical Interferences: Application to Monitoring of Anaerobic Digestion Processes." AppliedChem 2, no. 2 (June 20, 2022): 117–27. http://dx.doi.org/10.3390/appliedchem2020008.

Full text

Abstract:

The monitoring and control of bioprocesses rely on the measurement of the main metabolite concentrations. To this end, infrared spectroscopy (IR) is a good candidate with which to perform rapid and non-destructive measurements. However, IR-based measurements rely on a calibration step linking the measured spectra to the concentrations of the compounds of interest. This calibration may suffer with problems of robustness when the measuring conditions change, such as when some chemicals not present in the calibration spectra are added when using the IR sensor. In this study, a method based on orthogonal projection, dynamic orthogonal projection (DOP), was tested for its ability to cope with the robustness problem caused by the addition of ammonia in a pilot-scale anaerobic digester, whose volatile fatty acid concentrations were monitored by mid-IR spectrometry. The results demonstrate that DOP has significant potential as a form of process analytical technology.

APA, Harvard, Vancouver, ISO, and other styles

29

Chang, William C., Joseph W. Jackson, Kellie R. Machlus, Alisa S. Wolberg, and Mikhail V. Ovanesov. "Comparative Analysis of Thrombin Calibration Algorithms and Correction for Thrombin-α2macroglobulin Activity." Journal of Clinical Medicine 9, no. 10 (September 24, 2020): 3077. http://dx.doi.org/10.3390/jcm9103077.

Full text

Abstract:

Background: The thrombin generation (TG) test is useful for characterizing global hemostasis potential, but fluorescence substrate artifacts, such as thrombin-α2macroglobulin (T-α2MG) signal, inner filter effect (IFE), substrate consumption, and calibration algorithms have been suggested as sources of intra- and inter-laboratory variance, which may limit its clinical utility. Methods: Effects of internal vs. external normalization, IFE and T-α2MG on TG curves in normal plasma supplemented with coagulation factors, thrombomodulin, and tissue factor were studied using the Calibrated Automated Thrombinography (CAT; Diagnostica Stago, Parsippany, NJ, USA) and in-house software. Results: The various calibration methods demonstrated no significant difference in producing TG curves, nor increased the robustness of the TG assay. Several TG parameters, including thrombin peak height (TPH), produced from internal linear calibration did not differ significantly from uncalibrated TG parameters. Further, TPH values from internal linear and nonlinear calibration with or without T-α2MG correction correlated well with TPH from external calibration. Higher coefficients of variation (CVs) for TPH values were observed in both platelet-free and platelet-rich plasma with added thrombomodulin. Conclusions: Our work suggests minimal differences between distinct computational approaches toward calibrating and correcting fluorescence signals into TG levels, with most samples returning similar or equivalent TPH results.

APA, Harvard, Vancouver, ISO, and other styles

30

He, Zhong Hai, Xin Pan Wang, and Zhen He Ma. "Found Robust Calibration Model in Fermentation Process by Combining Different Sample Sets." Applied Mechanics and Materials 667 (October 2014): 372–75. http://dx.doi.org/10.4028/www.scientific.net/amm.667.372.

Full text

Abstract:

Robust calibration model is the key factor for spectroscopic measurement. The commonly used way is build calibration model by crude samples collected from process. There are two deficiencies in fermentation processes in that: matrix effects variation always existed for different batch of fermentation and, chance correlation is sure existed which spoil robust of calibration model. In the research being presented, method of overcoming the weakness is examined. By combing the standard analyte and fermentation broth and spiking solvend, the calibration model can correlate specific spectral features only with the measured analyte concentrations so have good robustness.

APA, Harvard, Vancouver, ISO, and other styles

31

Tang, Rui-Yin, Hong-Kun He, Zhou-Mo Zeng, and Feng Gao. "Calibration of Double Priority Camera Based on Circle Planar Target." International Journal of Automation Technology 9, no. 3 (May 5, 2015): 322–29. http://dx.doi.org/10.20965/ijat.2015.p0322.

Full text

Abstract:

After the advantages and disadvantages of current methods of calibration are analyzed and contrasted, the comparatively widely applied Zhang Zhengyou calibration method is adopted in this paper, but it is used to solve problems in a different way. The calibration of a double-priority camera on the basis of a round planar target is proposed, and a computation method based on the on-line intersection of the two circles with the closest proximity is put forward to fix the center of a circle. This method of calibration is simple and flexible, with good robustness, precision, and practical value.

APA, Harvard, Vancouver, ISO, and other styles

32

Liu, Wu, and Li. "Robust and Accurate Hand–Eye Calibration Method Based on Schur Matric Decomposition." Sensors 19, no. 20 (October 16, 2019): 4490. http://dx.doi.org/10.3390/s19204490.

Full text

Abstract:

To improve the accuracy and robustness of hand–eye calibration, a hand–eye calibration method based on Schur matric decomposition is proposed in this paper. The accuracy of these methods strongly depends on the quality of observation data. Therefore, preprocessing observation data is essential. As with traditional two-step hand–eye calibration methods, we first solve the rotation parameters and then the translation vector can be immediately determined. A general solution was obtained from one observation through Schur matric decomposition and then the degrees of freedom were decreased from three to two. Observation data preprocessing is one of the basic unresolved problems with hand–eye calibration methods. A discriminant equation to delete outliers was deduced based on Schur matric decomposition. Finally, the basic problem of observation data preprocessing was solved using outlier detection, which significantly improved robustness. The proposed method was validated by both simulations and experiments. The results show that the prediction error of rotation and translation was 0.06 arcmin and 1.01 mm respectively, and the proposed method performed much better in outlier detection. A minimal configuration for the unique solution was proven from a new perspective.

APA, Harvard, Vancouver, ISO, and other styles

33

Barbero-Álvarez, Miguel Antonio, José Manuel Menéndez, Juan Antonio Rodrigo, Blanca Ramírez-Barat, and Emilio Cano. "Assessment of the Robustness of a Color Monitoring Chart Calibration Method for Crowdsourcing-Based Preventive Conservation." Applied Sciences 11, no. 21 (October 27, 2021): 10067. http://dx.doi.org/10.3390/app112110067.

Full text

Abstract:

Monitoring environmental factors such as pollutants, relative humidity, light, etc. is needed to ensure a proper preventive conservation of cultural heritage. Since existing systems are expensive and difficult to maintain, we propose as a sustainable alternative the use crowdsourced photographs taken by visitors using their cell phones. These images of a tailor made panel, including sensitive materials and a calibration color chart, are calibrated and colorimetric information extracted from them. The aim of this paper is assessing the robustness of the color chart and the calibration method used, and evaluating how the ageing of the materials of the chart can affect the accuracy of the calibration process. A choice is made between four candidate materials and a set of industrial inks. Several tests have been performed and mathematical metrics extracted, so the most suitable material is adequately selected. It has been checked how the image calibration process, employed for homogenizing information from the crowdsourced pictures, performs with real-life materials and colors to assess the possible degradation that may happen. This work is a part of a bigger project with the aim of building a crowdsourcing-based monitoring system for preventive conservation of cultural heritage.

APA, Harvard, Vancouver, ISO, and other styles

34

Li, Wenxing, Yu Zhao, Qiubo Ye, and Bin Yang. "Adaptive Antenna Null Broadening Beamforming against Array Calibration Error Based on Adaptive Variable Diagonal Loading." International Journal of Antennas and Propagation 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/3265236.

Full text

Abstract:

An approach for null broadening beamforming is proposed based on adaptive variable diagonal loading (VDL) and combined with the covariance matrix taper (CMT) approach, aiming at improving the robustness of adaptive antenna null broadening beamforming when array calibration error exists. Hence, it is named VDL-CMT. In this novel approach, the signal-to-noise ratio in the tapered sample covariance matrix is estimated and the VDL factor can be obtained adaptively. Then, the covariance matrix of the CMT approach is loaded with the obtained VDL factor. According to simulation results, in the case of array calibration error, robustness of the VDL-CMT is significantly improved and its performance is better than that of the existing adaptive antenna null broadening beamforming approaches.

APA, Harvard, Vancouver, ISO, and other styles

35

Papafotis, Konstantinos, Dimitris Nikitas, and Paul P. Sotiriadis. "Magnetic Field Sensors’ Calibration: Algorithms’ Overview and Comparison." Sensors 21, no. 16 (August 5, 2021): 5288. http://dx.doi.org/10.3390/s21165288.

Full text

Abstract:

The calibration of three-axis magnetic field sensors is reviewed. Seven representative algorithms for in-situ calibration of magnetic field sensors without requiring any special piece of equipment are reviewed. The algorithms are presented in a user friendly, directly applicable step-by-step form, and are compared in terms of accuracy, computational efficiency and robustness using both real sensors’ data and artificial data with known sensor’s measurement distortion.

APA, Harvard, Vancouver, ISO, and other styles

36

Yuan, Yuan, and Yong Hui Ge. "More Efficient Methods among Commonly Used Robust Estimation Methods for Similarity Transformation." Advanced Materials Research 712-715 (June 2013): 2497–500. http://dx.doi.org/10.4028/www.scientific.net/amr.712-715.2497.

Full text

Abstract:

mage calibration is a necessary step in image processing. Similarity transformation is a widely used image calibration method. Robust estimation methods are often used to eliminate or weaken the influences of gross errors on image calibration. However, different robust estimation methods have different capabilities in eliminating or weakening gross errors. The current paper employed simulation experiments using different coincident points and the number of gross errors included in the observations to compare the robustness of 13 commonly used robust estimation methods. Results indicated that L1 and GermanMcClure methods are relatively more efficient than other robust estimation methods for image calibration based on similarity transformation.

APA, Harvard, Vancouver, ISO, and other styles

37

Ren, Haonan, Jian Yang, Xin Liu, Panpan Huang, and Lei Guo. "Sensor Modeling and Calibration Method Based on Extinction Ratio Error for Camera-Based Polarization Navigation Sensor." Sensors 20, no. 13 (July 6, 2020): 3779. http://dx.doi.org/10.3390/s20133779.

Full text

Abstract:

The performance of camera-based polarization sensors largely depends on the estimated model parameters obtained through calibration. Limited by manufacturing processes, the low extinction ratio and inconsistency of the polarizer can reduce the measurement accuracy of the sensor. To account for the challenges, one extinction ratio coefficient was introduced into the calibration model to unify the light intensity of two orthogonal channels. Since the introduced extinction ratio coefficient is associated with degree of polarization (DOP), a new calibration method considering both azimuth of polarization (AOP) error and DOP error for the bionic camera-based polarization sensor was proposed to improve the accuracy of the calibration model parameter estimation. To evaluate the performance of the proposed camera-based polarization calibration model using the new calibration method, both indoor and outdoor calibration experiments were carried out. It was found that the new calibration method for the proposed calibration model could achieve desirable performance in terms of stability and robustness of the calculated AOP and DOP values.

APA, Harvard, Vancouver, ISO, and other styles

38

Jiang, Xiang Kui. "A New Binocular Camera Calibration Method Based on an Improved Genetic Algorithm." Advanced Materials Research 411 (November 2011): 602–8. http://dx.doi.org/10.4028/www.scientific.net/amr.411.602.

Full text

Abstract:

In this paper,an improved genetic algorithm was proposed,which is applicable to binocular camera calibration. On the one hand, conventional encoding method is improved so that variable search interval can be adjusted adaptively. On the other hand, crossover and mutation probability is varied by using superiority inheritance principle to avoid premature question. Experimental results show that the proposed method has a higher calibration accuracy and better robustness, compared to those of non-linear calibration methods. The proposed method is able to improve the performance of global optimization effectively.

APA, Harvard, Vancouver, ISO, and other styles

39

Zhang, Xiaoming, Chen Lei, Jun Liu, Jie Li, Jie Tan, Chen Lu, Zheng-Zheng Chao, and Yu-Zhang Wan. "Real-time calibration algorithm of magnetometer for spinning projectiles." Sensor Review 40, no. 2 (September 26, 2019): 227–36. http://dx.doi.org/10.1108/sr-04-2018-0088.

Full text

Abstract:

Purpose In spite of the vehicle, magnetic field interference can be reduced by some measures and techniques in ammunition design and manufacturing stage, the corruption of the vehicle magnetic field can still reach hundreds to thousands of nanoteslas. Besides, the magnetic field that the ferromagnetic materials generate in response to the strong magnetic field in the vicinity of the body. So, a real-time and accurate vehicle magnetic field calibration method is needed to improve the real-time measurement accuracy of the geomagnetic field for spinning projectiles. Design/methodology/approach Unlike the past two-step calibration method, the algorithm uses a linear model to calibrate the magnetic measurement error in real-time. In the method, the elliptical model of magnetometer measurement is established to convert the coefficients of hard and soft iron errors into the parameters of the elliptic equation. Then, the parameters are estimated by recursive least square estimator in real-time. Finally, the initial conditions for the estimator are established using prior knowledge method or static calibration method. Findings Studies show the proposed algorithm has remarkable estimation accuracy and robustness and it realizes calibration the magnetic measurement error in real-time. A turntable experiments indicate that the post-calibration residuals approximate the measurement noise of the magnetometer and the roll accuracy is better than 1°. The algorithm is restricted to biaxial magnetometers’ calibration in real-time as expressed in this paper. It, however, should be possible to broaden this method’s applicability to triaxial magnetometers' calibration in real-time. Originality/value Unlike the past two-step calibration method, the algorithm uses a linear model to calibrate the magnetic measurement error in real-time and the calculation is small. Besides, it does not take up storage space. The proposed algorithm has remarkable estimation accuracy and robustness and it realizes calibration the magnetic measurement error in real time. The algorithm is restricted to biaxial magnetometers’ calibration in real-time as expressed in this paper. It, however, should be possible to broaden this method’s applicability to triaxial magnetometers’ calibration in real-time.

APA, Harvard, Vancouver, ISO, and other styles

40

Guthrie, J. A., K. B. Walsh, D. J. Reid, and C. J. Liebenberg. "Assessment of internal quality attributes of mandarin fruit. 1. NIR calibration model development." Australian Journal of Agricultural Research 56, no. 4 (2005): 405. http://dx.doi.org/10.1071/ar04257.

Full text

Abstract:

The utility of near infrared spectroscopy as a non-invasive technique for the assessment of internal eating quality parameters of mandarin fruit (Citrus reticulata cv. Imperial) was assessed. The calibration procedure for the attributes of TSS (total soluble solids) and DM (dry matter) was optimised with respect to a reference sampling technique, scan averaging, spectral window, data pre-treatment (in terms of derivative treatment and scatter correction routine) and regression procedure. The recommended procedure involved sampling of an equatorial position on the fruit with 1 scan per spectrum, and modified partial least squares model development on a 720–950-nm window, pre-treated as first derivative absorbance data (gap size of 4 data points) with standard normal variance and detrend scatter correction. Calibration model performance for the attributes of TSS and DM content was encouraging (typical Rc2 of >0.75 and 0.90, respectively; typical root mean squared standard error of calibration of <0.4 and 0.6%, respectively), whereas that for juiciness and total acidity was unacceptable. The robustness of the TSS and DM calibrations across new populations of fruit is documented in a companion study.

APA, Harvard, Vancouver, ISO, and other styles

41

Bai, Zixuan, Guang Jiang, and Ailing Xu. "LiDAR-Camera Calibration Using Line Correspondences." Sensors 20, no. 21 (November 5, 2020): 6319. http://dx.doi.org/10.3390/s20216319.

Full text

Abstract:

In this paper, we introduce a novel approach to estimate the extrinsic parameters between a LiDAR and a camera. Our method is based on line correspondences between the LiDAR point clouds and camera images. We solve the rotation matrix with 3D–2D infinity point pairs extracted from parallel lines. Then, the translation vector can be solved based on the point-on-line constraint. Different from other target-based methods, this method can be performed simply without preparing specific calibration objects because parallel lines are commonly presented in the environment. We validate our algorithm on both simulated and real data. Error analysis shows that our method can perform well in terms of robustness and accuracy.

APA, Harvard, Vancouver, ISO, and other styles

42

MARTINO, K. G., B. P. MARKS, D. T. CAMPOS, and M. L. TAMPLIN. "Quantifying the Robustness of a Broth-Based Model for Predicting Listeria monocytogenes Growth in Meat and Poultry Products." Journal of Food Protection 68, no. 11 (November 1, 2005): 2310–16. http://dx.doi.org/10.4315/0362-028x-68.11.2310.

Full text

Abstract:

Given the importance of Listeria monocytogenes as a risk factor in meat and poultry products, there is a need to evaluate the relative robustness of predictive growth models applied to meat products. The U.S. Department of Agriculture–Agricultural Research Service Pathogen Modeling Program is a tool widely used by the food industry to estimate pathogen growth, survival, and inactivation in food. However, the robustness of the Pathogen Modeling Program broth-based L. monocytogenes growth model in meat and poultry application has not, to our knowledge, been specifically evaluated. In the present study, this model was evaluated against independent data in terms of predicted microbial counts and covered a range of conditions inside and outside the original model domain. The robustness index was calculated as the ratio of the standard error of prediction (root mean square error of the model against an independent data set not used to create the model) to the standard error of calibration (root mean square error of the model against the data set used to create the model). Inside the calibration domain of the Pathogen Modeling Program, the best robustness index for application to meat products was 0.37; the worst was 3.96. Outside the domain, the best robustness index was 0.40, and the worst was 1.22. Product type influenced the robustness index values (P < 0.01). In general, the results indicated that broth-based predictive models should be validated against independent data in the domain of interest; otherwise, significant predictive errors can occur.

APA, Harvard, Vancouver, ISO, and other styles

43

Azim, Akramul, and Md Al Maruf. "A software-based calibration approach to increase the robustness of embedded systems." International Journal of Embedded Systems 13, no. 4 (2020): 466. http://dx.doi.org/10.1504/ijes.2020.10031197.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Maruf, Md Al, and Akramul Azim. "A software-based calibration approach to increase the robustness of embedded systems." International Journal of Embedded Systems 13, no. 4 (2020): 466. http://dx.doi.org/10.1504/ijes.2020.110662.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Gowers, Sally A. N., Michelle L. Rogers, Marsilea A. Booth, Chi L. Leong, Isabelle C. Samper, Tonghathai Phairatana, Sharon L. Jewell, Clemens Pahl, Anthony J. Strong, and Martyn G. Boutelle. "Clinical translation of microfluidic sensor devices: focus on calibration and analytical robustness." Lab on a Chip 19, no. 15 (2019): 2537–48. http://dx.doi.org/10.1039/c9lc00400a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Li, Dian-Qing, Xing Peng, Sara Khoshnevisan, and C. Hsein Juang. "Calibration of resistance factor for design of pile foundations considering feasibility robustness." Computers and Geotechnics 81 (January 2017): 229–38. http://dx.doi.org/10.1016/j.compgeo.2016.08.018.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Peiris, Kamaranga H. S., Scott R. Bean, Anuj Chiluwal, Ramasamy Perumal, and S. V. Krishna Jagadish. "Moisture effects on robustness of sorghum grain protein near‐infrared spectroscopy calibration." Cereal Chemistry 96, no. 4 (May 20, 2019): 678–88. http://dx.doi.org/10.1002/cche.10164.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Janik, L. J., J. O. Skjemstad, K. D. Shepherd, and L. R. Spouncer. "The prediction of soil carbon fractions using mid-infrared-partial least square analysis." Soil Research 45, no. 2 (2007): 73. http://dx.doi.org/10.1071/sr06083.

Full text

Abstract:

This paper describes the application of mid-infrared (MIR) spectroscopy and partial least-squares (PLS) analysis to predict the concentration of organic carbon fractions present in soil. The PLS calibrations were derived from a standard set of soils that had been analysed for total organic carbon (TOC), particulate organic carbon (POC), and charcoal carbon (char-C) using physical and chemical means. PLS calibration models from this standard set of soils allowed the prediction of TOC, POC, and char-C fractions with a coefficient of determination (R2) of measured v. predicted data ranging between 0.97 and 0.73. For the POC fraction, the coefficient of determination could be improved (R2 = 0.94) through the use of local calibration sets. The capacity to estimate soil fractions such as char-C rapidly and inexpensively makes this approach highly attractive for studies where large numbers of analyses are required. Inclusion of a set of soils from Kenya demonstrated the robustness of the method for total organic carbon and charcoal carbon prediction.

APA, Harvard, Vancouver, ISO, and other styles

49

Dumedah, Gift, Aaron A. Berg, and Mark Wineberg. "Pareto-optimality and a search for robustness: choosing solutions with desired properties in objective space and parameter space." Journal of Hydroinformatics 14, no. 2 (June 22, 2011): 270–85. http://dx.doi.org/10.2166/hydro.2011.120.

Full text

Abstract:

Multi-objective genetic algorithms are increasingly being applied to calibrate hydrological models by generating several competitive solutions usually referred to as a Pareto-optimal set. The Pareto-optimal set comprises non-dominated solutions at the calibration phase but it is usually unknown whether all or only a subset of non-dominated solutions at the calibration phase remains non-dominated at the validation phase. In practice, users would like to know solutions (and their associated properties) which remain non-dominated at both the calibration and validation phases. This study investigates robustness of the Pareto-optimal set by developing a model characterization framework (MCF). The MCF uses cluster analysis to examine the distribution of solutions in parameter space and objective space, and conditional probability to combine linkages between the distributions of solutions in both spaces. The MCF has been illustrated for calibration output generated from application of the Non-dominated Sorting Genetic Algorithm-II to calibrate the Soil and Water Assessment Tool for streamflow in the Fairchild Creek watershed in southern Ontario. Our results show that not all non-dominated solutions found at the calibration phase perform the same for different validation periods. The MCF illustrates that robust solutions – non-dominated solutions which cluster in similar locations in parameter space and objective space – performed consistently well for several validation periods.

APA, Harvard, Vancouver, ISO, and other styles

50

Alfieri, Michela, Giovanni Cabassi, Ephrem Habyarimana, Fabrizio Quaranta, Carlotta Balconi, and Rita Redaelli. "Discrimination and prediction of polyphenolic compounds and total antioxidant capacity in sorghum grains." Journal of Near Infrared Spectroscopy 27, no. 1 (January 20, 2019): 46–53. http://dx.doi.org/10.1177/0967033518825351.

Full text

Abstract:

One hundred and forty-seven sorghum samples, grown in 2015 and 2017, were used to build different near infrared spectroscopic calibration models able to predict total antioxidant capacity, total phenolics, total flavonoids and condensed tannins content. Samples were separated into calibration and validation sets using a nearest neighbours algorithm. The r2pred values ranged from 0.84 (condensed tannins) to 0.95 (total phenolics), whereas the Ratio of Performance to Deviation (RPD) values ranged from 1.9 (total flavonoids) to 3.0 (total phenolics). Comparison of prediction error estimates highlighted the best models with significant differences. Model robustness was tested through a reduction of sample numbers in the calibration set; the highest robustness was found for total antioxidant capacity and total flavonoids. In addition, a partial least squares discriminant analysis model to screen the samples for their tannins level was developed and resulted in good performance; it should be useful to select tannin-free genotypes for the food industry. These models could be used for rapid screening of sorghum breeding genotypes with high antioxidant compounds.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Calibration robustness'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles