Dynamic calibration of pan-tilt-zoom cameras for traffic monitoring.

PubMed

Song, Kai-Tai; Tai, Jen-Chao

2006-10-01

Pan-tilt-zoom (PTZ) cameras have been widely used in recent years for monitoring and surveillance applications. These cameras provide flexible view selection as well as a wider observation range. This makes them suitable for vision-based traffic monitoring and enforcement systems. To employ PTZ cameras for image measurement applications, one first needs to calibrate the camera to obtain meaningful results. For instance, the accuracy of estimating vehicle speed depends on the accuracy of camera calibration and that of vehicle tracking results. This paper presents a novel calibration method for a PTZ camera overlooking a traffic scene. The proposed approach requires no manual operation to select the positions of special features. It automatically uses a set of parallel lane markings and the lane width to compute the camera parameters, namely, focal length, tilt angle, and pan angle. Image processing procedures have been developed for automatically finding parallel lane markings. Interesting experimental results are presented to validate the robustness and accuracy of the proposed method.

Towards SWOT data assimilation for hydrology : automatic calibration of global flow routing model parameters in the Amazon basin

NASA Astrophysics Data System (ADS)

Mouffe, M.; Getirana, A.; Ricci, S. M.; Lion, C.; Biancamaria, S.; Boone, A.; Mognard, N. M.; Rogel, P.

2011-12-01

The Surface Water and Ocean Topography (SWOT) mission is a swath mapping radar interferometer that will provide global measurements of water surface elevation (WSE). The revisit time depends upon latitude and varies from two (low latitudes) to ten (high latitudes) per 22-day orbit repeat period. The high resolution and the global coverage of the SWOT data open the way for new hydrology studies. Here, the aim is to investigate the use of virtually generated SWOT data to improve discharge simulation using data assimilation techniques. In the framework of the SWOT virtual mission (VM), this study presents the first results of the automatic calibration of a global flow routing (GFR) scheme using SWOT VM measurements for the Amazon basin. The Hydrological Modeling and Analysis Platform (HyMAP) is used along with the MOCOM-UA multi-criteria global optimization algorithm. HyMAP has a 0.25-degree spatial resolution and runs at the daily time step to simulate discharge, water levels and floodplains. The surface runoff and baseflow drainage derived from the Interactions Sol-Biosphère-Atmosphère (ISBA) model are used as inputs for HyMAP. Previous works showed that the use of ENVISAT data enables the reduction of the uncertainty on some of the hydrological model parameters, such as river width and depth, Manning roughness coefficient and groundwater time delay. In the framework of the SWOT preparation work, the automatic calibration procedure was applied using SWOT VM measurements. For this Observing System Experiment (OSE), the synthetical data were obtained applying an instrument simulator (representing realistic SWOT errors) for one hydrological year to HYMAP simulated WSE using a "true" set of parameters. Only pixels representing rivers larger than 100 meters within the Amazon basin are considered to produce SWOT VM measurements. The automatic calibration procedure leads to the estimation of optimal parametersminimizing objective functions that formulate the difference between SWOT observations and modeled WSE using a perturbed set of parameters. Different formulations of the objective function were used, especially to account for SWOT observation errors, as well as various sets of calibration parameters.

Fermentation process tracking through enhanced spectral calibration modeling.

PubMed

Triadaphillou, Sophia; Martin, Elaine; Montague, Gary; Norden, Alison; Jeffkins, Paul; Stimpson, Sarah

2007-06-15

The FDA process analytical technology (PAT) initiative will materialize in a significant increase in the number of installations of spectroscopic instrumentation. However, to attain the greatest benefit from the data generated, there is a need for calibration procedures that extract the maximum information content. For example, in fermentation processes, the interpretation of the resulting spectra is challenging as a consequence of the large number of wavelengths recorded, the underlying correlation structure that is evident between the wavelengths and the impact of the measurement environment. Approaches to the development of calibration models have been based on the application of partial least squares (PLS) either to the full spectral signature or to a subset of wavelengths. This paper presents a new approach to calibration modeling that combines a wavelength selection procedure, spectral window selection (SWS), where windows of wavelengths are automatically selected which are subsequently used as the basis of the calibration model. However, due to the non-uniqueness of the windows selected when the algorithm is executed repeatedly, multiple models are constructed and these are then combined using stacking thereby increasing the robustness of the final calibration model. The methodology is applied to data generated during the monitoring of broth concentrations in an industrial fermentation process from on-line near-infrared (NIR) and mid-infrared (MIR) spectrometers. It is shown that the proposed calibration modeling procedure outperforms traditional calibration procedures, as well as enabling the identification of the critical regions of the spectra with regard to the fermentation process.

Monitoring groundwater and river interaction along the Hanford reach of the Columbia River

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, M.D.

1994-04-01

As an adjunct to efficient Hanford Site characterization and remediation of groundwater contamination, an automatic monitor network has been used to measure Columbia River and adjacent groundwater levels in several areas of the Hanford Site since 1991. Water levels, temperatures, and electrical conductivity measured by the automatic monitor network provided an initial database with which to calibrate models and from which to infer ground and river water interactions for site characterization and remediation activities. Measurements of the dynamic river/aquifer system have been simultaneous at 1-hr intervals, with a quality suitable for hydrologic modeling and for computer model calibration and testing.more » This report describes the equipment, procedures, and results from measurements done in 1993.« less

Evaluation of Particle Counter Technology for Detection of Fuel Contamination Detection Utilizing Advanced Aviation Forward Area Refueling System

DTIC Science & Technology

2014-01-24

8, Automatic Particle Counter, cleanliness, free water, Diesel 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT none 18. NUMBER OF...aircraft, or up to 10 mg/L for product used as a diesel product for ground use (1). Free water contamination (droplets) may appear as fine droplets or...published several methods and test procedures for the calibration and use of automatic particle counters. The transition of this technology to the fuel

The algorithm for automatic detection of the calibration object

NASA Astrophysics Data System (ADS)

Artem, Kruglov; Irina, Ugfeld

2017-06-01

The problem of the automatic image calibration is considered in this paper. The most challenging task of the automatic calibration is a proper detection of the calibration object. The solving of this problem required the appliance of the methods and algorithms of the digital image processing, such as morphology, filtering, edge detection, shape approximation. The step-by-step process of the development of the algorithm and its adopting to the specific conditions of the log cuts in the image's background is presented. Testing of the automatic calibration module was carrying out under the conditions of the production process of the logging enterprise. Through the tests the average possibility of the automatic isolating of the calibration object is 86.1% in the absence of the type 1 errors. The algorithm was implemented in the automatic calibration module within the mobile software for the log deck volume measurement.

Drift-insensitive distributed calibration of probe microscope scanner in nanometer range: Virtual mode

NASA Astrophysics Data System (ADS)

Lapshin, Rostislav V.

2016-08-01

A method of distributed calibration of a probe microscope scanner is suggested. The main idea consists in a search for a net of local calibration coefficients (LCCs) in the process of automatic measurement of a standard surface, whereby each point of the movement space of the scanner can be characterized by a unique set of scale factors. Feature-oriented scanning (FOS) methodology is used as a basis for implementation of the distributed calibration permitting to exclude in situ the negative influence of thermal drift, creep and hysteresis on the obtained results. Possessing the calibration database enables correcting in one procedure all the spatial systematic distortions caused by nonlinearity, nonorthogonality and spurious crosstalk couplings of the microscope scanner piezomanipulators. To provide high precision of spatial measurements in nanometer range, the calibration is carried out using natural standards - constants of crystal lattice. One of the useful modes of the developed calibration method is a virtual mode. In the virtual mode, instead of measurement of a real surface of the standard, the calibration program makes a surface image ;measurement; of the standard, which was obtained earlier using conventional raster scanning. The application of the virtual mode permits simulation of the calibration process and detail analysis of raster distortions occurring in both conventional and counter surface scanning. Moreover, the mode allows to estimate the thermal drift and the creep velocities acting while surface scanning. Virtual calibration makes possible automatic characterization of a surface by the method of scanning probe microscopy (SPM).

Heliostat calibration using attached cameras and artificial targets

NASA Astrophysics Data System (ADS)

Burisch, Michael; Sanchez, Marcelino; Olarra, Aitor; Villasante, Cristobal

2016-05-01

The efficiency of the solar field greatly depends on the ability of the heliostats to precisely reflect solar radiation onto a central receiver. To control the heliostats with such a precision requires the accurate knowledge of the motion of each of them. The motion of each heliostat can be described by a set of parameters, most notably the position and axis configuration. These parameters have to be determined individually for each heliostat during a calibration process. With the ongoing development of small sized heliostats, the ability to automatically perform such a calibration becomes more and more crucial as possibly hundreds of thousands of heliostats are involved. Furthermore, efficiency becomes an important factor as small sized heliostats potentially have to be recalibrated far more often, due to the limited stability of the components. In the following we present an automatic calibration procedure using cameras attached to each heliostat which are observing different targets spread throughout the solar field. Based on a number of observations of these targets under different heliostat orientations, the parameters describing the heliostat motion can be estimated with high precision.

Automatic Calibration of Global Flow Routing Model Parameters in the Amazon Basin Using Virtual SWOT Data

NASA Astrophysics Data System (ADS)

Mouffe, Melodie; Getirana, Augusto; Ricci, Sophie; Lion, Christine; Biancamaria, Sylvian; Boone, Aaron; Mognard, Nelly; Rogel, Philippe

2013-09-01

The Surface Water and Ocean Topography (SWOT) wide swath altimetry mission will provide measurements of water surface elevations (WSE) at a global scale. The aim of this study is to investigate the potential of these satellite data for the calibration of the hydrological model HyMAP, over the Amazon river basin. Since SWOT has not yet been launched, synthetical observations are used to calibrate the river bed depth and width, the Manning coefficient and the baseflow concentration time. The calibration process stands in the minimization of a cost function using an evolutionnary, global and multi-objective algorithm that describes the difference between the simulated and the observed WSE. We found that the calibration procedure is able to retrieve an optimal set of parameters such that it brings the simulated WSE closer to the observation. Still with a global calibration procedure where a uniform correction is applied, the improvement is limited to a mean correction over the catchment and the simulation period. We conclude that in order to benefit from the high resolution and complete coverage of the SWOT mission, the calibration process should be achieved sequentially in time over sub-domains as observations become available.

New software tools for enhanced precision in robot-assisted laser phonomicrosurgery.

PubMed

Dagnino, Giulio; Mattos, Leonardo S; Caldwell, Darwin G

2012-01-01

This paper describes a new software package created to enhance precision during robot-assisted laser phonomicrosurgery procedures. The new software is composed of three tools for camera calibration, automatic tumor segmentation, and laser tracking. These were designed and developed to improve the outcome of this demanding microsurgical technique, and were tested herein to produce quantitative performance data. The experimental setup was based on the motorized laser micromanipulator created by Istituto Italiano di Tecnologia and the experimental protocols followed are fully described in this paper. The results show the new tools are robust and effective: The camera calibration tool reduced residual errors (RMSE) to 0.009 ± 0.002 mm under 40× microscope magnification; the automatic tumor segmentation tool resulted in deep lesion segmentations comparable to manual segmentations (RMSE= 0.160 ± 0.028 mm under 40× magnification); and the laser tracker tool proved to be reliable even during cutting procedures (RMSE= 0.073 ± 0.023 mm under 40× magnification). These results demonstrate the new software package can provide excellent improvements to the previous microsurgical system, leading to important enhancements in surgical outcome.

User-friendly freehand ultrasound calibration using Lego bricks and automatic registration.

PubMed

Xiao, Yiming; Yan, Charles Xiao Bo; Drouin, Simon; De Nigris, Dante; Kochanowska, Anna; Collins, D Louis

2016-09-01

As an inexpensive, noninvasive, and portable clinical imaging modality, ultrasound (US) has been widely employed in many interventional procedures for monitoring potential tissue deformation, surgical tool placement, and locating surgical targets. The application requires the spatial mapping between 2D US images and 3D coordinates of the patient. Although positions of the devices (i.e., ultrasound transducer) and the patient can be easily recorded by a motion tracking system, the spatial relationship between the US image and the tracker attached to the US transducer needs to be estimated through an US calibration procedure. Previously, various calibration techniques have been proposed, where a spatial transformation is computed to match the coordinates of corresponding features in a physical phantom and those seen in the US scans. However, most of these methods are difficult to use for novel users. We proposed an ultrasound calibration method by constructing a phantom from simple Lego bricks and applying an automated multi-slice 2D-3D registration scheme without volumetric reconstruction. The method was validated for its calibration accuracy and reproducibility. Our method yields a calibration accuracy of [Formula: see text] mm and a calibration reproducibility of 1.29 mm. We have proposed a robust, inexpensive, and easy-to-use ultrasound calibration method.

Optimization of Equation of State and Burn Model Parameters for Explosives

NASA Astrophysics Data System (ADS)

Bergh, Magnus; Wedberg, Rasmus; Lundgren, Jonas

2017-06-01

A reactive burn model implemented in a multi-dimensional hydrocode can be a powerful tool for predicting non-ideal effects as well as initiation phenomena in explosives. Calibration against experiment is, however, critical and non-trivial. Here, a procedure is presented for calibrating the Ignition and Growth Model utilizing hydrocode simulation in conjunction with the optimization program LS-OPT. The model is applied to the explosive PBXN-109. First, a cylinder expansion test is presented together with a new automatic routine for product equation of state calibration. Secondly, rate stick tests and instrumented gap tests are presented. Data from these experiments are used to calibrate burn model parameters. Finally, we discuss the applicability and development of this optimization routine.

Accurate and automatic extrinsic calibration method for blade measurement system integrated by different optical sensors

NASA Astrophysics Data System (ADS)

He, Wantao; Li, Zhongwei; Zhong, Kai; Shi, Yusheng; Zhao, Can; Cheng, Xu

2014-11-01

Fast and precise 3D inspection system is in great demand in modern manufacturing processes. At present, the available sensors have their own pros and cons, and hardly exist an omnipotent sensor to handle the complex inspection task in an accurate and effective way. The prevailing solution is integrating multiple sensors and taking advantages of their strengths. For obtaining a holistic 3D profile, the data from different sensors should be registrated into a coherent coordinate system. However, some complex shape objects own thin wall feather such as blades, the ICP registration method would become unstable. Therefore, it is very important to calibrate the extrinsic parameters of each sensor in the integrated measurement system. This paper proposed an accurate and automatic extrinsic parameter calibration method for blade measurement system integrated by different optical sensors. In this system, fringe projection sensor (FPS) and conoscopic holography sensor (CHS) is integrated into a multi-axis motion platform, and the sensors can be optimally move to any desired position at the object's surface. In order to simple the calibration process, a special calibration artifact is designed according to the characteristics of the two sensors. An automatic registration procedure based on correlation and segmentation is used to realize the artifact datasets obtaining by FPS and CHS rough alignment without any manual operation and data pro-processing, and then the Generalized Gauss-Markoff model is used to estimate the optimization transformation parameters. The experiments show the measurement result of a blade, where several sampled patches are merged into one point cloud, and it verifies the performance of the proposed method.

Cross modality registration of video and magnetic tracker data for 3D appearance and structure modeling

NASA Astrophysics Data System (ADS)

Sargent, Dusty; Chen, Chao-I.; Wang, Yuan-Fang

2010-02-01

The paper reports a fully-automated, cross-modality sensor data registration scheme between video and magnetic tracker data. This registration scheme is intended for use in computerized imaging systems to model the appearance, structure, and dimension of human anatomy in three dimensions (3D) from endoscopic videos, particularly colonoscopic videos, for cancer research and clinical practices. The proposed cross-modality calibration procedure operates this way: Before a colonoscopic procedure, the surgeon inserts a magnetic tracker into the working channel of the endoscope or otherwise fixes the tracker's position on the scope. The surgeon then maneuvers the scope-tracker assembly to view a checkerboard calibration pattern from a few different viewpoints for a few seconds. The calibration procedure is then completed, and the relative pose (translation and rotation) between the reference frames of the magnetic tracker and the scope is determined. During the colonoscopic procedure, the readings from the magnetic tracker are used to automatically deduce the pose (both position and orientation) of the scope's reference frame over time, without complicated image analysis. Knowing the scope movement over time then allows us to infer the 3D appearance and structure of the organs and tissues in the scene. While there are other well-established mechanisms for inferring the movement of the camera (scope) from images, they are often sensitive to mistakes in image analysis, error accumulation, and structure deformation. The proposed method using a magnetic tracker to establish the camera motion parameters thus provides a robust and efficient alternative for 3D model construction. Furthermore, the calibration procedure does not require special training nor use expensive calibration equipment (except for a camera calibration pattern-a checkerboard pattern-that can be printed on any laser or inkjet printer).

Wavelength calibration of arc spectra using intensity modelling

NASA Astrophysics Data System (ADS)

Balona, L. A.

2010-12-01

Wavelength calibration for astronomical spectra usually involves the use of different arc lamps for different resolving powers to reduce the problem of line blending. We present a technique which eliminates the necessity of different lamps. A lamp producing a very rich spectrum, normally used only at high resolving powers, can be used at the lowest resolving power as well. This is accomplished by modelling the observed arc spectrum and solving for the wavelength calibration as part of the modelling procedure. Line blending is automatically incorporated as part of the model. The method has been implemented and successfully tested on spectra taken with the Robert Stobie spectrograph of the Southern African Large Telescope.

Performance analysis of a film dosimetric quality assurance procedure for IMRT with regard to the employment of quantitative evaluation methods.

PubMed

Winkler, Peter; Zurl, Brigitte; Guss, Helmuth; Kindl, Peter; Stuecklschweiger, Georg

2005-02-21

A system for dosimetric verification of intensity-modulated radiotherapy (IMRT) treatment plans using absolute calibrated radiographic films is presented. At our institution this verification procedure is performed for all IMRT treatment plans prior to patient irradiation. Therefore clinical treatment plans are transferred to a phantom and recalculated. Composite treatment plans are irradiated to a single film. Film density to absolute dose conversion is performed automatically based on a single calibration film. A software application encompassing film calibration, 2D registration of measurement and calculated distributions, image fusion, and a number of visual and quantitative evaluation utilities was developed. The main topic of this paper is a performance analysis for this quality assurance procedure, with regard to the specification of tolerance levels for quantitative evaluations. Spatial and dosimetric precision and accuracy were determined for the entire procedure, comprising all possible sources of error. The overall dosimetric and spatial measurement uncertainties obtained thereby were 1.9% and 0.8 mm respectively. Based on these results, we specified 5% dose difference and 3 mm distance-to-agreement as our tolerance levels for patient-specific quality assurance for IMRT treatments.

A flow-batch analyzer with piston propulsion applied to automatic preparation of calibration solutions for Mn determination in mineral waters by ET AAS.

PubMed

Almeida, Luciano F; Vale, Maria G R; Dessuy, Morgana B; Silva, Márcia M; Lima, Renato S; Santos, Vagner B; Diniz, Paulo H D; Araújo, Mário C U

2007-10-31

The increasing development of miniaturized flow systems and the continuous monitoring of chemical processes require dramatically simplified and cheap flow schemes and instrumentation with large potential for miniaturization and consequent portability. For these purposes, the development of systems based on flow and batch technologies may be a good alternative. Flow-batch analyzers (FBA) have been successfully applied to implement analytical procedures, such as: titrations, sample pre-treatment, analyte addition and screening analysis. In spite of its favourable characteristics, the previously proposed FBA uses peristaltic pumps to propel the fluids and this kind of propulsion presents high cost and large dimension, making unfeasible its miniaturization and portability. To overcome these drawbacks, a low cost, robust, compact and non-propelled by peristaltic pump FBA is proposed. It makes use of a lab-made piston coupled to a mixing chamber and a step motor controlled by a microcomputer. The piston-propelled FBA (PFBA) was applied for automatic preparation of calibration solutions for manganese determination in mineral waters by electrothermal atomic-absorption spectrometry (ET AAS). Comparing the results obtained with two sets of calibration curves (five by manual and five by PFBA preparations), no significant statistical differences at a 95% confidence level were observed by applying the paired t-test. The standard deviation of manual and PFBA procedures were always smaller than 0.2 and 0.1mugL(-1), respectively. By using PFBA it was possible to prepare about 80 calibration solutions per hour.

Semi-Automatic Determination of Rockfall Trajectories

PubMed Central

Volkwein, Axel; Klette, Johannes

2014-01-01

In determining rockfall trajectories in the field, it is essential to calibrate and validate rockfall simulation software. This contribution presents an in situ device and a complementary Local Positioning System (LPS) that allow the determination of parts of the trajectory. An assembly of sensors (herein called rockfall sensor) is installed in the falling block recording the 3D accelerations and rotational velocities. The LPS automatically calculates the position of the block along the slope over time based on Wi-Fi signals emitted from the rockfall sensor. The velocity of the block over time is determined through post-processing. The setup of the rockfall sensor is presented followed by proposed calibration and validation procedures. The performance of the LPS is evaluated by means of different experiments. The results allow for a quality analysis of both the obtained field data and the usability of the rockfall sensor for future/further applications in the field. PMID:25268916

Numerical Differentiation Methods for Computing Error Covariance Matrices in Item Response Theory Modeling: An Evaluation and a New Proposal

ERIC Educational Resources Information Center

Tian, Wei; Cai, Li; Thissen, David; Xin, Tao

2013-01-01

In item response theory (IRT) modeling, the item parameter error covariance matrix plays a critical role in statistical inference procedures. When item parameters are estimated using the EM algorithm, the parameter error covariance matrix is not an automatic by-product of item calibration. Cai proposed the use of Supplemented EM algorithm for…

The precision measurement and assembly for miniature parts based on double machine vision systems

NASA Astrophysics Data System (ADS)

Wang, X. D.; Zhang, L. F.; Xin, M. Z.; Qu, Y. Q.; Luo, Y.; Ma, T. M.; Chen, L.

2015-02-01

In the process of miniature parts' assembly, the structural features on the bottom or side of the parts often need to be aligned and positioned. The general assembly equipment integrated with one vertical downward machine vision system cannot satisfy the requirement. A precision automatic assembly equipment was developed with double machine vision systems integrated. In the system, a horizontal vision system is employed to measure the position of the feature structure at the parts' side view, which cannot be seen with the vertical one. The position measured by horizontal camera is converted to the vertical vision system with the calibration information. By careful calibration, the parts' alignment and positioning in the assembly process can be guaranteed. The developed assembly equipment has the characteristics of easy implementation, modularization and high cost performance. The handling of the miniature parts and assembly procedure were briefly introduced. The calibration procedure was given and the assembly error was analyzed for compensation.

A real-time freehand ultrasound calibration system with automatic accuracy feedback and control.

PubMed

Chen, Thomas Kuiran; Thurston, Adrian D; Ellis, Randy E; Abolmaesumi, Purang

2009-01-01

This article describes a fully automatic, real-time, freehand ultrasound calibration system. The system was designed to be simple and sterilizable, intended for operating-room usage. The calibration system employed an automatic-error-retrieval and accuracy-control mechanism based on a set of ground-truth data. Extensive validations were conducted on a data set of 10,000 images in 50 independent calibration trials to thoroughly investigate the accuracy, robustness, and performance of the calibration system. On average, the calibration accuracy (measured in three-dimensional reconstruction error against a known ground truth) of all 50 trials was 0.66 mm. In addition, the calibration errors converged to submillimeter in 98% of all trials within 12.5 s on average. Overall, the calibration system was able to consistently, efficiently and robustly achieve high calibration accuracy with real-time performance.

Preliminary flight prototype silver ion monitoring system

NASA Technical Reports Server (NTRS)

Brady, J.

1974-01-01

The design, fabrication, and testing of a preliminary flight prototype silver ion monitoring system based on potentiometric principles and utilizing a solid-state silver sulfide electrode paired with a pressurized double-junction reference electrode housing a replaceable electrolyte reservoir is described. The design provides automatic electronic calibration utilizing saturated silver bromide solution as a silver ion standard. The problem of loss of silver ion from recirculating fluid, its cause, and corrective procedures are reported. The instability of the silver sulfide electrode is discussed as well as difficulties met in implementing the autocalibration procedure.

Quantitative X-ray Map Analyser (Q-XRMA): A new GIS-based statistical approach to Mineral Image Analysis

NASA Astrophysics Data System (ADS)

Ortolano, Gaetano; Visalli, Roberto; Godard, Gaston; Cirrincione, Rosolino

2018-06-01

We present a new ArcGIS®-based tool developed in the Python programming language for calibrating EDS/WDS X-ray element maps, with the aim of acquiring quantitative information of petrological interest. The calibration procedure is based on a multiple linear regression technique that takes into account interdependence among elements and is constrained by the stoichiometry of minerals. The procedure requires an appropriate number of spot analyses for use as internal standards and provides several test indexes for a rapid check of calibration accuracy. The code is based on an earlier image-processing tool designed primarily for classifying minerals in X-ray element maps; the original Python code has now been enhanced to yield calibrated maps of mineral end-members or the chemical parameters of each classified mineral. The semi-automated procedure can be used to extract a dataset that is automatically stored within queryable tables. As a case study, the software was applied to an amphibolite-facies garnet-bearing micaschist. The calibrated images obtained for both anhydrous (i.e., garnet and plagioclase) and hydrous (i.e., biotite) phases show a good fit with corresponding electron microprobe analyses. This new GIS-based tool package can thus find useful application in petrology and materials science research. Moreover, the huge quantity of data extracted opens new opportunities for the development of a thin-section microchemical database that, using a GIS platform, can be linked with other major global geoscience databases.

Virtual Instrument for Determining Rate Constant of Second-Order Reaction by pX Based on LabVIEW 8.0.

PubMed

Meng, Hu; Li, Jiang-Yuan; Tang, Yong-Huai

2009-01-01

The virtual instrument system based on LabVIEW 8.0 for ion analyzer which can measure and analyze ion concentrations in solution is developed and comprises homemade conditioning circuit, data acquiring board, and computer. It can calibrate slope, temperature, and positioning automatically. When applied to determine the reaction rate constant by pX, it achieved live acquiring, real-time displaying, automatical processing of testing data, generating the report of results; and other functions. This method simplifies the experimental operation greatly, avoids complicated procedures of manual processing data and personal error, and improves veracity and repeatability of the experiment results.

Colorimetric calibration of wound photography with off-the-shelf devices

NASA Astrophysics Data System (ADS)

Bala, Subhankar; Sirazitdinova, Ekaterina; Deserno, Thomas M.

2017-03-01

Digital cameras are often used in recent days for photographic documentation in medical sciences. However, color reproducibility of same objects suffers from different illuminations and lighting conditions. This variation in color representation is problematic when the images are used for segmentation and measurements based on color thresholds. In this paper, motivated by photographic follow-up of chronic wounds, we assess the impact of (i) gamma correction, (ii) white balancing, (iii) background unification, and (iv) reference card-based color correction. Automatic gamma correction and white balancing are applied to support the calibration procedure, where gamma correction is a nonlinear color transform. For unevenly illuminated images, non- uniform illumination correction is applied. In the last step, we apply colorimetric calibration using a reference color card of 24 patches with known colors. A lattice detection algorithm is used for locating the card. The least squares algorithm is applied for affine color calibration in the RGB model. We have tested the algorithm on images with seven different types of illumination: with and without flash using three different off-the-shelf cameras including smartphones. We analyzed the spread of resulting color value of selected color patch before and after applying the calibration. Additionally, we checked the individual contribution of different steps of the whole calibration process. Using all steps, we were able to achieve a maximum of 81% reduction in standard deviation of color patch values in resulting images comparing to the original images. That supports manual as well as automatic quantitative wound assessments with off-the-shelf devices.

Automatic alignment method for calibration of hydrometers

NASA Astrophysics Data System (ADS)

Lee, Y. J.; Chang, K. H.; Chon, J. C.; Oh, C. Y.

2004-04-01

This paper presents a new method to automatically align specific scale-marks for the calibration of hydrometers. A hydrometer calibration system adopting the new method consists of a vision system, a stepping motor, and software to control the system. The vision system is composed of a CCD camera and a frame grabber, and is used to acquire images. The stepping motor moves the camera, which is attached to the vessel containing a reference liquid, along the hydrometer. The operating program has two main functions: to process images from the camera to find the position of the horizontal plane and to control the stepping motor for the alignment of the horizontal plane with a particular scale-mark. Any system adopting this automatic alignment method is a convenient and precise means of calibrating a hydrometer. The performance of the proposed method is illustrated by comparing the calibration results using the automatic alignment method with those obtained using the manual method.

Applying Hierarchical Model Calibration to Automatically Generated Items.

ERIC Educational Resources Information Center

Williamson, David M.; Johnson, Matthew S.; Sinharay, Sandip; Bejar, Isaac I.

This study explored the application of hierarchical model calibration as a means of reducing, if not eliminating, the need for pretesting of automatically generated items from a common item model prior to operational use. Ultimately the successful development of automatic item generation (AIG) systems capable of producing items with highly similar…

A Novel Protocol for Model Calibration in Biological Wastewater Treatment

PubMed Central

Zhu, Ao; Guo, Jianhua; Ni, Bing-Jie; Wang, Shuying; Yang, Qing; Peng, Yongzhen

2015-01-01

Activated sludge models (ASMs) have been widely used for process design, operation and optimization in wastewater treatment plants. However, it is still a challenge to achieve an efficient calibration for reliable application by using the conventional approaches. Hereby, we propose a novel calibration protocol, i.e. Numerical Optimal Approaching Procedure (NOAP), for the systematic calibration of ASMs. The NOAP consists of three key steps in an iterative scheme flow: i) global factors sensitivity analysis for factors fixing; ii) pseudo-global parameter correlation analysis for non-identifiable factors detection; and iii) formation of a parameter subset through an estimation by using genetic algorithm. The validity and applicability are confirmed using experimental data obtained from two independent wastewater treatment systems, including a sequencing batch reactor and a continuous stirred-tank reactor. The results indicate that the NOAP can effectively determine the optimal parameter subset and successfully perform model calibration and validation for these two different systems. The proposed NOAP is expected to use for automatic calibration of ASMs and be applied potentially to other ordinary differential equations models. PMID:25682959

A fully automated calibration method for an optical see-through head-mounted operating microscope with variable zoom and focus.

PubMed

Figl, Michael; Ede, Christopher; Hummel, Johann; Wanschitz, Felix; Ewers, Rolf; Bergmann, Helmar; Birkfellner, Wolfgang

2005-11-01

Ever since the development of the first applications in image-guided therapy (IGT), the use of head-mounted displays (HMDs) was considered an important extension of existing IGT technologies. Several approaches to utilizing HMDs and modified medical devices for augmented reality (AR) visualization were implemented. These approaches include video-see through systems, semitransparent mirrors, modified endoscopes, and modified operating microscopes. Common to all these devices is the fact that a precise calibration between the display and three-dimensional coordinates in the patient's frame of reference is compulsory. In optical see-through devices based on complex optical systems such as operating microscopes or operating binoculars-as in the case of the system presented in this paper-this procedure can become increasingly difficult since precise camera calibration for every focus and zoom position is required. We present a method for fully automatic calibration of the operating binocular Varioscope M5 AR for the full range of zoom and focus settings available. Our method uses a special calibration pattern, a linear guide driven by a stepping motor, and special calibration software. The overlay error in the calibration plane was found to be 0.14-0.91 mm, which is less than 1% of the field of view. Using the motorized calibration rig as presented in the paper, we were also able to assess the dynamic latency when viewing augmentation graphics on a mobile target; spatial displacement due to latency was found to be in the range of 1.1-2.8 mm maximum, the disparity between the true object and its computed overlay represented latency of 0.1 s. We conclude that the automatic calibration method presented in this paper is sufficient in terms of accuracy and time requirements for standard uses of optical see-through systems in a clinical environment.

Virtual Instrument for Determining Rate Constant of Second-Order Reaction by pX Based on LabVIEW 8.0

PubMed Central

Meng, Hu; Li, Jiang-Yuan; Tang, Yong-Huai

2009-01-01

The virtual instrument system based on LabVIEW 8.0 for ion analyzer which can measure and analyze ion concentrations in solution is developed and comprises homemade conditioning circuit, data acquiring board, and computer. It can calibrate slope, temperature, and positioning automatically. When applied to determine the reaction rate constant by pX, it achieved live acquiring, real-time displaying, automatical processing of testing data, generating the report of results; and other functions. This method simplifies the experimental operation greatly, avoids complicated procedures of manual processing data and personal error, and improves veracity and repeatability of the experiment results. PMID:19730752

Field Evaluation of Particle Counter Technology for Aviation Fuel Contamination Detection - Fort Rucker

DTIC Science & Technology

2013-06-20

Automatic Particle Counter, cleanliness, free water, Diesel 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT none 18. NUMBER OF PAGES...Governmental transfer receipts and 1.0 mg/L on issue to aircraft, or up to 10 mg/L for product used as a diesel product for ground use (1). Free...industry. The International Organization for Standardization (ISO) has published several methods and test procedures for the calibration and use of

Improved diffusing wave spectroscopy based on the automatized determination of the optical transport and absorption mean free path

NASA Astrophysics Data System (ADS)

Zhang, Chi; Reufer, Mathias; Gaudino, Danila; Scheffold, Frank

2017-11-01

Diffusing wave spectroscopy (DWS) can be employed as an optical rheology tool with numerous applications for studying the structure, dynamics and linear viscoelastic properties of complex fluids, foams, glasses and gels. To carry out DWS measurements, one first needs to quantify the static optical properties of the sample under investigation, i.e. the transport mean free path l * and the absorption length l a. In the absence of absorption this can be done by comparing the diffuse optical transmission to a calibration sample whose l * is known. Performing this comparison however is cumbersome, time consuming, and prone to mistakes by the operator. Moreover, already weak absorption can lead to significant errors. In this paper, we demonstrate the implementation of an automatized approach, based on which the DWS measurement procedure can be simplified significantly. By comparison with a comprehensive set of calibration measurements we cover the entire parameter space relating measured count rates ( CR t , CR b ) to ( l *, l a). Based on this approach we can determine l * and la of an unknown sample accurately thus making the additional measurement of a calibration sample obsolete. We illustrate the use of this approach by monitoring the coarsening of a commercially available shaving foam with DWS.

Automatic calibration system for analog instruments based on DSP and CCD sensor

NASA Astrophysics Data System (ADS)

Lan, Jinhui; Wei, Xiangqin; Bai, Zhenlong

2008-12-01

Currently, the calibration work of analog measurement instruments is mainly completed by manual and there are many problems waiting for being solved. In this paper, an automatic calibration system (ACS) based on Digital Signal Processor (DSP) and Charge Coupled Device (CCD) sensor is developed and a real-time calibration algorithm is presented. In the ACS, TI DM643 DSP processes the data received by CCD sensor and the outcome is displayed on Liquid Crystal Display (LCD) screen. For the algorithm, pointer region is firstly extracted for improving calibration speed. And then a math model of the pointer is built to thin the pointer and determine the instrument's reading. Through numbers of experiments, the time of once reading is no more than 20 milliseconds while it needs several seconds if it is done manually. At the same time, the error of the instrument's reading satisfies the request of the instruments. It is proven that the automatic calibration system can effectively accomplish the calibration work of the analog measurement instruments.

Automatic Calibration Method for Driver’s Head Orientation in Natural Driving Environment

PubMed Central

Fu, Xianping; Guan, Xiao; Peli, Eli; Liu, Hongbo; Luo, Gang

2013-01-01

Gaze tracking is crucial for studying driver’s attention, detecting fatigue, and improving driver assistance systems, but it is difficult in natural driving environments due to nonuniform and highly variable illumination and large head movements. Traditional calibrations that require subjects to follow calibrators are very cumbersome to be implemented in daily driving situations. A new automatic calibration method, based on a single camera for determining the head orientation and which utilizes the side mirrors, the rear-view mirror, the instrument board, and different zones in the windshield as calibration points, is presented in this paper. Supported by a self-learning algorithm, the system tracks the head and categorizes the head pose in 12 gaze zones based on facial features. The particle filter is used to estimate the head pose to obtain an accurate gaze zone by updating the calibration parameters. Experimental results show that, after several hours of driving, the automatic calibration method without driver’s corporation can achieve the same accuracy as a manual calibration method. The mean error of estimated eye gazes was less than 5°in day and night driving. PMID:24639620

Evaluation of Particle Counter Technology for Detection of Fuel Contamination Detection Utilizing Fuel System Supply Point

DTIC Science & Technology

2014-06-19

product used as a diesel product for ground use (1). Free water contamination (droplets) may appear as fine droplets or slugs of water in the fuel...methods and test procedures for the calibration and use of automatic particle counters. The transition of this technology to the fuel industry is...UNCLASSIFIED 6 UNCLASSIFIED Receipt Vehicle Fuel Tank Fuel Injector Aviation Fuel DEF (AUST) 5695B 18/16/13 Parker 18

Calibration of the LHAASO-KM2A electromagnetic particle detectors using charged particles within the extensive air showers

NASA Astrophysics Data System (ADS)

Lv, Hongkui; He, Huihai; Sheng, Xiangdong; Liu, Jia; Chen, Songzhan; Liu, Ye; Hou, Chao; Zhao, Jing; Zhang, Zhongquan; Wu, Sha; Wang, Yaping; Lhaaso Collaboration

2018-07-01

In the Large High Altitude Air Shower Observatory (LHAASO), one square kilometer array (KM2A), with 5242 electromagnetic particle detectors (EDs) and 1171 muon detectors (MDs), is designed to study ultra-high energy gamma-ray astronomy and cosmic ray physics. The remoteness and numerous detectors extremely demand a robust and automatic calibration procedure. In this paper, a self-calibration method which relies on the measurement of charged particles within the extensive air showers is proposed. The method is fully validated by Monte Carlo simulation and successfully applied in a KM2A prototype array experiment. Experimental results show that the self-calibration method can be used to determine the detector time offset constants at the sub-nanosecond level and the number density of particles collected by each ED with an accuracy of a few percents, which are adequate to meet the physical requirements of LHAASO experiment. This software calibration also offers an ideal method to realtime monitor the detector performances for next generation ground-based EAS experiments covering an area above square kilometers scale.

An integrated approach to monitoring the calibration stability of operational dual-polarization radars

DOE PAGES

Vaccarono, Mattia; Bechini, Renzo; Chandrasekar, Chandra V.; ...

2016-11-08

The stability of weather radar calibration is a mandatory aspect for quantitative applications, such as rainfall estimation, short-term weather prediction and initialization of numerical atmospheric and hydrological models. Over the years, calibration monitoring techniques based on external sources have been developed, specifically calibration using the Sun and calibration based on ground clutter returns. In this paper, these two techniques are integrated and complemented with a self-consistency procedure and an intercalibration technique. The aim of the integrated approach is to implement a robust method for online monitoring, able to detect significant changes in the radar calibration. The physical consistency of polarimetricmore » radar observables is exploited using the self-consistency approach, based on the expected correspondence between dual-polarization power and phase measurements in rain. This technique allows a reference absolute value to be provided for the radar calibration, from which eventual deviations may be detected using the other procedures. In particular, the ground clutter calibration is implemented on both polarization channels (horizontal and vertical) for each radar scan, allowing the polarimetric variables to be monitored and hardware failures to promptly be recognized. The Sun calibration allows monitoring the calibration and sensitivity of the radar receiver, in addition to the antenna pointing accuracy. It is applied using observations collected during the standard operational scans but requires long integration times (several days) in order to accumulate a sufficient amount of useful data. Finally, an intercalibration technique is developed and performed to compare colocated measurements collected in rain by two radars in overlapping regions. The integrated approach is performed on the C-band weather radar network in northwestern Italy, during July–October 2014. The set of methods considered appears suitable to establish an online tool to monitor the stability of the radar calibration with an accuracy of about 2 dB. In conclusion, this is considered adequate to automatically detect any unexpected change in the radar system requiring further data analysis or on-site measurements.« less

When to Make Mountains out of Molehills: The Pros and Cons of Simple and Complex Model Calibration Procedures

NASA Astrophysics Data System (ADS)

Smith, K. A.; Barker, L. J.; Harrigan, S.; Prudhomme, C.; Hannaford, J.; Tanguy, M.; Parry, S.

2017-12-01

Earth and environmental models are relied upon to investigate system responses that cannot otherwise be examined. In simulating physical processes, models have adjustable parameters which may, or may not, have a physical meaning. Determining the values to assign to these model parameters is an enduring challenge for earth and environmental modellers. Selecting different error metrics by which the models results are compared to observations will lead to different sets of calibrated model parameters, and thus different model results. Furthermore, models may exhibit `equifinal' behaviour, where multiple combinations of model parameters lead to equally acceptable model performance against observations. These decisions in model calibration introduce uncertainty that must be considered when model results are used to inform environmental decision-making. This presentation focusses on the uncertainties that derive from the calibration of a four parameter lumped catchment hydrological model (GR4J). The GR models contain an inbuilt automatic calibration algorithm that can satisfactorily calibrate against four error metrics in only a few seconds. However, a single, deterministic model result does not provide information on parameter uncertainty. Furthermore, a modeller interested in extreme events, such as droughts, may wish to calibrate against more low flows specific error metrics. In a comprehensive assessment, the GR4J model has been run with 500,000 Latin Hypercube Sampled parameter sets across 303 catchments in the United Kingdom. These parameter sets have been assessed against six error metrics, including two drought specific metrics. This presentation compares the two approaches, and demonstrates that the inbuilt automatic calibration can outperform the Latin Hypercube experiment approach in single metric assessed performance. However, it is also shown that there are many merits of the more comprehensive assessment, which allows for probabilistic model results, multi-objective optimisation, and better tailoring to calibrate the model for specific applications such as drought event characterisation. Modellers and decision-makers may be constrained in their choice of calibration method, so it is important that they recognise the strengths and limitations of their chosen approach.

Data analysis and calibration for a bulk-refractive-index-compensated surface plasmon resonance affinity sensor

NASA Astrophysics Data System (ADS)

Chinowsky, Timothy M.; Yee, Sinclair S.

2002-02-01

Surface plasmon resonance (SPR) affinity sensing, the problem of bulk refractive index (RI) interference in SPR sensing, and a sensor developed to overcome this problem are briefly reviewed. The sensor uses a design based on Texas Instruments' Spreeta SPR sensor to simultaneously measure both bulk and surface RI. The bulk RI measurement is then used to compensate the surface measurement and remove the effects of bulk RI interference. To achieve accurate compensation, robust data analysis and calibration techniques are necessary. Simple linear data analysis techniques derived from measurements of the sensor response were found to provide a versatile, low noise method for extracting measurements of bulk and surface refractive index from the raw sensor data. Automatic calibration using RI gradients was used to correct the linear estimates, enabling the sensor to produce accurate data even when the sensor has a complicated nonlinear response which varies with time. The calibration procedure is described, and the factors influencing calibration accuracy are discussed. Data analysis and calibration principles are illustrated with an experiment in which sucrose and detergent solutions are used to produce changes in bulk and surface RI, respectively.

Status of calibration and data evaluation of AMSR on board ADEOS-II

NASA Astrophysics Data System (ADS)

Imaoka, Keiji; Fujimoto, Yasuhiro; Kachi, Misako; Takeshima, Toshiaki; Igarashi, Tamotsu; Kawanishi, Toneo; Shibata, Akira

2004-02-01

The Advanced Microwave Scanning Radiometer (AMSR) is the multi-frequency, passive microwave radiometer on board the Advanced Earth Observing Satellite-II (ADEOS-II), currently called Midori-II. The instrument has eight-frequency channels with dual polarization (except 50-GHz band) covering frequencies between 6.925 and 89.0 GHz. Measurement of 50-GHz channels is the first attempt by this kind of conically scanning microwave radiometers. Basic concept of the instrument including hardware configuration and calibration method is almost the same as that of ASMR for EOS (AMSR-E), the modified version of AMSR. Its swath width of 1,600 km is wider than that of AMSR-E. In parallel with the calibration and data evaluation of AMSR-E instrument, almost identical calibration activities have been made for AMSR instrument. After finished the initial checkout phase, the instrument has been continuously obtaining the data in global basis. Time series of radiometer sensitivities and automatic gain control telemetry indicate the stable instrument performance. For the radiometric calibration, we are now trying to apply the same procedure that is being used for AMSR-E. This paper provides an overview of the instrument characteristics, instrument status, and preliminary results of calibration and data evaluation activities.

Direct Estimation of Power Distribution in Reactors for Nuclear Thermal Space Propulsion

NASA Astrophysics Data System (ADS)

Aldemir, Tunc; Miller, Don W.; Burghelea, Andrei

2004-02-01

A recently proposed constant temperature power sensor (CTPS) has the capability to directly measure the local power deposition rate in nuclear reactor cores proposed for space thermal propulsion. Such a capability reduces the uncertainties in the estimated power peaking factors and hence increases the reliability of the nuclear engine. The CTPS operation is sensitive to the changes in the local thermal conditions. A procedure is described for the automatic on-line calibration of the sensor through estimation of changes in thermal .conditions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vaccarono, Mattia; Bechini, Renzo; Chandrasekar, Chandra V.

The stability of weather radar calibration is a mandatory aspect for quantitative applications, such as rainfall estimation, short-term weather prediction and initialization of numerical atmospheric and hydrological models. Over the years, calibration monitoring techniques based on external sources have been developed, specifically calibration using the Sun and calibration based on ground clutter returns. In this paper, these two techniques are integrated and complemented with a self-consistency procedure and an intercalibration technique. The aim of the integrated approach is to implement a robust method for online monitoring, able to detect significant changes in the radar calibration. The physical consistency of polarimetricmore » radar observables is exploited using the self-consistency approach, based on the expected correspondence between dual-polarization power and phase measurements in rain. This technique allows a reference absolute value to be provided for the radar calibration, from which eventual deviations may be detected using the other procedures. In particular, the ground clutter calibration is implemented on both polarization channels (horizontal and vertical) for each radar scan, allowing the polarimetric variables to be monitored and hardware failures to promptly be recognized. The Sun calibration allows monitoring the calibration and sensitivity of the radar receiver, in addition to the antenna pointing accuracy. It is applied using observations collected during the standard operational scans but requires long integration times (several days) in order to accumulate a sufficient amount of useful data. Finally, an intercalibration technique is developed and performed to compare colocated measurements collected in rain by two radars in overlapping regions. The integrated approach is performed on the C-band weather radar network in northwestern Italy, during July–October 2014. The set of methods considered appears suitable to establish an online tool to monitor the stability of the radar calibration with an accuracy of about 2 dB. In conclusion, this is considered adequate to automatically detect any unexpected change in the radar system requiring further data analysis or on-site measurements.« less

An accurate on-site calibration system for electronic voltage transformers using a standard capacitor

NASA Astrophysics Data System (ADS)

Hu, Chen; Chen, Mian-zhou; Li, Hong-bin; Zhang, Zhu; Jiao, Yang; Shao, Haiming

2018-05-01

Ordinarily electronic voltage transformers (EVTs) are calibrated off-line and the calibration procedure requires complex switching operations, which will influence the reliability of the power grid and induce large economic losses. To overcome this problem, this paper investigates a 110 kV on-site calibration system for EVTs, including a standard channel, a calibrated channel and a PC equipped with the LabView environment. The standard channel employs a standard capacitor and an analogue integrating circuit to reconstruct the primary voltage signal. Moreover, an adaptive full-phase discrete Fourier transform (DFT) algorithm is proposed to extract electrical parameters. The algorithm involves the process of extracting the frequency of the grid, adjusting the operation points, and calculating the results using DFT. In addition, an insulated automatic lifting device is designed to realize the live connection of the standard capacitor, which is driven by a wireless remote controller. A performance test of the capacitor verifies the accurateness of the standard capacitor. A system calibration test shows that the system ratio error is less than 0.04% and the phase error is below 2‧, which meets the requirement of the 0.2 accuracy class. Finally, the developed calibration system was used in a substation, and the field test data validates the availability of the system.

Automatic Calibration of Stereo-Cameras Using Ordinary Chess-Board Patterns

NASA Astrophysics Data System (ADS)

Prokos, A.; Kalisperakis, I.; Petsa, E.; Karras, G.

2012-07-01

Automation of camera calibration is facilitated by recording coded 2D patterns. Our toolbox for automatic camera calibration using images of simple chess-board patterns is freely available on the Internet. But it is unsuitable for stereo-cameras whose calibration implies recovering camera geometry and their true-to-scale relative orientation. In contrast to all reported methods requiring additional specific coding to establish an object space coordinate system, a toolbox for automatic stereo-camera calibration relying on ordinary chess-board patterns is presented here. First, the camera calibration algorithm is applied to all image pairs of the pattern to extract nodes of known spacing, order them in rows and columns, and estimate two independent camera parameter sets. The actual node correspondences on stereo-pairs remain unknown. Image pairs of a textured 3D scene are exploited for finding the fundamental matrix of the stereo-camera by applying RANSAC to point matches established with the SIFT algorithm. A node is then selected near the centre of the left image; its match on the right image is assumed as the node closest to the corresponding epipolar line. This yields matches for all nodes (since these have already been ordered), which should also satisfy the 2D epipolar geometry. Measures for avoiding mismatching are taken. With automatically estimated initial orientation values, a bundle adjustment is performed constraining all pairs on a common (scaled) relative orientation. Ambiguities regarding the actual exterior orientations of the stereo-camera with respect to the pattern are irrelevant. Results from this automatic method show typical precisions not above 1/4 pixels for 640×480 web cameras.

Wind Tunnel Force Balance Calibration Study - Interim Results

NASA Technical Reports Server (NTRS)

Rhew, Ray D.

2012-01-01

Wind tunnel force balance calibration is preformed utilizing a variety of different methods and does not have a direct traceable standard such as standards used for most calibration practices (weights, and voltmeters). These different calibration methods and practices include, but are not limited to, the loading schedule, the load application hardware, manual and automatic systems, re-leveling and non-re-leveling. A study of the balance calibration techniques used by NASA was undertaken to develop metrics for reviewing and comparing results using sample calibrations. The study also includes balances of different designs, single and multi-piece. The calibration systems include, the manual, and the automatic that are provided by NASA and its vendors. The results to date will be presented along with the techniques for comparing the results. In addition, future planned calibrations and investigations based on the results will be provided.

Recent Research on the Automated Mass Measuring System

NASA Astrophysics Data System (ADS)

Yao, Hong; Ren, Xiao-Ping; Wang, Jian; Zhong, Rui-Lin; Ding, Jing-An

The research development of robotic measurement system as well as the representative automatic system were introduced in the paper, and then discussed a sub-multiple calibration scheme adopted on a fully-automatic CCR10 system effectively. Automatic robot system can be able to perform the dissemination of the mass scale without any manual intervention as well as the fast speed calibration of weight samples against a reference weight. At the last, evaluation of the expanded uncertainty was given out.

Calibration Method for IATS and Application in Multi-Target Monitoring Using Coded Targets

NASA Astrophysics Data System (ADS)

Zhou, Yueyin; Wagner, Andreas; Wunderlich, Thomas; Wasmeier, Peter

2017-06-01

The technique of Image Assisted Total Stations (IATS) has been studied for over ten years and is composed of two major parts: one is the calibration procedure which combines the relationship between the camera system and the theodolite system; the other is the automatic target detection on the image by various methods of photogrammetry or computer vision. Several calibration methods have been developed, mostly using prototypes with an add-on camera rigidly mounted on the total station. However, these prototypes are not commercially available. This paper proposes a calibration method based on Leica MS50 which has two built-in cameras each with a resolution of 2560 × 1920 px: an overview camera and a telescope (on-axis) camera. Our work in this paper is based on the on-axis camera which uses the 30-times magnification of the telescope. The calibration consists of 7 parameters to estimate. We use coded targets, which are common tools in photogrammetry for orientation, to detect different targets in IATS images instead of prisms and traditional ATR functions. We test and verify the efficiency and stability of this monitoring method with multi-target.

Development of a generic auto-calibration package for regional ecological modeling and application in the Central Plains of the United States

USGS Publications Warehouse

Wu, Yiping; Liu, Shuguang; Li, Zhengpeng; Dahal, Devendra; Young, Claudia J.; Schmidt, Gail L.; Liu, Jinxun; Davis, Brian; Sohl, Terry L.; Werner, Jeremy M.; Oeding, Jennifer

2014-01-01

Process-oriented ecological models are frequently used for predicting potential impacts of global changes such as climate and land-cover changes, which can be useful for policy making. It is critical but challenging to automatically derive optimal parameter values at different scales, especially at regional scale, and validate the model performance. In this study, we developed an automatic calibration (auto-calibration) function for a well-established biogeochemical model—the General Ensemble Biogeochemical Modeling System (GEMS)-Erosion Deposition Carbon Model (EDCM)—using data assimilation technique: the Shuffled Complex Evolution algorithm and a model-inversion R package—Flexible Modeling Environment (FME). The new functionality can support multi-parameter and multi-objective auto-calibration of EDCM at the both pixel and regional levels. We also developed a post-processing procedure for GEMS to provide options to save the pixel-based or aggregated county-land cover specific parameter values for subsequent simulations. In our case study, we successfully applied the updated model (EDCM-Auto) for a single crop pixel with a corn–wheat rotation and a large ecological region (Level II)—Central USA Plains. The evaluation results indicate that EDCM-Auto is applicable at multiple scales and is capable to handle land cover changes (e.g., crop rotations). The model also performs well in capturing the spatial pattern of grain yield production for crops and net primary production (NPP) for other ecosystems across the region, which is a good example for implementing calibration and validation of ecological models with readily available survey data (grain yield) and remote sensing data (NPP) at regional and national levels. The developed platform for auto-calibration can be readily expanded to incorporate other model inversion algorithms and potential R packages, and also be applied to other ecological models.

SCAMP: Automatic Astrometric and Photometric Calibration

NASA Astrophysics Data System (ADS)

Bertin, Emmanuel

2010-10-01

Astrometric and photometric calibrations have remained the most tiresome step in the reduction of large imaging surveys. SCAMP has been written to address this problem. The program efficiently computes accurate astrometric and photometric solutions for any arbitrary sequence of FITS images in a completely automatic way. SCAMP is released under the GNU General Public License.

Probabilistic calibration of the distributed hydrological model RIBS applied to real-time flood forecasting: the Harod river basin case study (Israel)

NASA Astrophysics Data System (ADS)

Nesti, Alice; Mediero, Luis; Garrote, Luis; Caporali, Enrica

2010-05-01

An automatic probabilistic calibration method for distributed rainfall-runoff models is presented. The high number of parameters in hydrologic distributed models makes special demands on the optimization procedure to estimate model parameters. With the proposed technique it is possible to reduce the complexity of calibration while maintaining adequate model predictions. The first step of the calibration procedure of the main model parameters is done manually with the aim to identify their variation range. Afterwards a Monte-Carlo technique is applied, which consists on repetitive model simulations with randomly generated parameters. The Monte Carlo Analysis Toolbox (MCAT) includes a number of analysis methods to evaluate the results of these Monte Carlo parameter sampling experiments. The study investigates the use of a global sensitivity analysis as a screening tool to reduce the parametric dimensionality of multi-objective hydrological model calibration problems, while maximizing the information extracted from hydrological response data. The method is applied to the calibration of the RIBS flood forecasting model in the Harod river basin, placed on Israel. The Harod basin has an extension of 180 km2. The catchment has a Mediterranean climate and it is mainly characterized by a desert landscape, with a soil that is able to absorb large quantities of rainfall and at the same time is capable to generate high peaks of discharge. Radar rainfall data with 6 minute temporal resolution are available as input to the model. The aim of the study is the validation of the model for real-time flood forecasting, in order to evaluate the benefits of improved precipitation forecasting within the FLASH European project.

Automatic force balance calibration system

NASA Technical Reports Server (NTRS)

Ferris, Alice T. (Inventor)

1995-01-01

A system for automatically calibrating force balances is provided. The invention uses a reference balance aligned with the balance being calibrated to provide superior accuracy while minimizing the time required to complete the calibration. The reference balance and the test balance are rigidly attached together with closely aligned moment centers. Loads placed on the system equally effect each balance, and the differences in the readings of the two balances can be used to generate the calibration matrix for the test balance. Since the accuracy of the test calibration is determined by the accuracy of the reference balance and current technology allows for reference balances to be calibrated to within +/-0.05% the entire system has an accuracy of +/-0.2%. The entire apparatus is relatively small and can be mounted on a movable base for easy transport between test locations. The system can also accept a wide variety of reference balances, thus allowing calibration under diverse load and size requirements.

Automatic force balance calibration system

NASA Technical Reports Server (NTRS)

Ferris, Alice T. (Inventor)

1996-01-01

A system for automatically calibrating force balances is provided. The invention uses a reference balance aligned with the balance being calibrated to provide superior accuracy while minimizing the time required to complete the calibration. The reference balance and the test balance are rigidly attached together with closely aligned moment centers. Loads placed on the system equally effect each balance, and the differences in the readings of the two balances can be used to generate the calibration matrix for the test balance. Since the accuracy of the test calibration is determined by the accuracy of the reference balance and current technology allows for reference balances to be calibrated to within .+-.0.05%, the entire system has an accuracy of a .+-.0.2%. The entire apparatus is relatively small and can be mounted on a movable base for easy transport between test locations. The system can also accept a wide variety of reference balances, thus allowing calibration under diverse load and size requirements.

First full dynamic range calibration of the JUNGFRAU photon detector

NASA Astrophysics Data System (ADS)

Redford, S.; Andrä, M.; Barten, R.; Bergamaschi, A.; Brückner, M.; Dinapoli, R.; Fröjdh, E.; Greiffenberg, D.; Lopez-Cuenca, C.; Mezza, D.; Mozzanica, A.; Ramilli, M.; Ruat, M.; Ruder, C.; Schmitt, B.; Shi, X.; Thattil, D.; Tinti, G.; Vetter, S.; Zhang, J.

2018-01-01

The JUNGFRAU detector is a charge integrating hybrid silicon pixel detector developed at the Paul Scherrer Institut for photon science applications, in particular for the upcoming free electron laser SwissFEL. With a high dynamic range, analogue readout, low noise and three automatically switching gains, JUNGFRAU promises excellent performance not only at XFELs but also at synchrotrons in areas such as protein crystallography, ptychography, pump-probe and time resolved measurements. To achieve its full potential, the detector must be calibrated on a pixel-by-pixel basis. This contribution presents the current status of the JUNGFRAU calibration project, in which a variety of input charge sources are used to parametrise the energy response of the detector across four orders of magnitude of dynamic range. Building on preliminary studies, the first full calibration procedure of a JUNGFRAU 0.5 Mpixel module is described. The calibration is validated using alternative sources of charge deposition, including laboratory experiments and measurements at ESRF and LCLS. The findings from these measurements are presented. Calibrated modules have already been used in proof-of-principle style protein crystallography experiments at the SLS. A first look at selected results is shown. Aspects such as the conversion of charge to number of photons, treatment of multi-size pixels and the origin of non-linear response are also discussed.

Minutes. Accredited Standards Committee on Acoustics, S1. U.S. Tag for ISO/TC43 Acoustics and IEC/TC29 Electroacoustics, Held in Denver, Colorado on 7 October 1993

DTIC Science & Technology

1993-10-07

Oroanizational matters and reports on working grouos . including regorts on letter ballots and international matters (continued) e) S1/WG5 - Band Filter Sets...Band Analog and Digital Filters "* ANSI S1.20-1988 Procedures for Calibration of Underwater Electroacoustics Transducers "* ANSI S;1.42-1986 Design ...New International Standards Available a IEC 118-2 - Amendment 1 - 1993 Hearing aids. Part 2: Hearina aids with automatic gain control circuits 9

Measurement of Hydrologic Resource Parameters Through Remote Sensing in the Feather River Headwaters Area

NASA Technical Reports Server (NTRS)

Thorley, G. A.; Draeger, W. C.; Lauer, D. T.; Lent, J.; Roberts, E.

1971-01-01

The four problem are as being investigated are: (1) determination of the feasibility of providing the resource manager with operationally useful information through the use of remote sensing techniques; (2) definition of the spectral characteristics of earth resources and the optimum procedures for calibrating tone and color characteristics of multispectral imagery (3) determination of the extent to which humans can extract useful earth resource information through remote sensing imagery; (4) determination of the extent to which automatic classification and data processing can extract useful information from remote sensing data.

Automatic Calibration of an Airborne Imaging System to an Inertial Navigation Unit

NASA Technical Reports Server (NTRS)

Ansar, Adnan I.; Clouse, Daniel S.; McHenry, Michael C.; Zarzhitsky, Dimitri V.; Pagdett, Curtis W.

2013-01-01

This software automatically calibrates a camera or an imaging array to an inertial navigation system (INS) that is rigidly mounted to the array or imager. In effect, it recovers the coordinate frame transformation between the reference frame of the imager and the reference frame of the INS. This innovation can automatically derive the camera-to-INS alignment using image data only. The assumption is that the camera fixates on an area while the aircraft flies on orbit. The system then, fully automatically, solves for the camera orientation in the INS frame. No manual intervention or ground tie point data is required.

Automatic calibration method for plenoptic camera

NASA Astrophysics Data System (ADS)

Luan, Yinsen; He, Xing; Xu, Bing; Yang, Ping; Tang, Guomao

2016-04-01

An automatic calibration method is proposed for a microlens-based plenoptic camera. First, all microlens images on the white image are searched and recognized automatically based on digital morphology. Then, the center points of microlens images are rearranged according to their relative position relationships. Consequently, the microlens images are located, i.e., the plenoptic camera is calibrated without the prior knowledge of camera parameters. Furthermore, this method is appropriate for all types of microlens-based plenoptic cameras, even the multifocus plenoptic camera, the plenoptic camera with arbitrarily arranged microlenses, or the plenoptic camera with different sizes of microlenses. Finally, we verify our method by the raw data of Lytro. The experiments show that our method has higher intelligence than the methods published before.

Corner detection and sorting method based on improved Harris algorithm in camera calibration

NASA Astrophysics Data System (ADS)

Xiao, Ying; Wang, Yonghong; Dan, Xizuo; Huang, Anqi; Hu, Yue; Yang, Lianxiang

2016-11-01

In traditional Harris corner detection algorithm, the appropriate threshold which is used to eliminate false corners is selected manually. In order to detect corners automatically, an improved algorithm which combines Harris and circular boundary theory of corners is proposed in this paper. After detecting accurate corner coordinates by using Harris algorithm and Forstner algorithm, false corners within chessboard pattern of the calibration plate can be eliminated automatically by using circular boundary theory. Moreover, a corner sorting method based on an improved calibration plate is proposed to eliminate false background corners and sort remaining corners in order. Experiment results show that the proposed algorithms can eliminate all false corners and sort remaining corners correctly and automatically.

Object Occlusion Detection Using Automatic Camera Calibration for a Wide-Area Video Surveillance System

PubMed Central

Jung, Jaehoon; Yoon, Inhye; Paik, Joonki

2016-01-01

This paper presents an object occlusion detection algorithm using object depth information that is estimated by automatic camera calibration. The object occlusion problem is a major factor to degrade the performance of object tracking and recognition. To detect an object occlusion, the proposed algorithm consists of three steps: (i) automatic camera calibration using both moving objects and a background structure; (ii) object depth estimation; and (iii) detection of occluded regions. The proposed algorithm estimates the depth of the object without extra sensors but with a generic red, green and blue (RGB) camera. As a result, the proposed algorithm can be applied to improve the performance of object tracking and object recognition algorithms for video surveillance systems. PMID:27347978

Regional groundwater characteristics and hydraulic conductivity based on geological units in Korean peninsula

NASA Astrophysics Data System (ADS)

Kim, Y.; Suk, H.

2011-12-01

In this study, about 2,000 deep observation wells, stream and/or river distribution, and river's density were analyzed to identify regional groundwater flow trend, based on the regional groundwater survey of four major river watersheds including Geum river, Han river, Youngsan-Seomjin river, and Nakdong river in Korea. Hydrogeologial data were collected to analyze regional groundwater flow characteristics according to geological units. Additionally, hydrological soil type data were collected to estimate direct runoff through SCS-CN method. Temperature and precipitation data were used to quantify infiltration rate. The temperature and precipitation data were also used to quantify evaporation by Thornthwaite method and to evaluate groundwater recharge, respectively. Understanding the regional groundwater characteristics requires the database of groundwater flow parameters, but most hydrogeological data include limited information such as groundwater level and well configuration. In this study, therefore, groundwater flow parameters such as hydraulic conductivities or transmissivities were estimated using observed groundwater level by inverse model, namely PEST (Non-linear Parameter ESTimation). Since groundwater modeling studies have some uncertainties in data collection, conceptualization, and model results, model calibration should be performed. The calibration may be manually performed by changing parameters step by step, or various parameters are simultaneously changed by automatic procedure using PEST program. In this study, both manual and automatic procedures were employed to calibrate and estimate hydraulic parameter distributions. In summary, regional groundwater survey data obtained from four major river watersheds and various data of hydrology, meteorology, geology, soil, and topography in Korea were used to estimate hydraulic conductivities using PEST program. Especially, in order to estimate hydraulic conductivity effectively, it is important to perform in such a way that areas of same or similar hydrogeological characteristics should be grouped into zones. Keywords: regional groundwater, database, hydraulic conductivity, PEST, Korean peninsular Acknowledgements: This work was supported by the Radioactive Waste Management of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (2011T100200152)

Automatic Astrometric and Photometric Calibration with SCAMP

NASA Astrophysics Data System (ADS)

Bertin, E.

2006-07-01

Astrometric and photometric calibrations have remained the most tiresome step in the reduction of large imaging surveys. I present a new software package, SCAMP which has been written to address this problem. SCAMP efficiently computes accurate astrometric and photometric solutions for any arbitrary sequence of FITS images in a completely automatic way. SCAMP is released under the GNU General Public Licence.

Automatic Calibration of a Distributed Rainfall-Runoff Model, Using the Degree-Day Formulation for Snow Melting, Within DMIP2 Project

NASA Astrophysics Data System (ADS)

Frances, F.; Orozco, I.

2010-12-01

This work presents the assessment of the TETIS distributed hydrological model in mountain basins of the American and Carson rivers in Sierra Nevada (USA) at hourly time discretization, as part of the DMIP2 Project. In TETIS each cell of the spatial grid conceptualizes the water cycle using six tanks connected among them. The relationship between tanks depends on the case, although at the end in most situations, simple linear reservoirs and flow thresholds schemes are used with exceptional results (Vélez et al., 1999; Francés et al., 2002). In particular, within the snow tank, snow melting is based in this work on the simple degree-day method with spatial constant parameters. The TETIS model includes an automatic calibration module, based on the SCE-UA algorithm (Duan et al., 1992; Duan et al., 1994) and the model effective parameters are organized following a split structure, as presented by Francés and Benito (1995) and Francés et al. (2007). In this way, the calibration involves in TETIS up to 9 correction factors (CFs), which correct globally the different parameter maps instead of each parameter cell value, thus reducing drastically the number of variables to be calibrated. This strategy allows for a fast and agile modification in different hydrological processes preserving the spatial structure of each parameter map. With the snowmelt submodel, automatic model calibration was carried out in three steps, separating the calibration of rainfall-runoff and snowmelt parameters. In the first step, the automatic calibration of the CFs during the period 05/20/1990 to 07/31/1990 in the American River (without snow influence), gave a Nash-Sutcliffe Efficiency (NSE) index of 0.92. The calibration of the three degree-day parameters was done using all the SNOTEL stations in the American and Carson rivers. Finally, using previous calibrations as initial values, the complete calibration done in the Carson River for the period 10/01/1992 to 07/31/1993 gave a NSE index of 0.86. The temporal and spatial validation using five periods must be considered in both rivers excellent for discharges (NSEs higher than 0.76) and good for snow distribution (daily spatial coverage errors ranging from -10 to 27%). In conclusion, this work demonstrates: 1.- The viability of automatic calibration of distributed models, with the corresponding personal time saving and maximum exploitation of the available information. 2.- The good performance of the degree-day snowmelt formulation even at hourly time discretization, in spite of its simplicity.

AUTOMATIC CALIBRATING SYSTEM FOR PRESSURE TRANSDUCERS

DOEpatents

Amonette, E.L.; Rodgers, G.W.

1958-01-01

An automatic system for calibrating a number of pressure transducers is described. The disclosed embodiment of the invention uses a mercurial manometer to measure the air pressure applied to the transducer. A servo system follows the top of the mercury column as the pressure is changed and operates an analog- to-digital converter This converter furnishes electrical pulses, each representing an increment of pressure change, to a reversible counterThe transducer furnishes a signal at each calibration point, causing an electric typewriter and a card-punch machine to record the pressure at the instant as indicated by the counter. Another counter keeps track of the calibration points so that a number identifying each point is recorded with the corresponding pressure. A special relay control system controls the pressure trend and programs the sequential calibration of several transducers.

Calibrating reaction rates for the CREST model

NASA Astrophysics Data System (ADS)

Handley, Caroline A.; Christie, Michael A.

2017-01-01

The CREST reactive-burn model uses entropy-dependent reaction rates that, until now, have been manually tuned to fit shock-initiation and detonation data in hydrocode simulations. This paper describes the initial development of an automatic method for calibrating CREST reaction-rate coefficients, using particle swarm optimisation. The automatic method is applied to EDC32, to help develop the first CREST model for this conventional high explosive.

ON-LINE MONITORING OF I&C TRANSMITTERS AND SENSORS FOR CALIBRATION VERIFICATION AND RESPONSE TIME TESTING WAS SUCCESSFULLY IMPLEMENTED AT ATR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erickson, Phillip A.; O'Hagan, Ryan; Shumaker, Brent

The Advanced Test Reactor (ATR) has always had a comprehensive procedure to verify the performance of its critical transmitters and sensors, including RTDs, and pressure, level, and flow transmitters. These transmitters and sensors have been periodically tested for response time and calibration verification to ensure accuracy. With implementation of online monitoring techniques at ATR, the calibration verification and response time testing of these transmitters and sensors are verified remotely, automatically, hands off, include more portions of the system, and can be performed at almost any time during process operations. The work was done under a DOE funded SBIR project carriedmore » out by AMS. As a result, ATR is now able to save the manpower that has been spent over the years on manual calibration verification and response time testing of its temperature and pressure sensors and refocus those resources towards more equipment reliability needs. More importantly, implementation of OLM will help enhance the overall availability, safety, and efficiency. Together with equipment reliability programs of ATR, the integration of OLM will also help with I&C aging management goals of the Department of Energy and long-time operation of ATR.« less

Improving integrity of on-line grammage measurement with traceable basic calibration.

PubMed

Kangasrääsiö, Juha

2010-07-01

The automatic control of grammage (basis weight) in paper and board production is based upon on-line grammage measurement. Furthermore, the automatic control of other quality variables such as moisture, ash content and coat weight, may rely on the grammage measurement. The integrity of Kr-85 based on-line grammage measurement systems was studied, by performing basic calibrations with traceably calibrated plastic reference standards. The calibrations were performed according to the EN ISO/IEC 17025 standard, which is a requirement for calibration laboratories. The observed relative measurement errors were 3.3% in the first time calibrations at the 95% confidence level. With the traceable basic calibration method, however, these errors can be reduced to under 0.5%, thus improving the integrity of on-line grammage measurements. Also a standardised algorithm, based on the experience from the performed calibrations, is proposed to ease the adjustment of the different grammage measurement systems. The calibration technique can basically be applied to all beta-radiation based grammage measurements. 2010 ISA. Published by Elsevier Ltd. All rights reserved.

3D reconstruction of microminiature objects based on contour line

NASA Astrophysics Data System (ADS)

Li, Cailin; Wang, Qiang; Guo, Baoyun

2009-10-01

A new 3D automatic reconstruction method of micro solid of revolution is presented in this paper. In the implementation procedure of this method, image sequence of the solid of revolution of 360° is obtained, which rotation speed is controlled by motor precisely, in the rotate photographic mode of back light. Firstly, we need calibrate the height of turntable, the size of pixel and rotation axis of turntable. Then according to the calibration result of rotation axis, the height of turntable, rotation angle and the pixel size, the contour points of each image can be transformed into 3D points in the reference coordinate system to generate the point cloud model. Finally, the surface geometrical model of solid of revolution is obtained by using the relationship of two adjacent contours. Experimental results on real images are presented, which demonstrate the effectiveness of the Approach.

Automatic multi-camera calibration for deployable positioning systems

NASA Astrophysics Data System (ADS)

Axelsson, Maria; Karlsson, Mikael; Rudner, Staffan

2012-06-01

Surveillance with automated positioning and tracking of subjects and vehicles in 3D is desired in many defence and security applications. Camera systems with stereo or multiple cameras are often used for 3D positioning. In such systems, accurate camera calibration is needed to obtain a reliable 3D position estimate. There is also a need for automated camera calibration to facilitate fast deployment of semi-mobile multi-camera 3D positioning systems. In this paper we investigate a method for automatic calibration of the extrinsic camera parameters (relative camera pose and orientation) of a multi-camera positioning system. It is based on estimation of the essential matrix between each camera pair using the 5-point method for intrinsically calibrated cameras. The method is compared to a manual calibration method using real HD video data from a field trial with a multicamera positioning system. The method is also evaluated on simulated data from a stereo camera model. The results show that the reprojection error of the automated camera calibration method is close to or smaller than the error for the manual calibration method and that the automated calibration method can replace the manual calibration.

Network operability of ground-based microwave radiometers: Calibration and standardization efforts

NASA Astrophysics Data System (ADS)

Pospichal, Bernhard; Löhnert, Ulrich; Küchler, Nils; Czekala, Harald

2017-04-01

Ground-based microwave radiometers (MWR) are already widely used by national weather services and research institutions all around the world. Most of the instruments operate continuously and are beginning to be implemented into data assimilation for atmospheric models. Especially their potential for continuously observing boundary-layer temperature profiles as well as integrated water vapor and cloud liquid water path makes them valuable for improving short-term weather forecasts. However until now, most MWR have been operated as stand-alone instruments. In order to benefit from a network of these instruments, standardization of calibration, operation and data format is necessary. In the frame of TOPROF (COST Action ES1303) several efforts have been undertaken, such as uncertainty and bias assessment, or calibration intercomparison campaigns. The goal was to establish protocols for providing quality controlled (QC) MWR data and their uncertainties. To this end, standardized calibration procedures for MWR have been developed and recommendations for radiometer users compiled. Based on the results of the TOPROF campaigns, a new, high-accuracy liquid-nitrogen calibration load has been introduced for MWR manufactured by Radiometer Physics GmbH (RPG). The new load improves the accuracy of the measurements considerably and will lead to even more reliable atmospheric observations. Next to the recommendations for set-up, calibration and operation of ground-based MWR within a future network, we will present homogenized methods to determine the accuracy of a running calibration as well as means for automatic data quality control. This sets the stage for the planned microwave calibration center at JOYCE (Jülich Observatory for Cloud Evolution), which will be shortly introduced.

A hardware-software system for the automation of verification and calibration of oil metering units secondary equipment

NASA Astrophysics Data System (ADS)

Boyarnikov, A. V.; Boyarnikova, L. V.; Kozhushko, A. A.; Sekachev, A. F.

2017-08-01

In the article the process of verification (calibration) of oil metering units secondary equipment is considered. The purpose of the work is to increase the reliability and reduce the complexity of this process by developing a software and hardware system that provides automated verification and calibration. The hardware part of this complex carries out the commutation of the measuring channels of the verified controller and the reference channels of the calibrator in accordance with the introduced algorithm. The developed software allows controlling the commutation of channels, setting values on the calibrator, reading the measured data from the controller, calculating errors and compiling protocols. This system can be used for checking the controllers of the secondary equipment of the oil metering units in the automatic verification mode (with the open communication protocol) or in the semi-automatic verification mode (without it). The peculiar feature of the approach used is the development of a universal signal switch operating under software control, which can be configured for various verification methods (calibration), which allows to cover the entire range of controllers of metering units secondary equipment. The use of automatic verification with the help of a hardware and software system allows to shorten the verification time by 5-10 times and to increase the reliability of measurements, excluding the influence of the human factor.

D Reconstruction of AN Underwater Archaelogical Site: Comparison Between Low Cost Cameras

NASA Astrophysics Data System (ADS)

Capra, A.; Dubbini, M.; Bertacchini, E.; Castagnetti, C.; Mancini, F.

2015-04-01

The 3D reconstruction with a metric content of a submerged area, where objects and structures of archaeological interest are found, could play an important role in the research and study activities and even in the digitization of the cultural heritage. The reconstruction of 3D object, of interest for archaeologists, constitutes a starting point in the classification and description of object in digital format and for successive fruition by user after delivering through several media. The starting point is a metric evaluation of the site obtained with photogrammetric surveying and appropriate 3D restitution. The authors have been applying the underwater photogrammetric technique since several years using underwater digital cameras and, in this paper, digital low cost cameras (off-the-shelf). Results of tests made on submerged objects with three cameras are presented: Canon Power Shot G12, Intova Sport HD e GoPro HERO 2. The experimentation had the goal to evaluate the precision in self-calibration procedures, essential for multimedia underwater photogrammetry, and to analyze the quality of 3D restitution. Precisions obtained in the calibration and orientation procedures was assessed by using three cameras, and an homogeneous set control points. Data were processed with Agisoft Photoscan. Successively, 3D models were created and the comparison of the models derived from the use of different cameras was performed. Different potentialities of the used cameras are reported in the discussion section. The 3D restitution of objects and structures was integrated with sea bottom floor morphology in order to achieve a comprehensive description of the site. A possible methodology of survey and representation of submerged objects is therefore illustrated, considering an automatic and a semi-automatic approach.

Automatically calibrating admittances in KATE's autonomous launch operations model

NASA Technical Reports Server (NTRS)

Morgan, Steve

1992-01-01

This report documents a 1000-line Symbolics LISP program that automatically calibrates all 15 fluid admittances in KATE's Autonomous Launch Operations (ALO) model. (KATE is Kennedy Space Center's Knowledge-based Autonomous Test Engineer, a diagnosis and repair expert system created for use on the Space Shuttle's various fluid flow systems.) As a new KATE application, the calibrator described here breaks new ground for KSC's Artificial Intelligence Lab by allowing KATE to both control and measure the hardware she supervises. By automating a formerly manual process, the calibrator: (1) saves the ALO model builder untold amounts of labor; (2) enables quick repairs after workmen accidently adjust ALO's hand valves; and (3) frees the modeler to pursue new KATE applications that previously were too complicated. Also reported are suggestions for enhancing the program: (1) to calibrate ALO's TV cameras, pumps, and sensor tolerances; and (2) to calibrate devices in other KATE models, such as the shuttle's LOX and Environment Control System (ECS).

Least-Squares Camera Calibration Including Lens Distortion and Automatic Editing of Calibration Points

NASA Technical Reports Server (NTRS)

Gennery, D. B.

1998-01-01

A method is described for calibrating cameras including radial lens distortion, by using known points such as those measured from a calibration fixture. The distortion terms are relative to the optical axis, which is included in the model so that it does not have to be orthogonal to the image sensor plane.

A Visual Servoing-Based Method for ProCam Systems Calibration

PubMed Central

Berry, Francois; Aider, Omar Ait; Mosnier, Jeremie

2013-01-01

Projector-camera systems are currently used in a wide field of applications, such as 3D reconstruction and augmented reality, and can provide accurate measurements, depending on the configuration and calibration. Frequently, the calibration task is divided into two steps: camera calibration followed by projector calibration. The latter still poses certain problems that are not easy to solve, such as the difficulty in obtaining a set of 2D–3D points to compute the projection matrix between the projector and the world. Existing methods are either not sufficiently accurate or not flexible. We propose an easy and automatic method to calibrate such systems that consists in projecting a calibration pattern and superimposing it automatically on a known printed pattern. The projected pattern is provided by a virtual camera observing a virtual pattern in an OpenGL model. The projector displays what the virtual camera visualizes. Thus, the projected pattern can be controlled and superimposed on the printed one with the aid of visual servoing. Our experimental results compare favorably with those of other methods considering both usability and accuracy. PMID:24084121

Note: A portable automatic capillary viscometer for transparent and opaque liquids

NASA Astrophysics Data System (ADS)

Soltani Ghalehjooghi, A.; Minaei, S.; Gholipour Zanjani, N.; Beheshti, B.

2017-07-01

A portable automatic capillary viscometer, equipped with an AVR microcontroller, was designed and developed. The viscometer was calibrated with Certified Reference Material (CRM) s200 and utilized for measurement of kinematic viscosity. A quadratic equation was developed for calibration of the instrument at various temperatures. Also, a model was developed for viscosity determination in terms of the viscometer dimensions. Development of the portable viscometer provides for on-site monitoring of engine oil viscosity.

Automatic 3D inspection metrology for high-temperature objects

NASA Astrophysics Data System (ADS)

Han, Liya; Li, Zhongwei; Zhong, Kai; Yi, Jie; Shi, Yusheng; Cheng, Xu; Zhan, Guomin; Chen, Ran

2017-06-01

3D Visual Inspection for high-temperature objects has attracted more and more attention in the industrial and manufacture field. Until now it is still difficult to measure the shape of high-temperature objects due to the following problems: 1) the radiation and heat transfer through the air seriously affect both human and measurement equipment, so the manual measurement is not capable in this situation. 2) Because of the difficulties to handle the surfaces of the hot objects, it is hard to use artificial markers to align different pieces of data. In order to solve these problems, an automatic 3D shape measurement system for high-temperature objects is proposed by combing an industrial robot with a structured blue light 3D scanner. In this system, the route for inspection is planned with the cooled object and then executed automatically with the same object in hot state to avoid artificial operations. The route is carefully planned to reduce the exposure time of the measurement equipment under the high-temperature situation. Then different pieces of data are premapped during the planning procedure. In the executing procedure, they can be aligned accurately thanks to the good repeatability of the industrial robot. Finally, different pieces of data are merged without artificial markers and the results are better than methods with traditional hand-eye calibration. Experiments verify that the proposed system can conduct the inspection of forging parts under the temperature of 900°C and the alignment precision is 0.0013rad and 0.28mm.

Type testing the Model 6600 plus automatic TLD reader.

PubMed

Velbeck, K J; Luo, L Z; Streetz, K L

2006-01-01

The Harshaw Model 6600 Plus is a reader with a capacity for 200 TLD cards or 800 extremity cards. The new unit integrates more functionality, and significantly automates the QC and calibration process compared to the Model 6600. The Model 6600 Plus was tested against the IEC 61066 (1991-2012) procedures using Harshaw TLD-700H and TLD-600H, LiF:Mg,Cu,P based TLD Cards. An overview of the type testing procedures is presented. These include batch homogeneity, detection threshold, reproducibility, linearity, self-irradiation, residue, light effects on dosemeter, light leakage to reader, voltage and frequency, dropping and reader stability. The new TLD reader was found to meet all the IEC criteria by large margins and appears well suited for whole body, extremity and environmental dosimetry applications, with a high degree of dosimetric performance.

Toward a More Robust Pruning Procedure for MLP Networks

NASA Technical Reports Server (NTRS)

Stepniewski, Slawomir W.; Jorgensen, Charles C.

1998-01-01

Choosing a proper neural network architecture is a problem of great practical importance. Smaller models mean not only simpler designs but also lower variance for parameter estimation and network prediction. The widespread utilization of neural networks in modeling highlights an issue in human factors. The procedure of building neural models should find an appropriate level of model complexity in a more or less automatic fashion to make it less prone to human subjectivity. In this paper we present a Singular Value Decomposition based node elimination technique and enhanced implementation of the Optimal Brain Surgeon algorithm. Combining both methods creates a powerful pruning engine that can be used for tuning feedforward connectionist models. The performance of the proposed method is demonstrated by adjusting the structure of a multi-input multi-output model used to calibrate a six-component wind tunnel strain gage.

Variable Selection for Regression Models of Percentile Flows

NASA Astrophysics Data System (ADS)

Fouad, G.

2017-12-01

Percentile flows describe the flow magnitude equaled or exceeded for a given percent of time, and are widely used in water resource management. However, these statistics are normally unavailable since most basins are ungauged. Percentile flows of ungauged basins are often predicted using regression models based on readily observable basin characteristics, such as mean elevation. The number of these independent variables is too large to evaluate all possible models. A subset of models is typically evaluated using automatic procedures, like stepwise regression. This ignores a large variety of methods from the field of feature (variable) selection and physical understanding of percentile flows. A study of 918 basins in the United States was conducted to compare an automatic regression procedure to the following variable selection methods: (1) principal component analysis, (2) correlation analysis, (3) random forests, (4) genetic programming, (5) Bayesian networks, and (6) physical understanding. The automatic regression procedure only performed better than principal component analysis. Poor performance of the regression procedure was due to a commonly used filter for multicollinearity, which rejected the strongest models because they had cross-correlated independent variables. Multicollinearity did not decrease model performance in validation because of a representative set of calibration basins. Variable selection methods based strictly on predictive power (numbers 2-5 from above) performed similarly, likely indicating a limit to the predictive power of the variables. Similar performance was also reached using variables selected based on physical understanding, a finding that substantiates recent calls to emphasize physical understanding in modeling for predictions in ungauged basins. The strongest variables highlighted the importance of geology and land cover, whereas widely used topographic variables were the weakest predictors. Variables suffered from a high degree of multicollinearity, possibly illustrating the co-evolution of climatic and physiographic conditions. Given the ineffectiveness of many variables used here, future work should develop new variables that target specific processes associated with percentile flows.

A data reduction package for multiple object spectroscopy

NASA Technical Reports Server (NTRS)

Hill, J. M.; Eisenhamer, J. D.; Silva, D. R.

1986-01-01

Experience with fiber-optic spectrometers has demonstrated improvements in observing efficiency for clusters of 30 or more objects that must in turn be matched by data reduction capability increases. The Medusa Automatic Reduction System reduces data generated by multiobject spectrometers in the form of two-dimensional images containing 44 to 66 individual spectra, using both software and hardware improvements to efficiently extract the one-dimensional spectra. Attention is given to the ridge-finding algorithm for automatic location of the spectra in the CCD frame. A simultaneous extraction of calibration frames allows an automatic wavelength calibration routine to determine dispersion curves, and both line measurements and cross-correlation techniques are used to determine galaxy redshifts.

SU-E-T-641: Proton Range Measurements Using a Geometrically Calibrated Liquid Scintillator Detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hui, C; Robertson, D; Alsanea, F

2015-06-15

Purpose: The purpose of this work is to develop a geometric calibration method to accurately calculate physical distances within a liquid scintillator detector and to assess the accuracy, consistency, and robustness of proton beam range measurements when using a liquid scintillator detector system with the proposed geometric calibration process. Methods: We developed a geometric calibration procedure to accurately convert pixel locations in the camera frame into physical locations in the scintillator frame. To ensure accuracy, the geometric calibration was performed before each experiment. The liquid scintillator was irradiated with spot scanning proton beams of 94 energies in two deliveries. Amore » CCD camera was used to capture the two-dimensional scintillation light profile of each of the proton energies. An algorithm was developed to automatically calculate the proton range from the acquired images. The measured range was compared to the nominal range to assess the accuracy of the detector. To evaluate the robustness of the detector between each setup, the experiments were repeated on three different days. To evaluate the consistency of the measurements between deliveries, three sets of measurements were acquired for each experiment. Results: Using this geometric calibration procedure, the proton beam ranges measured using the liquid scintillator system were all within 0.3mm of the nominal range. The average difference between the measured and nominal ranges was −0.20mm. The delivery-to-delivery standard deviation of the proton range measurement was 0.04mm, and the setup-to-setup standard deviation of the measurement was 0.10mm. Conclusion: The liquid scintillator system can measure the range of all 94 beams in just two deliveries. With the proposed geometric calibration, it can measure proton range with sub-millimeter accuracy, and the measurements were shown to be consistent between deliveries and setups. Therefore, we conclude that the liquid scintillator system provides a reliable and convenient tool for proton range measurement. This project was supported in part by award number CA182450 from the National Cancer Institute.« less

Automatic calibration and signal switching system for the particle beam fusion research data acquisition facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyer, W.B.

1979-09-01

This report describes both the hardware and software components of an automatic calibration and signal system (Autocal) for the data acquisition system for the Sandia particle beam fusion research accelerators Hydra, Proto I, and Proto II. The Autocal hardware consists of off-the-shelf commercial equipment. The various hardware components, special modifications and overall system configuration are described. Special software has been developed to support the Autocal hardware. Software operation and maintenance are described.

Measuring automatic retrieval: a comparison of implicit memory, process dissociation, and speeded response procedures.

PubMed

Horton, Keith D; Wilson, Daryl E; Vonk, Jennifer; Kirby, Sarah L; Nielsen, Tina

2005-07-01

Using the stem completion task, we compared estimates of automatic retrieval from an implicit memory task, the process dissociation procedure, and the speeded response procedure. Two standard manipulations were employed. In Experiment 1, a depth of processing effect was found on automatic retrieval using the speeded response procedure although this effect was substantially reduced in Experiment 2 when lexical processing was required of all words. In Experiment 3, the speeded response procedure showed an advantage of full versus divided attention at study on automatic retrieval. An implicit condition showed parallel effects in each study, suggesting that implicit stem completion may normally provide a good estimate of automatic retrieval. Also, we replicated earlier findings from the process dissociation procedure, but estimates of automatic retrieval from this procedure were consistently lower than those from the speeded response procedure, except when conscious retrieval was relatively low. We discuss several factors that may contribute to the conflicting outcomes, including the evidence for theoretical assumptions and criterial task differences between implicit and explicit tests.

77 FR 5058 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Automatic...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-01

... for OMB Review; Comment Request; Automatic Fire Sensor and Warning Devices Systems; Examination and..., ``Automatic Fire Sensor and Warning Devices Systems,'' to the Office of Management and Budget (OMB) for review... and warning device systems are maintained and calibrated in order to function properly at all times...

Software For Calibration Of Polarimetric SAR Data

NASA Technical Reports Server (NTRS)

Van Zyl, Jakob; Zebker, Howard; Freeman, Anthony; Holt, John; Dubois, Pascale; Chapman, Bruce

1994-01-01

POLCAL (Polarimetric Radar Calibration) software tool intended to assist in calibration of synthetic-aperture radar (SAR) systems. In particular, calibrates Stokes-matrix-format data produced as standard product by NASA/Jet Propulsion Laboratory (JPL) airborne imaging synthetic aperture radar (AIRSAR). Version 4.0 of POLCAL is upgrade of version 2.0. New options include automatic absolute calibration of 89/90 data, distributed-target analysis, calibration of nearby scenes with corner reflectors, altitude or roll-angle corrections, and calibration of errors introduced by known topography. Reduces crosstalk and corrects phase calibration without use of ground calibration equipment. Written in FORTRAN 77.

Calibration of ground-based microwave radiometers - Accuracy assessment and recommendations for network users

NASA Astrophysics Data System (ADS)

Pospichal, Bernhard; Küchler, Nils; Löhnert, Ulrich; Crewell, Susanne; Czekala, Harald; Güldner, Jürgen

2016-04-01

Ground-based microwave radiometers (MWR) are becoming widely used in atmospheric remote sensing and start to be routinely operated by national weather services and other institutions. However, common standards for calibration of these radiometers and a detailed knowledge about the error characteristics is needed, in order to assimilate the data into models. Intercomparisons of calibrations by different MWRs have rarely been done. Therefore, two calibration experiments in Lindenberg (2014) and Meckenheim (2015) were performed in the frame of TOPROF (Cost action ES1303) in order to assess uncertainties and differences between various instruments. In addition, a series of experiments were taken in Oklahoma in autumn 2014. The focus lay on the performance of the two main instrument types, which are currently used operationally. These are the MP-Profiler series by Radiometrics Corporation as well as the HATPRO series by Radiometer Physics GmbH (RPG). Both instrument types are operating in two frequency bands, one along the 22 GHz water vapour line, the other one at the lower wing of the 60 GHz oxygen absorption complex. The goal was to establish protocols for providing quality controlled (QC) MWR data and their uncertainties. To this end, standardized calibration procedures for MWR were developed and recommendations for radiometer users were compiled. We focus here mainly on data types, integration times and optimal settings for calibration intervals, both for absolute (liquid nitrogen, tipping curve) as well as relative (hot load, noise diode) calibrations. Besides the recommendations for ground-based MWR operators, we will present methods to determine the accuracy of the calibration as well as means for automatic data quality control. In addition, some results from the intercomparison of different radiometers will be discussed.

Geometry calibration for x-ray equipment in radiation treatment devices and estimation of remaining patient alignment errors

NASA Astrophysics Data System (ADS)

Selby, Boris P.; Sakas, Georgios; Walter, Stefan; Stilla, Uwe

2008-03-01

Positioning a patient accurately in treatment devices is crucial for radiological treatment, especially if accuracy vantages of particle beam treatment are exploited. To avoid sub-millimeter misalignments, X-ray images acquired from within the device are compared to a CT to compute respective alignment corrections. Unfortunately, deviations of the underlying geometry model for the imaging system degrade the achievable accuracy. We propose an automatic calibration routine, which bases on the geometry of a phantom and its automatic detection in digital radiographs acquired for various geometric device settings during the calibration. The results from the registration of the phantom's X-ray projections and its known geometry are used to update the model of the respective beamlines, which is used to compute the patient alignment correction. The geometric calibration of a beamline takes all nine relevant degrees of freedom into account, including detector translations in three directions, detector tilt by three axes and three possible translations for the X-ray tube. Introducing a stochastic model for the calibration we are able to predict the patient alignment deviations resulting from inaccuracies inherent to the phantom design and the calibration. Comparisons of the alignment results for a treatment device without calibrated imaging systems and a calibrated device show that an accurate calibration can enhance alignment accuracy.

Calibrating the stress-time curve of a combined finite-discrete element method to a Split Hopkinson Pressure Bar experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osthus, Dave; Godinez, Humberto C.; Rougier, Esteban

We presenmore » t a generic method for automatically calibrating a computer code to an experiment, with uncertainty, for a given “training” set of computer code runs. The calibration technique is general and probabilistic, meaning the calibration uncertainty is represented in the form of a probability distribution. We demonstrate the calibration method by calibrating a combined Finite-Discrete Element Method (FDEM) to a Split Hopkinson Pressure Bar (SHPB) experiment with a granite sample. The probabilistic calibration method combines runs of a FDEM computer simulation for a range of “training” settings and experimental uncertainty to develop a statistical emulator. The process allows for calibration of input parameters and produces output quantities with uncertainty estimates for settings where simulation results are desired. Input calibration and FDEM fitted results are presented. We find that the maximum shear strength σ t max and to a lesser extent maximum tensile strength σ n max govern the behavior of the stress-time curve before and around the peak, while the specific energy in Mode II (shear) E t largely governs the post-peak behavior of the stress-time curve. Good agreement is found between the calibrated FDEM and the SHPB experiment. Interestingly, we find the SHPB experiment to be rather uninformative for calibrating the softening-curve shape parameters (a, b, and c). This work stands as a successful demonstration of how a general probabilistic calibration framework can automatically calibrate FDEM parameters to an experiment.« less

Calibrating the stress-time curve of a combined finite-discrete element method to a Split Hopkinson Pressure Bar experiment

DOE PAGES

Osthus, Dave; Godinez, Humberto C.; Rougier, Esteban; ...

2018-05-01

We presenmore » t a generic method for automatically calibrating a computer code to an experiment, with uncertainty, for a given “training” set of computer code runs. The calibration technique is general and probabilistic, meaning the calibration uncertainty is represented in the form of a probability distribution. We demonstrate the calibration method by calibrating a combined Finite-Discrete Element Method (FDEM) to a Split Hopkinson Pressure Bar (SHPB) experiment with a granite sample. The probabilistic calibration method combines runs of a FDEM computer simulation for a range of “training” settings and experimental uncertainty to develop a statistical emulator. The process allows for calibration of input parameters and produces output quantities with uncertainty estimates for settings where simulation results are desired. Input calibration and FDEM fitted results are presented. We find that the maximum shear strength σ t max and to a lesser extent maximum tensile strength σ n max govern the behavior of the stress-time curve before and around the peak, while the specific energy in Mode II (shear) E t largely governs the post-peak behavior of the stress-time curve. Good agreement is found between the calibrated FDEM and the SHPB experiment. Interestingly, we find the SHPB experiment to be rather uninformative for calibrating the softening-curve shape parameters (a, b, and c). This work stands as a successful demonstration of how a general probabilistic calibration framework can automatically calibrate FDEM parameters to an experiment.« less

Automatic energy calibration algorithm for an RBS setup

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silva, Tiago F.; Moro, Marcos V.; Added, Nemitala

2013-05-06

This work describes a computer algorithm for automatic extraction of the energy calibration parameters from a Rutherford Back-Scattering Spectroscopy (RBS) spectrum. Parameters like the electronic gain, electronic offset and detection resolution (FWHM) of a RBS setup are usually determined using a standard sample. In our case, the standard sample comprises of a multi-elemental thin film made of a mixture of Ti-Al-Ta that is analyzed at the beginning of each run at defined beam energy. A computer program has been developed to extract automatically the calibration parameters from the spectrum of the standard sample. The code evaluates the first derivative ofmore » the energy spectrum, locates the trailing edges of the Al, Ti and Ta peaks and fits a first order polynomial for the energy-channel relation. The detection resolution is determined fitting the convolution of a pre-calculated theoretical spectrum. To test the code, data of two years have been analyzed and the results compared with the manual calculations done previously, obtaining good agreement.« less

Impact of automatic calibration techniques on HMD life cycle costs and sustainable performance

NASA Astrophysics Data System (ADS)

Speck, Richard P.; Herz, Norman E., Jr.

2000-06-01

Automatic test and calibration has become a valuable feature in many consumer products--ranging from antilock braking systems to auto-tune TVs. This paper discusses HMDs (Helmet Mounted Displays) and how similar techniques can reduce life cycle costs and increase sustainable performance if they are integrated into a program early enough. Optical ATE (Automatic Test Equipment) is already zeroing distortion in the HMDs and thereby making binocular displays a practical reality. A suitcase sized, field portable optical ATE unit could re-zero these errors in the Ready Room to cancel the effects of aging, minor damage and component replacement. Planning on this would yield large savings through relaxed component specifications and reduced logistic costs. Yet, the sustained performance would far exceed that attained with fixed calibration strategies. Major tactical benefits can come from reducing display errors, particularly in information fusion modules and virtual `beyond visual range' operations. Some versions of the ATE described are in production and examples of high resolution optical test data will be discussed.

3D Surface Reconstruction and Automatic Camera Calibration

NASA Technical Reports Server (NTRS)

Jalobeanu, Andre

2004-01-01

Illustrations in this view-graph presentation are presented on a Bayesian approach to 3D surface reconstruction and camera calibration.Existing methods, surface analysis and modeling,preliminary surface reconstruction results, and potential applications are addressed.

A procedure for accurate calibration of the orientation of the three sensors in a vector magnetometer. [at the Goddard Space Flight Center

NASA Technical Reports Server (NTRS)

Mcpherron, R. L.

1977-01-01

Procedures are described for the calibration of a vector magnetometer of high absolute accuracy. It is assumed that the calibration will be performed in the magnetic test facility of Goddard Space Flight Center (GSFC). The first main section of the report describes the test equipment and facility calibrations required. The second presents procedures for calibrating individual sensors. The third discusses the calibration of the sensor assembly. In a final section recommendations are made to GSFC for modification of the test facility required to carry out the calibration procedures.

Fast Beam-Based BPM Calibration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bertsche, K.; Loos, H.; Nuhn, H.-D.

2012-10-15

The Alignment Diagnostic System (ADS) of the LCLS undulator system indicates that the 33 undulator quadrupoles have extremely high position stability over many weeks. However, beam trajectory straightness and lasing efficiency degrade more quickly than this. A lengthy Beam Based Alignment (BBA) procedure must be executed every two to four weeks to re-optimize the X-ray beam parameters. The undulator system includes RF cavity Beam Position Monitors (RFBPMs), several of which are utilized by an automatic feedback system to align the incoming electron-beam trajectory to the undulator axis. The beam trajectory straightness degradation has been traced to electronic drifts of themore » gain and offset of the BPMs used in the beam feedback system. To quickly recover the trajectory straightness, we have developed a fast beam-based procedure to recalibrate the BPMs. This procedure takes advantage of the high-precision monitoring capability of the ADS, which allows highly repeatable positioning of undulator quadrupoles. This report describes the ADS, the position stability of the LCLS undulator quadrupoles, and some results of the new recovery procedure.« less

Development of a drift-correction procedure for a direct-reading spectrometer

NASA Technical Reports Server (NTRS)

Chapman, G. B., II; Gordon, W. A.

1977-01-01

A procedure which provides automatic correction for drifts in the radiometric sensitivity of each detector channel in a direct-reading emission spectrometer is described. Such drifts are customarily controlled by the regular analyses of standards, which provide corrections for changes in the excitational, optical, and electronic components of the instrument. This standardization procedure, however, corrects for the optical and electronic drifts. It is a step that must be taken if the time, effort, and cost of processing standards is to be minimized. This method of radiometric drift correction uses a 1,000-W tungsten-halogen reference lamp to illuminate each detector through the same optical path as that traversed during sample analysis. The responses of the detector channels to this reference light are regularly compared with channel response to the same light intensity at the time of analytical calibration in order to determine and correct for drift. Except for placing the lamp in position, the procedure is fully automated and compensates for changes in spectral intensity due to variations in lamp current. A discussion of the implementation of this drift-correction system is included.

Using an Automated 3D-tracking System to Record Individual and Shoals of Adult Zebrafish

PubMed Central

Maaswinkel, Hans; Zhu, Liqun; Weng, Wei

2013-01-01

Like many aquatic animals, zebrafish (Danio rerio) moves in a 3D space. It is thus preferable to use a 3D recording system to study its behavior. The presented automatic video tracking system accomplishes this by using a mirror system and a calibration procedure that corrects for the considerable error introduced by the transition of light from water to air. With this system it is possible to record both single and groups of adult zebrafish. Before use, the system has to be calibrated. The system consists of three modules: Recording, Path Reconstruction, and Data Processing. The step-by-step protocols for calibration and using the three modules are presented. Depending on the experimental setup, the system can be used for testing neophobia, white aversion, social cohesion, motor impairments, novel object exploration etc. It is especially promising as a first-step tool to study the effects of drugs or mutations on basic behavioral patterns. The system provides information about vertical and horizontal distribution of the zebrafish, about the xyz-components of kinematic parameters (such as locomotion, velocity, acceleration, and turning angle) and it provides the data necessary to calculate parameters for social cohesions when testing shoals. PMID:24336189

Computer Vision Assisted Virtual Reality Calibration

NASA Technical Reports Server (NTRS)

Kim, W.

1999-01-01

A computer vision assisted semi-automatic virtual reality (VR) calibration technology has been developed that can accurately match a virtual environment of graphically simulated three-dimensional (3-D) models to the video images of the real task environment.

Unanticipated error in HbA(1c) measurement on the HLC-723 G7 analyzer.

PubMed

van den Ouweland, Johannes M W; de Keijzer, Marinus H; van Daal, Henny

2010-04-01

Investigation of falsely elevated HbA(1c) measurements on the HLC-723 G7 analyser. Comparison of HbA(1c) in blood samples that were diluted either in hemolysis reagent or water. HbA(1c) results became falsely elevated when samples were diluted in hemolysis reagent, but not in water. QC-procedures failed to detect this error as calibrator and QC samples were manually diluted in water, according to manufacturer's instructions, whereas patient samples were automatically diluted using hemolysing reagent. After replacement of the instruments' sample-loop and rotor seal comparable HbA(1c) results were obtained, irrespective of dilution with hemolysing reagent or water. This case illustrates the importance of treating calibrator and QC materials similar to routine patient samples in order to prevent unnoticed drift in patient HbA(1c) results. Copyright 2010 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

ROSAS: a robotic station for atmosphere and surface characterization dedicated to on-orbit calibration

NASA Astrophysics Data System (ADS)

Meygret, Aimé; Santer, Richard P.; Berthelot, Béatrice

2011-10-01

La Crau test site is used by CNES since 1987 for vicarious calibration of SPOT cameras. The former calibration activities were conducted during field campaigns devoted to the characterization of the atmosphere and the site reflectances. Since 1997, au automatic photometric station (ROSAS) was set up on the site on a 10m height pole. This station measures at different wavelengths, the solar extinction and the sky radiances to fully characterize the optical properties of the atmosphere. It also measures the upwelling radiance over the ground to fully characterize the surface reflectance properties. The photometer samples the spectrum from 380nm to 1600nm with 9 narrow bands. Every non cloudy days the photometer automatically and sequentially performs its measurements. Data are transmitted by GSM (Global System for Mobile communications) to CNES and processed. The photometer is calibrated in situ over the sun for irradiance and cross-band calibration, and over the Rayleigh scattering for the short wavelengths radiance calibration. The data are processed by an operational software which calibrates the photometer, estimates the atmosphere properties, computes the bidirectional reflectance distribution function of the site, then simulates the top of atmosphere radiance seen by any sensor over-passing the site and calibrates it. This paper describes the instrument, its measurement protocol and its calibration principle. Calibration results are discussed and compared to laboratory calibration. It details the surface reflectance characterization and presents SPOT4 calibration results deduced from the estimated TOA radiance. The results are compared to the official calibration.

Calibration process of highly parameterized semi-distributed hydrological model

NASA Astrophysics Data System (ADS)

Vidmar, Andrej; Brilly, Mitja

2017-04-01

Hydrological phenomena take place in the hydrological system, which is governed by nature, and are essentially stochastic. These phenomena are unique, non-recurring, and changeable across space and time. Since any river basin with its own natural characteristics and any hydrological event therein, are unique, this is a complex process that is not researched enough. Calibration is a procedure of determining the parameters of a model that are not known well enough. Input and output variables and mathematical model expressions are known, while only some parameters are unknown, which are determined by calibrating the model. The software used for hydrological modelling nowadays is equipped with sophisticated algorithms for calibration purposes without possibility to manage process by modeler. The results are not the best. We develop procedure for expert driven process of calibration. We use HBV-light-CLI hydrological model which has command line interface and coupling it with PEST. PEST is parameter estimation tool which is used widely in ground water modeling and can be used also on surface waters. Process of calibration managed by expert directly, and proportionally to the expert knowledge, affects the outcome of the inversion procedure and achieves better results than if the procedure had been left to the selected optimization algorithm. First step is to properly define spatial characteristic and structural design of semi-distributed model including all morphological and hydrological phenomena, like karstic area, alluvial area and forest area. This step includes and requires geological, meteorological, hydraulic and hydrological knowledge of modeler. Second step is to set initial parameter values at their preferred values based on expert knowledge. In this step we also define all parameter and observation groups. Peak data are essential in process of calibration if we are mainly interested in flood events. Each Sub Catchment in the model has own observations group. Third step is to set appropriate bounds to parameters in their range of realistic values. Fourth step is to use of singular value decomposition (SVD) ensures that PEST maintains numerical stability, regardless of how ill-posed is the inverse problem Fifth step is to run PWTADJ1. This creates a new PEST control file in which weights are adjusted such that the contribution made to the total objective function by each observation group is the same. This prevents the information content of any group from being invisible to the inversion process. Sixth step is to add Tikhonov regularization to the PEST control file by running the ADDREG1 utility (Doherty, J, 2013). In adding regularization to the PEST control file ADDREG1 automatically provides a prior information equation for each parameter in which the preferred value of that parameter is equated to its initial value. Last step is to run PEST. We run BeoPEST which a parallel version of PEST and can be run on multiple computers in parallel in same time on TCP communications and this speedup process of calibrations. The case study with results of calibration and validation of the model will be presented.

Research on calibration error of carrier phase against antenna arraying

NASA Astrophysics Data System (ADS)

Sun, Ke; Hou, Xiaomin

2016-11-01

It is the technical difficulty of uplink antenna arraying that signals from various quarters can not be automatically aligned at the target in deep space. The size of the far-field power combining gain is directly determined by the accuracy of carrier phase calibration. It is necessary to analyze the entire arraying system in order to improve the accuracy of the phase calibration. This paper analyzes the factors affecting the calibration error of carrier phase of uplink antenna arraying system including the error of phase measurement and equipment, the error of the uplink channel phase shift, the position error of ground antenna, calibration receiver and target spacecraft, the error of the atmospheric turbulence disturbance. Discuss the spatial and temporal autocorrelation model of atmospheric disturbances. Each antenna of the uplink antenna arraying is no common reference signal for continuous calibration. So it must be a system of the periodic calibration. Calibration is refered to communication of one or more spacecrafts in a certain period. Because the deep space targets are not automatically aligned to multiplexing received signal. Therefore the aligned signal should be done in advance on the ground. Data is shown that the error can be controlled within the range of demand by the use of existing technology to meet the accuracy of carrier phase calibration. The total error can be controlled within a reasonable range.

Photogrammetric 3d Building Reconstruction from Thermal Images

NASA Astrophysics Data System (ADS)

Maset, E.; Fusiello, A.; Crosilla, F.; Toldo, R.; Zorzetto, D.

2017-08-01

This paper addresses the problem of 3D building reconstruction from thermal infrared (TIR) images. We show that a commercial Computer Vision software can be used to automatically orient sequences of TIR images taken from an Unmanned Aerial Vehicle (UAV) and to generate 3D point clouds, without requiring any GNSS/INS data about position and attitude of the images nor camera calibration parameters. Moreover, we propose a procedure based on Iterative Closest Point (ICP) algorithm to create a model that combines high resolution and geometric accuracy of RGB images with the thermal information deriving from TIR images. The process can be carried out entirely by the aforesaid software in a simple and efficient way.

Carbon monoxide measurement in the global atmospheric sampling program

NASA Technical Reports Server (NTRS)

Dudzinski, T. J.

1979-01-01

The carbon monoxide measurement system used in the NASA Global Atmospheric Sampling Program (GASP) is described. The system used a modified version of a commercially available infrared absorption analyzer. The modifications increased the sensitivity of the analyzer to 1 ppmv full scale, with a limit of detectability of 0.02 ppmv. Packaging was modified for automatic, unattended operation in an aircraft environment. The GASP system is described along with analyzer operation, calibration procedures, and measurement errors. Uncertainty of the CO measurement over a 2-year period ranged from + or - 3 to + or - 13 percent of reading, plus an error due to random fluctuation of the output signal + or - 3 to + or - 15 ppbv.

COSMOS: Carnegie Observatories System for MultiObject Spectroscopy

NASA Astrophysics Data System (ADS)

Oemler, A.; Clardy, K.; Kelson, D.; Walth, G.; Villanueva, E.

2017-05-01

COSMOS (Carnegie Observatories System for MultiObject Spectroscopy) reduces multislit spectra obtained with the IMACS and LDSS3 spectrographs on the Magellan Telescopes. It can be used for the quick-look analysis of data at the telescope as well as for pipeline reduction of large data sets. COSMOS is based on a precise optical model of the spectrographs, which allows (after alignment and calibration) an accurate prediction of the location of spectra features. This eliminates the line search procedure which is fundamental to many spectral reduction programs, and allows a robust data pipeline to be run in an almost fully automatic mode, allowing large amounts of data to be reduced with minimal intervention.

Nonlinear, non-stationary image processing technique for eddy current NDE

NASA Astrophysics Data System (ADS)

Yang, Guang; Dib, Gerges; Kim, Jaejoon; Zhang, Lu; Xin, Junjun; Udpa, Lalita

2012-05-01

Automatic analysis of eddy current (EC) data has facilitated the analysis of large volumes of data generated in the inspection of steam generator tubes in nuclear power plants. The traditional procedure for analysis of EC data includes data calibration, pre-processing, region of interest (ROI) detection, feature extraction and classification. Accurate ROI detection has been enhanced by pre-processing, which involves reducing noise and other undesirable components as well as enhancing defect indications in the raw measurement. This paper presents the Hilbert-Huang Transform (HHT) for feature extraction and support vector machine (SVM) for classification. The performance is shown to significantly better than the existing rule based classification approach used in industry.

Automatic calibration and control system for a combined oxygen and combustibles analyzer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woolbert, G.D.; Jewett, S.Y.; Robertson, J.W. Jr.

1989-08-01

This patent describes an automatic, periodically calibrating system for continuous output of calibrated signals from a combined oxygen and combustibles analyzer. It comprises: a combined oxygen and combustibles analyzer for sensing a level of oxygen and a level of combustibles in a volatile atmosphere and for producing a first sample signal indicative of the oxygen level and a second sample signal indicative of the combustibles level; means for introducing zero and span calibration test gases into the analyzer; means for periodically calibrating the analyzer. This including: a data control unit; a timer unit; a mechanical unit, means for calculating zeromore » and span values for oxygen and combustibles, means for comparing the calculated zero and span values for oxygen and combustibles to the preset alarm limits for oxygen and combustibles, means for activating an operator alarm, means for calculating oxygen and combustibles drift adjustments, a memory unit; and means for applying the oxygen and combustibles drift adjustments concurrently to the first and second sample signals, according to predetermined mathematical relationship, to obtain calibrated output signals indicative of the oxygen and combustibles level in the volatile atmosphere.« less

The DFMS sensor of ROSINA onboard Rosetta: A computer-assisted approach to resolve mass calibration, flux calibration, and fragmentation issues

NASA Astrophysics Data System (ADS)

Dhooghe, Frederik; De Keyser, Johan; Altwegg, Kathrin; Calmonte, Ursina; Fuselier, Stephen; Hässig, Myrtha; Berthelier, Jean-Jacques; Mall, Urs; Gombosi, Tamas; Fiethe, Björn

2014-05-01

Rosetta will rendezvous with comet 67P/Churyumov-Gerasimenko in May 2014. The Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument comprises three sensors: the pressure sensor (COPS) and two mass spectrometers (RTOF and DFMS). The double focusing mass spectrometer DFMS is optimized for mass resolution and consists of an ion source, a mass analyser and a detector package operated in analogue mode. The magnetic sector of the analyser provides the mass dispersion needed for use with the position-sensitive microchannel plate (MCP) detector. Ions that hit the MCP release electrons that are recorded digitally using a linear electron detector array with 512 pixels. Raw data for a given commanded mass are obtained as ADC counts as a function of pixel number. We have developed a computer-assisted approach to address the problem of calibrating such raw data. Mass calibration: Ion identification is based on their mass-over-charge (m/Z) ratio and requires an accurate correlation of pixel number and m/Z. The m/Z scale depends on the commanded mass and the magnetic field and can be described by an offset of the pixel associated with the commanded mass from the centre of the detector array and a scaling factor. Mass calibration is aided by the built-in gas calibration unit (GCU), which allows one to inject a known gas mixture into the instrument. In a first, fully automatic step of the mass calibration procedure, the calibration uses all GCU spectra and extracts information about the mass peak closest to the centre pixel, since those peaks can be identified unambiguously. This preliminary mass-calibration relation can then be applied to all spectra. Human-assisted identification of additional mass peaks further improves the mass calibration. Ion flux calibration: ADC counts per pixel are converted to ion counts per second using the overall gain, the individual pixel gain, and the total data accumulation time. DFMS can perform an internal scan to determine the pixel gain and related detector aging. The software automatically corrects for these effects to calibrate the fluxes. The COPS sensor can be used for an a posteriori calibration of the fluxes. Neutral gas number densities: Neutrals are ionized in the ion source before they are transferred to the mass analyser, but during this process fragmentation may occur. Our software allows one to identify which neutrals entered the instrument, given the ion fragments that are detected. First, multiple spectra with a limited mass range are combined to provide an overview of as many ion fragments as possible. We then exploit a fragmentation database to assist in figuring out the relation between entering species and recorded fragments. Finally, using experimentally determined sensitivities, gas number densities are obtained. The instrument characterisation (experimental determination of sensitivities, fragmentation patterns for the most common neutral species, etc.) has been conducted by the consortium using an instrument copy in the University of Bern test facilities during the cruise phase of the mission.

A portable foot-parameter-extracting system

NASA Astrophysics Data System (ADS)

Zhang, MingKai; Liang, Jin; Li, Wenpan; Liu, Shifan

2016-03-01

In order to solve the problem of automatic foot measurement in garment customization, a new automatic footparameter- extracting system based on stereo vision, photogrammetry and heterodyne multiple frequency phase shift technology is proposed and implemented. The key technologies applied in the system are studied, including calibration of projector, alignment of point clouds, and foot measurement. Firstly, a new projector calibration algorithm based on plane model has been put forward to get the initial calibration parameters and a feature point detection scheme of calibration board image is developed. Then, an almost perfect match of two clouds is achieved by performing a first alignment using the Sampled Consensus - Initial Alignment algorithm (SAC-IA) and refining the alignment using the Iterative Closest Point algorithm (ICP). Finally, the approaches used for foot-parameterextracting and the system scheme are presented in detail. Experimental results show that the RMS error of the calibration result is 0.03 pixel and the foot parameter extracting experiment shows the feasibility of the extracting algorithm. Compared with the traditional measurement method, the system can be more portable, accurate and robust.

40 CFR Appendix B to Part 75 - Quality Assurance and Quality Control Procedures

Code of Federal Regulations, 2012 CFR

2012-07-01

... Systems 1.2.1Calibration Error Test and Linearity Check Procedures Keep a written record of the procedures used for daily calibration error tests and linearity checks (e.g., how gases are to be injected..., and when calibration adjustments should be made). Identify any calibration error test and linearity...

40 CFR Appendix B to Part 75 - Quality Assurance and Quality Control Procedures

Code of Federal Regulations, 2013 CFR

2013-07-01

... Systems 1.2.1Calibration Error Test and Linearity Check Procedures Keep a written record of the procedures used for daily calibration error tests and linearity checks (e.g., how gases are to be injected..., and when calibration adjustments should be made). Identify any calibration error test and linearity...

Multiple-Objective Stepwise Calibration Using Luca

USGS Publications Warehouse

Hay, Lauren E.; Umemoto, Makiko

2007-01-01

This report documents Luca (Let us calibrate), a multiple-objective, stepwise, automated procedure for hydrologic model calibration and the associated graphical user interface (GUI). Luca is a wizard-style user-friendly GUI that provides an easy systematic way of building and executing a calibration procedure. The calibration procedure uses the Shuffled Complex Evolution global search algorithm to calibrate any model compiled with the U.S. Geological Survey's Modular Modeling System. This process assures that intermediate and final states of the model are simulated consistently with measured values.

Enhanced anatomical calibration in human movement analysis.

PubMed

Donati, Marco; Camomilla, Valentina; Vannozzi, Giuseppe; Cappozzo, Aurelio

2007-07-01

The representation of human movement requires knowledge of both movement and morphology of bony segments. The determination of subject-specific morphology data and their registration with movement data is accomplished through an anatomical calibration procedure (calibrated anatomical systems technique: CAST). This paper describes a novel approach to this calibration (UP-CAST) which, as compared with normally used techniques, achieves better repeatability, a shorter application time, and can be effectively performed by non-skilled examiners. Instead of the manual location of prominent bony anatomical landmarks, the description of which is affected by subjective interpretation, a large number of unlabelled points is acquired over prominent parts of the subject's bone, using a wand fitted with markers. A digital model of a template-bone is then submitted to isomorphic deformation and re-orientation to optimally match the above-mentioned points. The locations of anatomical landmarks are automatically made available. The UP-CAST was validated considering the femur as a paradigmatic case. Intra- and inter-examiner repeatability of the identification of anatomical landmarks was assessed both in vivo, using average weight subjects, and on bare bones. Accuracy of the identification was assessed using the anatomical landmark locations manually located on bare bones as reference. The repeatability of this method was markedly higher than that reported in the literature and obtained using the conventional palpation (ranges: 0.9-7.6 mm and 13.4-17.9, respectively). Accuracy resulted, on average, in a maximal error of 11 mm. Results suggest that the principal source of variability resides in the discrepancy between subject's and template bone morphology and not in the inter-examiner differences. The UP-CAST anatomical calibration could be considered a promising alternative to conventional calibration contributing to a more repeatable 3D human movement analysis.

Analysis of regional rainfall-runoff parameters for the Lake Michigan Diversion hydrological modeling

USGS Publications Warehouse

Soong, David T.; Over, Thomas M.

2015-01-01

Recalibration of the HSPF parameters to the updated inputs and land covers was completed on two representative watershed models selected from the nine by using a manual method (HSPEXP) and an automatic method (PEST). The objective of the recalibration was to develop a regional parameter set that improves the accuracy in runoff volume prediction for the nine study watersheds. Knowledge about flow and watershed characteristics plays a vital role for validating the calibration in both manual and automatic methods. The best performing parameter set was determined by the automatic calibration method on a two-watershed model. Applying this newly determined parameter set to the nine watersheds for runoff volume simulation resulted in “very good” ratings in five watersheds, an improvement as compared to “very good” ratings achieved for three watersheds by the North Branch parameter set.

Radiometer Calibration and Characterization (RCC) User's Manual: Windows Version 4.0

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andreas, Afshin M.; Wilcox, Stephen M.

2016-02-29

The Radiometer Calibration and Characterization (RCC) software is a data acquisition and data archival system for performing Broadband Outdoor Radiometer Calibrations (BORCAL). RCC provides a unique method of calibrating broadband atmospheric longwave and solar shortwave radiometers using techniques that reduce measurement uncertainty and better characterize a radiometer's response profile. The RCC software automatically monitors and controls many of the components that contribute to uncertainty in an instrument's responsivity. This is a user's manual and guide to the RCC software.

Definition and sensitivity of the conceptual MORDOR rainfall-runoff model parameters using different multi-criteria calibration strategies

NASA Astrophysics Data System (ADS)

Garavaglia, F.; Seyve, E.; Gottardi, F.; Le Lay, M.; Gailhard, J.; Garçon, R.

2014-12-01

MORDOR is a conceptual hydrological model extensively used in Électricité de France (EDF, French electric utility company) operational applications: (i) hydrological forecasting, (ii) flood risk assessment, (iii) water balance and (iv) climate change studies. MORDOR is a lumped, reservoir, elevation based model with hourly or daily areal rainfall and air temperature as the driving input data. The principal hydrological processes represented are evapotranspiration, direct and indirect runoff, ground water, snow accumulation and melt and routing. The model has been intensively used at EDF for more than 20 years, in particular for modeling French mountainous watersheds. In the matter of parameters calibration we propose and test alternative multi-criteria techniques based on two specific approaches: automatic calibration using single-objective functions and a priori parameter calibration founded on hydrological watershed features. The automatic calibration approach uses single-objective functions, based on Kling-Gupta efficiency, to quantify the good agreement between the simulated and observed runoff focusing on four different runoff samples: (i) time-series sample, (I) annual hydrological regime, (iii) monthly cumulative distribution functions and (iv) recession sequences.The primary purpose of this study is to analyze the definition and sensitivity of MORDOR parameters testing different calibration techniques in order to: (i) simplify the model structure, (ii) increase the calibration-validation performance of the model and (iii) reduce the equifinality problem of calibration process. We propose an alternative calibration strategy that reaches these goals. The analysis is illustrated by calibrating MORDOR model to daily data for 50 watersheds located in French mountainous regions.

MOESHA: A genetic algorithm for automatic calibration and estimation of parameter uncertainty and sensitivity of hydrologic models

EPA Science Inventory

Characterization of uncertainty and sensitivity of model parameters is an essential and often overlooked facet of hydrological modeling. This paper introduces an algorithm called MOESHA that combines input parameter sensitivity analyses with a genetic algorithm calibration routin...

Automatic Camera Calibration for Cultural Heritage Applications Using Unstructured Planar Objects

NASA Astrophysics Data System (ADS)

Adam, K.; Kalisperakis, I.; Grammatikopoulos, L.; Karras, G.; Petsa, E.

2013-07-01

As a rule, image-based documentation of cultural heritage relies today on ordinary digital cameras and commercial software. As such projects often involve researchers not familiar with photogrammetry, the question of camera calibration is important. Freely available open-source user-friendly software for automatic camera calibration, often based on simple 2D chess-board patterns, are an answer to the demand for simplicity and automation. However, such tools cannot respond to all requirements met in cultural heritage conservation regarding possible imaging distances and focal lengths. Here we investigate the practical possibility of camera calibration from unknown planar objects, i.e. any planar surface with adequate texture; we have focused on the example of urban walls covered with graffiti. Images are connected pair-wise with inter-image homographies, which are estimated automatically through a RANSAC-based approach after extracting and matching interest points with the SIFT operator. All valid points are identified on all images on which they appear. Provided that the image set includes a "fronto-parallel" view, inter-image homographies with this image are regarded as emulations of image-to-world homographies and allow computing initial estimates for the interior and exterior orientation elements. Following this initialization step, the estimates are introduced into a final self-calibrating bundle adjustment. Measures are taken to discard unsuitable images and verify object planarity. Results from practical experimentation indicate that this method may produce satisfactory results. The authors intend to incorporate the described approach into their freely available user-friendly software tool, which relies on chess-boards, to assist non-experts in their projects with image-based approaches.

A procedure for automating CFD simulations of an inlet-bleed problem

NASA Technical Reports Server (NTRS)

Chyu, Wei J.; Rimlinger, Mark J.; Shih, Tom I.-P.

1995-01-01

A procedure was developed to improve the turn-around time for computational fluid dynamics (CFD) simulations of an inlet-bleed problem involving oblique shock-wave/boundary-layer interactions on a flat plate with bleed into a plenum through one or more circular holes. This procedure is embodied in a preprocessor called AUTOMAT. With AUTOMAT, once data for the geometry and flow conditions have been specified (either interactively or via a namelist), it will automatically generate all input files needed to perform a three-dimensional Navier-Stokes simulation of the prescribed inlet-bleed problem by using the PEGASUS and OVERFLOW codes. The input files automatically generated by AUTOMAT include those for the grid system and those for the initial and boundary conditions. The grid systems automatically generated by AUTOMAT are multi-block structured grids of the overlapping type. Results obtained by using AUTOMAT are presented to illustrate its capability.

PET/CT alignment calibration with a non-radioactive phantom and the intrinsic 176Lu radiation of PET detector

NASA Astrophysics Data System (ADS)

Wei, Qingyang; Ma, Tianyu; Wang, Shi; Liu, Yaqiang; Gu, Yu; Dai, Tiantian

2016-11-01

Positron emission tomography/computed tomography (PET/CT) is an important tool for clinical studies and pre-clinical researches which provides both functional and anatomical images. To achieve high quality co-registered PET/CT images, alignment calibration of PET and CT scanner is a critical procedure. The existing methods reported use positron source phantoms imaged both by PET and CT scanner and then derive the transformation matrix from the reconstructed images of the two modalities. In this paper, a novel PET/CT alignment calibration method with a non-radioactive phantom and the intrinsic 176Lu radiation of the PET detector was developed. Firstly, a multi-tungsten-alloy-sphere phantom without positron source was designed and imaged by CT and the PET scanner using intrinsic 176Lu radiation included in LYSO. Secondly, the centroids of the spheres were derived and matched by an automatic program. Lastly, the rotation matrix and the translation vector were calculated by least-square fitting of the centroid data. The proposed method was employed in an animal PET/CT system (InliView-3000) developed in our lab. Experimental results showed that the proposed method achieves high accuracy and is feasible to replace the conventional positron source based methods.

System Design, Calibration and Performance Analysis of a Novel 360° Stereo Panoramic Mobile Mapping System

NASA Astrophysics Data System (ADS)

Blaser, S.; Nebiker, S.; Cavegn, S.

2017-05-01

Image-based mobile mapping systems enable the efficient acquisition of georeferenced image sequences, which can later be exploited in cloud-based 3D geoinformation services. In order to provide a 360° coverage with accurate 3D measuring capabilities, we present a novel 360° stereo panoramic camera configuration. By using two 360° panorama cameras tilted forward and backward in combination with conventional forward and backward looking stereo camera systems, we achieve a full 360° multi-stereo coverage. We furthermore developed a fully operational new mobile mapping system based on our proposed approach, which fulfils our high accuracy requirements. We successfully implemented a rigorous sensor and system calibration procedure, which allows calibrating all stereo systems with a superior accuracy compared to that of previous work. Our study delivered absolute 3D point accuracies in the range of 4 to 6 cm and relative accuracies of 3D distances in the range of 1 to 3 cm. These results were achieved in a challenging urban area. Furthermore, we automatically reconstructed a 3D city model of our study area by employing all captured and georeferenced mobile mapping imagery. The result is a very high detailed and almost complete 3D city model of the street environment.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Egorov, Oleg; O'Hara, Matthew J.; Grate, Jay W.

An automated fluidic instrument is described that rapidly determines the total 99Tc content of aged nuclear waste samples, where the matrix is chemically and radiologically complex and the existing speciation of the 99Tc is variable. The monitor links microwave-assisted sample preparation with an automated anion exchange column separation and detection using a flow-through solid scintillator detector. The sample preparation steps acidify the sample, decompose organics, and convert all Tc species to the pertechnetate anion. The column-based anion exchange procedure separates the pertechnetate from the complex sample matrix, so that radiometric detection can provide accurate measurement of 99Tc. We developed amore » preprogrammed spike addition procedure to automatically determine matrix-matched calibration. The overall measurement efficiency that is determined simultaneously provides a self-diagnostic parameter for the radiochemical separation and overall instrument function. Continuous, automated operation was demonstrated over the course of 54 h, which resulted in the analysis of 215 samples plus 54 hly spike-addition samples, with consistent overall measurement efficiency for the operation of the monitor. A sample can be processed and measured automatically in just 12.5 min with a detection limit of 23.5 Bq/mL of 99Tc in low activity waste (0.495 mL sample volume), with better than 10% RSD precision at concentrations above the quantification limit. This rapid automated analysis method was developed to support nuclear waste processing operations planned for the Hanford nuclear site.« less

Integration of kerma-area product and cumulative air kerma determination into a skin dose tracking system for fluoroscopic imaging procedures

NASA Astrophysics Data System (ADS)

Vijayan, Sarath; Shankar, Alok; Rudin, Stephen; Bednarek, Daniel R.

2016-03-01

The skin dose tracking system (DTS) that we developed provides a color-coded mapping of the cumulative skin dose distribution on a 3D graphic of the patient during fluoroscopic procedures in real time. The DTS has now been modified to also calculate the kerma area product (KAP) and cumulative air kerma (CAK) for fluoroscopic interventions using data obtained in real-time from the digital bus on a Toshiba Infinix system. KAP is the integral of air kerma over the beam area and is typically measured with a large-area transmission ionization chamber incorporated into the collimator assembly. In this software, KAP is automatically determined for each x-ray pulse as the product of the air kerma/ mAs from a calibration file for the given kVp and beam filtration times the mAs per pulse times the length and width of the beam times a field nonuniformity correction factor. Field nonuniformity is primarily the result of the heel effect and the correction factor was determined from the beam profile measured using radio-chromic film. Dividing the KAP by the beam area at the interventional reference point provides the area averaged CAK. The KAP and CAK per x-ray pulse are summed after each pulse to obtain the total procedure values in real-time. The calculated KAP and CAK were compared to the values displayed by the fluoroscopy machine with excellent agreement. The DTS now is able to automatically calculate both KAP and CAK without the need for measurement by an add-on transmission ionization chamber.

Reconstructing the calibrated strain signal in the Advanced LIGO detectors

NASA Astrophysics Data System (ADS)

Viets, A. D.; Wade, M.; Urban, A. L.; Kandhasamy, S.; Betzwieser, J.; Brown, Duncan A.; Burguet-Castell, J.; Cahillane, C.; Goetz, E.; Izumi, K.; Karki, S.; Kissel, J. S.; Mendell, G.; Savage, R. L.; Siemens, X.; Tuyenbayev, D.; Weinstein, A. J.

2018-05-01

Advanced LIGO’s raw detector output needs to be calibrated to compute dimensionless strain h(t) . Calibrated strain data is produced in the time domain using both a low-latency, online procedure and a high-latency, offline procedure. The low-latency h(t) data stream is produced in two stages, the first of which is performed on the same computers that operate the detector’s feedback control system. This stage, referred to as the front-end calibration, uses infinite impulse response (IIR) filtering and performs all operations at a 16 384 Hz digital sampling rate. Due to several limitations, this procedure currently introduces certain systematic errors in the calibrated strain data, motivating the second stage of the low-latency procedure, known as the low-latency gstlal calibration pipeline. The gstlal calibration pipeline uses finite impulse response (FIR) filtering to apply corrections to the output of the front-end calibration. It applies time-dependent correction factors to the sensing and actuation components of the calibrated strain to reduce systematic errors. The gstlal calibration pipeline is also used in high latency to recalibrate the data, which is necessary due mainly to online dropouts in the calibrated data and identified improvements to the calibration models or filters.

A method of automatic control procedures cardiopulmonary resuscitation

NASA Astrophysics Data System (ADS)

Bureev, A. Sh.; Zhdanov, D. S.; Kiseleva, E. Yu.; Kutsov, M. S.; Trifonov, A. Yu.

2015-11-01

The study is to present the results of works on creation of methods of automatic control procedures of cardiopulmonary resuscitation (CPR). A method of automatic control procedure of CPR by evaluating the acoustic data of the dynamics of blood flow in the bifurcation of carotid arteries and the dynamics of air flow in a trachea according to the current guidelines for CPR is presented. Evaluation of the patient is carried out by analyzing the respiratory noise and blood flow in the interspaces between the chest compressions and artificial pulmonary ventilation. The device operation algorithm of automatic control procedures of CPR and its block diagram has been developed.

Automated response matching for organic scintillation detector arrays

NASA Astrophysics Data System (ADS)

Aspinall, M. D.; Joyce, M. J.; Cave, F. D.; Plenteda, R.; Tomanin, A.

2017-07-01

This paper identifies a digitizer technology with unique features that facilitates feedback control for the realization of a software-based technique for automatically calibrating detector responses. Three such auto-calibration techniques have been developed and are described along with an explanation of the main configuration settings and potential pitfalls. Automating this process increases repeatability, simplifies user operation, enables remote and periodic system calibration where consistency across detectors' responses are critical.

Coupling a regional warning system to a semantic engine on online news for enhancing landslide prediction

NASA Astrophysics Data System (ADS)

Battistini, Alessandro; Rosi, Ascanio; Segoni, Samuele; Catani, Filippo; Casagli, Nicola

2017-04-01

Landslide inventories are basic data for large scale landslide modelling, e.g. they are needed to calibrate and validate rainfall thresholds, physically based models and early warning systems. The setting up of landslide inventories with traditional methods (e.g. remote sensing, field surveys and manual retrieval of data from technical reports and local newspapers) is time consuming. The objective of this work is to automatically set up a landslide inventory using a state-of-the art semantic engine based on data mining on online news (Battistini et al., 2013) and to evaluate if the automatically generated inventory can be used to validate a regional scale landslide warning system based on rainfall-thresholds. The semantic engine scanned internet news in real time in a 50 months test period. At the end of the process, an inventory of approximately 900 landslides was set up for the Tuscany region (23,000 km2, Italy). The inventory was compared with the outputs of the regional landslide early warning system based on rainfall thresholds, and a good correspondence was found: e.g. 84% of the events reported in the news is correctly identified by the model. In addition, the cases of not correspondence were forwarded to the rainfall threshold developers, which used these inputs to update some of the thresholds. On the basis of the results obtained, we conclude that automatic validation of landslide models using geolocalized landslide events feedback is possible. The source of data for validation can be obtained directly from the internet channel using an appropriate semantic engine. We also automated the validation procedure, which is based on a comparison between forecasts and reported events. We verified that our approach can be automatically used for a near real time validation of the warning system and for a semi-automatic update of the rainfall thresholds, which could lead to an improvement of the forecasting effectiveness of the warning system. In the near future, the proposed procedure could operate in continuous time and could allow for a periodic update of landslide hazard models and landslide early warning systems with minimum human intervention. References: Battistini, A., Segoni, S., Manzo, G., Catani, F., Casagli, N. (2013). Web data mining for automatic inventory of geohazards at national scale. Applied Geography, 43, 147-158.

Phantom study and accuracy evaluation of an image-to-world registration approach used with electro-magnetic tracking system for neurosurgery

NASA Astrophysics Data System (ADS)

Li, Senhu; Sarment, David

2015-12-01

Minimally invasive neurosurgery needs intraoperative imaging updates and high efficient image guide system to facilitate the procedure. An automatic image guided system utilized with a compact and mobile intraoperative CT imager was introduced in this work. A tracking frame that can be easily attached onto the commercially available skull clamp was designed. With known geometry of fiducial and tracking sensor arranged on this rigid frame that was fabricated through high precision 3D printing, not only was an accurate, fully automatic registration method developed in a simple and less-costly approach, but also it helped in estimating the errors from fiducial localization in image space through image processing, and in patient space through the calibration of tracking frame. Our phantom study shows the fiducial registration error as 0.348+/-0.028mm, comparing the manual registration error as 1.976+/-0.778mm. The system in this study provided a robust and accurate image-to-patient registration without interruption of routine surgical workflow and any user interactions involved through the neurosurgery.

Automatic Calibration of a Semi-Distributed Hydrologic Model Using Particle Swarm Optimization

NASA Astrophysics Data System (ADS)

Bekele, E. G.; Nicklow, J. W.

2005-12-01

Hydrologic simulation models need to be calibrated and validated before using them for operational predictions. Spatially-distributed hydrologic models generally have a large number of parameters to capture the various physical characteristics of a hydrologic system. Manual calibration of such models is a very tedious and daunting task, and its success depends on the subjective assessment of a particular modeler, which includes knowledge of the basic approaches and interactions in the model. In order to alleviate these shortcomings, an automatic calibration model, which employs an evolutionary optimization technique known as Particle Swarm Optimizer (PSO) for parameter estimation, is developed. PSO is a heuristic search algorithm that is inspired by social behavior of bird flocking or fish schooling. The newly-developed calibration model is integrated to the U.S. Department of Agriculture's Soil and Water Assessment Tool (SWAT). SWAT is a physically-based, semi-distributed hydrologic model that was developed to predict the long term impacts of land management practices on water, sediment and agricultural chemical yields in large complex watersheds with varying soils, land use, and management conditions. SWAT was calibrated for streamflow and sediment concentration. The calibration process involves parameter specification, whereby sensitive model parameters are identified, and parameter estimation. In order to reduce the number of parameters to be calibrated, parameterization was performed. The methodology is applied to a demonstration watershed known as Big Creek, which is located in southern Illinois. Application results show the effectiveness of the approach and model predictions are significantly improved.

40 CFR 85.2233 - Steady state test equipment calibrations, adjustments, and quality control-EPA 91.

Code of Federal Regulations, 2010 CFR

2010-07-01

... compensated for automatically and statistical process control demonstrates equal or better quality control... calibrations, adjustments, and quality control-EPA 91. 85.2233 Section 85.2233 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM MOBILE...

Complete scanpaths analysis toolbox.

PubMed

Augustyniak, Piotr; Mikrut, Zbigniew

2006-01-01

This paper presents a complete open software environment for control, data processing and assessment of visual experiments. Visual experiments are widely used in research on human perception physiology and the results are applicable to various visual information-based man-machine interfacing, human-emulated automatic visual systems or scanpath-based learning of perceptual habits. The toolbox is designed for Matlab platform and supports infra-red reflection-based eyetracker in calibration and scanpath analysis modes. Toolbox procedures are organized in three layers: the lower one, communicating with the eyetracker output file, the middle detecting scanpath events on a physiological background and the one upper consisting of experiment schedule scripts, statistics and summaries. Several examples of visual experiments carried out with use of the presented toolbox complete the paper.

A Calibration-Free Laser-Induced Breakdown Spectroscopy (CF-LIBS) Quantitative Analysis Method Based on the Auto-Selection of an Internal Reference Line and Optimized Estimation of Plasma Temperature.

PubMed

Yang, Jianhong; Li, Xiaomeng; Xu, Jinwu; Ma, Xianghong

2018-01-01

The quantitative analysis accuracy of calibration-free laser-induced breakdown spectroscopy (CF-LIBS) is severely affected by the self-absorption effect and estimation of plasma temperature. Herein, a CF-LIBS quantitative analysis method based on the auto-selection of internal reference line and the optimized estimation of plasma temperature is proposed. The internal reference line of each species is automatically selected from analytical lines by a programmable procedure through easily accessible parameters. Furthermore, the self-absorption effect of the internal reference line is considered during the correction procedure. To improve the analysis accuracy of CF-LIBS, the particle swarm optimization (PSO) algorithm is introduced to estimate the plasma temperature based on the calculation results from the Boltzmann plot. Thereafter, the species concentrations of a sample can be calculated according to the classical CF-LIBS method. A total of 15 certified alloy steel standard samples of known compositions and elemental weight percentages were used in the experiment. Using the proposed method, the average relative errors of Cr, Ni, and Fe calculated concentrations were 4.40%, 6.81%, and 2.29%, respectively. The quantitative results demonstrated an improvement compared with the classical CF-LIBS method and the promising potential of in situ and real-time application.

The development of an automatically produced cholangiography procedure using the reconstruction of portal-phase multidetector-row computed tomography images: preliminary experience.

PubMed

Hirose, Tomoaki; Igami, Tsuyoshi; Koga, Kusuto; Hayashi, Yuichiro; Ebata, Tomoki; Yokoyama, Yukihiro; Sugawara, Gen; Mizuno, Takashi; Yamaguchi, Junpei; Mori, Kensaku; Nagino, Masato

2017-03-01

Fusion angiography using reconstructed multidetector-row computed tomography (MDCT) images, and cholangiography using reconstructed images from MDCT with a cholangiographic agent include an anatomical gap due to the different periods of MDCT scanning. To conquer such gaps, we attempted to develop a cholangiography procedure that automatically reconstructs a cholangiogram from portal-phase MDCT images. The automatically produced cholangiography procedure utilized an original software program that was developed by the Graduate School of Information Science, Nagoya University. This program structured 5 candidate biliary tracts, and automatically selected one as the candidate for cholangiography. The clinical value of the automatically produced cholangiography procedure was estimated based on a comparison with manually produced cholangiography. Automatically produced cholangiograms were reconstructed for 20 patients who underwent MDCT scanning before biliary drainage for distal biliary obstruction. The procedure showed the ability to extract the 5 main biliary branches and the 21 subsegmental biliary branches in 55 and 25 % of the cases, respectively. The extent of aberrant connections and aberrant extractions outside the biliary tract was acceptable. Among all of the cholangiograms, 5 were clinically applied with no correction, 8 were applied with modest improvements, and 3 produced a correct cholangiography before automatic selection. Although our procedure requires further improvement based on the analysis of additional patient data, it may represent an alternative to direct cholangiography in the future.

Automatic scoring of dicentric chromosomes as a tool in large scale radiation accidents.

PubMed

Romm, H; Ainsbury, E; Barnard, S; Barrios, L; Barquinero, J F; Beinke, C; Deperas, M; Gregoire, E; Koivistoinen, A; Lindholm, C; Moquet, J; Oestreicher, U; Puig, R; Rothkamm, K; Sommer, S; Thierens, H; Vandersickel, V; Vral, A; Wojcik, A

2013-08-30

Mass casualty scenarios of radiation exposure require high throughput biological dosimetry techniques for population triage in order to rapidly identify individuals who require clinical treatment. The manual dicentric assay is a highly suitable technique, but it is also very time consuming and requires well trained scorers. In the framework of the MULTIBIODOSE EU FP7 project, semi-automated dicentric scoring has been established in six European biodosimetry laboratories. Whole blood was irradiated with a Co-60 gamma source resulting in 8 different doses between 0 and 4.5Gy and then shipped to the six participating laboratories. To investigate two different scoring strategies, cell cultures were set up with short term (2-3h) or long term (24h) colcemid treatment. Three classifiers for automatic dicentric detection were applied, two of which were developed specifically for these two different culture techniques. The automation procedure included metaphase finding, capture of cells at high resolution and detection of dicentric candidates. The automatically detected dicentric candidates were then evaluated by a trained human scorer, which led to the term 'semi-automated' being applied to the analysis. The six participating laboratories established at least one semi-automated calibration curve each, using the appropriate classifier for their colcemid treatment time. There was no significant difference between the calibration curves established, regardless of the classifier used. The ratio of false positive to true positive dicentric candidates was dose dependent. The total staff effort required for analysing 150 metaphases using the semi-automated approach was 2 min as opposed to 60 min for manual scoring of 50 metaphases. Semi-automated dicentric scoring is a useful tool in a large scale radiation accident as it enables high throughput screening of samples for fast triage of potentially exposed individuals. Furthermore, the results from the participating laboratories were comparable which supports networking between laboratories for this assay. Copyright © 2013 Elsevier B.V. All rights reserved.

Instruments and Methodologies for the Underwater Tridimensional Digitization and Data Musealization

NASA Astrophysics Data System (ADS)

Repola, L.; Memmolo, R.; Signoretti, D.

2015-04-01

In the research started within the SINAPSIS project of the Università degli Studi Suor Orsola Benincasa an underwater stereoscopic scanning aimed at surveying of submerged archaeological sites, integrable to standard systems for geomorphological detection of the coast, has been developed. The project involves the construction of hardware consisting of an aluminum frame supporting a pair of GoPro Hero Black Edition cameras and software for the production of point clouds and the initial processing of data. The software has features for stereoscopic vision system calibration, reduction of noise and the of distortion of underwater captured images, searching for corresponding points of stereoscopic images using stereo-matching algorithms (dense and sparse), for points cloud generating and filtering. Only after various calibration and survey tests carried out during the excavations envisaged in the project, the mastery of methods for an efficient acquisition of data has been achieved. The current development of the system has allowed generation of portions of digital models of real submerged scenes. A semi-automatic procedure for global registration of partial models is under development as a useful aid for the study and musealization of sites.

Forward Model Studies of Water Vapor Using Scanning Microwave Radiometers, Global Positioning System, and Radiosondes during the Cloudiness Intercomparison Experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mattioli, Vinia; Westwater, Ed R.; Gutman, S.

2005-05-01

Brightness temperatures computed from five absorption models and radiosonde observations were analyzed by comparing them with measurements from three microwave radiometers at 23.8 and 31.4 GHz. Data were obtained during the Cloudiness Inter-Comparison experiment at the U.S. Department of Energy's Atmospheric Radiation Measurement Program's (ARM) site in North-Central Oklahoma in 2003. The radiometers were calibrated using two procedures, the so-called instantaneous ?tipcal? method and an automatic self-calibration algorithm. Measurements from the radiometers were in agreement, with less than a 0.4-K difference during clear skies, when the instantaneous method was applied. Brightness temperatures from the radiometer and the radiosonde showed anmore » agreement of less than 0.55 K when the most recent absorption models were considered. Precipitable water vapor (PWV) computed from the radiometers were also compared to the PWV derived from a Global Positioning System station that operates at the ARM site. The instruments agree to within 0.1 cm in PWV retrieval.« less

Information theoretic methods for image processing algorithm optimization

NASA Astrophysics Data System (ADS)

Prokushkin, Sergey F.; Galil, Erez

2015-01-01

Modern image processing pipelines (e.g., those used in digital cameras) are full of advanced, highly adaptive filters that often have a large number of tunable parameters (sometimes > 100). This makes the calibration procedure for these filters very complex, and the optimal results barely achievable in the manual calibration; thus an automated approach is a must. We will discuss an information theory based metric for evaluation of algorithm adaptive characteristics ("adaptivity criterion") using noise reduction algorithms as an example. The method allows finding an "orthogonal decomposition" of the filter parameter space into the "filter adaptivity" and "filter strength" directions. This metric can be used as a cost function in automatic filter optimization. Since it is a measure of a physical "information restoration" rather than perceived image quality, it helps to reduce the set of the filter parameters to a smaller subset that is easier for a human operator to tune and achieve a better subjective image quality. With appropriate adjustments, the criterion can be used for assessment of the whole imaging system (sensor plus post-processing).

Geometrical pose and structural estimation from a single image for automatic inspection of filter components

NASA Astrophysics Data System (ADS)

Liu, Yonghuai; Rodrigues, Marcos A.

2000-03-01

This paper describes research on the application of machine vision techniques to a real time automatic inspection task of air filter components in a manufacturing line. A novel calibration algorithm is proposed based on a special camera setup where defective items would show a large calibration error. The algorithm makes full use of rigid constraints derived from the analysis of geometrical properties of reflected correspondence vectors which have been synthesized into a single coordinate frame and provides a closed form solution to the estimation of all parameters. For a comparative study of performance, we also developed another algorithm based on this special camera setup using epipolar geometry. A number of experiments using synthetic data have shown that the proposed algorithm is generally more accurate and robust than the epipolar geometry based algorithm and that the geometric properties of reflected correspondence vectors provide effective constraints to the calibration of rigid body transformations.

Fully integrated low-noise readout circuit with automatic offset cancellation loop for capacitive microsensors.

PubMed

Song, Haryong; Park, Yunjong; Kim, Hyungseup; Cho, Dong-Il Dan; Ko, Hyoungho

2015-10-14

Capacitive sensing schemes are widely used for various microsensors; however, such microsensors suffer from severe parasitic capacitance problems. This paper presents a fully integrated low-noise readout circuit with automatic offset cancellation loop (AOCL) for capacitive microsensors. The output offsets of the capacitive sensing chain due to the parasitic capacitances and process variations are automatically removed using AOCL. The AOCL generates electrically equivalent offset capacitance and enables charge-domain fine calibration using a 10-bit R-2R digital-to-analog converter, charge-transfer switches, and a charge-storing capacitor. The AOCL cancels the unwanted offset by binary-search algorithm based on 10-bit successive approximation register (SAR) logic. The chip is implemented using 0.18 μm complementary metal-oxide-semiconductor (CMOS) process with an active area of 1.76 mm². The power consumption is 220 μW with 3.3 V supply. The input parasitic capacitances within the range of -250 fF to 250 fF can be cancelled out automatically, and the required calibration time is lower than 10 ms.

Fully Integrated Low-Noise Readout Circuit with Automatic Offset Cancellation Loop for Capacitive Microsensors

PubMed Central

Song, Haryong; Park, Yunjong; Kim, Hyungseup; Cho, Dong-il Dan; Ko, Hyoungho

2015-01-01

Capacitive sensing schemes are widely used for various microsensors; however, such microsensors suffer from severe parasitic capacitance problems. This paper presents a fully integrated low-noise readout circuit with automatic offset cancellation loop (AOCL) for capacitive microsensors. The output offsets of the capacitive sensing chain due to the parasitic capacitances and process variations are automatically removed using AOCL. The AOCL generates electrically equivalent offset capacitance and enables charge-domain fine calibration using a 10-bit R-2R digital-to-analog converter, charge-transfer switches, and a charge-storing capacitor. The AOCL cancels the unwanted offset by binary-search algorithm based on 10-bit successive approximation register (SAR) logic. The chip is implemented using 0.18 μm complementary metal-oxide-semiconductor (CMOS) process with an active area of 1.76 mm2. The power consumption is 220 μW with 3.3 V supply. The input parasitic capacitances within the range of −250 fF to 250 fF can be cancelled out automatically, and the required calibration time is lower than 10 ms. PMID:26473877

Assessment of Space Power Related Measurement Requirements of the Strategic Defense Initiative

DTIC Science & Technology

1989-04-01

calibration techniques are available and estimated uncertainties vary between 5 and 10%. At low rf power levels (~ 10mW ), NIST maintains standard calibration... bands single or dual six-port automatic network analyzers [24] are used as transfer systems with detectors calibrated using the NIST micro calorimeter...Probable designs for the multimegawatt space reactor program indicate the need to measure neutron fluxes up to 1016 neutrons/cm2- s (1019 neutrons

Automatic camera to laser calibration for high accuracy mobile mapping systems using INS

NASA Astrophysics Data System (ADS)

Goeman, Werner; Douterloigne, Koen; Gautama, Sidharta

2013-09-01

A mobile mapping system (MMS) is a mobile multi-sensor platform developed by the geoinformation community to support the acquisition of huge amounts of geodata in the form of georeferenced high resolution images and dense laser clouds. Since data fusion and data integration techniques are increasingly able to combine the complementary strengths of different sensor types, the external calibration of a camera to a laser scanner is a common pre-requisite on today's mobile platforms. The methods of calibration, nevertheless, are often relatively poorly documented, are almost always time-consuming, demand expert knowledge and often require a carefully constructed calibration environment. A new methodology is studied and explored to provide a high quality external calibration for a pinhole camera to a laser scanner which is automatic, easy to perform, robust and foolproof. The method presented here, uses a portable, standard ranging pole which needs to be positioned on a known ground control point. For calibration, a well studied absolute orientation problem needs to be solved. In many cases, the camera and laser sensor are calibrated in relation to the INS system. Therefore, the transformation from camera to laser contains the cumulated error of each sensor in relation to the INS. Here, the calibration of the camera is performed in relation to the laser frame using the time synchronization between the sensors for data association. In this study, the use of the inertial relative movement will be explored to collect more useful calibration data. This results in a better intersensor calibration allowing better coloring of the clouds and a more accurate depth mask for images, especially on the edges of objects in the scene.

Calibration of Automatically Generated Items Using Bayesian Hierarchical Modeling.

ERIC Educational Resources Information Center

Johnson, Matthew S.; Sinharay, Sandip

For complex educational assessments, there is an increasing use of "item families," which are groups of related items. However, calibration or scoring for such an assessment requires fitting models that take into account the dependence structure inherent among the items that belong to the same item family. C. Glas and W. van der Linden…

Calibration Of Partial-Pressure-Of-Oxygen Sensors

NASA Technical Reports Server (NTRS)

Yount, David W.; Heronimus, Kevin

1995-01-01

Report and analysis of, and discussion of improvements in, procedure for calibrating partial-pressure-of-oxygen sensors to satisfy Spacelab calibration requirements released. Sensors exhibit fast drift, which results in short calibration period not suitable for Spacelab. By assessing complete process of determining total drift range available, calibration procedure modified to eliminate errors and still satisfy requirements without compromising integrity of system.

Experimental calibration procedures for rotating Lorentz-force flowmeters

DOE PAGES

Hvasta, M. G.; Slighton, N. T.; Kolemen, E.; ...

2017-07-14

Rotating Lorentz-force flowmeters are a novel and useful technology with a range of applications in a variety of different industries. However, calibrating these flowmeters can be challenging, time-consuming, and expensive. In this paper, simple calibration procedures for rotating Lorentz-force flowmeters are presented. These procedures eliminate the need for expensive equipment, numerical modeling, redundant flowmeters, and system down-time. Finally, the calibration processes are explained in a step-by-step manner and compared to experimental results.

Experimental calibration procedures for rotating Lorentz-force flowmeters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hvasta, M. G.; Slighton, N. T.; Kolemen, E.

Rotating Lorentz-force flowmeters are a novel and useful technology with a range of applications in a variety of different industries. However, calibrating these flowmeters can be challenging, time-consuming, and expensive. In this paper, simple calibration procedures for rotating Lorentz-force flowmeters are presented. These procedures eliminate the need for expensive equipment, numerical modeling, redundant flowmeters, and system down-time. Finally, the calibration processes are explained in a step-by-step manner and compared to experimental results.

FlowCal: A user-friendly, open source software tool for automatically converting flow cytometry data from arbitrary to calibrated units

PubMed Central

Castillo-Hair, Sebastian M.; Sexton, John T.; Landry, Brian P.; Olson, Evan J.; Igoshin, Oleg A.; Tabor, Jeffrey J.

2017-01-01

Flow cytometry is widely used to measure gene expression and other molecular biological processes with single cell resolution via fluorescent probes. Flow cytometers output data in arbitrary units (a.u.) that vary with the probe, instrument, and settings. Arbitrary units can be converted to the calibrated unit molecules of equivalent fluorophore (MEF) using commercially available calibration particles. However, there is no convenient, non-proprietary tool available to perform this calibration. Consequently, most researchers report data in a.u., limiting interpretation. Here, we report a software tool named FlowCal to overcome current limitations. FlowCal can be run using an intuitive Microsoft Excel interface, or customizable Python scripts. The software accepts Flow Cytometry Standard (FCS) files as inputs and is compatible with different calibration particles, fluorescent probes, and cell types. Additionally, FlowCal automatically gates data, calculates common statistics, and produces publication quality plots. We validate FlowCal by calibrating a.u. measurements of E. coli expressing superfolder GFP (sfGFP) collected at 10 different detector sensitivity (gain) settings to a single MEF value. Additionally, we reduce day-to-day variability in replicate E. coli sfGFP expression measurements due to instrument drift by 33%, and calibrate S. cerevisiae mVenus expression data to MEF units. Finally, we demonstrate a simple method for using FlowCal to calibrate fluorescence units across different cytometers. FlowCal should ease the quantitative analysis of flow cytometry data within and across laboratories and facilitate the adoption of standard fluorescence units in synthetic biology and beyond. PMID:27110723

An integrated exhaust gas analysis system with self-contained data processing and automatic calibration

NASA Technical Reports Server (NTRS)

Anderson, R. C.; Summers, R. L.

1981-01-01

An integrated gas analysis system designed to operate in automatic, semiautomatic, and manual modes from a remote control panel is described. The system measures the carbon monoxide, oxygen, water vapor, total hydrocarbons, carbon dioxide, and oxides of nitrogen. A pull through design provides increased reliability and eliminates the need for manual flow rate adjustment and pressure correction. The system contains two microprocessors to range the analyzers, calibrate the system, process the raw data to units of concentration, and provides information to the facility research computer and to the operator through terminal and the control panels. After initial setup, the system operates for several hours without significant operator attention.

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR HARVARD PM IMPACTOR CALIBRATION AND LEAK TESTING (UA-L-7.1)

EPA Science Inventory

The purpose of this SOP is to describe the procedures for the periodic calibration and leak testing of Harvard particulate matter (PM) impactor units. This procedure applies directly to the calibration and leak testing of Harvard PM impactor units used during the Arizona NHEXAS ...

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR HARVARD PM IMPACTOR CALIBRATION AND LEAK TESTING (UA-L-7.1)

EPA Science Inventory

The purpose of this SOP is to describe the procedures for the periodic calibration and leak testing of Harvard particulate matter (PM) impactor units. This procedure applies directly to the calibration and leak testing of Harvard PM impactor units used during the Arizona NHEXAS ...

Partitioning of net carbon dioxide flux measured by automatic transparent chamber

NASA Astrophysics Data System (ADS)

Dyukarev, EA

2018-03-01

Mathematical model was developed for describing carbon dioxide fluxes at open sedge-sphagnum fen during growing season. The model was calibrated using the results of observations from automatic transparent chamber and it allows us to estimate autotrophic, heterotrophic and ecosystem respiration fluxes, gross and net primary vegetation production, and the net carbon balance.

Using Automatic Item Generation to Meet the Increasing Item Demands of High-Stakes Educational and Occupational Assessment

ERIC Educational Resources Information Center

Arendasy, Martin E.; Sommer, Markus

2012-01-01

The use of new test administration technologies such as computerized adaptive testing in high-stakes educational and occupational assessments demands large item pools. Classic item construction processes and previous approaches to automatic item generation faced the problems of a considerable loss of items after the item calibration phase. In this…

A Dual-Range Strain Gage Weighing Transducer Employing Automatic Switching

Treesearch

Rodger A. Arola

1968-01-01

Describes a dual-range strain gage transducer which has proven to be an excellent weight-sensing device for weighing trees and tree-length logs; discusses basic principals of the design and operation; and shows that a single transducer having two sensitivity ranges with automatic internal switching can sense weight with good repeatability and that one calibration curve...

A BPM calibration procedure using TBT data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, M.J.; Crisp, J.; Prieto, P.

2007-06-01

Accurate BPM calibration is crucial for lattice analysis. It is also reassuring when the calibration can be independently verified. This paper outlines a procedure that can extract BPM calibration information from TBT orbit data. The procedure is developed as an extension to the Turn-By-Turn lattice analysis [1]. Its application to data from both Recycler Ring and Main Injector (MI) at Fermilab have produced very encouraging results. Some specifics in hardware design will be mentioned to contrast that of analysis results.

Radiometrie recalibration procedure for landsat-5 thematic mapper data

USGS Publications Warehouse

Chander, G.; Micijevic, E.; Hayes, R.W.; Barsi, J.A.

2008-01-01

The Landsat-5 (L5) satellite was launched on March 01, 1984, with a design life of three years. Incredibly, the L5 Thematic Mapper (TM) has collected data for 23 years. Over this time, the detectors have aged, and its radiometric characteristics have changed since launch. The calibration procedures and parameters have also changed with time. Revised radiometric calibrations have improved the radiometric accuracy of recently processed data; however, users with data that were processed prior to the calibration update do not benefit from the revisions. A procedure has been developed to give users the ability to recalibrate their existing Level 1 (L1) products without having to purchase reprocessed data from the U.S. Geological Survey (USGS). The accuracy of the recalibration is dependent on the knowledge of the prior calibration applied to the data. The ""Work Order" file, included with standard National Land Archive Production System (NLAFS) data products, gives parameters that define the applied calibration. These are the Internal Calibrator (IC) calibration parameters or the default prelaunch calibration, if there were problems with the IC calibration. This paper details the recalibration procedure for data processed using IC, in which users have the Work Order file. ?? 2001 IEEE.

Heliostat kinematic system calibration using uncalibrated cameras

NASA Astrophysics Data System (ADS)

Burisch, Michael; Gomez, Luis; Olasolo, David; Villasante, Cristobal

2017-06-01

The efficiency of the solar field greatly depends on the ability of the heliostats to precisely reflect solar radiation onto a central receiver. To control the heliostats with such a precision accurate knowledge of the motion of each of them modeled as a kinematic system is required. Determining the parameters of this system for each heliostat by a calibration system is crucial for the efficient operation of the solar field. For small sized heliostats being able to make such a calibration in a fast and automatic manner is imperative as the solar field potentially contain tens or even hundreds of thousands of them. A calibration system which can rapidly recalibrate a whole solar field would also allow reducing costs. Heliostats are generally designed to provide stability over a large period of time. Being able to relax this requirement and compensate any occurring error by adapting parameters in a model, the costs of the heliostat can be reduced. The presented method describes such an automatic calibration system using uncalibrated cameras rigidly attached to each heliostat. The cameras are used to observe targets spread out through the solar field; based on this the kinematic system of the heliostat can be estimated with high precision. A comparison of this approach to similar solutions shows the viability of the proposed solution.

Calibrating Item Families and Summarizing the Results Using Family Expected Response Functions

ERIC Educational Resources Information Center

Sinharay, Sandip; Johnson, Matthew S.; Williamson, David M.

2003-01-01

Item families, which are groups of related items, are becoming increasingly popular in complex educational assessments. For example, in automatic item generation (AIG) systems, a test may consist of multiple items generated from each of a number of item models. Item calibration or scoring for such an assessment requires fitting models that can…

Normalized Metadata Generation for Human Retrieval Using Multiple Video Surveillance Cameras.

PubMed

Jung, Jaehoon; Yoon, Inhye; Lee, Seungwon; Paik, Joonki

2016-06-24

Since it is impossible for surveillance personnel to keep monitoring videos from a multiple camera-based surveillance system, an efficient technique is needed to help recognize important situations by retrieving the metadata of an object-of-interest. In a multiple camera-based surveillance system, an object detected in a camera has a different shape in another camera, which is a critical issue of wide-range, real-time surveillance systems. In order to address the problem, this paper presents an object retrieval method by extracting the normalized metadata of an object-of-interest from multiple, heterogeneous cameras. The proposed metadata generation algorithm consists of three steps: (i) generation of a three-dimensional (3D) human model; (ii) human object-based automatic scene calibration; and (iii) metadata generation. More specifically, an appropriately-generated 3D human model provides the foot-to-head direction information that is used as the input of the automatic calibration of each camera. The normalized object information is used to retrieve an object-of-interest in a wide-range, multiple-camera surveillance system in the form of metadata. Experimental results show that the 3D human model matches the ground truth, and automatic calibration-based normalization of metadata enables a successful retrieval and tracking of a human object in the multiple-camera video surveillance system.

Normalized Metadata Generation for Human Retrieval Using Multiple Video Surveillance Cameras

PubMed Central

Jung, Jaehoon; Yoon, Inhye; Lee, Seungwon; Paik, Joonki

2016-01-01

Since it is impossible for surveillance personnel to keep monitoring videos from a multiple camera-based surveillance system, an efficient technique is needed to help recognize important situations by retrieving the metadata of an object-of-interest. In a multiple camera-based surveillance system, an object detected in a camera has a different shape in another camera, which is a critical issue of wide-range, real-time surveillance systems. In order to address the problem, this paper presents an object retrieval method by extracting the normalized metadata of an object-of-interest from multiple, heterogeneous cameras. The proposed metadata generation algorithm consists of three steps: (i) generation of a three-dimensional (3D) human model; (ii) human object-based automatic scene calibration; and (iii) metadata generation. More specifically, an appropriately-generated 3D human model provides the foot-to-head direction information that is used as the input of the automatic calibration of each camera. The normalized object information is used to retrieve an object-of-interest in a wide-range, multiple-camera surveillance system in the form of metadata. Experimental results show that the 3D human model matches the ground truth, and automatic calibration-based normalization of metadata enables a successful retrieval and tracking of a human object in the multiple-camera video surveillance system. PMID:27347961

Calibration of steady-state car-following models using macroscopic loop detector data.

DOT National Transportation Integrated Search

2010-05-01

The paper develops procedures for calibrating the steady-state component of various car following models using : macroscopic loop detector data. The calibration procedures are developed for a number of commercially available : microscopic traffic sim...

Calibration procedure for a laser triangulation scanner with uncertainty evaluation

NASA Astrophysics Data System (ADS)

Genta, Gianfranco; Minetola, Paolo; Barbato, Giulio

2016-11-01

Most of low cost 3D scanning devices that are nowadays available on the market are sold without a user calibration procedure to correct measurement errors related to changes in environmental conditions. In addition, there is no specific international standard defining a procedure to check the performance of a 3D scanner along time. This paper aims at detailing a thorough methodology to calibrate a 3D scanner and assess its measurement uncertainty. The proposed procedure is based on the use of a reference ball plate and applied to a triangulation laser scanner. Experimental results show that the metrological performance of the instrument can be greatly improved by the application of the calibration procedure that corrects systematic errors and reduces the device's measurement uncertainty.

PFMCal : Photonic force microscopy calibration extended for its application in high-frequency microrheology

NASA Astrophysics Data System (ADS)

Butykai, A.; Domínguez-García, P.; Mor, F. M.; Gaál, R.; Forró, L.; Jeney, S.

2017-11-01

The present document is an update of the previously published MatLab code for the calibration of optical tweezers in the high-resolution detection of the Brownian motion of non-spherical probes [1]. In this instance, an alternative version of the original code, based on the same physical theory [2], but focused on the automation of the calibration of measurements using spherical probes, is outlined. The new added code is useful for high-frequency microrheology studies, where the probe radius is known but the viscosity of the surrounding fluid maybe not. This extended calibration methodology is automatic, without the need of a user's interface. A code for calibration by means of thermal noise analysis [3] is also included; this is a method that can be applied when using viscoelastic fluids if the trap stiffness is previously estimated [4]. The new code can be executed in MatLab and using GNU Octave. Program Files doi:http://dx.doi.org/10.17632/s59f3gz729.1 Licensing provisions: GPLv3 Programming language: MatLab 2016a (MathWorks Inc.) and GNU Octave 4.0 Operating system: Linux and Windows. Supplementary material: A new document README.pdf includes basic running instructions for the new code. Journal reference of previous version: Computer Physics Communications, 196 (2015) 599 Does the new version supersede the previous version?: No. It adds alternative but compatible code while providing similar calibration factors. Nature of problem (approx. 50-250 words): The original code uses a MatLab-provided user's interface, which is not available in GNU Octave, and cannot be used outside of a proprietary software as MatLab. Besides, the process of calibration when using spherical probes needs an automatic method when calibrating big amounts of different data focused to microrheology. Solution method (approx. 50-250 words): The new code can be executed in the latest version of MatLab and using GNU Octave, a free and open-source alternative to MatLab. This code generates an automatic calibration process which requires only to write the input data in the main script. Additionally, we include a calibration method based on thermal noise statistics, which can be used with viscoelastic fluids if the trap stiffness is previously estimated. Reasons for the new version: This version extends the functionality of PFMCal for the particular case of spherical probes and unknown fluid viscosities. The extended code is automatic, works in different operating systems and it is compatible with GNU Octave. Summary of revisions: The original MatLab program in the previous version, which is executed by PFMCal.m, is not changed. Here, we have added two additional main archives named PFMCal_auto.m and PFMCal_histo.m, which implement automatic calculations of the calibration process and calibration through Boltzmann statistics, respectively. The process of calibration using this code for spherical beads is described in the README.pdf file provided in the new code submission. Here, we obtain different calibration factors, β (given in μm/V), according to [2], related to two statistical quantities: the mean-squared displacement (MSD), βMSD, and the velocity autocorrelation function (VAF), βVAF. Using that methodology, the trap stiffness, k, and the zero-shear viscosity of the fluid, η, can be calculated if the value of the particle's radius, a, is previously known. For comparison, we include in the extended code the method of calibration using the corner frequency of the power-spectral density (PSD) [5], providing a calibration factor βPSD. Besides, with the prior estimation of the trap stiffness, along with the known value of the particle's radius, we can use thermal noise statistics to obtain calibration factors, β, according to the quadratic form of the optical potential, βE, and related to the Gaussian distribution of the bead's positions, βσ2. This method has been demonstrated to be applicable to the calibration of optical tweezers when using non-Newtonian viscoelastic polymeric liquids [4]. An example of the results using this calibration process is summarized in Table 1. Using the data provided in the new code submission, for water and acetone fluids, we calculate all the calibration factors by using the original PFMCal.m and by the new non-GUI code PFMCal_auto.m and PFMCal_histo.m. Regarding the new code, PFMCal_auto.m returns η, k, βMSD, βVAF and βPSD, while PFMCal_histo.m provides βσ2 and βE. Table 1 shows how we obtain the expected viscosity of the two fluids at this temperature and how the different methods provide good agreement between trap stiffnesses and calibration factors. Additional comments including Restrictions and Unusual features (approx. 50-250 words): The original code, PFMCal.m, runs under MatLab using the Statistics Toolbox. The extended code, PFMCal_auto.m and PFMCal_histo.m, can be executed without modification using MatLab or GNU Octave. The code has been tested in Linux and Windows operating systems.

Headspace gas chromatographic method for the measurement of difluoroethane in blood.

PubMed

Broussard, L A; Broussard, A; Pittman, T; Lafferty, D; Presley, L

2001-01-01

To develop a gas chromatographic assay for the analysis of difluoroethane, a volatile substance, in blood and to determine assay characteristics including linearity, limit of quantitation, precision, and specificity. Referral toxicology laboratory Difluoroethane, a colorless, odorless, highly flammable gas used as a refrigerant blend component and aerosol propellant, may be abused via inhalation. A headspace gas chromatographic procedure for the identification and quantitation of difluoroethane in blood is presented. A methanolic stock standard prepared from pure gaseous difluoroethane was used to prepare whole blood calibrators. Quantitation of difluoroethane was performed using a six-point calibration curve and an internal standard of 1-propanol. The assay is linear from 0 to 115 mg/L including a low calibrator at 4 mg/L, the limit of quantitation. Within-run coefficients of variation at mean concentrations of 13.8 mg/L and 38.5 mg/L were 5.8% and 6.8% respectively. Between-run coefficients of variation at mean concentrations of 15.9 mg/L and 45.7 mg/L were 13.4% and 9.8% respectively. Several volatile substances were tested as potential interfering compounds with propane having a retention time identical to that of difluoroethane. This method requires minimal sample preparation, is rapid and reproducible, can be modified for the quantitation of other volatiles, and could be automated using an automatic sampler/injector system.

Methods for Calibration of Prout-Tompkins Kinetics Parameters Using EZM Iteration and GLO

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wemhoff, A P; Burnham, A K; de Supinski, B

2006-11-07

This document contains information regarding the standard procedures used to calibrate chemical kinetics parameters for the extended Prout-Tompkins model to match experimental data. Two methods for calibration are mentioned: EZM calibration and GLO calibration. EZM calibration matches kinetics parameters to three data points, while GLO calibration slightly adjusts kinetic parameters to match multiple points. Information is provided regarding the theoretical approach and application procedure for both of these calibration algorithms. It is recommended that for the calibration process, the user begin with EZM calibration to provide a good estimate, and then fine-tune the parameters using GLO. Two examples have beenmore » provided to guide the reader through a general calibrating process.« less

Parallelization of a hydrological model using the message passing interface

USGS Publications Warehouse

Wu, Yiping; Li, Tiejian; Sun, Liqun; Chen, Ji

2013-01-01

With the increasing knowledge about the natural processes, hydrological models such as the Soil and Water Assessment Tool (SWAT) are becoming larger and more complex with increasing computation time. Additionally, other procedures such as model calibration, which may require thousands of model iterations, can increase running time and thus further reduce rapid modeling and analysis. Using the widely-applied SWAT as an example, this study demonstrates how to parallelize a serial hydrological model in a Windows® environment using a parallel programing technology—Message Passing Interface (MPI). With a case study, we derived the optimal values for the two parameters (the number of processes and the corresponding percentage of work to be distributed to the master process) of the parallel SWAT (P-SWAT) on an ordinary personal computer and a work station. Our study indicates that model execution time can be reduced by 42%–70% (or a speedup of 1.74–3.36) using multiple processes (two to five) with a proper task-distribution scheme (between the master and slave processes). Although the computation time cost becomes lower with an increasing number of processes (from two to five), this enhancement becomes less due to the accompanied increase in demand for message passing procedures between the master and all slave processes. Our case study demonstrates that the P-SWAT with a five-process run may reach the maximum speedup, and the performance can be quite stable (fairly independent of a project size). Overall, the P-SWAT can help reduce the computation time substantially for an individual model run, manual and automatic calibration procedures, and optimization of best management practices. In particular, the parallelization method we used and the scheme for deriving the optimal parameters in this study can be valuable and easily applied to other hydrological or environmental models.

Automatic real-time control of suspended sediment based upon high frequency in situ measurements of nephelometric turbidity

Treesearch

Jack Lewis; Rand Eads

1998-01-01

Abstract - For estimating suspended sediment concentration (SSC) in rivers, turbidity is potentially a much better predictor than water discharge. Since about 1990, it has been feasible to automatically collect high frequency turbidity data at remote sites using battery-powered turbidity probes that are properly mounted in the river or stream. With sensors calibrated...

Research on auto-calibration technology of the image plane's center of 360-degree and all round looking camera

NASA Astrophysics Data System (ADS)

Zhang, Shaojun; Xu, Xiping

2015-10-01

The 360-degree and all round looking camera, as its characteristics of suitable for automatic analysis and judgment on the ambient environment of the carrier by image recognition algorithm, is usually applied to opto-electronic radar of robots and smart cars. In order to ensure the stability and consistency of image processing results of mass production, it is necessary to make sure the centers of image planes of different cameras are coincident, which requires to calibrate the position of the image plane's center. The traditional mechanical calibration method and electronic adjusting mode of inputting the offsets manually, both exist the problem of relying on human eyes, inefficiency and large range of error distribution. In this paper, an approach of auto- calibration of the image plane of this camera is presented. The imaging of the 360-degree and all round looking camera is a ring-shaped image consisting of two concentric circles, the center of the image is a smaller circle and the outside is a bigger circle. The realization of the technology is just to exploit the above characteristics. Recognizing the two circles through HOUGH TRANSFORM algorithm and calculating the center position, we can get the accurate center of image, that the deviation of the central location of the optic axis and image sensor. The program will set up the image sensor chip through I2C bus automatically, we can adjusting the center of the image plane automatically and accurately. The technique has been applied to practice, promotes productivity and guarantees the consistent quality of products.

Development of a new calibration procedure and its experimental validation applied to a human motion capture system.

PubMed

Royo Sánchez, Ana Cristina; Aguilar Martín, Juan José; Santolaria Mazo, Jorge

2014-12-01

Motion capture systems are often used for checking and analyzing human motion in biomechanical applications. It is important, in this context, that the systems provide the best possible accuracy. Among existing capture systems, optical systems are those with the highest accuracy. In this paper, the development of a new calibration procedure for optical human motion capture systems is presented. The performance and effectiveness of that new calibration procedure are also checked by experimental validation. The new calibration procedure consists of two stages. In the first stage, initial estimators of intrinsic and extrinsic parameters are sought. The camera calibration method used in this stage is the one proposed by Tsai. These parameters are determined from the camera characteristics, the spatial position of the camera, and the center of the capture volume. In the second stage, a simultaneous nonlinear optimization of all parameters is performed to identify the optimal values, which minimize the objective function. The objective function, in this case, minimizes two errors. The first error is the distance error between two markers placed in a wand. The second error is the error of position and orientation of the retroreflective markers of a static calibration object. The real co-ordinates of the two objects are calibrated in a co-ordinate measuring machine (CMM). The OrthoBio system is used to validate the new calibration procedure. Results are 90% lower than those from the previous calibration software and broadly comparable with results from a similarly configured Vicon system.

Multi-sensor calibration of low-cost magnetic, angular rate and gravity systems.

PubMed

Lüken, Markus; Misgeld, Berno J E; Rüschen, Daniel; Leonhardt, Steffen

2015-10-13

We present a new calibration procedure for low-cost nine degrees-of-freedom (9DOF) magnetic, angular rate and gravity (MARG) sensor systems, which relies on a calibration cube, a reference table and a body sensor network (BSN). The 9DOF MARG sensor is part of our recently-developed "Integrated Posture and Activity Network by Medit Aachen" (IPANEMA) BSN. The advantage of this new approach is the use of the calibration cube, which allows for easy integration of two sensor nodes of the IPANEMA BSN. One 9DOF MARG sensor node is thereby used for calibration; the second 9DOF MARG sensor node is used for reference measurements. A novel algorithm uses these measurements to further improve the performance of the calibration procedure by processing arbitrarily-executed motions. In addition, the calibration routine can be used in an alignment procedure to minimize errors in the orientation between the 9DOF MARG sensor system and a motion capture inertial reference system. A two-stage experimental study is conducted to underline the performance of our calibration procedure. In both stages of the proposed calibration procedure, the BSN data, as well as reference tracking data are recorded. In the first stage, the mean values of all sensor outputs are determined as the absolute measurement offset to minimize integration errors in the derived movement model of the corresponding body segment. The second stage deals with the dynamic characteristics of the measurement system where the dynamic deviation of the sensor output compared to a reference system is Sensors 2015, 15 25920 corrected. In practical validation experiments, this procedure showed promising results with a maximum RMS error of 3.89°.

Multi-Sensor Calibration of Low-Cost Magnetic, Angular Rate and Gravity Systems

PubMed Central

Lüken, Markus; Misgeld, Berno J.E.; Rüschen, Daniel; Leonhardt, Steffen

2015-01-01

We present a new calibration procedure for low-cost nine degrees-of-freedom (9DOF) magnetic, angular rate and gravity (MARG) sensor systems, which relies on a calibration cube, a reference table and a body sensor network (BSN). The 9DOF MARG sensor is part of our recently-developed “Integrated Posture and Activity Network by Medit Aachen” (IPANEMA) BSN. The advantage of this new approach is the use of the calibration cube, which allows for easy integration of two sensor nodes of the IPANEMA BSN. One 9DOF MARG sensor node is thereby used for calibration; the second 9DOF MARG sensor node is used for reference measurements. A novel algorithm uses these measurements to further improve the performance of the calibration procedure by processing arbitrarily-executed motions. In addition, the calibration routine can be used in an alignment procedure to minimize errors in the orientation between the 9DOF MARG sensor system and a motion capture inertial reference system. A two-stage experimental study is conducted to underline the performance of our calibration procedure. In both stages of the proposed calibration procedure, the BSN data, as well as reference tracking data are recorded. In the first stage, the mean values of all sensor outputs are determined as the absolute measurement offset to minimize integration errors in the derived movement model of the corresponding body segment. The second stage deals with the dynamic characteristics of the measurement system where the dynamic deviation of the sensor output compared to a reference system is corrected. In practical validation experiments, this procedure showed promising results with a maximum RMS error of 3.89°. PMID:26473873

Parameterisation of rainfall-runoff models for forecasting low and average flows, I: Conceptual modelling

NASA Astrophysics Data System (ADS)

Castiglioni, S.; Toth, E.

2009-04-01

In the calibration procedure of continuously-simulating models, the hydrologist has to choose which part of the observed hydrograph is most important to fit, either implicitly, through the visual agreement in manual calibration, or explicitly, through the choice of the objective function(s). Changing the objective functions it is in fact possible to emphasise different kind of errors, giving them more weight in the calibration phase. The objective functions used for calibrating hydrological models are generally of the quadratic type (mean squared error, correlation coefficient, coefficient of determination, etc) and are therefore oversensitive to high and extreme error values, that typically correspond to high and extreme streamflow values. This is appropriate when, like in the majority of streamflow forecasting applications, the focus is on the ability to reproduce potentially dangerous flood events; on the contrary, if the aim of the modelling is the reproduction of low and average flows, as it is the case in water resource management problems, this may result in a deterioration of the forecasting performance. This contribution presents the results of a series of automatic calibration experiments of a continuously-simulating rainfall-runoff model applied over several real-world case-studies, where the objective function is chosen so to highlight the fit of average and low flows. In this work a simple conceptual model will be used, of the lumped type, with a relatively low number of parameters to be calibrated. The experiments will be carried out for a set of case-study watersheds in Central Italy, covering an extremely wide range of geo-morphologic conditions and for whom at least five years of contemporary daily series of streamflow, precipitation and evapotranspiration estimates are available. Different objective functions will be tested in calibration and the results will be compared, over validation data, against those obtained with traditional squared functions. A companion work presents the results, over the same case-study watersheds and observation periods, of a system-theoretic model, again calibrated for reproducing average and low streamflows.

Applying modern psychometric techniques to melodic discrimination testing: Item response theory, computerised adaptive testing, and automatic item generation.

PubMed

Harrison, Peter M C; Collins, Tom; Müllensiefen, Daniel

2017-06-15

Modern psychometric theory provides many useful tools for ability testing, such as item response theory, computerised adaptive testing, and automatic item generation. However, these techniques have yet to be integrated into mainstream psychological practice. This is unfortunate, because modern psychometric techniques can bring many benefits, including sophisticated reliability measures, improved construct validity, avoidance of exposure effects, and improved efficiency. In the present research we therefore use these techniques to develop a new test of a well-studied psychological capacity: melodic discrimination, the ability to detect differences between melodies. We calibrate and validate this test in a series of studies. Studies 1 and 2 respectively calibrate and validate an initial test version, while Studies 3 and 4 calibrate and validate an updated test version incorporating additional easy items. The results support the new test's viability, with evidence for strong reliability and construct validity. We discuss how these modern psychometric techniques may also be profitably applied to other areas of music psychology and psychological science in general.

Calibration-free gaze tracking for automatic measurement of visual acuity in human infants.

PubMed

Xiong, Chunshui; Huang, Lei; Liu, Changping

2014-01-01

Most existing vision-based methods for gaze tracking need a tedious calibration process. In this process, subjects are required to fixate on a specific point or several specific points in space. However, it is hard to cooperate, especially for children and human infants. In this paper, a new calibration-free gaze tracking system and method is presented for automatic measurement of visual acuity in human infants. As far as I know, it is the first time to apply the vision-based gaze tracking in the measurement of visual acuity. Firstly, a polynomial of pupil center-cornea reflections (PCCR) vector is presented to be used as the gaze feature. Then, Gaussian mixture models (GMM) is employed for gaze behavior classification, which is trained offline using labeled data from subjects with healthy eyes. Experimental results on several subjects show that the proposed method is accurate, robust and sufficient for the application of measurement of visual acuity in human infants.

Measuring Light Air Ions in a Speleotherapeutic Cave

NASA Astrophysics Data System (ADS)

Roubal, Z.; Bartušek, K.; Szabó, Z.; Drexler, P.; Überhuberová, J.

2017-02-01

The paper deals with a methodology proposed for measuring the concentration of air ions in the environment of speleotherapeutic caves, and with the implementation of the AK-UTEE-v2 ionmeter. Speleotherapy, in the context of its general definition, is the medical therapy that utilizes the climate of selected caves to treat patients with health problems such as asthma. These spaces are characterized by the presence of high air humidity and they make extreme demands on the execution of the measuring device, the Gerdien tube (GT in the following) in particular, and on the amplifier electronics. The result is an automated measuring system using a GT with low-volume air flow, enabling long-term measuring of air ion concentration and determination of spectral ion characteristics. Interesting from the instrumentation viewpoint are the GT design, active shielding, and execution of the electrometric amplifier. A specific method for the calculation of spectral ion characteristics and the mode of automatic calibration were proposed and a procedure of automatic measurement in the absence of attendants was set up. The measuring system is designed for studying and long-term monitoring of the concentration of light negative ions in dependence on climatic conditions and on the mobility of ions occurring in the cave.

A robotic multi-channel platform for interstitial photodynamic therapy

PubMed Central

Sharikova, Anna V.; Finlay, Jarod C.; Dimofte, Andreea; Zhu, Timothy C.

2015-01-01

A custom-made robotic multichannel platform for interstitial photodynamic therapy (PDT) and diffuse optical tomography (DOT) was developed and tested in a phantom experiment. The system, which was compatible with the operating room (OR) environment, had 16 channels for independent positioning of light sources and/or isotropic detectors in separate catheters. Each channel’s motor had an optical encoder for position feedback, with resolution of 1.5 mm, and a maximum speed of 5 cm/s. Automatic calibration of detector positions was implemented using an optical diode beam that defined the starting position of each motor, and by means of feedback algorithms controlling individual channels. As a result, the accuracy of zero position of 0.1 mm for all channels was achieved. We have also employed scanning procedures where detectors automatically covered the appropriate range around source positions. Thus, total scan time for a typical optical properties (OP) measurement throughout the phantom was about 1.5 minutes with point sources. The OP were determined based on the measured light fluence rates. These enhancements allow a tremendous improvement of treatment quality for a bulk tumor compared to the systems employed in previous clinical trials. PMID:25914794

Laser Calibration of an Impact Disdrometer

NASA Technical Reports Server (NTRS)

Lane, John E.; Kasparis, Takis; Metzger, Philip T.; Jones, W. Linwood

2014-01-01

A practical approach to developing an operational low-cost disdrometer hinges on implementing an effective in situ adaptive calibration strategy. This calibration strategy lowers the cost of the device and provides a method to guarantee continued automatic calibration. In previous work, a collocated tipping bucket rain gauge was utilized to provide a calibration signal to the disdrometer's digital signal processing software. Rainfall rate is proportional to the 11/3 moment of the drop size distribution (a 7/2 moment can also be assumed, depending on the choice of terminal velocity relationship). In the previous case, the disdrometer calibration was characterized and weighted to the 11/3 moment of the drop size distribution (DSD). Optical extinction by rainfall is proportional to the 2nd moment of the DSD. Using visible laser light as a means to focus and generate an auxiliary calibration signal, the adaptive calibration processing is significantly improved.

Landsat-5 TM reflective-band absolute radiometric calibration

USGS Publications Warehouse

Chander, G.; Helder, D.L.; Markham, B.L.; Dewald, J.D.; Kaita, E.; Thome, K.J.; Micijevic, E.; Ruggles, T.A.

2004-01-01

The Landsat-5 Thematic Mapper (TM) sensor provides the longest running continuous dataset of moderate spatial resolution remote sensing imagery, dating back to its launch in March 1984. Historically, the radiometric calibration procedure for this imagery used the instrument's response to the Internal Calibrator (IC) on a scene-by-scene basis to determine the gain and offset of each detector. Due to observed degradations in the IC, a new procedure was implemented for U.S.-processed data in May 2003. This new calibration procedure is based on a lifetime radiometric calibration model for the instrument's reflective bands (1-5 and 7) and is derived, in part, from the IC response without the related degradation effects and is tied to the cross calibration with the Landsat-7 Enhanced Thematic Mapper Plus. Reflective-band absolute radiometric accuracy of the instrument tends to be on the order of 7% to 10%, based on a variety of calibration methods.

Automatic Control Of Length Of Welding Arc

NASA Technical Reports Server (NTRS)

Iceland, William F.

1991-01-01

Nonlinear relationships among current, voltage, and length stored in electronic memory. Conceptual microprocessor-based control subsystem maintains constant length of welding arc in gas/tungsten arc-welding system, even when welding current varied. Uses feedback of current and voltage from welding arc. Directs motor to set position of torch according to previously measured relationships among current, voltage, and length of arc. Signal paths marked "calibration" or "welding" used during those processes only. Other signal paths used during both processes. Control subsystem added to existing manual or automatic welding system equipped with automatic voltage control.

Performance of automatic scanning microscope for nuclear emulsion experiments

NASA Astrophysics Data System (ADS)

Güler, A. Murat; Altınok, Özgür

2015-12-01

The impressive improvements in scanning technology and methods let nuclear emulsion to be used as a target in recent large experiments. We report the performance of an automatic scanning microscope for nuclear emulsion experiments. After successful calibration and alignment of the system, we have reached 99% tracking efficiency for the minimum ionizing tracks that penetrating through the emulsions films. The automatic scanning system is successfully used for the scanning of emulsion films in the OPERA experiment and plan to use for the next generation of nuclear emulsion experiments.

Automatized alignment control of wing mechanization in aerodynamic contour of aircraft

NASA Astrophysics Data System (ADS)

Odnokurtsev, K. A.

2018-05-01

The method of automatized control of accuracy of an aircraft aerodynamic contour when mounting wing mechanization elements is described in the article. A control device in the stand of the wing assembling, equipped with the distance sensors, is suggested to be used. The measurement of control points’ inaccuracies is made automatically in a special computer program. Two kinds of sensor calibration are made in advance in order to increase the accuracy of measurements. As a result, the duration of control and adjustment of mechanization elements is reduced.

Performance of automatic scanning microscope for nuclear emulsion experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Güler, A. Murat, E-mail: mguler@newton.physics.metu.edu.tr; Altınok, Özgür; Tufts University, Medford, MA 02155

The impressive improvements in scanning technology and methods let nuclear emulsion to be used as a target in recent large experiments. We report the performance of an automatic scanning microscope for nuclear emulsion experiments. After successful calibration and alignment of the system, we have reached 99% tracking efficiency for the minimum ionizing tracks that penetrating through the emulsions films. The automatic scanning system is successfully used for the scanning of emulsion films in the OPERA experiment and plan to use for the next generation of nuclear emulsion experiments.

A New Calibration Method for Commercial RGB-D Sensors.

PubMed

Darwish, Walid; Tang, Shenjun; Li, Wenbin; Chen, Wu

2017-05-24

Commercial RGB-D sensors such as Kinect and Structure Sensors have been widely used in the game industry, where geometric fidelity is not of utmost importance. For applications in which high quality 3D is required, i.e., 3D building models of centimeter‑level accuracy, accurate and reliable calibrations of these sensors are required. This paper presents a new model for calibrating the depth measurements of RGB-D sensors based on the structured light concept. Additionally, a new automatic method is proposed for the calibration of all RGB-D parameters, including internal calibration parameters for all cameras, the baseline between the infrared and RGB cameras, and the depth error model. When compared with traditional calibration methods, this new model shows a significant improvement in depth precision for both near and far ranges.

Energy calibration issues in nuclear resonant vibrational spectroscopy: observing small spectral shifts and making fast calibrations.

PubMed

Wang, Hongxin; Yoda, Yoshitaka; Dong, Weibing; Huang, Songping D

2013-09-01

The conventional energy calibration for nuclear resonant vibrational spectroscopy (NRVS) is usually long. Meanwhile, taking NRVS samples out of the cryostat increases the chance of sample damage, which makes it impossible to carry out an energy calibration during one NRVS measurement. In this study, by manipulating the 14.4 keV beam through the main measurement chamber without moving out the NRVS sample, two alternative calibration procedures have been proposed and established: (i) an in situ calibration procedure, which measures the main NRVS sample at stage A and the calibration sample at stage B simultaneously, and calibrates the energies for observing extremely small spectral shifts; for example, the 0.3 meV energy shift between the 100%-(57)Fe-enriched [Fe4S4Cl4](=) and 10%-(57)Fe and 90%-(54)Fe labeled [Fe4S4Cl4](=) has been well resolved; (ii) a quick-switching energy calibration procedure, which reduces each calibration time from 3-4 h to about 30 min. Although the quick-switching calibration is not in situ, it is suitable for normal NRVS measurements.

Automatic Intra-Operative Stitching of Non-Overlapping Cone-Beam CT Acquisitions

PubMed Central

Fotouhi, Javad; Fuerst, Bernhard; Unberath, Mathias; Reichenstein, Stefan; Lee, Sing Chun; Johnson, Alex A.; Osgood, Greg M.; Armand, Mehran; Navab, Nassir

2018-01-01

Purpose Cone-Beam Computed Tomography (CBCT) is one of the primary imaging modalities in radiation therapy, dentistry, and orthopedic interventions. While CBCT provides crucial intraoperative information, it is bounded by a limited imaging volume, resulting in reduced effectiveness. This paper introduces an approach allowing real-time intraoperative stitching of overlapping and non-overlapping CBCT volumes to enable 3D measurements on large anatomical structures. Methods A CBCT-capable mobile C-arm is augmented with a Red-Green-Blue-Depth (RGBD) camera. An off-line co-calibration of the two imaging modalities results in co-registered video, infrared, and X-ray views of the surgical scene. Then, automatic stitching of multiple small, non-overlapping CBCT volumes is possible by recovering the relative motion of the C-arm with respect to the patient based on the camera observations. We propose three methods to recover the relative pose: RGB-based tracking of visual markers that are placed near the surgical site, RGBD-based simultaneous localization and mapping (SLAM) of the surgical scene which incorporates both color and depth information for pose estimation, and surface tracking of the patient using only depth data provided by the RGBD sensor. Results On an animal cadaver, we show stitching errors as low as 0.33 mm, 0.91 mm, and 1.72mm when the visual marker, RGBD SLAM, and surface data are used for tracking, respectively. Conclusions The proposed method overcomes one of the major limitations of CBCT C-arm systems by integrating vision-based tracking and expanding the imaging volume without any intraoperative use of calibration grids or external tracking systems. We believe this solution to be most appropriate for 3D intraoperative verification of several orthopedic procedures. PMID:29569728

Automatic Generation of Rasch-Calibrated Items: Figural Matrices Test GEOM and Endless-Loops Test EC

ERIC Educational Resources Information Center

Arendasy, Martin

2005-01-01

The future of test construction for certain psychological ability domains that can be analyzed well in a structured manner may lie--at the very least for reasons of test security--in the field of automatic item generation. In this context, a question that has not been explicitly addressed is whether it is possible to embed an item response theory…

Challenges in modeling the X-29 flight test performance

NASA Technical Reports Server (NTRS)

Hicks, John W.; Kania, Jan; Pearce, Robert; Mills, Glen

1987-01-01

Presented are methods, instrumentation, and difficulties associated with drag measurement of the X-29A aircraft. The initial performance objective of the X-29A program emphasized drag polar shapes rather than absolute drag levels. Priorities during the flight envelope expansion restricted the evaluation of aircraft performance. Changes in aircraft configuration, uncertainties in angle-of-attack calibration, and limitations in instrumentation complicated the analysis. Limited engine instrumentation with uncertainties in overall in-flight thrust accuracy made it difficult to obtain reliable values of coefficient of parasite drag. The aircraft was incapable of tracking the automatic camber control trim schedule for optimum wing flaperon deflection during typical dynamic performance maneuvers; this has also complicated the drag polar shape modeling. The X-29A was far enough off the schedule that the developed trim drag correction procedure has proven inadequate. However, good drag polar shapes have been developed throughout the flight envelope. Preliminary flight results have compared well with wind tunnel predictions. A more comprehensive analysis must be done to complete performance models. The detailed flight performance program with a calibrated engine will benefit from the experience gained during this preliminary performance phase.

Challenges in modeling the X-29A flight test performance

NASA Technical Reports Server (NTRS)

Hicks, John W.; Kania, Jan; Pearce, Robert; Mills, Glen

1987-01-01

The paper presents the methods, instrumentation, and difficulties associated with drag measurement of the X-29A aircraft. The initial performance objective of the X-29A program emphasized drag polar shapes rather than absolute drag levels. Priorities during the flight envelope expansion restricted the evaluation of aircraft performance. Changes in aircraft configuration, uncertainties in angle-of-attack calibration, and limitations in instrumentation complicated the analysis. Limited engine instrumentation with uncertainties in overall in-flight thrust accuracy made it difficult to obtain reliable values of coefficient of parasite drag. The aircraft was incapable of tracking the automatic camber control trim schedule for optimum wing flaperon deflection during typical dynamic performance maneuvers; this has also complicated the drag polar shape modeling. The X-29A was far enough off the schedule that the developed trim drag correction procedure has proven inadequate. Despite these obstacles, good drag polar shapes have been developed throughout the flight envelope. Preliminary flight results have compared well with wind tunnel predictions. A more comprehensive analysis must be done to complete the performance models. The detailed flight performance program with a calibrated engine will benefit from the experience gained during this preliminary performance phase.

Automatic Classification of Extensive Aftershock Sequences Using Empirical Matched Field Processing

NASA Astrophysics Data System (ADS)

Gibbons, Steven J.; Harris, David B.; Kværna, Tormod; Dodge, Douglas A.

2013-04-01

The aftershock sequences that follow large earthquakes create considerable problems for data centers attempting to produce comprehensive event bulletins in near real-time. The greatly increased number of events which require processing can overwhelm analyst resources and reduce the capacity for analyzing events of monitoring interest. This exacerbates a potentially reduced detection capability at key stations, due the noise generated by the sequence, and a deterioration in the quality of the fully automatic preliminary event bulletins caused by the difficulty in associating the vast numbers of closely spaced arrivals over the network. Considerable success has been enjoyed by waveform correlation methods for the automatic identification of groups of events belonging to the same geographical source region, facilitating the more time-efficient analysis of event ensembles as opposed to individual events. There are, however, formidable challenges associated with the automation of correlation procedures. The signal generated by a very large earthquake seldom correlates well enough with the signals generated by far smaller aftershocks for a correlation detector to produce statistically significant triggers at the correct times. Correlation between events within clusters of aftershocks is significantly better, although the issues of when and how to initiate new pattern detectors are still being investigated. Empirical Matched Field Processing (EMFP) is a highly promising method for detecting event waveforms suitable as templates for correlation detectors. EMFP is a quasi-frequency-domain technique that calibrates the spatial structure of a wavefront crossing a seismic array in a collection of narrow frequency bands. The amplitude and phase weights that result are applied in a frequency-domain beamforming operation that compensates for scattering and refraction effects not properly modeled by plane-wave beams. It has been demonstrated to outperform waveform correlation as a classifier of ripple-fired mining blasts since the narrowband procedure is insensitive to differences in the source-time functions. For sequences in which the spectral content and time-histories of the signals from the main shock and aftershocks vary greatly, the spatial structure calibrated by EMFP is an invariant that permits reliable detection of events in the specific source region. Examples from the 2005 Kashmir and 2011 Van earthquakes demonstrate how EMFP templates from the main events detect arrivals from the aftershock sequences with high sensitivity and exceptionally low false alarm rates. Classical waveform correlation detectors are demonstrated to fail for these examples. Even arrivals with SNR below unity can produce significant EMFP triggers as the spatial pattern of the incoming wavefront is identified, leading to robust detections at a greater number of stations and potentially more reliable automatic bulletins. False EMFP triggers are readily screened by scanning a space of phase shifts relative to the imposed template. EMFP has the potential to produce a rapid and robust overview of the evolving aftershock sequence such that correlation and subspace detectors can be applied semi-autonomously, with well-chosen parameter specifications, to identify and classify clusters of very closely spaced aftershocks.

New Method of Calibrating IRT Models.

ERIC Educational Resources Information Center

Jiang, Hai; Tang, K. Linda

This discussion of new methods for calibrating item response theory (IRT) models looks into new optimization procedures, such as the Genetic Algorithm (GA) to improve on the use of the Newton-Raphson procedure. The advantages of using a global optimization procedure like GA is that this kind of procedure is not easily affected by local optima and…

Automatic classification of blank substrate defects

NASA Astrophysics Data System (ADS)

Boettiger, Tom; Buck, Peter; Paninjath, Sankaranarayanan; Pereira, Mark; Ronald, Rob; Rost, Dan; Samir, Bhamidipati

2014-10-01

Mask preparation stages are crucial in mask manufacturing, since this mask is to later act as a template for considerable number of dies on wafer. Defects on the initial blank substrate, and subsequent cleaned and coated substrates, can have a profound impact on the usability of the finished mask. This emphasizes the need for early and accurate identification of blank substrate defects and the risk they pose to the patterned reticle. While Automatic Defect Classification (ADC) is a well-developed technology for inspection and analysis of defects on patterned wafers and masks in the semiconductors industry, ADC for mask blanks is still in the early stages of adoption and development. Calibre ADC is a powerful analysis tool for fast, accurate, consistent and automatic classification of defects on mask blanks. Accurate, automated classification of mask blanks leads to better usability of blanks by enabling defect avoidance technologies during mask writing. Detailed information on blank defects can help to select appropriate job-decks to be written on the mask by defect avoidance tools [1][4][5]. Smart algorithms separate critical defects from the potentially large number of non-critical defects or false defects detected at various stages during mask blank preparation. Mechanisms used by Calibre ADC to identify and characterize defects include defect location and size, signal polarity (dark, bright) in both transmitted and reflected review images, distinguishing defect signals from background noise in defect images. The Calibre ADC engine then uses a decision tree to translate this information into a defect classification code. Using this automated process improves classification accuracy, repeatability and speed, while avoiding the subjectivity of human judgment compared to the alternative of manual defect classification by trained personnel [2]. This paper focuses on the results from the evaluation of Automatic Defect Classification (ADC) product at MP Mask Technology Center (MPMask). The Calibre ADC tool was qualified on production mask blanks against the manual classification. The classification accuracy of ADC is greater than 95% for critical defects with an overall accuracy of 90%. The sensitivity to weak defect signals and locating the defect in the images is a challenge we are resolving. The performance of the tool has been demonstrated on multiple mask types and is ready for deployment in full volume mask manufacturing production flow. Implementation of Calibre ADC is estimated to reduce the misclassification of critical defects by 60-80%.

Step wise, multiple objective calibration of a hydrologic model for a snowmelt dominated basin

USGS Publications Warehouse

Hay, L.E.; Leavesley, G.H.; Clark, M.P.; Markstrom, S.L.; Viger, R.J.; Umemoto, M.

2006-01-01

The ability to apply a hydrologic model to large numbers of basins for forecasting purposes requires a quick and effective calibration strategy. This paper presents a step wise, multiple objective, automated procedure for hydrologic model calibration. This procedure includes the sequential calibration of a model's simulation of solar radiation (SR), potential evapotranspiration (PET), water balance, and daily runoff. The procedure uses the Shuffled Complex Evolution global search algorithm to calibrate the U.S. Geological Survey's Precipitation Runoff Modeling System in the Yampa River basin of Colorado. This process assures that intermediate states of the model (SR and PET on a monthly mean basis), as well as the water balance and components of the daily hydrograph are simulated, consistently with measured values.

Inexpensive portable drug detector

NASA Technical Reports Server (NTRS)

Dimeff, J.; Heimbuch, A. H.; Parker, J. A.

1977-01-01

Inexpensive, easy-to-use, self-scanning, self-calibrating, portable unit automatically graphs fluorescence spectrum of drug sample. Device also measures rate of movement through chromatographic column for forensic and medical testing.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sels, Seppe, E-mail: Seppe.Sels@uantwerpen.be; Ribbens, Bart; Mertens, Luc

Scanning laser Doppler vibrometers (LDV) are used to measure full-field vibration shapes of products and structures. In most commercially available scanning laser Doppler vibrometer systems the user manually draws a grid of measurement locations on a 2D camera image of the product. The determination of the correct physical measurement locations can be a time consuming and diffcult task. In this paper we present a new methodology for product testing and quality control that integrates 3D imaging techniques with vibration measurements. This procedure allows to test prototypes in a shorter period because physical measurements locations will be located automatically. The proposedmore » methodology uses a 3D time-of-flight camera to measure the location and orientation of the test-object. The 3D image of the time-of-flight camera is then matched with the 3D-CAD model of the object in which measurement locations are pre-defined. A time of flight camera operates strictly in the near infrared spectrum. To improve the signal to noise ratio in the time-of-flight measurement, a time-of-flight camera uses a band filter. As a result of this filter, the laser spot of most laser vibrometers is invisible in the time-of-flight image. Therefore a 2D RGB-camera is used to find the laser-spot of the vibrometer. The laser spot is matched to the 3D image obtained by the time-of-flight camera. Next an automatic calibration procedure is used to aim the laser at the (pre)defined locations. Another benefit from this methodology is that it incorporates automatic mapping between a CAD model and the vibration measurements. This mapping can be used to visualize measurements directly on a 3D CAD model. Secondly the orientation of the CAD model is known with respect to the laser beam. This information can be used to find the direction of the measured vibration relatively to the surface of the object. With this direction, the vibration measurements can be compared more precisely with numerical experiments.« less

Calibration of 3D ultrasound to an electromagnetic tracking system

NASA Astrophysics Data System (ADS)

Lang, Andrew; Parthasarathy, Vijay; Jain, Ameet

2011-03-01

The use of electromagnetic (EM) tracking is an important guidance tool that can be used to aid procedures requiring accurate localization such as needle injections or catheter guidance. Using EM tracking, the information from different modalities can be easily combined using pre-procedural calibration information. These calibrations are performed individually, per modality, allowing different imaging systems to be mixed and matched according to the procedure at hand. In this work, a framework for the calibration of a 3D transesophageal echocardiography probe to EM tracking is developed. The complete calibration framework includes three required steps: data acquisition, needle segmentation, and calibration. Ultrasound (US) images of an EM tracked needle must be acquired with the position of the needles in each volume subsequently extracted by segmentation. The calibration transformation is determined through a registration between the segmented points and the recorded EM needle positions. Additionally, the speed of sound is compensated for since calibration is performed in water that has a different speed then is assumed by the US machine. A statistical validation framework has also been developed to provide further information related to the accuracy and consistency of the calibration. Further validation of the calibration showed an accuracy of 1.39 mm.

Fully automatic three-dimensional visualization of intravascular optical coherence tomography images: methods and feasibility in vivo

PubMed Central

Ughi, Giovanni J; Adriaenssens, Tom; Desmet, Walter; D’hooge, Jan

2012-01-01

Intravascular optical coherence tomography (IV-OCT) is an imaging modality that can be used for the assessment of intracoronary stents. Recent publications pointed to the fact that 3D visualizations have potential advantages compared to conventional 2D representations. However, 3D imaging still requires a time consuming manual procedure not suitable for on-line application during coronary interventions. We propose an algorithm for a rapid and fully automatic 3D visualization of IV-OCT pullbacks. IV-OCT images are first processed for the segmentation of the different structures. This also allows for automatic pullback calibration. Then, according to the segmentation results, different structures are depicted with different colors to visualize the vessel wall, the stent and the guide-wire in details. Final 3D rendering results are obtained through the use of a commercial 3D DICOM viewer. Manual analysis was used as ground-truth for the validation of the segmentation algorithms. A correlation value of 0.99 and good limits of agreement (Bland Altman statistics) were found over 250 images randomly extracted from 25 in vivo pullbacks. Moreover, 3D rendering was compared to angiography, pictures of deployed stents made available by the manufacturers and to conventional 2D imaging corroborating visualization results. Computational time for the visualization of an entire data sets resulted to be ~74 sec. The proposed method allows for the on-line use of 3D IV-OCT during percutaneous coronary interventions, potentially allowing treatments optimization. PMID:23243578

Projection Mapping User Interface for Disabled People

PubMed Central

Simutis, Rimvydas; Maskeliūnas, Rytis

2018-01-01

Difficulty in communicating is one of the key challenges for people suffering from severe motor and speech disabilities. Often such person can communicate and interact with the environment only using assistive technologies. This paper presents a multifunctional user interface designed to improve communication efficiency and person independence. The main component of this interface is a projection mapping technique used to highlight objects in the environment. Projection mapping makes it possible to create a natural augmented reality information presentation method. The user interface combines a depth sensor and a projector to create camera-projector system. We provide a detailed description of camera-projector system calibration procedure. The described system performs tabletop object detection and automatic projection mapping. Multiple user input modalities have been integrated into the multifunctional user interface. Such system can be adapted to the needs of people with various disabilities. PMID:29686827

Projection Mapping User Interface for Disabled People.

PubMed

Gelšvartas, Julius; Simutis, Rimvydas; Maskeliūnas, Rytis

2018-01-01

Difficulty in communicating is one of the key challenges for people suffering from severe motor and speech disabilities. Often such person can communicate and interact with the environment only using assistive technologies. This paper presents a multifunctional user interface designed to improve communication efficiency and person independence. The main component of this interface is a projection mapping technique used to highlight objects in the environment. Projection mapping makes it possible to create a natural augmented reality information presentation method. The user interface combines a depth sensor and a projector to create camera-projector system. We provide a detailed description of camera-projector system calibration procedure. The described system performs tabletop object detection and automatic projection mapping. Multiple user input modalities have been integrated into the multifunctional user interface. Such system can be adapted to the needs of people with various disabilities.

The compilation of the instrumental seismic catalogue of Italy: 1975-1984

NASA Astrophysics Data System (ADS)

Giardini, D.; Velonà, M. A.; Boschi, E.

1992-12-01

We compile a homogeneous and complete catalogue of the seismicity of the Italian region for 1975-1984, the period marking the transition from standard analogue seismometry to the new digital era. The work is developed in three phases: (1) the creation of a uniform digital databank of all seismic station readings, unifying the database available at the Istituto Nazionale di Geofisica with the catalogue of the International Seismological Centre; (2) the preparation of numerical procedures for automatic association of arrival data and for hypocentre location, using arrivals from local, regional and teleseismic stations in a spherical geometry; (3) the introduction of lateral heterogeneity by calibrating regional travel-time curves and station corrections. The first two phases have been completed, providing a new instrumental catalogue obtained using a spherical Earth model; the third phase is presented here in a preliminary stage.

Automatic identification of physical activity types and sedentary behaviors from triaxial accelerometer: laboratory-based calibrations are not enough.

PubMed

Bastian, Thomas; Maire, Aurélia; Dugas, Julien; Ataya, Abbas; Villars, Clément; Gris, Florence; Perrin, Emilie; Caritu, Yanis; Doron, Maeva; Blanc, Stéphane; Jallon, Pierre; Simon, Chantal

2015-03-15

"Objective" methods to monitor physical activity and sedentary patterns in free-living conditions are necessary to further our understanding of their impacts on health. In recent years, many software solutions capable of automatically identifying activity types from portable accelerometry data have been developed, with promising results in controlled conditions, but virtually no reports on field tests. An automatic classification algorithm initially developed using laboratory-acquired data (59 subjects engaging in a set of 24 standardized activities) to discriminate between 8 activity classes (lying, slouching, sitting, standing, walking, running, and cycling) was applied to data collected in the field. Twenty volunteers equipped with a hip-worn triaxial accelerometer performed at their own pace an activity set that included, among others, activities such as walking the streets, running, cycling, and taking the bus. Performances of the laboratory-calibrated classification algorithm were compared with those of an alternative version of the same model including field-collected data in the learning set. Despite good results in laboratory conditions, the performances of the laboratory-calibrated algorithm (assessed by confusion matrices) decreased for several activities when applied to free-living data. Recalibrating the algorithm with data closer to real-life conditions and from an independent group of subjects proved useful, especially for the detection of sedentary behaviors while in transports, thereby improving the detection of overall sitting (sensitivity: laboratory model = 24.9%; recalibrated model = 95.7%). Automatic identification methods should be developed using data acquired in free-living conditions rather than data from standardized laboratory activity sets only, and their limits carefully tested before they are used in field studies. Copyright © 2015 the American Physiological Society.

Calcium (Ca2+) waves data calibration and analysis using image processing techniques

PubMed Central

2013-01-01

Background Calcium (Ca2+) propagates within tissues serving as an important information carrier. In particular, cilia beat frequency in oviduct cells is partially regulated by Ca2+ changes. Thus, measuring the calcium density and characterizing the traveling wave plays a key role in understanding biological phenomena. However, current methods to measure propagation velocities and other wave characteristics involve several manual or time-consuming procedures. This limits the amount of information that can be extracted, and the statistical quality of the analysis. Results Our work provides a framework based on image processing procedures that enables a fast, automatic and robust characterization of data from two-filter fluorescence Ca2+ experiments. We calculate the mean velocity of the wave-front, and use theoretical models to extract meaningful parameters like wave amplitude, decay rate and time of excitation. Conclusions Measurements done by different operators showed a high degree of reproducibility. This framework is also extended to a single filter fluorescence experiments, allowing higher sampling rates, and thus an increased accuracy in velocity measurements. PMID:23679062

Method for in-situ calibration of electrophoretic analysis systems

DOEpatents

Liu, Changsheng; Zhao, Hequan

2005-05-08

An electrophoretic system having a plurality of separation lanes is provided with an automatic calibration feature in which each lane is separately calibrated. For each lane, the calibration coefficients map a spectrum of received channel intensities onto values reflective of the relative likelihood of each of a plurality of dyes being present. Individual peaks, reflective of the influence of a single dye, are isolated from among the various sets of detected light intensity spectra, and these can be used to both detect the number of dye components present, and also to establish exemplary vectors for the calibration coefficients which may then be clustered and further processed to arrive at a calibration matrix for the system. The system of the present invention thus permits one to use different dye sets to tag DNA nucleotides in samples which migrate in separate lanes, and also allows for in-situ calibration with new, previously unused dye sets.

SPRT Calibration Uncertainties and Internal Quality Control at a Commercial SPRT Calibration Facility

NASA Astrophysics Data System (ADS)

Wiandt, T. J.

2008-06-01

The Hart Scientific Division of the Fluke Corporation operates two accredited standard platinum resistance thermometer (SPRT) calibration facilities, one at the Hart Scientific factory in Utah, USA, and the other at a service facility in Norwich, UK. The US facility is accredited through National Voluntary Laboratory Accreditation Program (NVLAP), and the UK facility is accredited through UKAS. Both provide SPRT calibrations using similar equipment and procedures, and at similar levels of uncertainty. These uncertainties are among the lowest available commercially. To achieve and maintain low uncertainties, it is required that the calibration procedures be thorough and optimized. However, to minimize customer downtime, it is also important that the instruments be calibrated in a timely manner and returned to the customer. Consequently, subjecting the instrument to repeated calibrations or extensive repeated measurements is not a viable approach. Additionally, these laboratories provide SPRT calibration services involving a wide variety of SPRT designs. These designs behave differently, yet predictably, when subjected to calibration measurements. To this end, an evaluation strategy involving both statistical process control and internal consistency measures is utilized to provide confidence in both the instrument calibration and the calibration process. This article describes the calibration facilities, procedure, uncertainty analysis, and internal quality assurance measures employed in the calibration of SPRTs. Data will be reviewed and generalities will be presented. Finally, challenges and considerations for future improvements will be discussed.

Hand-Eye Calibration of Robonaut

NASA Technical Reports Server (NTRS)

Nickels, Kevin; Huber, Eric

2004-01-01

NASA's Human Space Flight program depends heavily on Extra-Vehicular Activities (EVA's) performed by human astronauts. EVA is a high risk environment that requires extensive training and ground support. In collaboration with the Defense Advanced Research Projects Agency (DARPA), NASA is conducting a ground development project to produce a robotic astronaut's assistant, called Robonaut, that could help reduce human EVA time and workload. The project described in this paper designed and implemented a hand-eye calibration scheme for Robonaut, Unit A. The intent of this calibration scheme is to improve hand-eye coordination of the robot. The basic approach is to use kinematic and stereo vision measurements, namely the joint angles self-reported by the right arm and 3-D positions of a calibration fixture as measured by vision, to estimate the transformation from Robonaut's base coordinate system to its hand coordinate system and to its vision coordinate system. Two methods of gathering data sets have been developed, along with software to support each. In the first, the system observes the robotic arm and neck angles as the robot is operated under external control, and measures the 3-D position of a calibration fixture using Robonaut's stereo cameras, and logs these data. In the second, the system drives the arm and neck through a set of pre-recorded configurations, and data are again logged. Two variants of the calibration scheme have been developed. The full calibration scheme is a batch procedure that estimates all relevant kinematic parameters of the arm and neck of the robot The daily calibration scheme estimates only joint offsets for each rotational joint on the arm and neck, which are assumed to change from day to day. The schemes have been designed to be automatic and easy to use so that the robot can be fully recalibrated when needed such as after repair, upgrade, etc, and can be partially recalibrated after each power cycle. The scheme has been implemented on Robonaut Unit A and has been shown to reduce mismatch between kinematically derived positions and visually derived positions from a mean of 13.75cm using the previous calibration to means of 1.85cm using a full calibration and 2.02cm using a suboptimal but faster daily calibration. This improved calibration has already enabled the robot to more accurately reach for and grasp objects that it sees within its workspace. The system has been used to support an autonomous wrench-grasping experiment and significantly improved the workspace positioning of the hand based on visually derived wrench position. estimates.

A Semi-Automatic Image-Based Close Range 3D Modeling Pipeline Using a Multi-Camera Configuration

PubMed Central

Rau, Jiann-Yeou; Yeh, Po-Chia

2012-01-01

The generation of photo-realistic 3D models is an important task for digital recording of cultural heritage objects. This study proposes an image-based 3D modeling pipeline which takes advantage of a multi-camera configuration and multi-image matching technique that does not require any markers on or around the object. Multiple digital single lens reflex (DSLR) cameras are adopted and fixed with invariant relative orientations. Instead of photo-triangulation after image acquisition, calibration is performed to estimate the exterior orientation parameters of the multi-camera configuration which can be processed fully automatically using coded targets. The calibrated orientation parameters of all cameras are applied to images taken using the same camera configuration. This means that when performing multi-image matching for surface point cloud generation, the orientation parameters will remain the same as the calibrated results, even when the target has changed. Base on this invariant character, the whole 3D modeling pipeline can be performed completely automatically, once the whole system has been calibrated and the software was seamlessly integrated. Several experiments were conducted to prove the feasibility of the proposed system. Images observed include that of a human being, eight Buddhist statues, and a stone sculpture. The results for the stone sculpture, obtained with several multi-camera configurations were compared with a reference model acquired by an ATOS-I 2M active scanner. The best result has an absolute accuracy of 0.26 mm and a relative accuracy of 1:17,333. It demonstrates the feasibility of the proposed low-cost image-based 3D modeling pipeline and its applicability to a large quantity of antiques stored in a museum. PMID:23112656

A semi-automatic image-based close range 3D modeling pipeline using a multi-camera configuration.

PubMed

Rau, Jiann-Yeou; Yeh, Po-Chia

2012-01-01

The generation of photo-realistic 3D models is an important task for digital recording of cultural heritage objects. This study proposes an image-based 3D modeling pipeline which takes advantage of a multi-camera configuration and multi-image matching technique that does not require any markers on or around the object. Multiple digital single lens reflex (DSLR) cameras are adopted and fixed with invariant relative orientations. Instead of photo-triangulation after image acquisition, calibration is performed to estimate the exterior orientation parameters of the multi-camera configuration which can be processed fully automatically using coded targets. The calibrated orientation parameters of all cameras are applied to images taken using the same camera configuration. This means that when performing multi-image matching for surface point cloud generation, the orientation parameters will remain the same as the calibrated results, even when the target has changed. Base on this invariant character, the whole 3D modeling pipeline can be performed completely automatically, once the whole system has been calibrated and the software was seamlessly integrated. Several experiments were conducted to prove the feasibility of the proposed system. Images observed include that of a human being, eight Buddhist statues, and a stone sculpture. The results for the stone sculpture, obtained with several multi-camera configurations were compared with a reference model acquired by an ATOS-I 2M active scanner. The best result has an absolute accuracy of 0.26 mm and a relative accuracy of 1:17,333. It demonstrates the feasibility of the proposed low-cost image-based 3D modeling pipeline and its applicability to a large quantity of antiques stored in a museum.

A New Calibration Method for Commercial RGB-D Sensors

PubMed Central

Darwish, Walid; Tang, Shenjun; Li, Wenbin; Chen, Wu

2017-01-01

Commercial RGB-D sensors such as Kinect and Structure Sensors have been widely used in the game industry, where geometric fidelity is not of utmost importance. For applications in which high quality 3D is required, i.e., 3D building models of centimeter-level accuracy, accurate and reliable calibrations of these sensors are required. This paper presents a new model for calibrating the depth measurements of RGB-D sensors based on the structured light concept. Additionally, a new automatic method is proposed for the calibration of all RGB-D parameters, including internal calibration parameters for all cameras, the baseline between the infrared and RGB cameras, and the depth error model. When compared with traditional calibration methods, this new model shows a significant improvement in depth precision for both near and far ranges. PMID:28538695

Standardization of gamma-glutamyltransferase assays by intermethod calibration. Effect on determining common reference limits.

PubMed

Steinmetz, Josiane; Schiele, Françoise; Gueguen, René; Férard, Georges; Henny, Joseph

2007-01-01

The improvement of the consistency of gamma-glutamyltransferase (GGT) activity results among different assays after calibration with a common material was estimated. We evaluated if this harmonization could lead to reference limits common to different routine methods. Seven laboratories measured GGT activity using their own routine analytical system both according to the manufacturer's recommendation and after calibration with a multi-enzyme calibrator [value assigned by the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) reference procedure]. All samples were re-measured using the IFCC reference procedure. Two groups of subjects were selected in each laboratory: a group of healthy men aged 18-25 years without long-term medication and with alcohol consumption less than 44 g/day and a group of subjects with elevated GGT activity. The day-to-day coefficients of variation were less than 2.9% in each laboratory. The means obtained in the group of healthy subjects without common calibration (range of the means 16-23 U/L) were significantly different from those obtained by the IFCC procedure in five laboratories. After calibration, the means remained significantly different from the IFCC procedure results in only one laboratory. For three calibrated methods, the slope values of linear regression vs. the IFCC procedure were not different from the value 1. The results obtained with these three methods for healthy subjects (n=117) were gathered and reference limits were calculated. These were 11-49 U/L (2.5th-97.5th percentiles). The calibration also improved the consistency of elevated results when compared to the IFCC procedure. The common calibration improved the level of consistency between different routine methods. It permitted to define common reference limits which are quite similar to those proposed by the IFCC. This approach should lead to a real benefit in terms of prevention, screening, diagnosis, therapeutic monitoring and for epidemiological studies.

A fast calibration method for 3-D tracking of ultrasound images using a spatial localizer.

PubMed

Pagoulatos, N; Haynor, D R; Kim, Y

2001-09-01

We have developed a fast calibration method for computing the position and orientation of 2-D ultrasound (US) images in 3-D space where a position sensor is mounted on the US probe. This calibration is required in the fields of 3-D ultrasound and registration of ultrasound with other imaging modalities. Most of the existing calibration methods require a complex and tedious experimental procedure. Our method is simple and it is based on a custom-built phantom. Thirty N-fiducials (markers in the shape of the letter "N") embedded in the phantom provide the basis for our calibration procedure. We calibrated a 3.5-MHz sector phased-array probe with a magnetic position sensor, and we studied the accuracy and precision of our method. A typical calibration procedure requires approximately 2 min. We conclude that we can achieve accurate and precise calibration using a single US image, provided that a large number (approximately ten) of N-fiducials are captured within the US image, enabling a representative sampling of the imaging plane.

Polymers for Traveling Wave Ion Mobility Spectrometry Calibration

NASA Astrophysics Data System (ADS)

Duez, Quentin; Chirot, Fabien; Liénard, Romain; Josse, Thomas; Choi, ChangMin; Coulembier, Olivier; Dugourd, Philippe; Cornil, Jérôme; Gerbaux, Pascal; De Winter, Julien

2017-07-01

One of the main issues when using traveling wave ion mobility spectrometry (TWIMS) for the determination of collisional cross-section (CCS) concerns the need for a robust calibration procedure built from referent ions of known CCS. Here, we implement synthetic polymer ions as CCS calibrants in positive ion mode. Based on their intrinsic polydispersities, polymers offer in a single sample the opportunity to generate, upon electrospray ionization, numerous ions covering a broad mass range and a large CCS window for different charge states at a time. In addition, the key advantage of polymer ions as CCS calibrants lies in the robustness of their gas-phase structure with respect to the instrumental conditions, making them less prone to collisional-induced unfolding (CIU) than protein ions. In this paper, we present a CCS calibration procedure using sodium cationized polylactide and polyethylene glycol, PLA and PEG, as calibrants with reference CCS determined on a home-made drift tube. Our calibration procedure is further validated by testing the polymer calibration to determine CCS of numerous different ions for which CCS are reported in the literature. [Figure not available: see fulltext.

An automatic agricultural zone classification procedure for crop inventory satellite images

NASA Technical Reports Server (NTRS)

Parada, N. D. J. (Principal Investigator); Kux, H. J.; Velasco, F. R. D.; Deoliveira, M. O. B.

1982-01-01

A classification procedure for assessing crop areal proportion in multispectral scanner image is discussed. The procedure is into four parts: labeling; classification; proportion estimation; and evaluation. The procedure also has the following characteristics: multitemporal classification; the need for a minimum field information; and verification capability between automatic classification and analyst labeling. The processing steps and the main algorithms involved are discussed. An outlook on the future of this technology is also presented.

NASA Glenn Icing Research Tunnel: 2012 Cloud Calibration Procedure and Results

NASA Technical Reports Server (NTRS)

VanZante, Judith Foss; Ide, Robert F.; Steen, Laura E.

2012-01-01

In 2011, NASA Glenn s Icing Research Tunnel underwent a major modification to it s refrigeration plant and heat exchanger. This paper presents the results of the subsequent full cloud calibration. Details of the calibration procedure and results are presented herein. The steps include developing a nozzle transfer map, establishing a uniform cloud, conducting a drop sizing calibration and finally a liquid water content calibration. The goal of the calibration is to develop a uniform cloud, and to build a transfer map from the inputs of air speed, spray bar atomizing air pressure and water pressure to the output of median volumetric droplet diameter and liquid water content.

Micro-mass standards to calibrate the sensitivity of mass comparators

NASA Astrophysics Data System (ADS)

Madec, Tanguy; Mann, Gaëlle; Meury, Paul-André; Rabault, Thierry

2007-10-01

In mass metrology, the standards currently used are calibrated by a chain of comparisons, performed using mass comparators, that extends ultimately from the international prototype (which is the definition of the unit of mass) to the standards in routine use. The differences measured in the course of these comparisons become smaller and smaller as the standards approach the definitions of their units, precisely because of how accurately they have been adjusted. One source of uncertainty in the determination of the difference of mass between the mass compared and the reference mass is the sensitivity error of the comparator used. Unfortunately, in the market there are no mass standards small enough (of the order of a few hundreds of micrograms) for a valid evaluation of this source of uncertainty. The users of these comparators therefore have no choice but to rely on the characteristics claimed by the makers of the comparators, or else to determine this sensitivity error at higher values (at least 1 mg) and interpolate from this result to smaller differences of mass. For this reason, the LNE decided to produce and calibrate micro-mass standards having nominal values between 100 µg and 900 µg. These standards were developed, then tested in multiple comparisons on an A5 type automatic comparator. They have since been qualified and calibrated in a weighing design, repeatedly and over an extended period of time, to establish their stability with respect to oxidation and the harmlessness of the handling and storage procedure associated with their use. Finally, the micro-standards so qualified were used to characterize the sensitivity errors of two of the LNE's mass comparators, including the one used to tie France's Platinum reference standard (Pt 35) to stainless steel and superalloy standards.

Self-calibrating multiplexer circuit

DOEpatents

Wahl, Chris P.

1997-01-01

A time domain multiplexer system with automatic determination of acceptable multiplexer output limits, error determination, or correction is comprised of a time domain multiplexer, a computer, a constant current source capable of at least three distinct current levels, and two series resistances employed for calibration and testing. A two point linear calibration curve defining acceptable multiplexer voltage limits may be defined by the computer by determining the voltage output of the multiplexer to very accurately known input signals developed from predetermined current levels across the series resistances. Drift in the multiplexer may be detected by the computer when the output voltage limits, expected during normal operation, are exceeded, or the relationship defined by the calibration curve is invalidated.

Automatic inference of geometric camera parameters and inter-camera topology in uncalibrated disjoint surveillance cameras

NASA Astrophysics Data System (ADS)

den Hollander, Richard J. M.; Bouma, Henri; Baan, Jan; Eendebak, Pieter T.; van Rest, Jeroen H. C.

2015-10-01

Person tracking across non-overlapping cameras and other types of video analytics benefit from spatial calibration information that allows an estimation of the distance between cameras and a relation between pixel coordinates and world coordinates within a camera. In a large environment with many cameras, or for frequent ad-hoc deployments of cameras, the cost of this calibration is high. This creates a barrier for the use of video analytics. Automating the calibration allows for a short configuration time, and the use of video analytics in a wider range of scenarios, including ad-hoc crisis situations and large scale surveillance systems. We show an autocalibration method entirely based on pedestrian detections in surveillance video in multiple non-overlapping cameras. In this paper, we show the two main components of automatic calibration. The first shows the intra-camera geometry estimation that leads to an estimate of the tilt angle, focal length and camera height, which is important for the conversion from pixels to meters and vice versa. The second component shows the inter-camera topology inference that leads to an estimate of the distance between cameras, which is important for spatio-temporal analysis of multi-camera tracking. This paper describes each of these methods and provides results on realistic video data.

Automatic Texture Mapping of Architectural and Archaeological 3d Models

NASA Astrophysics Data System (ADS)

Kersten, T. P.; Stallmann, D.

2012-07-01

Today, detailed, complete and exact 3D models with photo-realistic textures are increasingly demanded for numerous applications in architecture and archaeology. Manual texture mapping of 3D models by digital photographs with software packages, such as Maxon Cinema 4D, Autodesk 3Ds Max or Maya, still requires a complex and time-consuming workflow. So, procedures for automatic texture mapping of 3D models are in demand. In this paper two automatic procedures are presented. The first procedure generates 3D surface models with textures by web services, while the second procedure textures already existing 3D models with the software tmapper. The program tmapper is based on the Multi Layer 3D image (ML3DImage) algorithm and developed in the programming language C++. The studies showing that the visibility analysis using the ML3DImage algorithm is not sufficient to obtain acceptable results of automatic texture mapping. To overcome the visibility problem the Point Cloud Painter algorithm in combination with the Z-buffer-procedure will be applied in the future.

Procedures for establishing and maintaining consistent air-kerma strength standards for low-energy, photon-emitting brachytherapy sources: recommendations of the Calibration Laboratory Accreditation Subcommittee of the American Association of Physicists in Medicine.

PubMed

DeWerd, Larry A; Huq, M Saiful; Das, Indra J; Ibbott, Geoffrey S; Hanson, William F; Slowey, Thomas W; Williamson, Jeffrey F; Coursey, Bert M

2004-03-01

Low dose rate brachytherapy is being used extensively for the treatment of prostate cancer. As of September 2003, there are a total of thirteen 125I and seven 103Pd sources that have calibrations from the National Institute of Standards and Technology (NIST) and the Accredited Dosimetry Calibration Laboratories (ADCLs) of the American Association of Physicists in Medicine (AAPM). The dosimetry standards for these sources are traceable to the NIST wide-angle free-air chamber. Procedures have been developed by the AAPM Calibration Laboratory Accreditation Subcommittee to standardize quality assurance and calibration, and to maintain the dosimetric traceability of these sources to ensure accurate clinical dosimetry. A description of these procedures is provided to the clinical users for traceability purposes as well as to provide guidance to the manufacturers of brachytherapy sources and ADCLs with regard to these procedures.

40 CFR 91.320 - Carbon dioxide analyzer calibration.

Code of Federal Regulations, 2014 CFR

2014-07-01

... required (see following table). Example calibration points (percent) Acceptable for calibration? 20, 30, 40... periodic interference, system check, and calibration test procedures specified in 40 CFR part 1065...

Evaluation of “Autotune” calibration against manual calibration of building energy models

DOE PAGES

Chaudhary, Gaurav; New, Joshua; Sanyal, Jibonananda; ...

2016-08-26

Our paper demonstrates the application of Autotune, a methodology aimed at automatically producing calibrated building energy models using measured data, in two case studies. In the first case, a building model is de-tuned by deliberately injecting faults into more than 60 parameters. This model was then calibrated using Autotune and its accuracy with respect to the original model was evaluated in terms of the industry-standard normalized mean bias error and coefficient of variation of root mean squared error metrics set forth in ASHRAE Guideline 14. In addition to whole-building energy consumption, outputs including lighting, plug load profiles, HVAC energy consumption,more » zone temperatures, and other variables were analyzed. In the second case, Autotune calibration is compared directly to experts’ manual calibration of an emulated-occupancy, full-size residential building with comparable calibration results in much less time. Lastly, our paper concludes with a discussion of the key strengths and weaknesses of auto-calibration approaches.« less

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR CALIBRATION OF HARVARD PM SAMPLERS (UA-L-6.1)

EPA Science Inventory

The purpose of this SOP is to describe the procedures for calibrating Harvard particulate matter (PM) samplers. This procedure applies directly to the Harvard particulate matter (PM) samplers used during the Arizona NHEXAS project and the "Border" study. Keywords: lab; equipmen...

10 CFR 431.242 - Test Procedures [Reserved

Code of Federal Regulations, 2014 CFR

2014-01-01

..., automatically operated, fossil fuel-fired appliance that is designed to automatically open the flue outlet... individual, automatically operated, fossil fuel-fired appliance either in the outlet or downstream of the...

10 CFR 431.242 - Test Procedures [Reserved

Code of Federal Regulations, 2012 CFR

2012-01-01

..., automatically operated, fossil fuel-fired appliance that is designed to automatically open the flue outlet... individual, automatically operated, fossil fuel-fired appliance either in the outlet or downstream of the...

10 CFR 431.242 - Test Procedures [Reserved

Code of Federal Regulations, 2013 CFR

2013-01-01

..., automatically operated, fossil fuel-fired appliance that is designed to automatically open the flue outlet... individual, automatically operated, fossil fuel-fired appliance either in the outlet or downstream of the...

An automatic identification procedure to promote the use of FES-cycling training for hemiparetic patients.

PubMed

Ambrosini, Emilia; Ferrante, Simona; Schauer, Thomas; Ferrigno, Giancarlo; Molteni, Franco; Pedrocchi, Alessandra

2014-01-01

Cycling induced by Functional Electrical Stimulation (FES) training currently requires a manual setting of different parameters, which is a time-consuming and scarcely repeatable procedure. We proposed an automatic procedure for setting session-specific parameters optimized for hemiparetic patients. This procedure consisted of the identification of the stimulation strategy as the angular ranges during which FES drove the motion, the comparison between the identified strategy and the physiological muscular activation strategy, and the setting of the pulse amplitude and duration of each stimulated muscle. Preliminary trials on 10 healthy volunteers helped define the procedure. Feasibility tests on 8 hemiparetic patients (5 stroke, 3 traumatic brain injury) were performed. The procedure maximized the motor output within the tolerance constraint, identified a biomimetic strategy in 6 patients, and always lasted less than 5 minutes. Its reasonable duration and automatic nature make the procedure usable at the beginning of every training session, potentially enhancing the performance of FES-cycling training.

Accurate multi-robot targeting for keyhole neurosurgery based on external sensor monitoring.

PubMed

Comparetti, Mirko Daniele; Vaccarella, Alberto; Dyagilev, Ilya; Shoham, Moshe; Ferrigno, Giancarlo; De Momi, Elena

2012-05-01

Robotics has recently been introduced in surgery to improve intervention accuracy, to reduce invasiveness and to allow new surgical procedures. In this framework, the ROBOCAST system is an optically surveyed multi-robot chain aimed at enhancing the accuracy of surgical probe insertion during keyhole neurosurgery procedures. The system encompasses three robots, connected as a multiple kinematic chain (serial and parallel), totalling 13 degrees of freedom, and it is used to automatically align the probe onto a desired planned trajectory. The probe is then inserted in the brain, towards the planned target, by means of a haptic interface. This paper presents a new iterative targeting approach to be used in surgical robotic navigation, where the multi-robot chain is used to align the surgical probe to the planned pose, and an external sensor is used to decrease the alignment errors. The iterative targeting was tested in an operating room environment using a skull phantom, and the targets were selected on magnetic resonance images. The proposed targeting procedure allows about 0.3 mm to be obtained as the residual median Euclidean distance between the planned and the desired targets, thus satisfying the surgical accuracy requirements (1 mm), due to the resolution of the diffused medical images. The performances proved to be independent of the robot optical sensor calibration accuracy.

Workcell calibration for effective offline programming

NASA Technical Reports Server (NTRS)

Stiles, Roger D.; Jones, Clyde S.

1989-01-01

In the application of graphics systems for off-line programming (OLP) of robotic systems, the inevitability of errors in the model representation of real-world situations requires that a method to map these differences is incorporated as an integral part of the overall system progamming procedures. This paper discusses several proven robot-to-positioner calibration techniques necessary to reflect real-world parameters in a work-cell model. Particular attention is given to the procedures used to adjust a graphics model to an acceptable degree of accuracy for integration of OLP for the Space Shuttle Main Engine welding automation. Consideration is given to the levels of calibration, requirements, special considerations for coordinated motion, and calibration procedures.

Strain Gauge Balance Calibration and Data Reduction at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Ferris, A. T. Judy

1999-01-01

This paper will cover the standard force balance calibration and data reduction techniques used at Langley Research Center. It will cover balance axes definition, balance type, calibration instrumentation, traceability of standards to NIST, calibration loading procedures, balance calibration mathematical model, calibration data reduction techniques, balance accuracy reporting, and calibration frequency.

Sensitivity and Calibration of Non-Destructive Evaluation Method That Uses Neural-Net Processing of Characteristic Fringe Patterns

NASA Technical Reports Server (NTRS)

Decker, Arthur J.; Weiland, Kenneth E.

2003-01-01

This paper answers some performance and calibration questions about a non-destructive-evaluation (NDE) procedure that uses artificial neural networks to detect structural damage or other changes from sub-sampled characteristic patterns. The method shows increasing sensitivity as the number of sub-samples increases from 108 to 6912. The sensitivity of this robust NDE method is not affected by noisy excitations of the first vibration mode. A calibration procedure is proposed and demonstrated where the output of a trained net can be correlated with the outputs of the point sensors used for vibration testing. The calibration procedure is based on controlled changes of fastener torques. A heterodyne interferometer is used as a displacement sensor for a demonstration of the challenges to be handled in using standard point sensors for calibration.

Robot calibration with a photogrammetric on-line system using reseau scanning cameras

NASA Astrophysics Data System (ADS)

Diewald, Bernd; Godding, Robert; Henrich, Andreas

1994-03-01

The possibility for testing and calibration of industrial robots becomes more and more important for manufacturers and users of such systems. Exacting applications in connection with the off-line programming techniques or the use of robots as measuring machines are impossible without a preceding robot calibration. At the LPA an efficient calibration technique has been developed. Instead of modeling the kinematic behavior of a robot, the new method describes the pose deviations within a user-defined section of the robot's working space. High- precision determination of 3D coordinates of defined path positions is necessary for calibration and can be done by digital photogrammetric systems. For the calibration of a robot at the LPA a digital photogrammetric system with three Rollei Reseau Scanning Cameras was used. This system allows an automatic measurement of a large number of robot poses with high accuracy.

Onsite Calibration of a Precision IPRT Based on Gallium and Gallium-Based Small-Size Eutectic Points

NASA Astrophysics Data System (ADS)

Sun, Jianping; Hao, Xiaopeng; Zeng, Fanchao; Zhang, Lin; Fang, Xinyun

2017-04-01

Onsite thermometer calibration with temperature scale transfer technology based on fixed points can effectively improve the level of industrial temperature measurement and calibration. The present work performs an onsite calibration of a precision industrial platinum resistance thermometer near room temperature. The calibration is based on a series of small-size eutectic points, including Ga-In (15.7°C), Ga-Sn (20.5°C), Ga-Zn (25.2°C), and a Ga fixed point (29.7°C), developed in a portable multi-point automatic realization apparatus. The temperature plateaus of the Ga-In, Ga-Sn, and Ga-Zn eutectic points and the Ga fixed point last for longer than 2 h, and their reproducibility was better than 5 mK. The device is suitable for calibrating non-detachable temperature sensors in advanced environmental laboratories and industrial fields.

Temporal Analysis and Automatic Calibration of the Velodyne HDL-32E LiDAR System

NASA Astrophysics Data System (ADS)

Chan, T. O.; Lichti, D. D.; Belton, D.

2013-10-01

At the end of the first quarter of 2012, more than 600 Velodyne LiDAR systems had been sold worldwide for various robotic and high-accuracy survey applications. The ultra-compact Velodyne HDL-32E LiDAR has become a predominant sensor for many applications that require lower sensor size/weight and cost. For high accuracy applications, cost-effective calibration methods with minimal manual intervention are always desired by users. However, the calibrations are complicated by the Velodyne LiDAR's narrow vertical field of view and the very highly time-variant nature of its measurements. In the paper, the temporal stability of the HDL-32E is first analysed as the motivation for developing a new, automated calibration method. This is followed by a detailed description of the calibration method that is driven by a novel segmentation method for extracting vertical cylindrical features from the Velodyne point clouds. The proposed segmentation method utilizes the Velodyne point cloud's slice-like nature and first decomposes the point clouds into 2D layers. Then the layers are treated as 2D images and are processed with the Generalized Hough Transform which extracts the points distributed in circular patterns from the point cloud layers. Subsequently, the vertical cylindrical features can be readily extracted from the whole point clouds based on the previously extracted points. The points are passed to the calibration that estimates the cylinder parameters and the LiDAR's additional parameters simultaneously by constraining the segmented points to fit to the cylindrical geometric model in such a way the weighted sum of the adjustment residuals are minimized. The proposed calibration is highly automatic and this allows end users to obtain the time-variant additional parameters instantly and frequently whenever there are vertical cylindrical features presenting in scenes. The methods were verified with two different real datasets, and the results suggest that up to 78.43% accuracy improvement for the HDL-32E can be achieved using the proposed calibration method.

Non-uniformity calibration for MWIR polarization imagery obtained with integrated microgrid polarimeters

NASA Astrophysics Data System (ADS)

Liu, Hai-Zheng; Shi, Ze-Lin; Feng, Bin; Hui, Bin; Zhao, Yao-Hong

2016-03-01

Integrating microgrid polarimeters on focal plane array (FPA) of an infrared detector causes non-uniformity of polarization response. In order to reduce the effect of polarization non-uniformity, this paper constructs an experimental setup for capturing raw flat-field images and proposes a procedure for acquiring non-uniform calibration (NUC) matrix and calibrating raw polarization images. The proposed procedure takes the incident radiation as a polarization vector and offers a calibration matrix for each pixel. Both our matrix calibration and two-point calibration are applied to our mid-wavelength infrared (MWIR) polarization imaging system with integrated microgrid polarimeters. Compared with two point calibration, our matrix calibration reduces non-uniformity by 30 40% under condition of flat-field data test with polarization. The ourdoor scene observation experiment indicates that our calibration can effectively reduce polarization non-uniformity and improve the image quality of our MWIR polarization imaging system.

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR CALIBRATION OF HARVARD PM SAMPLERS (UA-L-6.1)

EPA Science Inventory

The purpose of this SOP is to describe the procedures for calibrating Harvard particulate matter (PM) samplers. This procedure applies directly to the Harvard particulate matter (PM) samplers used during the Arizona NHEXAS project and the Border study. Keywords: lab; equipment;...

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR CALIBRATION, MAINTENANCE AND OPERATION OF ELECTRONIC BALANCES (BCO-L-23.0)

EPA Science Inventory

The purpose of this SOP is to describe the general procedures to be followed for the operation, calibration and maintenance of electronic balances. This procedure was followed to ensure consistent data retrieval during the Arizona NHEXAS project and the "Border" study. Keywords: ...

Laboratory Evaluation of Light Obscuration Particle Counter Contamination Limits for Aviation Fuel

DTIC Science & Technology

2015-11-01

diesel product for ground use (1). At a minimum free water and particulate by color (as specified in the appendix of ASTM D2276) are checked daily...used in the hydraulics/hydraulic fluid industry. In 1999 ISO adopted ISO 11171 Hydraulic fluid power — Calibration of automatic particle counters...for liquids, replacing ISO 4402, as an international standard for the calibration of liquid particle counters giving NIST traceability to particle

Light Obscuration Particle Counter Fuel Contamination Limits

DTIC Science & Technology

2015-10-08

or up to 10 mg/L for product used as a diesel product for ground use (1). At a minimum free water and particulate by color (as specified in the...contamination is frequently used in the hydraulics/hydraulic fluid industry. In 1999 ISO adopted ISO 11171 Hydraulic fluid power — Calibration of automatic...particle counters for liquids, replacing ISO 4402, as an international standard for the calibration of liquid particle counters giving NIST

Automated Camera Array Fine Calibration

NASA Technical Reports Server (NTRS)

Clouse, Daniel; Padgett, Curtis; Ansar, Adnan; Cheng, Yang

2008-01-01

Using aerial imagery, the JPL FineCalibration (JPL FineCal) software automatically tunes a set of existing CAHVOR camera models for an array of cameras. The software finds matching features in the overlap region between images from adjacent cameras, and uses these features to refine the camera models. It is not necessary to take special imagery of a known target and no surveying is required. JPL FineCal was developed for use with an aerial, persistent surveillance platform.

Calibration and correction procedures for cosmic-ray neutron soil moisture probes located across Australia

NASA Astrophysics Data System (ADS)

Hawdon, Aaron; McJannet, David; Wallace, Jim

2014-06-01

The cosmic-ray probe (CRP) provides continuous estimates of soil moisture over an area of ˜30 ha by counting fast neutrons produced from cosmic rays which are predominantly moderated by water molecules in the soil. This paper describes the setup, measurement correction procedures, and field calibration of CRPs at nine locations across Australia with contrasting soil type, climate, and land cover. These probes form the inaugural Australian CRP network, which is known as CosmOz. CRP measurements require neutron count rates to be corrected for effects of atmospheric pressure, water vapor pressure changes, and variations in incoming neutron intensity. We assess the magnitude and importance of these corrections and present standardized approaches for network-wide analysis. In particular, we present a new approach to correct for incoming neutron intensity variations and test its performance against existing procedures used in other studies. Our field calibration results indicate that a generalized calibration function for relating neutron counts to soil moisture is suitable for all soil types, with the possible exception of very sandy soils with low water content. Using multiple calibration data sets, we demonstrate that the generalized calibration function only applies after accounting for persistent sources of hydrogen in the soil profile. Finally, we demonstrate that by following standardized correction procedures and scaling neutron counting rates of all CRPs to a single reference location, differences in calibrations between sites are related to site biomass. This observation provides a means for estimating biomass at a given location or for deriving coefficients for the calibration function in the absence of field calibration data.

Self-Calibrating and Remote Programmable Signal Conditioning Amplifier System and Method

NASA Technical Reports Server (NTRS)

Medelius, Pedro J. (Inventor); Hallberg, Carl G. (Inventor); Simpson, Howard J., III (Inventor); Thayer, Stephen W. (Inventor)

1998-01-01

A self-calibrating, remote programmable signal conditioning amplifier system employs information read from a memory attached to a measurement transducer for automatic calibration. The signal conditioning amplifier is self-calibrated on a continuous basis through use of a dual input path arrangement, with each path containing a multiplexer and a programmable amplifier. A digital signal processor controls operation of the system such that a transducer signal is applied to one of the input paths, while one or more calibration signals are applied to the second input path. Once the second path is calibrated, the digital signal processor switches the transducer signal to the second path. and then calibrates the first path. This process is continually repeated so that each path is calibrated on an essentially continuous basis. Dual output paths are also employed which are calibrated in the same manner. The digital signal processor also allows the implementation of a variety of digital filters which are either programmed into the system or downloaded by an operator, and performs up to eighth order linearization.

Geometrical Characterisation of a 2D Laser System and Calibration of a Cross-Grid Encoder by Means of a Self-Calibration Methodology

PubMed Central

Torralba, Marta; Díaz-Pérez, Lucía C.

2017-01-01

This article presents a self-calibration procedure and the experimental results for the geometrical characterisation of a 2D laser system operating along a large working range (50 mm × 50 mm) with submicrometre uncertainty. Its purpose is to correct the geometric errors of the 2D laser system setup generated when positioning the two laser heads and the plane mirrors used as reflectors. The non-calibrated artefact used in this procedure is a commercial grid encoder that is also a measuring instrument. Therefore, the self-calibration procedure also allows the determination of the geometrical errors of the grid encoder, including its squareness error. The precision of the proposed algorithm is tested using virtual data. Actual measurements are subsequently registered, and the algorithm is applied. Once the laser system is characterised, the error of the grid encoder is calculated along the working range, resulting in an expanded submicrometre calibration uncertainty (k = 2) for the X and Y axes. The results of the grid encoder calibration are comparable to the errors provided by the calibration certificate for its main central axes. It is, therefore, possible to confirm the suitability of the self-calibration methodology proposed in this article. PMID:28858239

Final results of the PERSEE experiment

NASA Astrophysics Data System (ADS)

Le Duigou, J. M.; Lozi, J.; Cassaing, F.; Houairi, K.; Sorrente, B.; Montri, J.; Jacquinod, S.; Reess, J.-M.; Pham, L.; Lhome, E.; Buey, T.; Hénault, F.; Marcotto, A.; Girard, P.; Mauclert, N.; Barillot, M.; Coudé du Foresto, V.; Ollivier, M.

2012-07-01

The PERSEE breadboard, developed by a consortium including CNES, IAS, LESIA, OCA, ONERA and TAS since 2005, is a nulling demonstrator that couples an infrared nulling interferometer with a formation flying simulator able to introduce realistic disturbances in the set-up. The general idea is to prove that an adequate optical design can considerably relax the constraints applying at the spacecrafts level of a future interferometric space mission like Darwin/TPF or one of its precursors. The breadboard is now fully operational and the measurements sequences are managed from a remote control room using automatic procedures. A set of excellent results were obtained in 2011. The measured polychromatic nulling depth with non polarized light is 8.8 10-6 stabilized at 9 10-8 in the 1.65-2.45 μm spectral band (37 % bandwidth) during 100 s. This result was extended to a 7h duration thanks to an automatic calibration process. The various contributors are identified and the nulling budget is now well mastered. We also proved that harmonic disturbances in the 1-100 Hz up to several ten’s of nm rms can be very efficiently corrected by a Linear Quadratic Control (LQG) if a sufficient flux is available. These results are important contributions to the feasibility of a future space based nulling interferometer.

Final results of the PERSEE experiment

NASA Astrophysics Data System (ADS)

Le Duigou, J.-M.; Lozi, J.; Cassaing, F.; Houairi, K.; Sorrente, B.; Montri, J.; Jacquinod, S.; Réess, J.-M.; Pham, L.; Lhomé, E.; Buey, T.; Hénault, F.; Marcotto, A.; Girard, P.; Mauclert, N.; Barillot, M.; Coudé du Foresto, V.; Ollivier, M.

2017-11-01

The PERSEE breadboard, developed by a consortium including CNES, IAS, LESIA, OCA, ONERA and TAS since 2006, is a nulling demonstrator that couples an infrared nulling interferometer with a formation flying simulator able to introduce realistic disturbances in the set-up. The general idea is to prove that an adequate optical design can considerably release the constraints applied at the spacecrafts level of a future interferometric space mission like Darwin/TPF or one of its precursors. The breadboard is now fully operational and the measurements sequences are managed from a remote control room using automatic procedures. A set of excellent results were obtained in 2011: the measured polychromatic nulling depth with non polarized light is 8.8x10-6 stabilized at 9x10-8 in the [1.65-2.45] μm spectral band (37% bandwidth) during 100s. This result was extended to a 7h duration thanks to an automatic calibration process. The various contributors are identified and the nulling budget is now well mastered. We also proved that harmonic disturbances in the 1-100Hz up to several tens of nm rms can be very efficiently corrected by a Linear Quadratic Control (LQG) if a sufficient flux is available. These results are important contributions to the feasibility of a future space based nulling interferometer.

Parameter Estimation of Computationally Expensive Watershed Models Through Efficient Multi-objective Optimization and Interactive Decision Analytics

NASA Astrophysics Data System (ADS)

Akhtar, Taimoor; Shoemaker, Christine

2016-04-01

Watershed model calibration is inherently a multi-criteria problem. Conflicting trade-offs exist between different quantifiable calibration criterions indicating the non-existence of a single optimal parameterization. Hence, many experts prefer a manual approach to calibration where the inherent multi-objective nature of the calibration problem is addressed through an interactive, subjective, time-intensive and complex decision making process. Multi-objective optimization can be used to efficiently identify multiple plausible calibration alternatives and assist calibration experts during the parameter estimation process. However, there are key challenges to the use of multi objective optimization in the parameter estimation process which include: 1) multi-objective optimization usually requires many model simulations, which is difficult for complex simulation models that are computationally expensive; and 2) selection of one from numerous calibration alternatives provided by multi-objective optimization is non-trivial. This study proposes a "Hybrid Automatic Manual Strategy" (HAMS) for watershed model calibration to specifically address the above-mentioned challenges. HAMS employs a 3-stage framework for parameter estimation. Stage 1 incorporates the use of an efficient surrogate multi-objective algorithm, GOMORS, for identification of numerous calibration alternatives within a limited simulation evaluation budget. The novelty of HAMS is embedded in Stages 2 and 3 where an interactive visual and metric based analytics framework is available as a decision support tool to choose a single calibration from the numerous alternatives identified in Stage 1. Stage 2 of HAMS provides a goodness-of-fit measure / metric based interactive framework for identification of a small subset (typically less than 10) of meaningful and diverse set of calibration alternatives from the numerous alternatives obtained in Stage 1. Stage 3 incorporates the use of an interactive visual analytics framework for decision support in selection of one parameter combination from the alternatives identified in Stage 2. HAMS is applied for calibration of flow parameters of a SWAT model, (Soil and Water Assessment Tool) designed to simulate flow in the Cannonsville watershed in upstate New York. Results from the application of HAMS to Cannonsville indicate that efficient multi-objective optimization and interactive visual and metric based analytics can bridge the gap between the effective use of both automatic and manual strategies for parameter estimation of computationally expensive watershed models.

Method to improve the blade tip-timing accuracy of fiber bundle sensor under varying tip clearance

NASA Astrophysics Data System (ADS)

Duan, Fajie; Zhang, Jilong; Jiang, Jiajia; Guo, Haotian; Ye, Dechao

2016-01-01

Blade vibration measurement based on the blade tip-timing method has become an industry-standard procedure. Fiber bundle sensors are widely used for tip-timing measurement. However, the variation of clearance between the sensor and the blade will bring a tip-timing error to fiber bundle sensors due to the change in signal amplitude. This article presents methods based on software and hardware to reduce the error caused by the tip clearance change. The software method utilizes both the rising and falling edges of the tip-timing signal to determine the blade arrival time, and a calibration process suitable for asymmetric tip-timing signals is presented. The hardware method uses an automatic gain control circuit to stabilize the signal amplitude. Experiments are conducted and the results prove that both methods can effectively reduce the impact of tip clearance variation on the blade tip-timing and improve the accuracy of measurements.

Results from a portable Adaptive Optics system on the 1 meter telescope at the Naval Observatory Flagstaff Station

NASA Astrophysics Data System (ADS)

Restaino, Sergio R.; Gilbreath, G. Charmaine; Payne, Don M.; Baker, Jeffrey T.; Martinez, Ty; DiVittorio, Michael; Mozurkewich, David; Friedman, Jeffrey

2003-02-01

In this paper we present results using a compact, portable adaptive optics system. The system was developed as a joint venture between the Naval Research Laboratory, Air Force Research Laboratory, and two small, New Mexico based-businesses. The system has a footprint of 18x24x18 inches and weighs less than 100 lbs. Key hardware design characteristics enable portability, easy mounting, and stable alignment. The system also enables quick calibration procedures, stable performance, and automatic adaptability to various pupil configurations. The system was tested during an engineering run in late July 2002 at the Naval Observatory Flagstaff Station one-meter telescope. Weather prevented extensive testing and the seeing during the run was marginal but a sufficient opportunity was provided for proof-of-concept, initial characterization of closed loop performance, and to start addressing some of the most pressing engineering and scientific issues.

ESO/ST-ECF Data Analysis Workshop, 5th, Garching, Germany, Apr. 26, 27, 1993, Proceedings

NASA Astrophysics Data System (ADS)

Grosbol, Preben; de Ruijsscher, Resy

1993-01-01

Various papers on astronomical data analysis are presented. Individual optics addressed include: surface photometry of early-type galaxies, wavelet transform and adaptive filtering, package for surface photometry of galaxies, calibration of large-field mosaics, surface photometry of galaxies with HST, wavefront-supported image deconvolution, seeing effects on elliptical galaxies, multiple algorithms deconvolution program, enhancement of Skylab X-ray images, MIDAS procedures for the image analysis of E-S0 galaxies, photometric data reductions under MIDAS, crowded field photometry with deconvolved images, the DENIS Deep Near Infrared Survey. Also discussed are: analysis of astronomical time series, detection of low-amplitude stellar pulsations, new SOT method for frequency analysis, chaotic attractor reconstruction and applications to variable stars, reconstructing a 1D signal from irregular samples, automatic analysis for time series with large gaps, prospects for content-based image retrieval, redshift survey in the South Galactic Pole Region.

Toward a standard line for use in multibeam echo sounder calibration

NASA Astrophysics Data System (ADS)

Weber, Thomas C.; Rice, Glen; Smith, Michael

2018-06-01

A procedure is suggested in which a relative calibration for the intensity output of a multibeam echo sounder (MBES) can be performed. This procedure identifies a common survey line (i.e., a standard line), over which acoustic backscatter from the seafloor is collected with multiple MBES systems or by the same system multiple times. A location on the standard line which exhibits temporal stability in its seafloor backscatter response is used to bring the intensity output of the multiple MBES systems to a common reference. This relative calibration procedure has utility for MBES users wishing to generate an aggregate seafloor backscatter mosaic using multiple systems, revisiting an area to detect changes in substrate type, and comparing substrate types in the same general area but with different systems or different system settings. The calibration procedure is demonstrated using three different MBES systems over 3 different years in New Castle, NH, USA.

14 CFR 60.27 - Automatic loss of qualification and procedures for restoration of qualification.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Automatic loss of qualification and procedures for restoration of qualification. 60.27 Section 60.27 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRMEN FLIGHT SIMULATION TRAINING DEVICE INITIAL AND...

14 CFR 60.27 - Automatic loss of qualification and procedures for restoration of qualification.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Automatic loss of qualification and procedures for restoration of qualification. 60.27 Section 60.27 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRMEN FLIGHT SIMULATION TRAINING DEVICE INITIAL AND...

14 CFR 60.27 - Automatic loss of qualification and procedures for restoration of qualification.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Automatic loss of qualification and procedures for restoration of qualification. 60.27 Section 60.27 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRMEN FLIGHT SIMULATION TRAINING DEVICE INITIAL AND...

14 CFR 60.27 - Automatic loss of qualification and procedures for restoration of qualification.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Automatic loss of qualification and procedures for restoration of qualification. 60.27 Section 60.27 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRMEN FLIGHT SIMULATION TRAINING DEVICE INITIAL AND...

14 CFR 60.27 - Automatic loss of qualification and procedures for restoration of qualification.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Automatic loss of qualification and procedures for restoration of qualification. 60.27 Section 60.27 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRMEN FLIGHT SIMULATION TRAINING DEVICE INITIAL AND...

The analytical calibration in (bio)imaging/mapping of the metallic elements in biological samples--definitions, nomenclature and strategies: state of the art.

PubMed

Jurowski, Kamil; Buszewski, Bogusław; Piekoszewski, Wojciech

2015-01-01

Nowadays, studies related to the distribution of metallic elements in biological samples are one of the most important issues. There are many articles dedicated to specific analytical atomic spectrometry techniques used for mapping/(bio)imaging the metallic elements in various kinds of biological samples. However, in such literature, there is a lack of articles dedicated to reviewing calibration strategies, and their problems, nomenclature, definitions, ways and methods used to obtain quantitative distribution maps. The aim of this article was to characterize the analytical calibration in the (bio)imaging/mapping of the metallic elements in biological samples including (1) nomenclature; (2) definitions, and (3) selected and sophisticated, examples of calibration strategies with analytical calibration procedures applied in the different analytical methods currently used to study an element's distribution in biological samples/materials such as LA ICP-MS, SIMS, EDS, XRF and others. The main emphasis was placed on the procedures and methodology of the analytical calibration strategy. Additionally, the aim of this work is to systematize the nomenclature for the calibration terms: analytical calibration, analytical calibration method, analytical calibration procedure and analytical calibration strategy. The authors also want to popularize the division of calibration methods that are different than those hitherto used. This article is the first work in literature that refers to and emphasizes many different and complex aspects of analytical calibration problems in studies related to (bio)imaging/mapping metallic elements in different kinds of biological samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Improving the Calibration of the SN Ia Anchor Datasets with a Bayesian Hierarchal Model

NASA Astrophysics Data System (ADS)

Currie, Miles; Rubin, David

2018-01-01

Inter-survey calibration remains one of the largest systematic uncertainties in SN Ia cosmology today. Ideally, each survey would measure their system throughputs and observe well characterized spectrophotometric standard stars, but many important surveys have not done so. For these surveys, we calibrate using tertiary survey stars tied to SDSS and Pan-STARRS. We improve on previous efforts by taking the spatially variable response of each telescope/camera into account, and using improved color transformations in the surveys’ natural instrumental photometric system. We use a global hierarchical model of the data, automatically providing a covariance matrix of magnitude offsets and bandpass shifts which reduces the systematic uncertainty in inter-survey calibration, thereby providing better cosmological constraints.

A multi-objective approach to improve SWAT model calibration in alpine catchments

NASA Astrophysics Data System (ADS)

Tuo, Ye; Marcolini, Giorgia; Disse, Markus; Chiogna, Gabriele

2018-04-01

Multi-objective hydrological model calibration can represent a valuable solution to reduce model equifinality and parameter uncertainty. The Soil and Water Assessment Tool (SWAT) model is widely applied to investigate water quality and water management issues in alpine catchments. However, the model calibration is generally based on discharge records only, and most of the previous studies have defined a unique set of snow parameters for an entire basin. Only a few studies have considered snow observations to validate model results or have taken into account the possible variability of snow parameters for different subbasins. This work presents and compares three possible calibration approaches. The first two procedures are single-objective calibration procedures, for which all parameters of the SWAT model were calibrated according to river discharge alone. Procedures I and II differ from each other by the assumption used to define snow parameters: The first approach assigned a unique set of snow parameters to the entire basin, whereas the second approach assigned different subbasin-specific sets of snow parameters to each subbasin. The third procedure is a multi-objective calibration, in which we considered snow water equivalent (SWE) information at two different spatial scales (i.e. subbasin and elevation band), in addition to discharge measurements. We tested these approaches in the Upper Adige river basin where a dense network of snow depth measurement stations is available. Only the set of parameters obtained with this multi-objective procedure provided an acceptable prediction of both river discharge and SWE. These findings offer the large community of SWAT users a strategy to improve SWAT modeling in alpine catchments.

Automatic control design procedures for restructurable aircraft control

NASA Technical Reports Server (NTRS)

Looze, D. P.; Krolewski, S.; Weiss, J.; Barrett, N.; Eterno, J.

1985-01-01

A simple, reliable automatic redesign procedure for restructurable control is discussed. This procedure is based on Linear Quadratic (LQ) design methodologies. It employs a robust control system design for the unfailed aircraft to minimize the effects of failed surfaces and to extend the time available for restructuring the Flight Control System. The procedure uses the LQ design parameters for the unfailed system as a basis for choosing the design parameters of the failed system. This philosophy alloys the engineering trade-offs that were present in the nominal design to the inherited by the restructurable design. In particular, it alloys bandwidth limitations and performance trade-offs to be incorporated in the redesigned system. The procedure also has several other desirable features. It effectively redistributes authority among the available control effectors to maximize the system performance subject to actuator limitations and constraints. It provides a graceful performance degradation as the amount of control authority lessens. When given the parameters of the unfailed aircraft, the automatic redesign procedure reproduces the nominal control system design.

Design and analysis of an automatic method of measuring silicon-controlled-rectifier holding current

NASA Technical Reports Server (NTRS)

Maslowski, E. A.

1971-01-01

The design of an automated SCR holding-current measurement system is described. The circuits used in the measurement system were designed to meet the major requirements of automatic data acquisition, reliability, and repeatability. Performance data are presented and compared with calibration data. The data verified the accuracy of the measurement system. Data taken over a 48-hr period showed that the measurement system operated satisfactorily and met all the design requirements.

The Calibration of dc Voltage Standards at NIST

PubMed Central

Field, Bruce F.

1990-01-01

This document describes the procedures used at NIST to calibrate dc voltage standards in terms of the NIST volt. Three calibration services are offered by the Electricity Division: Regular Calibration Service (RCS) of client standard cells at NIST; the Volt Transfer Program (VTP) a process to determine the difference between the NIST volt and the volt as maintained by a group of standard cells in a client laboratory; and the calibration of client solid-state dc voltage standards at NIST. The operational procedures used to compare these voltage standards to NIST voltage standards and to maintain the NIST volt via the ac Josephson effect are discussed. PMID:28179777

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION, CALIBRATION AND MAINTENANCE OF FIXED AND ADJUSTABLE VOLUME PIPETTE GUNS (BCO-L-9.0)

EPA Science Inventory

The purpose of this SOP is to describe the general procedures for the operation, calibration, and maintenance of fixed- and adjustable-volume pipette guns. This procedure was followed to ensure consistent data retrieval during the Arizona NHEXAS project and the "Border" study. Ke...

Mathematical calibration procedure of a capacitive sensor-based indexed metrology platform

NASA Astrophysics Data System (ADS)

Brau-Avila, A.; Santolaria, J.; Acero, R.; Valenzuela-Galvan, M.; Herrera-Jimenez, V. M.; Aguilar, J. J.

2017-03-01

The demand for faster and more reliable measuring tasks for the control and quality assurance of modern production systems has created new challenges for the field of coordinate metrology. Thus, the search for new solutions in coordinate metrology systems and the need for the development of existing ones still persists. One example of such a system is the portable coordinate measuring machine (PCMM), the use of which in industry has considerably increased in recent years, mostly due to its flexibility for accomplishing in-line measuring tasks as well as its reduced cost and operational advantages compared to traditional coordinate measuring machines. Nevertheless, PCMMs have a significant drawback derived from the techniques applied in the verification and optimization procedures of their kinematic parameters. These techniques are based on the capture of data with the measuring instrument from a calibrated gauge object, fixed successively in various positions so that most of the instrument measuring volume is covered, which results in time-consuming, tedious and expensive verification and optimization procedures. In this work the mathematical calibration procedure of a capacitive sensor-based indexed metrology platform (IMP) is presented. This calibration procedure is based on the readings and geometric features of six capacitive sensors and their targets with nanometer resolution. The final goal of the IMP calibration procedure is to optimize the geometric features of the capacitive sensors and their targets in order to use the optimized data in the verification procedures of PCMMs.

A new method for automatic discontinuity traces sampling on rock mass 3D model

NASA Astrophysics Data System (ADS)

Umili, G.; Ferrero, A.; Einstein, H. H.

2013-02-01

A new automatic method for discontinuity traces mapping and sampling on a rock mass digital model is described in this work. The implemented procedure allows one to automatically identify discontinuity traces on a Digital Surface Model: traces are detected directly as surface breaklines, by means of maximum and minimum principal curvature values of the vertices that constitute the model surface. Color influence and user errors, that usually characterize the trace mapping on images, are eliminated. Also trace sampling procedures based on circular windows and circular scanlines have been implemented: they are used to infer trace data and to calculate values of mean trace length, expected discontinuity diameter and intensity of rock discontinuities. The method is tested on a case study: results obtained applying the automatic procedure on the DSM of a rock face are compared to those obtained performing a manual sampling on the orthophotograph of the same rock face.

Hazardous Environment Robotics

NASA Technical Reports Server (NTRS)

1996-01-01

Jet Propulsion Laboratory (JPL) developed video overlay calibration and demonstration techniques for ground-based telerobotics. Through a technology sharing agreement with JPL, Deneb Robotics added this as an option to its robotics software, TELEGRIP. The software is used for remotely operating robots in nuclear and hazardous environments in industries including automotive and medical. The option allows the operator to utilize video to calibrate 3-D computer models with the actual environment, and thus plan and optimize robot trajectories before the program is automatically generated.

Development of Automatic Control of Bayer Plant Digestion

NASA Astrophysics Data System (ADS)

Riffaud, J. P.

Supervisory computer control has been achieved in Alcan's Bayer Plants at Arvida, Quebec, Canada. The purpose of the automatic control system is to stabilize and consequently increase, the alumina/caustic ratio within the digester train and in the blow-off liquor. Measurements of the electrical conductivity of the liquor are obtained from electrodeless conductivity meters. These signals, along with several others are scanned by the computer and converted to engineering units, using specific relationships which are updated periodically for calibration purposes. On regular time intervals, values of ratio are compared to target values and adjustments are made to the bauxite flow entering the digesters. Dead time compensation included in the control algorithm enables a faster rate for corrections. Modification of production rate is achieved through careful timing of various flow changes. Calibration of the conductivity meters is achieved by sampling at intervals the liquor flowing through them, and analysing it with a thermometric titrator. Calibration of the thermometric titrator is done at intervals with a standard solution. Calculations for both calibrations are performed by computer from data entered by the analyst. The computer was used for on-line data collection, modelling of the digester system, calculation of disturbances and simulation of control strategies before implementing the most successful strategy in the Plant. Control of ratio has been improved by the integrated system, resulting in increased Plant productivity.

Evaluation of the use of performance reference compounds in an oasis-HLB adsorbent based passive sampler for improving water concentration estimates of polar herbicides in freshwater

USGS Publications Warehouse

Mazzella, N.; Lissalde, S.; Moreira, S.; Delmas, F.; Mazellier, P.; Huckins, J.N.

2010-01-01

Passive samplers such as the Polar Organic Chemical Integrative Sampler (POCIS) are useful tools for monitoring trace levels of polar organic chemicals in aquatic environments. The use of performance reference compounds (PRC) spiked into the POCIS adsorbent for in situ calibration may improve the semiquantitative nature of water concentration estimates based on this type of sampler. In this work, deuterium labeled atrazine-desisopropyl (DIA-d5) was chosen as PRC because of its relatively high fugacity from Oasis HLB (the POCIS adsorbent used) and our earlier evidence of its isotropic exchange. In situ calibration of POCIS spiked with DIA-d5was performed, and the resulting time-weighted average concentration estimates were compared with similar values from an automatic sampler equipped with Oasis HLB cartridges. Before PRC correction, water concentration estimates based on POCIS data sampling ratesfrom a laboratory calibration exposure were systematically lower than the reference concentrations obtained with the automatic sampler. Use of the DIA-d5 PRC data to correct POCIS sampling rates narrowed differences between corresponding values derived from the two methods. Application of PRCs for in situ calibration seems promising for improving POCIS-derived concentration estimates of polar pesticides. However, careful attention must be paid to the minimization of matrix effects when the quantification is performed by HPLC-ESI-MS/MS. ?? 2010 American Chemical Society.

10 CFR 431.134 - Uniform test methods for the measurement of energy consumption and water consumption of automatic...

Code of Federal Regulations, 2011 CFR

2011-01-01

... consumption and water consumption of automatic commercial ice makers. 431.134 Section 431.134 Energy... EQUIPMENT Automatic Commercial Ice Makers Test Procedures § 431.134 Uniform test methods for the measurement of energy consumption and water consumption of automatic commercial ice makers. (a) Scope. This...

Hydrodynamic Energy Saving Enhancements for DDG 51 Class Ships

DTIC Science & Technology

2012-02-01

temperature and pressure in the hydraulic pitch control system, expansion and contraction of the pitch control rods, improper pitch calibration procedure ...outdated pitch calibration, etc. Experience during hot pitch calibration procedures conducted by NSWCCD prior to powering trials has indicated that...18% increase in power.10 Sea trials conducted during a long-term evaluation on the USS WHIPPLE (FF 1062), showed that by 800 days out of drydock

Development of a calibration equipment for spectrometer qualification

NASA Astrophysics Data System (ADS)

Michel, C.; Borguet, B.; Boueé, A.; Blain, P.; Deep, A.; Moreau, V.; François, M.; Maresi, L.; Myszkowiak, A.; Taccola, M.; Versluys, J.; Stockman, Y.

2017-09-01

With the development of new spectrometer concepts, it is required to adapt the calibration facilities to characterize correctly their performances. These spectro-imaging performances are mainly Modulation Transfer Function, spectral response, resolution and registration; polarization, straylight and radiometric calibration. The challenge of this calibration development is to achieve better performance than the item under test using mostly standard items. Because only the subsystem spectrometer needs to be calibrated, the calibration facility needs to simulate the geometrical "behaviours" of the imaging system. A trade-off study indicates that no commercial devices are able to fulfil completely all the requirements so that it was necessary to opt for an in home telecentric achromatic design. The proposed concept is based on an Offner design. This allows mainly to use simple spherical mirrors and to cover the spectral range. The spectral range is covered with a monochromator. Because of the large number of parameters to record the calibration facility is fully automatized. The performances of the calibration system have been verified by analysis and experimentally. Results achieved recently on a free-form grating Offner spectrometer demonstrate the capacities of this new calibration facility. In this paper, a full calibration facility is described, developed specifically for a new free-form spectro-imager.

SWAT: Model use, calibration, and validation

USDA-ARS?s Scientific Manuscript database

SWAT (Soil and Water Assessment Tool) is a comprehensive, semi-distributed river basin model that requires a large number of input parameters which complicates model parameterization and calibration. Several calibration techniques have been developed for SWAT including manual calibration procedures...

40 CFR 1065.325 - Intake-flow calibration.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Section 1065.325 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calibrations and Verifications Flow-Related Measurements § 1065.325 Intake-flow calibration. (a) Calibrate intake-air flow meters upon initial installation. Follow the...

Automatic delineation of brain regions on MRI and PET images from the pig.

PubMed

Villadsen, Jonas; Hansen, Hanne D; Jørgensen, Louise M; Keller, Sune H; Andersen, Flemming L; Petersen, Ida N; Knudsen, Gitte M; Svarer, Claus

2018-01-15

The increasing use of the pig as a research model in neuroimaging requires standardized processing tools. For example, extraction of regional dynamic time series from brain PET images requires parcellation procedures that benefit from being automated. Manual inter-modality spatial normalization to a MRI atlas is operator-dependent, time-consuming, and can be inaccurate with lack of cortical radiotracer binding or skull uptake. A parcellated PET template that allows for automatic spatial normalization to PET images of any radiotracer. MRI and [ 11 C]Cimbi-36 PET scans obtained in sixteen pigs made the basis for the atlas. The high resolution MRI scans allowed for creation of an accurately averaged MRI template. By aligning the within-subject PET scans to their MRI counterparts, an averaged PET template was created in the same space. We developed an automatic procedure for spatial normalization of the averaged PET template to new PET images and hereby facilitated transfer of the atlas regional parcellation. Evaluation of the automatic spatial normalization procedure found the median voxel displacement to be 0.22±0.08mm using the MRI template with individual MRI images and 0.92±0.26mm using the PET template with individual [ 11 C]Cimbi-36 PET images. We tested the automatic procedure by assessing eleven PET radiotracers with different kinetics and spatial distributions by using perfusion-weighted images of early PET time frames. We here present an automatic procedure for accurate and reproducible spatial normalization and parcellation of pig PET images of any radiotracer with reasonable blood-brain barrier penetration. Copyright © 2017 Elsevier B.V. All rights reserved.

Simulation model calibration and validation : phase II : development of implementation handbook and short course.

DOT National Transportation Integrated Search

2006-01-01

A previous study developed a procedure for microscopic simulation model calibration and validation and evaluated the procedure via two relatively simple case studies using three microscopic simulation models. Results showed that default parameters we...

40 CFR 1066.215 - Summary of verification and calibration procedures for chassis dynamometers.

Code of Federal Regulations, 2012 CFR

2012-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS VEHICLE-TESTING PROCEDURES Dynamometer... manufacturer instructions and good engineering judgment. (c) Automated dynamometer verifications and... accomplish the verifications and calibrations specified in this subpart. You may use these automated...

40 CFR 1066.215 - Summary of verification and calibration procedures for chassis dynamometers.

Code of Federal Regulations, 2013 CFR

2013-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS VEHICLE-TESTING PROCEDURES Dynamometer... manufacturer instructions and good engineering judgment. (c) Automated dynamometer verifications and... accomplish the verifications and calibrations specified in this subpart. You may use these automated...

26 CFR 157.6081-1 - Automatic extension of time for filing a return due under chapter 55.

Code of Federal Regulations, 2010 CFR

2010-04-01

... SETTLEMENT FACTORING TRANSACTIONS Procedure and Administration § 157.6081-1 Automatic extension of time for..., “Excise Tax on Structured Settlement Factoring Transactions”, will be allowed an automatic 6-month...

Automatic Coding of Dialogue Acts in Collaboration Protocols

ERIC Educational Resources Information Center

Erkens, Gijsbert; Janssen, Jeroen

2008-01-01

Although protocol analysis can be an important tool for researchers to investigate the process of collaboration and communication, the use of this method of analysis can be time consuming. Hence, an automatic coding procedure for coding dialogue acts was developed. This procedure helps to determine the communicative function of messages in online…

40 CFR 90.320 - Carbon dioxide analyzer calibration.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (64 percent) is required (see following table). Example calibration points (%) Acceptable for... periodic interference, system check, and calibration test procedures specified in 40 CFR part 1065...

40 CFR 90.320 - Carbon dioxide analyzer calibration.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (64 percent) is required (see following table). Example calibration points (%) Acceptable for... periodic interference, system check, and calibration test procedures specified in 40 CFR part 1065...

40 CFR 90.320 - Carbon dioxide analyzer calibration.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (64 percent) is required (see following table). Example calibration points (%) Acceptable for... periodic interference, system check, and calibration test procedures specified in 40 CFR part 1065...

MetaQuant: a tool for the automatic quantification of GC/MS-based metabolome data.

PubMed

Bunk, Boyke; Kucklick, Martin; Jonas, Rochus; Münch, Richard; Schobert, Max; Jahn, Dieter; Hiller, Karsten

2006-12-01

MetaQuant is a Java-based program for the automatic and accurate quantification of GC/MS-based metabolome data. In contrast to other programs MetaQuant is able to quantify hundreds of substances simultaneously with minimal manual intervention. The integration of a self-acting calibration function allows the parallel and fast calibration for several metabolites simultaneously. Finally, MetaQuant is able to import GC/MS data in the common NetCDF format and to export the results of the quantification into Systems Biology Markup Language (SBML), Comma Separated Values (CSV) or Microsoft Excel (XLS) format. MetaQuant is written in Java and is available under an open source license. Precompiled packages for the installation on Windows or Linux operating systems are freely available for download. The source code as well as the installation packages are available at http://bioinformatics.org/metaquant

eCTG: an automatic procedure to extract digital cardiotocographic signals from digital images.

PubMed

Sbrollini, Agnese; Agostinelli, Angela; Marcantoni, Ilaria; Morettini, Micaela; Burattini, Luca; Di Nardo, Francesco; Fioretti, Sandro; Burattini, Laura

2018-03-01

Cardiotocography (CTG), consisting in the simultaneous recording of fetal heart rate (FHR) and maternal uterine contractions (UC), is a popular clinical test to assess fetal health status. Typically, CTG machines provide paper reports that are visually interpreted by clinicians. Consequently, visual CTG interpretation depends on clinician's experience and has a poor reproducibility. The lack of databases containing digital CTG signals has limited number and importance of retrospective studies finalized to set up procedures for automatic CTG analysis that could contrast visual CTG interpretation subjectivity. In order to help overcoming this problem, this study proposes an electronic procedure, termed eCTG, to extract digital CTG signals from digital CTG images, possibly obtainable by scanning paper CTG reports. eCTG was specifically designed to extract digital CTG signals from digital CTG images. It includes four main steps: pre-processing, Otsu's global thresholding, signal extraction and signal calibration. Its validation was performed by means of the "CTU-UHB Intrapartum Cardiotocography Database" by Physionet, that contains digital signals of 552 CTG recordings. Using MATLAB, each signal was plotted and saved as a digital image that was then submitted to eCTG. Digital CTG signals extracted by eCTG were eventually compared to corresponding signals directly available in the database. Comparison occurred in terms of signal similarity (evaluated by the correlation coefficient ρ, and the mean signal error MSE) and clinical features (including FHR baseline and variability; number, amplitude and duration of tachycardia, bradycardia, acceleration and deceleration episodes; number of early, variable, late and prolonged decelerations; and UC number, amplitude, duration and period). The value of ρ between eCTG and reference signals was 0.85 (P < 10 -560 ) for FHR and 0.97 (P < 10 -560 ) for UC. On average, MSE value was 0.00 for both FHR and UC. No CTG feature was found significantly different when measured in eCTG vs. reference signals. eCTG procedure is a promising useful tool to accurately extract digital FHR and UC signals from digital CTG images. Copyright © 2018 Elsevier B.V. All rights reserved.

SU-E-T-749: Thorough Calibration of MOSFET Dosimeters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plenkovich, D; Thomas, J

Purpose: To improve the accuracy of the MOSFET calibration procedure by performing the measurement several times and calculating the average value of the calibration factor for various photon and electron energies. Methods: The output of three photon and six electron beams of Varian Trilogy linear accelerator SN 5878 was calibrated. Five reinforced standard sensitivity MOSFET dosimeters were placed in the calibration jig and connected to the Reader Module. As the backscatter material was used 7 cm of Virtual Water. The MOSFET dosimeters were covered with 1.5 cm thick bolus for the regular and SRS 6 MV beams, 3 cm bolusmore » for 15 MV beam, 1.5 cm bolus for 6 MeV electron beam, and 2 cm bolus for the electron energies of 9, 12, 15, 18, and 22 MeV. The dosimeters were exposed to 100 MU, and the calibration factor was determined using the mobileMOSFET software. To improve the accuracy of calibration, this procedure was repeated ten times and the calibration factors were averaged. Results: As the number of calibrations was increasing the variability of calibration factors of different dosimeters was decreasing. After ten calibrations, the calibration factors for all five dosimeters were within 1% of one another for all energies, except 6 MV SRS photons and 6 MeV electrons, for which the variability was 2%. Conclusions: The described process results in calibration factors which are almost independent of modality or energy. Once calibrated, the dosimeters may be used for in-vivo dosimetry or for daily verification of the beam output. Measurement of the radiation dose under bolus and scatter to the eye are examples of frequent use of calibrated MOSFET dosimeters. The calibration factor determined for full build-up is used under these circumstances. To the best of our knowledge, such thorough procedure for calibrating MOSFET dosimeters has not been reported previously. Best Medical Canada provided MOSFET dosimeters for this project.« less

40 CFR Appendix B to Part 75 - Quality Assurance and Quality Control Procedures

Code of Federal Regulations, 2010 CFR

2010-07-01

... in section 2.3 of this appendix and the Hg emission tests described in §§ 75.81(c) and 75.81(d)(4). 1.2Specific Requirements for Continuous Emissions Monitoring Systems 1.2.1Calibration Error Test and Linearity Check Procedures Keep a written record of the procedures used for daily calibration error tests and...

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION, CALIBRATION AND MAINTENANCE OF FIXED AND ADJUSTABLE VOLUME PIPETTE GUNS (BCO-L-9.0)

EPA Science Inventory

The purpose of this SOP is to describe the general procedures for the operation, calibration, and maintenance of fixed- and adjustable-volume pipette guns. This procedure was followed to ensure consistent data retrieval during the Arizona NHEXAS project and the Border study. Keyw...

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION, CALIBRATION AND ROUTINE USE OF THE SPECTRACE 9000 FIELD PORTABLE X-RAY FLUORESCENCE ANALYZER (UA-L-10.1)

EPA Science Inventory

The purpose of this SOP is to describe the procedures for operating and calibrating the Spectrace 9000 field portable X-ray fluorescence analyzer. This procedure applies to the determination of metal concentrations in samples during the Arizona NHEXAS project and the "Border" st...

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION, CALIBRATION AND MAINTENANCE OF THE PERKIN-ELMER 1100B ATOMIC ABSORPTION SPECTROMETER (BCO-L-5.1)

EPA Science Inventory

The purpose of this SOP is to outline the start-up, calibration, operation, and maintenance procedures for the Perkin-Elmer 5100 PC Atomic Absorption Spectrophotometer (PE 5100). These procedures are used for the determination of the target trace metal, as in soil, house dust, f...

40 CFR 91.320 - Carbon dioxide analyzer calibration.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (64 percent) is required (see following table). Example calibration points (percent) Acceptable for...) The initial and periodic interference, system check, and calibration test procedures specified in 40...

40 CFR 91.320 - Carbon dioxide analyzer calibration.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (64 percent) is required (see following table). Example calibration points (percent) Acceptable for...) The initial and periodic interference, system check, and calibration test procedures specified in 40...

40 CFR 91.320 - Carbon dioxide analyzer calibration.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (64 percent) is required (see following table). Example calibration points (percent) Acceptable for...) The initial and periodic interference, system check, and calibration test procedures specified in 40...

Automatic anatomy partitioning of the torso region on CT images by using multiple organ localizations with a group-wise calibration technique

NASA Astrophysics Data System (ADS)

Zhou, Xiangrong; Morita, Syoichi; Zhou, Xinxin; Chen, Huayue; Hara, Takeshi; Yokoyama, Ryujiro; Kanematsu, Masayuki; Hoshi, Hiroaki; Fujita, Hiroshi

2015-03-01

This paper describes an automatic approach for anatomy partitioning on three-dimensional (3D) computedtomography (CT) images that divide the human torso into several volume-of-interesting (VOI) images based on anatomical definition. The proposed approach combines several individual detections of organ-location with a groupwise organ-location calibration and correction to achieve an automatic and robust multiple-organ localization task. The essence of the proposed method is to jointly detect the 3D minimum bounding box for each type of organ shown on CT images based on intra-organ-image-textures and inter-organ-spatial-relationship in the anatomy. Machine-learning-based template matching and generalized Hough transform-based point-distribution estimation are used in the detection and calibration processes. We apply this approach to the automatic partitioning of a torso region on CT images, which are divided into 35 VOIs presenting major organ regions and tissues required by routine diagnosis in clinical medicine. A database containing 4,300 patient cases of high-resolution 3D torso CT images is used for training and performance evaluations. We confirmed that the proposed method was successful in target organ localization on more than 95% of CT cases. Only two organs (gallbladder and pancreas) showed a lower success rate: 71 and 78% respectively. In addition, we applied this approach to another database that included 287 patient cases of whole-body CT images scanned for positron emission tomography (PET) studies and used for additional performance evaluation. The experimental results showed that no significant difference between the anatomy partitioning results from those two databases except regarding the spleen. All experimental results showed that the proposed approach was efficient and useful in accomplishing localization tasks for major organs and tissues on CT images scanned using different protocols.

Calibrating SANS data for instrument geometry and pixel sensitivity effects: access to an extended Q range

PubMed Central

Karge, Lukas; Gilles, Ralph

2017-01-01

An improved data-reduction procedure is proposed and demonstrated for small-angle neutron scattering (SANS) measurements. Its main feature is the correction of geometry- and wavelength-dependent intensity variations on the detector in a separate step from the different pixel sensitivities: the geometric and wavelength effects can be corrected analytically, while pixel sensitivities have to be calibrated to a reference measurement. The geometric effects are treated for position-sensitive 3He proportional counter tubes, where they are anisotropic owing to the cylindrical geometry of the gas tubes. For the calibration of pixel sensitivities, a procedure is developed that is valid for isotropic and anisotropic signals. The proposed procedure can save a significant amount of beamtime which has hitherto been used for calibration measurements. PMID:29021734

Neural-Net Based Optical NDE Method for Structural Health Monitoring

NASA Technical Reports Server (NTRS)

Decker, Arthur J.; Weiland, Kenneth E.

2003-01-01

This paper answers some performance and calibration questions about a non-destructive-evaluation (NDE) procedure that uses artificial neural networks to detect structural damage or other changes from sub-sampled characteristic patterns. The method shows increasing sensitivity as the number of sub-samples increases from 108 to 6912. The sensitivity of this robust NDE method is not affected by noisy excitations of the first vibration mode. A calibration procedure is proposed and demonstrated where the output of a trained net can be correlated with the outputs of the point sensors used for vibration testing. The calibration procedure is based on controlled changes of fastener torques. A heterodyne interferometer is used as a displacement sensor for a demonstration of the challenges to be handled in using standard point sensors for calibration.

Parts-Per-Billion Mass Measurement Accuracy Achieved through the Combination of Multiple Linear Regression and Automatic Gain Control in a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer

PubMed Central

Williams, D. Keith; Muddiman, David C.

2008-01-01

Fourier transform ion cyclotron resonance mass spectrometry has the ability to achieve unprecedented mass measurement accuracy (MMA); MMA is one of the most significant attributes of mass spectrometric measurements as it affords extraordinary molecular specificity. However, due to space-charge effects, the achievable MMA significantly depends on the total number of ions trapped in the ICR cell for a particular measurement. Even through the use of automatic gain control (AGC), the total ion population is not constant between spectra. Multiple linear regression calibration in conjunction with AGC is utilized in these experiments to formally account for the differences in total ion population in the ICR cell between the external calibration spectra and experimental spectra. This ability allows for the extension of dynamic range of the instrument while allowing mean MMA values to remain less than 1 ppm. In addition, multiple linear regression calibration is used to account for both differences in total ion population in the ICR cell as well as relative ion abundance of a given species, which also affords mean MMA values at the parts-per-billion level. PMID:17539605

Parameterization and Uncertainty Analysis of SWAT model in Hydrological Simulation of Chaohe River Basin

NASA Astrophysics Data System (ADS)

Jie, M.; Zhang, J.; Guo, B. B.

2017-12-01

As a typical distributed hydrological model, the SWAT model also has a challenge in calibrating parameters and analysis their uncertainty. This paper chooses the Chaohe River Basin China as the study area, through the establishment of the SWAT model, loading the DEM data of the Chaohe river basin, the watershed is automatically divided into several sub-basins. Analyzing the land use, soil and slope which are on the basis of the sub-basins and calculating the hydrological response unit (HRU) of the study area, after running SWAT model, the runoff simulation values in the watershed are obtained. On this basis, using weather data, known daily runoff of three hydrological stations, combined with the SWAT-CUP automatic program and the manual adjustment method are used to analyze the multi-site calibration of the model parameters. Furthermore, the GLUE algorithm is used to analyze the parameters uncertainty of the SWAT model. Through the sensitivity analysis, calibration and uncertainty study of SWAT, the results indicate that the parameterization of the hydrological characteristics of the Chaohe river is successful and feasible which can be used to simulate the Chaohe river basin.

Measurement of electromagnetic tracking error in a navigated breast surgery setup

NASA Astrophysics Data System (ADS)

Harish, Vinyas; Baksh, Aidan; Ungi, Tamas; Lasso, Andras; Baum, Zachary; Gauvin, Gabrielle; Engel, Jay; Rudan, John; Fichtinger, Gabor

2016-03-01

PURPOSE: The measurement of tracking error is crucial to ensure the safety and feasibility of electromagnetically tracked, image-guided procedures. Measurement should occur in a clinical environment because electromagnetic field distortion depends on positioning relative to the field generator and metal objects. However, we could not find an accessible and open-source system for calibration, error measurement, and visualization. We developed such a system and tested it in a navigated breast surgery setup. METHODS: A pointer tool was designed for concurrent electromagnetic and optical tracking. Software modules were developed for automatic calibration of the measurement system, real-time error visualization, and analysis. The system was taken to an operating room to test for field distortion in a navigated breast surgery setup. Positional and rotational electromagnetic tracking errors were then calculated using optical tracking as a ground truth. RESULTS: Our system is quick to set up and can be rapidly deployed. The process from calibration to visualization also only takes a few minutes. Field distortion was measured in the presence of various surgical equipment. Positional and rotational error in a clean field was approximately 0.90 mm and 0.31°. The presence of a surgical table, an electrosurgical cautery, and anesthesia machine increased the error by up to a few tenths of a millimeter and tenth of a degree. CONCLUSION: In a navigated breast surgery setup, measurement and visualization of tracking error defines a safe working area in the presence of surgical equipment. Our system is available as an extension for the open-source 3D Slicer platform.

40 CFR 204.54 - Test procedures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... frequency response calibration and an attenuator (gain control) calibration plus a measurement of dynamic... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Test procedures. 204.54 Section 204.54 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS NOISE EMISSION...

Psychophysical contrast calibration

PubMed Central

To, Long; Woods, Russell L; Goldstein, Robert B; Peli, Eli

2013-01-01

Electronic displays and computer systems offer numerous advantages for clinical vision testing. Laboratory and clinical measurements of various functions and in particular of (letter) contrast sensitivity require accurately calibrated display contrast. In the laboratory this is achieved using expensive light meters. We developed and evaluated a novel method that uses only psychophysical responses of a person with normal vision to calibrate the luminance contrast of displays for experimental and clinical applications. Our method combines psychophysical techniques (1) for detection (and thus elimination or reduction) of display saturating nonlinearities; (2) for luminance (gamma function) estimation and linearization without use of a photometer; and (3) to measure without a photometer the luminance ratios of the display’s three color channels that are used in a bit-stealing procedure to expand the luminance resolution of the display. Using a photometer we verified that the calibration achieved with this procedure is accurate for both LCD and CRT displays enabling testing of letter contrast sensitivity to 0.5%. Our visual calibration procedure enables clinical, internet and home implementation and calibration verification of electronic contrast testing. PMID:23643843

40 CFR 91.425 - CVS calibration frequency.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test Procedures § 91.425 CVS calibration frequency. Calibrate the CVS positive displacement pump or critical flow venturi...

40 CFR 91.425 - CVS calibration frequency.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test Procedures § 91.425 CVS calibration frequency. Calibrate the CVS positive displacement pump or critical flow venturi...

40 CFR 91.425 - CVS calibration frequency.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test Procedures § 91.425 CVS calibration frequency. Calibrate the CVS positive displacement pump or critical flow venturi...

40 CFR 91.425 - CVS calibration frequency.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test Procedures § 91.425 CVS calibration frequency. Calibrate the CVS positive displacement pump or critical flow venturi...

40 CFR 91.425 - CVS calibration frequency.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test Procedures § 91.425 CVS calibration frequency. Calibrate the CVS positive displacement pump or critical flow venturi...

Automatic Camera Calibration Using Multiple Sets of Pairwise Correspondences.

PubMed

Vasconcelos, Francisco; Barreto, Joao P; Boyer, Edmond

2018-04-01

We propose a new method to add an uncalibrated node into a network of calibrated cameras using only pairwise point correspondences. While previous methods perform this task using triple correspondences, these are often difficult to establish when there is limited overlap between different views. In such challenging cases we must rely on pairwise correspondences and our solution becomes more advantageous. Our method includes an 11-point minimal solution for the intrinsic and extrinsic calibration of a camera from pairwise correspondences with other two calibrated cameras, and a new inlier selection framework that extends the traditional RANSAC family of algorithms to sampling across multiple datasets. Our method is validated on different application scenarios where a lack of triple correspondences might occur: addition of a new node to a camera network; calibration and motion estimation of a moving camera inside a camera network; and addition of views with limited overlap to a Structure-from-Motion model.

On-line calibration of high-response pressure transducers during jet-engine testing

NASA Technical Reports Server (NTRS)

Armentrout, E. C.

1974-01-01

Jet engine testing is reported concerned with the effect of inlet pressure and temperature distortions on engine performance and involves the use of numerous miniature pressure transducers. Despite recent improvements in the manufacture of miniature pressure transducers, they still exhibit sensitivity change and zero-shift with temperature and time. To obtain meaningful data, a calibration system is needed to determine these changes. A system has been developed which provides for computer selection of appropriate reference pressures selected from nine different sources to provide a two- or three-point calibration. Calibrations are made on command, before and sometimes after each data point. A unique no leak matrix valve design is used in the reference pressure system. Zero-shift corrections are measured and the values are automatically inserted into the data reduction program.

Challenges in the Development of a Self-Calibrating Network of Ceilometers.

NASA Astrophysics Data System (ADS)

Hervo, Maxime; Wagner, Frank; Mattis, Ina; Baars, Holger; Haefele, Alexander

2015-04-01

There are more than 700 Automatic Lidars and Ceilometers (ALCs) currently operating in Europe. Modern ceilometers can do more than simply measure the cloud base height. They can also measure aerosol layers like volcanic ash, Saharan dust or aerosols within the planetary boundary layer. In the frame of E-PROFILE, which is part of EUMETNET, a European network of automatic lidars and ceilometers will be set up exploiting this new capability. To be able to monitor the evolution of aerosol layers over a large spatial scale, the measurements need to be consistent from one site to another. Currently, most of the instruments do not provide calibrated, only relative measurements. Thus, it is necessary to calibrate the instruments to develop a consistent product for all the instruments from various network and to combine them in an European Network like E-PROFILE. As it is not possible to use an external reference (like a sun photometer or a Raman Lidar) to calibrate all the ALCs in the E-PROFILE network, it is necessary to use a self-calibration algorithm. Two calibration methods have been identified which are suited for automated use in a network: the Rayleigh and the liquid cloud calibration methods In the Rayleigh method, backscatter signals from molecules (this is the Rayleigh signal) can be measured and used to calculate the lidar constant (Wiegner et al. 2012). At the wavelength used for most ceilometers, this signal is weak and can be easily measured only during cloud-free nights. However, with the new algorithm implemented in the frame of the TOPROF COST Action, the Rayleigh calibration was successfully performed on a CHM15k for more than 50% of the nights from October 2013 to September 2014. This method was validated against two reference instruments, the collocated EARLINET PollyXT lidar and the CALIPSO space-borne lidar. The lidar constant was on average within 5.5% compare to the lidar constant determined by the EARLINET lidar. It confirms the validity of the self-calibration method. For 3 CALIPSO overpasses the agreement was on average 20.0%. It is less accurate due to the large uncertainties of CALIPSO data close to the surface. In opposition to the Rayleigh method, Cloud calibration method uses the complete attenuation of the transmitter beam by a liquid water cloud to calculate the lidar constant (O'Connor 2004). The main challenge is the selection of accurately measured water clouds. These clouds should not contain any ice crystals and the detector should not get into saturation. The first problem is especially important during winter time and the second problem is especially important for low clouds. Furthermore the overlap function should be known accurately, especially when the water cloud is located at a distance where the overlap between laser beam and telescope field-of-view is still incomplete. In the E-PROFILE pilot network, the Rayleigh calibration is already performed automatically. This demonstration network maked available, in real time, calibrated ALC measurements from 8 instruments of 4 different types in 6 countries. In collaboration with TOPROF and 20 national weathers services, E-PROFILE will provide, in 2017, near real time ALC measurements in most of Europe.

10 CFR 431.134 - Uniform test methods for the measurement of energy and water consumption of automatic commercial...

Code of Federal Regulations, 2013 CFR

2013-01-01

... water consumption of automatic commercial ice makers. 431.134 Section 431.134 Energy DEPARTMENT OF... Automatic Commercial Ice Makers Test Procedures § 431.134 Uniform test methods for the measurement of energy and water consumption of automatic commercial ice makers. (a) Scope. This section provides the test...

10 CFR 431.134 - Uniform test methods for the measurement of energy and water consumption of automatic commercial...

Code of Federal Regulations, 2014 CFR

2014-01-01

... water consumption of automatic commercial ice makers. 431.134 Section 431.134 Energy DEPARTMENT OF... Automatic Commercial Ice Makers Test Procedures § 431.134 Uniform test methods for the measurement of energy and water consumption of automatic commercial ice makers. (a) Scope. This section provides the test...

40 CFR 1065.640 - Flow meter calibration calculations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Flow meter calibration calculations... POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.640 Flow meter calibration calculations. This section describes the calculations for calibrating various flow meters. After...

Finding trap stiffness of optical tweezers using digital filters.

PubMed

Almendarez-Rangel, Pedro; Morales-Cruzado, Beatriz; Sarmiento-Gómez, Erick; Pérez-Gutiérrez, Francisco G

2018-02-01

Obtaining trap stiffness and calibration of the position detection system is the basis of a force measurement using optical tweezers. Both calibration quantities can be calculated using several experimental methods available in the literature. In most cases, stiffness determination and detection system calibration are performed separately, often requiring procedures in very different conditions, and thus confidence of calibration methods is not assured due to possible changes in the environment. In this work, a new method to simultaneously obtain both the detection system calibration and trap stiffness is presented. The method is based on the calculation of the power spectral density of positions through digital filters to obtain the harmonic contributions of the position signal. This method has the advantage of calculating both trap stiffness and photodetector calibration factor from the same dataset in situ. It also provides a direct method to avoid unwanted frequencies that could greatly affect calibration procedure, such as electric noise, for example.

a Contemporary Approach for Evaluation of the best Measurement Capability of a Force Calibration Machine

NASA Astrophysics Data System (ADS)

Kumar, Harish

The present paper discusses the procedure for evaluation of best measurement capability of a force calibration machine. The best measurement capability of force calibration machine is evaluated by a comparison through the precision force transfer standards to the force standard machines. The force transfer standards are calibrated by the force standard machine and then by the force calibration machine by adopting the similar procedure. The results are reported and discussed in the paper and suitable discussion has been made for force calibration machine of 200 kN capacity. Different force transfer standards of nominal capacity 20 kN, 50 kN and 200 kN are used. It is found that there are significant variations in the .uncertainty of force realization by the force calibration machine according to the proposed method in comparison to the earlier method adopted.

Radiometer calibration methods and resulting irradiance differences: Radiometer calibration methods and resulting irradiance differences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Habte, Aron; Sengupta, Manajit; Andreas, Afshin

Accurate solar radiation measured by radiometers depends on instrument performance specifications, installation method, calibration procedure, measurement conditions, maintenance practices, location, and environmental conditions. This study addresses the effect of different calibration methodologies and resulting differences provided by radiometric calibration service providers such as the National Renewable Energy Laboratory (NREL) and manufacturers of radiometers. Some of these methods calibrate radiometers indoors and some outdoors. To establish or understand the differences in calibration methodologies, we processed and analyzed field-measured data from radiometers deployed for 10 months at NREL's Solar Radiation Research Laboratory. These different methods of calibration resulted in a difference ofmore » +/-1% to +/-2% in solar irradiance measurements. Analyzing these differences will ultimately assist in determining the uncertainties of the field radiometer data and will help develop a consensus on a standard for calibration. Further advancing procedures for precisely calibrating radiometers to world reference standards that reduce measurement uncertainties will help the accurate prediction of the output of planned solar conversion projects and improve the bankability of financing solar projects.« less

Effects of line fiducial parameters and beamforming on ultrasound calibration

PubMed Central

Ameri, Golafsoun; Baxter, John S. H.; McLeod, A. Jonathan; Peters, Terry M.; Chen, Elvis C. S.

2017-01-01

Abstract. Ultrasound (US)-guided interventions are often enhanced via integration with an augmented reality environment, a necessary component of which is US calibration. Calibration requires the segmentation of fiducials, i.e., a phantom, in US images. Fiducial localization error (FLE) can decrease US calibration accuracy, which fundamentally affects the total accuracy of the interventional guidance system. Here, we investigate the effects of US image reconstruction techniques as well as phantom material and geometry on US calibration. It was shown that the FLE was reduced by 29% with synthetic transmit aperture imaging compared with conventional B-mode imaging in a Z-bar calibration, resulting in a 10% reduction of calibration error. In addition, an evaluation of a variety of calibration phantoms with different geometrical and material properties was performed. The phantoms included braided wire, plastic straws, and polyvinyl alcohol cryogel tubes with different diameters. It was shown that these properties have a significant effect on calibration error, which is a variable based on US beamforming techniques. These results would have important implications for calibration procedures and their feasibility in the context of image-guided procedures. PMID:28331886

Effects of line fiducial parameters and beamforming on ultrasound calibration.

PubMed

Ameri, Golafsoun; Baxter, John S H; McLeod, A Jonathan; Peters, Terry M; Chen, Elvis C S

2017-01-01

Ultrasound (US)-guided interventions are often enhanced via integration with an augmented reality environment, a necessary component of which is US calibration. Calibration requires the segmentation of fiducials, i.e., a phantom, in US images. Fiducial localization error (FLE) can decrease US calibration accuracy, which fundamentally affects the total accuracy of the interventional guidance system. Here, we investigate the effects of US image reconstruction techniques as well as phantom material and geometry on US calibration. It was shown that the FLE was reduced by 29% with synthetic transmit aperture imaging compared with conventional B-mode imaging in a Z-bar calibration, resulting in a 10% reduction of calibration error. In addition, an evaluation of a variety of calibration phantoms with different geometrical and material properties was performed. The phantoms included braided wire, plastic straws, and polyvinyl alcohol cryogel tubes with different diameters. It was shown that these properties have a significant effect on calibration error, which is a variable based on US beamforming techniques. These results would have important implications for calibration procedures and their feasibility in the context of image-guided procedures.

Uncertainty Analysis of Inertial Model Attitude Sensor Calibration and Application with a Recommended New Calibration Method

NASA Technical Reports Server (NTRS)

Tripp, John S.; Tcheng, Ping

1999-01-01

Statistical tools, previously developed for nonlinear least-squares estimation of multivariate sensor calibration parameters and the associated calibration uncertainty analysis, have been applied to single- and multiple-axis inertial model attitude sensors used in wind tunnel testing to measure angle of attack and roll angle. The analysis provides confidence and prediction intervals of calibrated sensor measurement uncertainty as functions of applied input pitch and roll angles. A comparative performance study of various experimental designs for inertial sensor calibration is presented along with corroborating experimental data. The importance of replicated calibrations over extended time periods has been emphasized; replication provides independent estimates of calibration precision and bias uncertainties, statistical tests for calibration or modeling bias uncertainty, and statistical tests for sensor parameter drift over time. A set of recommendations for a new standardized model attitude sensor calibration method and usage procedures is included. The statistical information provided by these procedures is necessary for the uncertainty analysis of aerospace test results now required by users of industrial wind tunnel test facilities.

Raman water vapor lidar calibration

NASA Astrophysics Data System (ADS)

Landulfo, E.; Da Costa, R. F.; Torres, A. S.; Lopes, F. J. S.; Whiteman, D. N.; Venable, D. D.

2009-09-01

We show here new results of a Raman LIDAR calibration methodology effort putting emphasis in the assessment of the cross-section ratio between water vapor and nitrogen by the use of a calibrated NIST traceable tungsten lamp. Therein we give a step by step procedure of how to employ such equipment by means of a mapping/scanning procedure over the receiving optics of a water vapor Raman LIDAR. This methodology has been independently used at Howard University Raman LIDAR and at IPEN Raman LIDAR what strongly supports its reproducibility and points towards an independently calibration methodology to be carried on within an experiment routine.

Calibration and application of an automated seepage meter for monitoring water flow across the sediment-water interface.

PubMed

Zhu, Tengyi; Fu, Dafang; Jenkinson, Byron; Jafvert, Chad T

2015-04-01

The advective flow of sediment pore water is an important parameter for understanding natural geochemical processes within lake, river, wetland, and marine sediments and also for properly designing permeable remedial sediment caps placed over contaminated sediments. Automated heat pulse seepage meters can be used to measure the vertical component of sediment pore water flow (i.e., vertical Darcy velocity); however, little information on meter calibration as a function of ambient water temperature exists in the literature. As a result, a method with associated equations for calibrating a heat pulse seepage meter as a function of ambient water temperature is fully described in this paper. Results of meter calibration over the temperature range 7.5 to 21.2 °C indicate that errors in accuracy are significant if proper temperature-dependence calibration is not performed. The proposed calibration method allows for temperature corrections to be made automatically in the field at any ambient water temperature. The significance of these corrections is discussed.

Standing on the shoulders of giants: improving medical image segmentation via bias correction.

PubMed

Wang, Hongzhi; Das, Sandhitsu; Pluta, John; Craige, Caryne; Altinay, Murat; Avants, Brian; Weiner, Michael; Mueller, Susanne; Yushkevich, Paul

2010-01-01

We propose a simple strategy to improve automatic medical image segmentation. The key idea is that without deep understanding of a segmentation method, we can still improve its performance by directly calibrating its results with respect to manual segmentation. We formulate the calibration process as a bias correction problem, which is addressed by machine learning using training data. We apply this methodology on three segmentation problems/methods and show significant improvements for all of them.

Microwave Interferometry (90 GHz) for Hall Thruster Plume Density Characterization

DTIC Science & Technology

2005-06-01

Hall thruster . The interferometer has been modified to overcome initial difficulties encountered during the preliminary testing. The modifications include the ability to perform remote and automated calibrations as well as an aluminum enclosure to shield the interferometer from the Hall thruster plume. With these modifications, it will be possible to make unambiguous electron density measurements of the thruster plume as well as to rapidly and automatically calibrate the interferometer to eliminate the effects of signal drift. Due to the versatility

Elixir - how to handle 2 trillion pixels

NASA Astrophysics Data System (ADS)

Magnier, Eugene A.; Cuillandre, Jean-Charles

2002-12-01

The Elixir system at CFHT provides automatic data quality assurance and calibration for the wide-field mosaic imager camera CFH12K. Elixir consists of a variety of tools, including: a real-time analysis suite which runs at the telescope to provide quick feedback to the observers; a detailed analysis of the calibration data; and an automated pipeline for processing data to be distributed to observers. To date, 2.4 × 1012 night-time sky pixels from CFH12K have been processed by the Elixir system.

Automatic detection of solar features in HSOS full-disk solar images using guided filter

NASA Astrophysics Data System (ADS)

Yuan, Fei; Lin, Jiaben; Guo, Jingjing; Wang, Gang; Tong, Liyue; Zhang, Xinwei; Wang, Bingxiang

2018-02-01

A procedure is introduced for the automatic detection of solar features using full-disk solar images from Huairou Solar Observing Station (HSOS), National Astronomical Observatories of China. In image preprocessing, median filter is applied to remove the noises. Guided filter is adopted to enhance the edges of solar features and restrain the solar limb darkening, which is first introduced into the astronomical target detection. Then specific features are detected by Otsu algorithm and further threshold processing technique. Compared with other automatic detection procedures, our procedure has some advantages such as real time and reliability as well as no need of local threshold. Also, it reduces the amount of computation largely, which is benefited from the efficient guided filter algorithm. The procedure has been tested on one month sequences (December 2013) of HSOS full-disk solar images and the result shows that the number of features detected by our procedure is well consistent with the manual one.

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION, CALIBRATION, AND ROUTINE USE OF THE SPECTRACE 9000 FIELD PORTABLE X-RAY FLUORESCENCE ANALYZER (UA-L-10.1)

EPA Science Inventory

The purpose of this SOP is to describe the procedures for operating and calibrating the Spectrace 9000 field portable X-ray fluorescence analyzer. This procedure applies to the determination of metal concentrations in samples during the Arizona NHEXAS project and the Border stud...

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION, CALIBRATION, AND MAINTENANCE OF THE PERKIN-ELMER 5100 PC ATOMIC ABSORPTION SPECTROMETER (BCO-L-5.1)

EPA Science Inventory

The purpose of this SOP is to outline the start-up, calibration, operation, and maintenance procedures for the Perkin-Elmer 5100 PC Atomic Absorption Spectrophotometer (PE 5100). These procedures are used for the determination of the target trace metal, as in soil, house dust, f...

49 CFR 552.12 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Expedited Rulemaking To Establish Dynamic Automatic Suppression System Test Procedures for Federal Motor... subpart, the following definitions apply: (a) Dynamic automatic suppression system (DASS) means a portion of an air bag system that automatically controls whether or not the air bag deploys during a crash by...

30 CFR 57.4761 - Underground shops.

Code of Federal Regulations, 2011 CFR

2011-07-01

... an automatic fire suppression system in conjunction with an alternate escape route. The alternative... core, are acceptable provided that an automatic sprinkler or deluge system is installed that provides... conditions and procedures. (d) Automatic fire suppression system and escape route. If used as an alternative...

30 CFR 57.4761 - Underground shops.

Code of Federal Regulations, 2013 CFR

2013-07-01

... an automatic fire suppression system in conjunction with an alternate escape route. The alternative... core, are acceptable provided that an automatic sprinkler or deluge system is installed that provides... conditions and procedures. (d) Automatic fire suppression system and escape route. If used as an alternative...

30 CFR 57.4761 - Underground shops.

Code of Federal Regulations, 2014 CFR

2014-07-01

... an automatic fire suppression system in conjunction with an alternate escape route. The alternative... core, are acceptable provided that an automatic sprinkler or deluge system is installed that provides... conditions and procedures. (d) Automatic fire suppression system and escape route. If used as an alternative...

30 CFR 57.4761 - Underground shops.

Code of Federal Regulations, 2012 CFR

2012-07-01

... an automatic fire suppression system in conjunction with an alternate escape route. The alternative... core, are acceptable provided that an automatic sprinkler or deluge system is installed that provides... conditions and procedures. (d) Automatic fire suppression system and escape route. If used as an alternative...

40 CFR 90.425 - CVS calibration frequency.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Gaseous Exhaust Test Procedures § 90.425 CVS calibration frequency. Calibrate the CVS positive displacement pump or...

40 CFR 90.425 - CVS calibration frequency.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Gaseous Exhaust Test Procedures § 90.425 CVS calibration frequency. Calibrate the CVS positive displacement pump or...

40 CFR 90.425 - CVS calibration frequency.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Gaseous Exhaust Test Procedures § 90.425 CVS calibration frequency. Calibrate the CVS positive displacement pump or...

40 CFR 90.425 - CVS calibration frequency.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Gaseous Exhaust Test Procedures § 90.425 CVS calibration frequency. Calibrate the CVS positive displacement pump or...

40 CFR 90.425 - CVS calibration frequency.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Gaseous Exhaust Test Procedures § 90.425 CVS calibration frequency. Calibrate the CVS positive displacement pump or...

Development of A Two-Stage Procedure for the Automatic Recognition of Dysfluencies in the Speech of Children Who Stutter: I. Psychometric Procedures Appropriate for Selection of Training Material for Lexical Dysfluency Classifiers

PubMed Central

Howell, Peter; Sackin, Stevie; Glenn, Kazan

2007-01-01

This program of work is intended to develop automatic recognition procedures to locate and assess stuttered dysfluencies. This and the following article together, develop and test recognizers for repetitions and prolongations. The automatic recognizers classify the speech in two stages: In the first, the speech is segmented and in the second the segments are categorized. The units that are segmented are words. Here assessments by human judges on the speech of 12 children who stutter are described using a corresponding procedure. The accuracy of word boundary placement across judges, categorization of the words as fluent, repetition or prolongation, and duration of the different fluency categories are reported. These measures allow reliable instances of repetitions and prolongations to be selected for training and assessing the recognizers in the subsequent paper. PMID:9328878

40 CFR 86.1524 - Carbon dioxide analyzer calibration.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 20 2012-07-01 2012-07-01 false Carbon dioxide analyzer calibration. 86.1524 Section 86.1524 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Test Procedures § 86.1524 Carbon dioxide analyzer calibration. (a) The calibration requirements for the...

40 CFR 86.1524 - Carbon dioxide analyzer calibration.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 19 2014-07-01 2014-07-01 false Carbon dioxide analyzer calibration. 86.1524 Section 86.1524 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Procedures § 86.1524 Carbon dioxide analyzer calibration. (a) The calibration requirements for the dilute...

40 CFR 86.1325-94 - Methane analyzer calibration.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Methane analyzer calibration. 86.1325... Procedures § 86.1325-94 Methane analyzer calibration. Prior to introduction into service and monthly thereafter, the methane analyzer shall be calibrated: (a) Follow the manufacturer's instructions for...

40 CFR 86.1325-94 - Methane analyzer calibration.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 20 2012-07-01 2012-07-01 false Methane analyzer calibration. 86.1325... Procedures § 86.1325-94 Methane analyzer calibration. Prior to introduction into service and monthly thereafter, the methane analyzer shall be calibrated: (a) Follow the manufacturer's instructions for...

40 CFR 86.1325-94 - Methane analyzer calibration.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 20 2013-07-01 2013-07-01 false Methane analyzer calibration. 86.1325... Procedures § 86.1325-94 Methane analyzer calibration. Prior to introduction into service and monthly thereafter, the methane analyzer shall be calibrated: (a) Follow the manufacturer's instructions for...

40 CFR 86.1325-94 - Methane analyzer calibration.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 19 2011-07-01 2011-07-01 false Methane analyzer calibration. 86.1325... Procedures § 86.1325-94 Methane analyzer calibration. Prior to introduction into service and monthly thereafter, the methane analyzer shall be calibrated: (a) Follow the manufacturer's instructions for...

Four years of Landsat-7 on-orbit geometric calibration and performance

USGS Publications Warehouse

Lee, D.S.; Storey, James C.; Choate, M.J.; Hayes, R.W.

2004-01-01

Unlike its predecessors, Landsat-7 has undergone regular geometric and radiometric performance monitoring and calibration since launch in April 1999. This ongoing activity, which includes issuing quarterly updates to calibration parameters, has generated a wealth of geometric performance data over the four-year on-orbit period of operations. A suite of geometric characterization (measurement and evaluation procedures) and calibration (procedures to derive improved estimates of instrument parameters) methods are employed by the Landsat-7 Image Assessment System to maintain the geometric calibration and to track specific aspects of geometric performance. These include geodetic accuracy, band-to-band registration accuracy, and image-to-image registration accuracy. These characterization and calibration activities maintain image product geometric accuracy at a high level - by monitoring performance to determine when calibration is necessary, generating new calibration parameters, and verifying that new parameters achieve desired improvements in accuracy. Landsat-7 continues to meet and exceed all geometric accuracy requirements, although aging components have begun to affect performance.

40 CFR 205.174 - Remedial orders.

Code of Federal Regulations, 2014 CFR

2014-07-01

... calibrated with the acoustic calibrator as often as is necessary throughout testing to maintain the accuracy... TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycle Exhaust Systems § 205.174 Remedial orders. The... Noise Emission Test Procedures Appendix I-1 to Subparts D and E—Test Procedure for Street and off-road...

Adaptive inferential sensors based on evolving fuzzy models.

PubMed

Angelov, Plamen; Kordon, Arthur

2010-04-01

A new technique to the design and use of inferential sensors in the process industry is proposed in this paper, which is based on the recently introduced concept of evolving fuzzy models (EFMs). They address the challenge that the modern process industry faces today, namely, to develop such adaptive and self-calibrating online inferential sensors that reduce the maintenance costs while keeping the high precision and interpretability/transparency. The proposed new methodology makes possible inferential sensors to recalibrate automatically, which reduces significantly the life-cycle efforts for their maintenance. This is achieved by the adaptive and flexible open-structure EFM used. The novelty of this paper lies in the following: (1) the overall concept of inferential sensors with evolving and self-developing structure from the data streams; (2) the new methodology for online automatic selection of input variables that are most relevant for the prediction; (3) the technique to detect automatically a shift in the data pattern using the age of the clusters (and fuzzy rules); (4) the online standardization technique used by the learning procedure of the evolving model; and (5) the application of this innovative approach to several real-life industrial processes from the chemical industry (evolving inferential sensors, namely, eSensors, were used for predicting the chemical properties of different products in The Dow Chemical Company, Freeport, TX). It should be noted, however, that the methodology and conclusions of this paper are valid for the broader area of chemical and process industries in general. The results demonstrate that well-interpretable and with-simple-structure inferential sensors can automatically be designed from the data stream in real time, which predict various process variables of interest. The proposed approach can be used as a basis for the development of a new generation of adaptive and evolving inferential sensors that can address the challenges of the modern advanced process industry.

76 FR 62644 - Request To Consider Automatic Termination Controls

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-11

... Consider Automatic Termination Controls AGENCY: Office of the General Counsel, Department of Energy (DOE... dryer test procedure be amended to address the effectiveness of automatic termination controls such as moisture and temperature sensor controls. Public comment is requested on whether DOE should grant the...

AUTOMATIC CALIBRATION OF A STOCHASTIC-LAGRANGIAN TRANSPORT MODEL (SLAM)

EPA Science Inventory

Numerical models are a useful tool in evaluating and designing NAPL remediation systems. Traditional constitutive finite difference and finite element models are complex and expensive to apply. For this reason, this paper presents the application of a simplified stochastic-Lagran...

Spectral method for the correction of the Cerenkov light effect in plastic scintillation detectors: A comparison study of calibration procedures and validation in Cerenkov light-dominated situations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guillot, Mathieu; Gingras, Luc; Archambault, Louis

2011-04-15

Purpose: The purposes of this work were: (1) To determine if a spectral method can accurately correct the Cerenkov light effect in plastic scintillation detectors (PSDs) for situations where the Cerenkov light is dominant over the scintillation light and (2) to develop a procedural guideline for accurately determining the calibration factors of PSDs. Methods: The authors demonstrate, by using the equations of the spectral method, that the condition for accurately correcting the effect of Cerenkov light is that the ratio of the two calibration factors must be equal to the ratio of the Cerenkov light measured within the two differentmore » spectral regions used for analysis. Based on this proof, the authors propose two new procedures to determine the calibration factors of PSDs, which were designed to respect this condition. A PSD that consists of a cylindrical polystyrene scintillating fiber (1.6 mm{sup 3}) coupled to a plastic optical fiber was calibrated by using these new procedures and the two reference procedures described in the literature. To validate the extracted calibration factors, relative dose profiles and output factors for a 6 MV photon beam from a medical linac were measured with the PSD and an ionization chamber. Emphasis was placed on situations where the Cerenkov light is dominant over the scintillation light and on situations dissimilar to the calibration conditions. Results: The authors found that the accuracy of the spectral method depends on the procedure used to determine the calibration factors of the PSD and on the attenuation properties of the optical fiber used. The results from the relative dose profile measurements showed that the spectral method can correct the Cerenkov light effect with an accuracy level of 1%. The results obtained also indicate that PSDs measure output factors that are lower than those measured with ionization chambers for square field sizes larger than 25x25 cm{sup 2}, in general agreement with previously published Monte Carlo results. Conclusions: The authors conclude that the spectral method can be used to accurately correct the Cerenkov light effect in PSDs. The authors confirmed the importance of maximizing the difference of Cerenkov light production between calibration measurements. The authors also found that the attenuation of the optical fiber, which is assumed to be constant in the original formulation of the spectral method, may cause a variation of the calibration factors in some experimental setups.« less

40 CFR 86.125-94 - Methane analyzer calibration.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Methane analyzer calibration. 86.125... Complete Heavy-Duty Vehicles; Test Procedures § 86.125-94 Methane analyzer calibration. Prior to introduction into service and monthly thereafter, the methane analyzer shall be calibrated: (a) Follow the...

40 CFR 86.125-94 - Methane analyzer calibration.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Methane analyzer calibration. 86.125... Complete Heavy-Duty Vehicles; Test Procedures § 86.125-94 Methane analyzer calibration. Prior to introduction into service and monthly thereafter, the methane analyzer shall be calibrated: (a) Follow the...

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION, CALIBRATION, AND MAINTENANCE OF THE THERMO JARRELL ASH ICAP 61-975 PLASMA ATOMCOMP EMISSION SPECTROMETER (BCO-L-8.0)

EPA Science Inventory

The purpose of this SOP is to detail the procedures for the start-up, operation, calibration, shut-down, and maintenance of the Thermo Jarrell Ash ICAP 61-975 Plasma AtomComp Emission Spectrometer. These procedures were used in determining the trace target metals Al, As, Ba, Cd,...

Development of a Portable Torque Wrench Tester

NASA Astrophysics Data System (ADS)

Wang, Y.; Zhang, Q.; Gou, C.; Su, D.

2018-03-01

A portable torque wrench tester (PTWT) with calibration range from 0.5 Nm to 60 Nm has been developed and evaluated for periodic or on-site calibration of setting type torque wrenches, indicating type torque wrenches and hand torque screwdrivers. The PTWT is easy to carry with weight about 10 kg, simple and efficient operation and energy saving with an automatic loading and calibrating system. The relative expanded uncertainty of torque realized by the PTWT was estimated to be 0.8%, with the coverage factor k=2. A comparison experiment has been done between the PTWT and a reference torque standard at our laboratory. The consistency between these two devices under the claimed uncertainties was verified.

40 CFR 91.316 - Hydrocarbon analyzer calibration.

Code of Federal Regulations, 2010 CFR

2010-07-01

... operating adjustment using the appropriate fuel (see § 91.312) and purified synthetic air or zero-grade nitrogen. (2) One of the following procedures is required for FID or HFID optimization: (i) The procedure...) Initial and periodic calibration. Prior to introduction into service and monthly thereafter, or within one...

16 CFR 1209.8 - Procedure for calibration of radiation instrumentation.

Code of Federal Regulations, 2012 CFR

2012-01-01

... SAFETY ACT REGULATIONS INTERIM SAFETY STANDARD FOR CELLULOSE INSULATION The Standard § 1209.8 Procedure... radiation pyrometer. Repeat for each temperature. (b) Total heat flux meter. The total flux meter shall be... meter. This latter calibration shall make use of the radiant panel tester as the heat source...

16 CFR 1209.8 - Procedure for calibration of radiation instrumentation.

Code of Federal Regulations, 2014 CFR

2014-01-01

... SAFETY ACT REGULATIONS INTERIM SAFETY STANDARD FOR CELLULOSE INSULATION The Standard § 1209.8 Procedure... radiation pyrometer. Repeat for each temperature. (b) Total heat flux meter. The total flux meter shall be... meter. This latter calibration shall make use of the radiant panel tester as the heat source...

16 CFR 1209.8 - Procedure for calibration of radiation instrumentation.

Code of Federal Regulations, 2011 CFR

2011-01-01

... SAFETY ACT REGULATIONS INTERIM SAFETY STANDARD FOR CELLULOSE INSULATION The Standard § 1209.8 Procedure... radiation pyrometer. Repeat for each temperature. (b) Total heat flux meter. The total flux meter shall be... meter. This latter calibration shall make use of the radiant panel tester as the heat source...

16 CFR 1209.8 - Procedure for calibration of radiation instrumentation.

Code of Federal Regulations, 2010 CFR

2010-01-01

... SAFETY ACT REGULATIONS INTERIM SAFETY STANDARD FOR CELLULOSE INSULATION The Standard § 1209.8 Procedure... radiation pyrometer. Repeat for each temperature. (b) Total heat flux meter. The total flux meter shall be... meter. This latter calibration shall make use of the radiant panel tester as the heat source...

Video-guided calibration of an augmented reality mobile C-arm.

PubMed

Chen, Xin; Naik, Hemal; Wang, Lejing; Navab, Nassir; Fallavollita, Pascal

2014-11-01

The augmented reality (AR) fluoroscope augments an X-ray image by video and provides the surgeon with a real-time in situ overlay of the anatomy. The overlay alignment is crucial for diagnostic and intra-operative guidance, so precise calibration of the AR fluoroscope is required. The first and most complex step of the calibration procedure is the determination of the X-ray source position. Currently, this is achieved using a biplane phantom with movable metallic rings on its top layer and fixed X-ray opaque markers on its bottom layer. The metallic rings must be moved to positions where at least two pairs of rings and markers are isocentric in the X-ray image. The current "trial and error" calibration process currently requires acquisition of many X-ray images, a task that is both time consuming and radiation intensive. An improved process was developed and tested for C-arm calibration. Video guidance was used to drive the calibration procedure to minimize both X-ray exposure and the time involved. For this, a homography between X-ray and video images is estimated. This homography is valid for the plane at which the metallic rings are positioned and is employed to guide the calibration procedure. Eight users having varying calibration experience (i.e., 2 experts, 2 semi-experts, 4 novices) were asked to participate in the evaluation. The video-guided technique reduced the number of intra-operative X-ray calibration images by 89% and decreased the total time required by 59%. A video-based C-arm calibration method has been developed that improves the usability of the AR fluoroscope with a friendlier interface, reduced calibration time and clinically acceptable radiation doses.

The Sixth SeaWiFS/SIMBIOS Intercalibration Round-Robin Experiment (SIRREX-6)

NASA Technical Reports Server (NTRS)

Riley, Thomas; Bailey, Sean

1998-01-01

For the sixth Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) Intercalibration Round-Robin Experiment (SIRREX-6), NASA personnel carried the same four Satlantic in-water radiometers to nine separate laboratories and calibrated them. Two of the sensors were seven-channel radiance heads and two were seven-channel irradiance heads. The calibration and data reduction procedures used at each site followed that laboratory's normal procedures. The reference lamps normally used for the calibration of these types of instruments by the various laboratories were also used for this experiment. NASA personnel processed the data to produce calibration parameters from the various laboratories

A New Approach to the Internal Calibration of Reverberation-Mapping Spectra

NASA Astrophysics Data System (ADS)

Fausnaugh, M. M.

2017-02-01

We present a new procedure for the internal (night-to-night) calibration of timeseries spectra, with specific applications to optical AGN reverberation mapping data. The traditional calibration technique assumes that the narrow [O iii] λ5007 emission-line profile is constant in time; given a reference [O iii] λ5007 line profile, nightly spectra are aligned by fitting for a wavelength shift, a flux rescaling factor, and a change in the spectroscopic resolution. We propose the following modifications to this procedure: (1) we stipulate a constant spectral resolution for the final calibrated spectra, (2) we employ a more flexible model for changes in the spectral resolution, and (3) we use a Bayesian modeling framework to assess uncertainties in the calibration. In a test case using data for MCG+08-11-011, these modifications result in a calibration precision of ˜1 millimagnitude, which is approximately a factor of five improvement over the traditional technique. At this level, other systematic issues (e.g., the nightly sensitivity functions and Feii contamination) limit the final precision of the observed light curves. We implement this procedure as a python package (mapspec), which we make available to the community.

Velocity precision measurements using laser Doppler anemometry

NASA Astrophysics Data System (ADS)

Dopheide, D.; Taux, G.; Narjes, L.

1985-07-01

A Laser Doppler Anemometer (LDA) was calibrated to determine its applicability to high pressure measurements (up to 10 bars) for industrial purposes. The measurement procedure with LDA and the experimental computerized layouts are presented. The calibration procedure is based on absolute accuracy of Doppler frequency and calibration of interference strip intervals. A four-quadrant detector allows comparison of the interference strip distance measurements and computer profiles. Further development of LDA is recommended to increase accuracy (0.1% inaccuracy) and to apply the method industrially.

40 CFR 86.124-78 - Carbon dioxide analyzer calibration.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Carbon dioxide analyzer calibration... Complete Heavy-Duty Vehicles; Test Procedures § 86.124-78 Carbon dioxide analyzer calibration. Prior to its introduction into service and monthly thereafter the NDIR carbon dioxide analyzer shall be calibrated: (a...

40 CFR 86.124-78 - Carbon dioxide analyzer calibration.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 19 2014-07-01 2014-07-01 false Carbon dioxide analyzer calibration... Complete Heavy-Duty Vehicles; Test Procedures § 86.124-78 Carbon dioxide analyzer calibration. Prior to its introduction into service and monthly thereafter the NDIR carbon dioxide analyzer shall be calibrated: (a...

40 CFR 86.124-78 - Carbon dioxide analyzer calibration.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Carbon dioxide analyzer calibration... Complete Heavy-Duty Vehicles; Test Procedures § 86.124-78 Carbon dioxide analyzer calibration. Prior to its introduction into service and monthly thereafter the NDIR carbon dioxide analyzer shall be calibrated: (a...

40 CFR 86.519-90 - Constant volume sampler calibration.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Constant volume sampler calibration... Regulations for 1978 and Later New Motorcycles; Test Procedures § 86.519-90 Constant volume sampler calibration. (a) The CVS (Constant Volume Sampler) is calibrated using an accurate flowmeter and restrictor...

40 CFR 86.519-90 - Constant volume sampler calibration.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Constant volume sampler calibration... Regulations for 1978 and Later New Motorcycles; Test Procedures § 86.519-90 Constant volume sampler calibration. (a) The CVS (Constant Volume Sampler) is calibrated using an accurate flowmeter and restrictor...

40 CFR 86.519-90 - Constant volume sampler calibration.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Constant volume sampler calibration... Regulations for 1978 and Later New Motorcycles; Test Procedures § 86.519-90 Constant volume sampler calibration. (a) The CVS (Constant Volume Sampler) is calibrated using an accurate flowmeter and restrictor...

40 CFR 86.519-90 - Constant volume sampler calibration.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 19 2014-07-01 2014-07-01 false Constant volume sampler calibration... Regulations for 1978 and Later New Motorcycles; Test Procedures § 86.519-90 Constant volume sampler calibration. (a) The CVS (Constant Volume Sampler) is calibrated using an accurate flowmeter and restrictor...

40 CFR 86.519-90 - Constant volume sampler calibration.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Constant volume sampler calibration... Regulations for 1978 and Later New Motorcycles; Test Procedures § 86.519-90 Constant volume sampler calibration. (a) The CVS (Constant Volume Sampler) is calibrated using an accurate flowmeter and restrictor...

40 CFR 86.516-90 - Calibrations, frequency and overview.

Code of Federal Regulations, 2011 CFR

2011-07-01

... be checked at a frequency consistent with observed column life or when the indicator of the column... Regulations for 1978 and Later New Motorcycles; Test Procedures § 86.516-90 Calibrations, frequency and...) At least monthly or after any maintenance which could alter calibration, the following calibrations...

40 CFR 86.516-90 - Calibrations, frequency and overview.

Code of Federal Regulations, 2010 CFR

2010-07-01

... be checked at a frequency consistent with observed column life or when the indicator of the column... Regulations for 1978 and Later New Motorcycles; Test Procedures § 86.516-90 Calibrations, frequency and...) At least monthly or after any maintenance which could alter calibration, the following calibrations...

Self-calibration method for rotating laser positioning system using interscanning technology and ultrasonic ranging.

PubMed

Wu, Jun; Yu, Zhijing; Zhuge, Jingchang

2016-04-01

A rotating laser positioning system (RLPS) is an efficient measurement method for large-scale metrology. Due to multiple transmitter stations, which consist of a measurement network, the position relationship of these stations must be first calibrated. However, with such auxiliary devices such as a laser tracker, scale bar, and complex calibration process, the traditional calibration methods greatly reduce the measurement efficiency. This paper proposes a self-calibration method for RLPS, which can automatically obtain the position relationship. The method is implemented through interscanning technology by using a calibration bar mounted on the transmitter station. Each bar is composed of three RLPS receivers and one ultrasonic sensor whose coordinates are known in advance. The calibration algorithm is mainly based on multiplane and distance constraints and is introduced in detail through a two-station mathematical model. The repeated experiments demonstrate that the coordinate measurement uncertainty of spatial points by using this method is about 0.1 mm, and the accuracy experiments show that the average coordinate measurement deviation is about 0.3 mm compared with a laser tracker. The accuracy can meet the requirements of most applications, while the calibration efficiency is significantly improved.

Camera calibration: active versus passive targets

NASA Astrophysics Data System (ADS)

Schmalz, Christoph; Forster, Frank; Angelopoulou, Elli

2011-11-01

Traditionally, most camera calibrations rely on a planar target with well-known marks. However, the localization error of the marks in the image is a source of inaccuracy. We propose the use of high-resolution digital displays as active calibration targets to obtain more accurate calibration results for all types of cameras. The display shows a series of coded patterns to generate correspondences between world points and image points. This has several advantages. No special calibration hardware is necessary because suitable displays are practically ubiquitious. The method is fully automatic, and no identification of marks is necessary. For a coding scheme based on phase shifting, the localization accuracy is approximately independent of the camera's focus settings. Most importantly, higher accuracy can be achieved compared to passive targets, such as printed checkerboards. A rigorous evaluation is performed to substantiate this claim. Our active target method is compared to standard calibrations using a checkerboard target. We perform camera, calibrations with different combinations of displays, cameras, and lenses, as well as with simulated images and find markedly lower reprojection errors when using active targets. For example, in a stereo reconstruction task, the accuracy of a system calibrated with an active target is five times better.

Auto-calibrated scanning-angle prism-type total internal reflection microscopy for nanometer-precision axial position determination and optional variable-illumination-depth pseudo total internal reflection microscopy

DOEpatents

Fang, Ning; Sun, Wei

2015-04-21

A method, apparatus, and system for improved VA-TIRFM microscopy. The method comprises automatically controlled calibration of one or more laser sources by precise control of presentation of each laser relative a sample for small incremental changes of incident angle over a range of critical TIR angles. The calibration then allows precise scanning of the sample for any of those calibrated angles for higher and more accurate resolution, and better reconstruction of the scans for super resolution reconstruction of the sample. Optionally the system can be controlled for incident angles of the excitation laser at sub-critical angles for pseudo TIRFM. Optionally both above-critical angle and sub critical angle measurements can be accomplished with the same system.

Automatic Phase Calibration for RF Cavities using Beam-Loading Signals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edelen, J. P.; Chase, B. E.

Precise calibration of the cavity phase signals is necessary for the operation of any particle accelerator. For many systems this requires human in the loop adjustments based on measurements of the beam parameters downstream. Some recent work has developed a scheme for the calibration of the cavity phase using beam measurements and beam-loading however this scheme is still a multi-step process that requires heavy automation or human in the loop. In this paper we analyze a new scheme that uses only RF signals reacting to beam-loading to calculate the phase of the beam relative to the cavity. This technique couldmore » be used in slow control loops to provide real-time adjustment of the cavity phase calibration without human intervention thereby increasing the stability and reliability of the accelerator.« less

Use of «MLCM3» software for flash flood forecasting

NASA Astrophysics Data System (ADS)

Sokolova, Daria; Kuzmin, Vadim

2017-04-01

Accurate and timely flash floods forecasting, especially, in ungauged and poorly gauged basins, is one of the most important and challenging problems to be solved by the international hydrological community.In changing climate and variable anthropogenic impact on river basins, as well as due to low density of surface hydrometeorological network, flash flood forecasting based on "traditional" physically based, or conceptual, or statistical hydrological models often becomes inefficient. Unfortunately, most of river basins in Russia are poorly gauged or ungauged; besides, lack of hydrogeological data is quite typical, especially, in remote regions of Siberia. However, the developing economy and population safety make us to issue warnings based on reliable forecasts. For this purpose, a new hydrological model, MLCM3 (Multi-Layer Conceptual Model, 3rd generation) has been developed in the Russian State Hydrometeorological University. MLCM3 is a "rainfall-runoff"model with flexible structure and high level of"conceptualization".Model forcing includes precipitation and evaporation data basically coming from NWP model output. Water comes to the outlet through several layers; their number as well as two parameters (thickness and infiltration rate) for each of them, surface flow velocity (when the top layer is full of water) are optimized. The main advantage of the MLCM3, in comparison to the Sacramento Soil Moisture Accounting Model (SAC-SMA), Australian Water Balance Model (AWBM), Soil Moisture Accounting and Routing (SMAR) model and similar models, is that its automatic calibration is very fast and efficient with less volume of information. For instance, in comparison to SAC-SMA, which is calibrated using either Shuffled Complex Evolution algorithm (SCE-UA), or Stepwise Line Search (SLS), automatically calibrated MLCM3 gives better or comparable results without using any "a priori" data or essential processor resources. This advantage allows using the MLCM3 for very fast streamflow prediction in many basins. When assimilated NWP model output data used to force the model, the forecasts accuracy is quite acceptable and enough for automatic warning. Also please note that, in comparison to the 2nd generation of the model, a very useful new option has been added. Now it is possible to set upvariable infiltration rate of the top layer; this option is quite promising in terms of spring floods modeling. (At the moment it is necessary to perform more numerical experiments with snow melting; obtained results will be reported later). Recently new software for MLCM3 was developed. It contains quite usual and understandable options. Formation of the model "input" can be done in manual and automatic mode. Manual or automatic calibration of the model can be performed using either purposely developed for this model optimization algorithm, or Nelder-Mead's one, or SLS. For the model calibration, the multi-scale objective function (MSOF) proposed by Koren is used. It has shown its very high efficiency when model forcing data have high level of uncertainty. Other types of objective functions also can be used, such as mean square error and Nash-Sutcliff criterion. The model showed good results in more than 50 tested basins.

Anatomical frame identification and reconstruction for repeatable lower limb joint kinematics estimates.

PubMed

Donati, Marco; Camomilla, Valentina; Vannozzi, Giuseppe; Cappozzo, Aurelio

2008-07-19

The quantitative description of joint mechanics during movement requires the reconstruction of the position and orientation of selected anatomical axes with respect to a laboratory reference frame. These anatomical axes are identified through an ad hoc anatomical calibration procedure and their position and orientation are reconstructed relative to bone-embedded frames normally derived from photogrammetric marker positions and used to describe movement. The repeatability of anatomical calibration, both within and between subjects, is crucial for kinematic and kinetic end results. This paper illustrates an anatomical calibration approach, which does not require anatomical landmark manual palpation, described in the literature to be prone to great indeterminacy. This approach allows for the estimate of subject-specific bone morphology and automatic anatomical frame identification. The experimental procedure consists of digitization through photogrammetry of superficial points selected over the areas of the bone covered with a thin layer of soft tissue. Information concerning the location of internal anatomical landmarks, such as a joint center obtained using a functional approach, may also be added. The data thus acquired are matched with the digital model of a deformable template bone. Consequently, the repeatability of pelvis, knee and hip joint angles is determined. Five volunteers, each of whom performed five walking trials, and six operators, with no specific knowledge of anatomy, participated in the study. Descriptive statistics analysis was performed during upright posture, showing a limited dispersion of all angles (less than 3 deg) except for hip and knee internal-external rotation (6 deg and 9 deg, respectively). During level walking, the ratio of inter-operator and inter-trial error and an absolute subject-specific repeatability were assessed. For pelvic and hip angles, and knee flexion-extension the inter-operator error was equal to the inter-trial error-the absolute error ranging from 0.1 deg to 0.9 deg. Knee internal-external rotation and ab-adduction showed, on average, inter-operator errors, which were 8% and 28% greater than the relevant inter-trial errors, respectively. The absolute error was in the range 0.9-2.9 deg.

Equipment and New Products

ERIC Educational Resources Information Center

Poitras, Adrian W., Ed.

1973-01-01

The following items are discussed: Digital Counters and Readout Devices, Automatic Burette Outfits, Noise Exposure System, Helium-Cadmium Laser, New pH Buffers and Flip-Top Dispenser, Voltage Calibrator Transfer Standard, Photomicrographic Stereo Zoom Microscope, Portable pH Meter, Micromanipulators, The Snuffer, Electronic Top-Loading Balances,…

Network design and quality checks in automatic orientation of close-range photogrammetric blocks.

PubMed

Dall'Asta, Elisa; Thoeni, Klaus; Santise, Marina; Forlani, Gianfranco; Giacomini, Anna; Roncella, Riccardo

2015-04-03

Due to the recent improvements of automatic measurement procedures in photogrammetry, multi-view 3D reconstruction technologies are becoming a favourite survey tool. Rapidly widening structure-from-motion (SfM) software packages offer significantly easier image processing workflows than traditional photogrammetry packages. However, while most orientation and surface reconstruction strategies will almost always succeed in any given task, estimating the quality of the result is, to some extent, still an open issue. An assessment of the precision and reliability of block orientation is necessary and should be included in every processing pipeline. Such a need was clearly felt from the results of close-range photogrammetric surveys of in situ full-scale and laboratory-scale experiments. In order to study the impact of the block control and the camera network design on the block orientation accuracy, a series of Monte Carlo simulations was performed. Two image block configurations were investigated: a single pseudo-normal strip and a circular highly-convergent block. The influence of surveying and data processing choices, such as the number and accuracy of the ground control points, autofocus and camera calibration was investigated. The research highlights the most significant aspects and processes to be taken into account for adequate in situ and laboratory surveys, when modern SfM software packages are used, and evaluates their effect on the quality of the results of the surface reconstruction.

A Patch-Based Method for Repetitive and Transient Event Detection in Fluorescence Imaging

PubMed Central

Boulanger, Jérôme; Gidon, Alexandre; Kervran, Charles; Salamero, Jean

2010-01-01

Automatic detection and characterization of molecular behavior in large data sets obtained by fast imaging in advanced light microscopy become key issues to decipher the dynamic architectures and their coordination in the living cell. Automatic quantification of the number of sudden and transient events observed in fluorescence microscopy is discussed in this paper. We propose a calibrated method based on the comparison of image patches expected to distinguish sudden appearing/vanishing fluorescent spots from other motion behaviors such as lateral movements. We analyze the performances of two statistical control procedures and compare the proposed approach to a frame difference approach using the same controls on a benchmark of synthetic image sequences. We have then selected a molecular model related to membrane trafficking and considered real image sequences obtained in cells stably expressing an endocytic-recycling trans-membrane protein, the Langerin-YFP, for validation. With this model, we targeted the efficient detection of fast and transient local fluorescence concentration arising in image sequences from a data base provided by two different microscopy modalities, wide field (WF) video microscopy using maximum intensity projection along the axial direction and total internal reflection fluorescence microscopy. Finally, the proposed detection method is briefly used to statistically explore the effect of several perturbations on the rate of transient events detected on the pilot biological model. PMID:20976222

Virtobot--a multi-functional robotic system for 3D surface scanning and automatic post mortem biopsy.

PubMed

Ebert, Lars Christian; Ptacek, Wolfgang; Naether, Silvio; Fürst, Martin; Ross, Steffen; Buck, Ursula; Weber, Stefan; Thali, Michael

2010-03-01

The Virtopsy project, a multi-disciplinary project that involves forensic science, diagnostic imaging, computer science, automation technology, telematics and biomechanics, aims to develop new techniques to improve the outcome of forensic investigations. This paper presents a new approach in the field of minimally invasive virtual autopsy for a versatile robotic system that is able to perform three-dimensional (3D) surface scans as well as post mortem image-guided soft tissue biopsies. The system consists of an industrial six-axis robot with additional extensions (i.e. a linear axis to increase working space, a tool-changing system and a dedicated safety system), a multi-slice CT scanner with equipment for angiography, a digital photogrammetry and 3D optical surface-scanning system, a 3D tracking system, and a biopsy end effector for automatic needle placement. A wax phantom was developed for biopsy accuracy tests. Surface scanning times were significantly reduced (scanning times cut in half, calibration three times faster). The biopsy module worked with an accuracy of 3.2 mm. Using the Virtobot, the surface-scanning procedure could be standardized and accelerated. The biopsy module is accurate enough for use in biopsies in a forensic setting. The Virtobot can be utilized for several independent tasks in the field of forensic medicine, and is sufficiently versatile to be adapted to different tasks in the future. (c) 2009 John Wiley & Sons, Ltd.

Properties of star clusters - I. Automatic distance and extinction estimates

NASA Astrophysics Data System (ADS)

Buckner, Anne S. M.; Froebrich, Dirk

2013-12-01

Determining star cluster distances is essential to analyse their properties and distribution in the Galaxy. In particular, it is desirable to have a reliable, purely photometric distance estimation method for large samples of newly discovered cluster candidates e.g. from the Two Micron All Sky Survey, the UK Infrared Deep Sky Survey Galactic Plane Survey and VVV. Here, we establish an automatic method to estimate distances and reddening from near-infrared photometry alone, without the use of isochrone fitting. We employ a decontamination procedure of JHK photometry to determine the density of stars foreground to clusters and a galactic model to estimate distances. We then calibrate the method using clusters with known properties. This allows us to establish distance estimates with better than 40 per cent accuracy. We apply our method to determine the extinction and distance values to 378 known open clusters and 397 cluster candidates from the list of Froebrich, Scholz & Raftery. We find that the sample is biased towards clusters of a distance of approximately 3 kpc, with typical distances between 2 and 6 kpc. Using the cluster distances and extinction values, we investigate how the average extinction per kiloparsec distance changes as a function of the Galactic longitude. We find a systematic dependence that can be approximated by AH(l) [mag kpc-1] = 0.10 + 0.001 × |l - 180°|/° for regions more than 60° from the Galactic Centre.

A new calibration code for the JET polarimeter.

PubMed

Gelfusa, M; Murari, A; Gaudio, P; Boboc, A; Brombin, M; Orsitto, F P; Giovannozzi, E

2010-05-01

An equivalent model of JET polarimeter is presented, which overcomes the drawbacks of previous versions of the fitting procedures used to provide calibrated results. First of all the signal processing electronics has been simulated, to confirm that it is still working within the original specifications. Then the effective optical path of both the vertical and lateral chords has been implemented to produce the calibration curves. The principle approach to the model has allowed obtaining a unique procedure which can be applied to any manual calibration and remains constant until the following one. The optical model of the chords is then applied to derive the plasma measurements. The results are in good agreement with the estimates of the most advanced full wave propagation code available and have been benchmarked with other diagnostics. The devised procedure has proved to work properly also for the most recent campaigns and high current experiments.

10 CFR 431.133 - Materials incorporated by reference.

Code of Federal Regulations, 2014 CFR

2014-01-01

... AND INDUSTRIAL EQUIPMENT Automatic Commercial Ice Makers Test Procedures § 431.133 Materials..., (“AHRI 810”), Performance Rating of Automatic Commercial Ice-Makers, March 2011; IBR approved for §§ 431... Automatic Ice Makers, (including Errata Sheets issued April 8, 2010 and April 21, 2010), approved January 28...

10 CFR 431.133 - Materials incorporated by reference.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AND INDUSTRIAL EQUIPMENT Automatic Commercial Ice Makers Test Procedures § 431.133 Materials..., (“AHRI 810”), Performance Rating of Automatic Commercial Ice-Makers, March 2011; IBR approved for §§ 431... Automatic Ice Makers, (including Errata Sheets issued April 8, 2010 and April 21, 2010), approved January 28...

Improved infra-red procedure for the evaluation of calibrating units.

DOT National Transportation Integrated Search

2011-01-04

Introduction. The NHTSA Model Specifications for Calibrating Units for Breath : Alcohol Testers (FR 72 34742-34748) requires that calibration units submitted for : inclusion on the NHTSA Conforming Products List for such devices be evaluated using : ...

Wind Tunnel Balance Calibration: Are 1,000,000 Data Points Enough?

NASA Technical Reports Server (NTRS)

Rhew, Ray D.; Parker, Peter A.

2016-01-01

Measurement systems are typically calibrated based on standard practices established by a metrology standards laboratory, for example the National Institute for Standards and Technology (NIST), or dictated by an organization's metrology manual. Therefore, the calibration is designed and executed according to an established procedure. However, for many aerodynamic research measurement systems a universally accepted standard, traceable approach does not exist. Therefore, a strategy for how to develop a calibration protocol is left to the developer or user to define based on experience and recommended practice in their respective industry. Wind tunnel balances are one such measurement system. Many different calibration systems, load schedules and procedures have been developed for balances with little consensus on a recommended approach. Especially lacking is guidance the number of calibration data points needed. Regrettably, the number of data points tends to be correlated with the perceived quality of the calibration. Often, the number of data points is associated with ones ability to generate the data rather than by a defined need in support of measurement objectives. Hence the title of the paper was conceived to challenge recent observations in the wind tunnel balance community that shows an ever increasing desire for more data points per calibration absent of guidance to determine when there are enough. This paper presents fundamental concepts and theory to aid in the development of calibration procedures for wind tunnel balances and provides a framework that is generally applicable to the characterization and calibration of other measurement systems. Questions that need to be answered are for example: What constitutes an adequate calibration? How much data are needed in the calibration? How good is the calibration? This paper will assist a practitioner in answering these questions by presenting an underlying theory on how to evaluate a calibration based on objective measures. This will enable the developer and user to design calibrations with quantified performance in terms of their capability to meet the user's objectives and a basis for comparing existing calibrations that may have been developed in an ad-hoc manner.

Algorithm for automatic analysis of electro-oculographic data

PubMed Central

2013-01-01

Background Large amounts of electro-oculographic (EOG) data, recorded during electroencephalographic (EEG) measurements, go underutilized. We present an automatic, auto-calibrating algorithm that allows efficient analysis of such data sets. Methods The auto-calibration is based on automatic threshold value estimation. Amplitude threshold values for saccades and blinks are determined based on features in the recorded signal. The performance of the developed algorithm was tested by analyzing 4854 saccades and 213 blinks recorded in two different conditions: a task where the eye movements were controlled (saccade task) and a task with free viewing (multitask). The results were compared with results from a video-oculography (VOG) device and manually scored blinks. Results The algorithm achieved 93% detection sensitivity for blinks with 4% false positive rate. The detection sensitivity for horizontal saccades was between 98% and 100%, and for oblique saccades between 95% and 100%. The classification sensitivity for horizontal and large oblique saccades (10 deg) was larger than 89%, and for vertical saccades larger than 82%. The duration and peak velocities of the detected horizontal saccades were similar to those in the literature. In the multitask measurement the detection sensitivity for saccades was 97% with a 6% false positive rate. Conclusion The developed algorithm enables reliable analysis of EOG data recorded both during EEG and as a separate metrics. PMID:24160372

Algorithm for automatic analysis of electro-oculographic data.

PubMed

Pettersson, Kati; Jagadeesan, Sharman; Lukander, Kristian; Henelius, Andreas; Haeggström, Edward; Müller, Kiti

2013-10-25

Large amounts of electro-oculographic (EOG) data, recorded during electroencephalographic (EEG) measurements, go underutilized. We present an automatic, auto-calibrating algorithm that allows efficient analysis of such data sets. The auto-calibration is based on automatic threshold value estimation. Amplitude threshold values for saccades and blinks are determined based on features in the recorded signal. The performance of the developed algorithm was tested by analyzing 4854 saccades and 213 blinks recorded in two different conditions: a task where the eye movements were controlled (saccade task) and a task with free viewing (multitask). The results were compared with results from a video-oculography (VOG) device and manually scored blinks. The algorithm achieved 93% detection sensitivity for blinks with 4% false positive rate. The detection sensitivity for horizontal saccades was between 98% and 100%, and for oblique saccades between 95% and 100%. The classification sensitivity for horizontal and large oblique saccades (10 deg) was larger than 89%, and for vertical saccades larger than 82%. The duration and peak velocities of the detected horizontal saccades were similar to those in the literature. In the multitask measurement the detection sensitivity for saccades was 97% with a 6% false positive rate. The developed algorithm enables reliable analysis of EOG data recorded both during EEG and as a separate metrics.

A Laser-Based Measuring System for Online Quality Control of Car Engine Block.

PubMed

Li, Xing-Qiang; Wang, Zhong; Fu, Lu-Hua

2016-11-08

For online quality control of car engine production, pneumatic measurement instrument plays an unshakeable role in measuring diameters inside engine block because of its portability and high-accuracy. To the limitation of its measuring principle, however, the working space between the pneumatic device and measured surface is too small to require manual operation. This lowers the measuring efficiency and becomes an obstacle to perform automatic measurement. In this article, a high-speed, automatic measuring system is proposed to take the place of pneumatic devices by using a laser-based measuring unit. The measuring unit is considered as a set of several measuring modules, where each of them acts like a single bore gauge and is made of four laser triangulation sensors (LTSs), which are installed on different positions and in opposite directions. The spatial relationship among these LTSs was calibrated before measurements. Sampling points from measured shaft holes can be collected by the measuring unit. A unified mathematical model was established for both calibration and measurement. Based on the established model, the relative pose between the measuring unit and measured workpiece does not impact the measuring accuracy. This frees the measuring unit from accurate positioning or adjustment, and makes it possible to realize fast and automatic measurement. The proposed system and method were finally validated by experiments.

All-automatic swimmer tracking system based on an optimized scaled composite JTC technique

NASA Astrophysics Data System (ADS)

Benarab, D.; Napoléon, T.; Alfalou, A.; Verney, A.; Hellard, P.

2016-04-01

In this paper, an all-automatic optimized JTC based swimmer tracking system is proposed and evaluated on real video database outcome from national and international swimming competitions (French National Championship, Limoges 2015, FINA World Championships, Barcelona 2013 and Kazan 2015). First, we proposed to calibrate the swimming pool using the DLT algorithm (Direct Linear Transformation). DLT calculates the homography matrix given a sufficient set of correspondence points between pixels and metric coordinates: i.e. DLT takes into account the dimensions of the swimming pool and the type of the swim. Once the swimming pool is calibrated, we extract the lane. Then we apply a motion detection approach to detect globally the swimmer in this lane. Next, we apply our optimized Scaled Composite JTC which consists of creating an adapted input plane that contains the predicted region and the head reference image. This latter is generated using a composite filter of fin images chosen from the database. The dimension of this reference will be scaled according to the ratio between the head's dimension and the width of the swimming lane. Finally, applying the proposed approach improves the performances of our previous tracking method by adding a detection module in order to achieve an all-automatic swimmer tracking system.

Astrometrica: Astrometric data reduction of CCD images

NASA Astrophysics Data System (ADS)

Raab, Herbert

2012-03-01

Astrometrica is an interactive software tool for scientific grade astrometric data reduction of CCD images. The current version of the software is for the Windows 32bit operating system family. Astrometrica reads FITS (8, 16 and 32 bit integer files) and SBIG image files. The size of the images is limited only by available memory. It also offers automatic image calibration (Dark Frame and Flat Field correction), automatic reference star identification, automatic moving object detection and identification, and access to new-generation star catalogs (PPMXL, UCAC 3 and CMC-14), in addition to online help and other features. Astrometrica is shareware, available for use for a limited period of time (100 days) for free; special arrangements can be made for educational projects.

Automatic exposure control calibration and optimisation for abdomen, pelvis and lumbar spine imaging with an Agfa computed radiography system.

PubMed

Moore, C S; Wood, T J; Avery, G; Balcam, S; Needler, L; Joshi, H; Saunderson, J R; Beavis, A W

2016-11-07

The use of three physical image quality metrics, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and mean effective noise equivalent quanta (eNEQ m ) have recently been examined by our group for their appropriateness in the calibration of an automatic exposure control (AEC) device for chest radiography with an Agfa computed radiography (CR) imaging system. This study uses the same methodology but investigates AEC calibration for abdomen, pelvis and spine CR imaging. AEC calibration curves were derived using a simple uniform phantom (equivalent to 20 cm water) to ensure each metric was held constant across the tube voltage range. Each curve was assessed for its clinical appropriateness by generating computer simulated abdomen, pelvis and spine images (created from real patient CT datasets) with appropriate detector air kermas for each tube voltage, and grading these against reference images which were reconstructed at detector air kermas correct for the constant detector dose indicator (DDI) curve currently programmed into the AEC device. All simulated images contained clinically realistic projected anatomy and were scored by experienced image evaluators. Constant DDI and CNR curves did not provide optimized performance but constant eNEQ m and SNR did, with the latter being the preferred calibration metric given that it is easier to measure in practice. This result was consistent with the previous investigation for chest imaging with AEC devices. Medical physicists may therefore use a simple and easily accessible uniform water equivalent phantom to measure the SNR image quality metric described here when calibrating AEC devices for abdomen, pelvis and spine imaging with Agfa CR systems, in the confidence that clinical image quality will be sufficient for the required clinical task. However, to ensure appropriate levels of detector air kerma the advice of expert image evaluators must be sought.

Automatic exposure control calibration and optimisation for abdomen, pelvis and lumbar spine imaging with an Agfa computed radiography system

NASA Astrophysics Data System (ADS)

Moore, C. S.; Wood, T. J.; Avery, G.; Balcam, S.; Needler, L.; Joshi, H.; Saunderson, J. R.; Beavis, A. W.

2016-11-01

The use of three physical image quality metrics, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and mean effective noise equivalent quanta (eNEQm) have recently been examined by our group for their appropriateness in the calibration of an automatic exposure control (AEC) device for chest radiography with an Agfa computed radiography (CR) imaging system. This study uses the same methodology but investigates AEC calibration for abdomen, pelvis and spine CR imaging. AEC calibration curves were derived using a simple uniform phantom (equivalent to 20 cm water) to ensure each metric was held constant across the tube voltage range. Each curve was assessed for its clinical appropriateness by generating computer simulated abdomen, pelvis and spine images (created from real patient CT datasets) with appropriate detector air kermas for each tube voltage, and grading these against reference images which were reconstructed at detector air kermas correct for the constant detector dose indicator (DDI) curve currently programmed into the AEC device. All simulated images contained clinically realistic projected anatomy and were scored by experienced image evaluators. Constant DDI and CNR curves did not provide optimized performance but constant eNEQm and SNR did, with the latter being the preferred calibration metric given that it is easier to measure in practice. This result was consistent with the previous investigation for chest imaging with AEC devices. Medical physicists may therefore use a simple and easily accessible uniform water equivalent phantom to measure the SNR image quality metric described here when calibrating AEC devices for abdomen, pelvis and spine imaging with Agfa CR systems, in the confidence that clinical image quality will be sufficient for the required clinical task. However, to ensure appropriate levels of detector air kerma the advice of expert image evaluators must be sought.

[Fundamental aspects for accrediting medical equipment calibration laboratories in Colombia].

PubMed

Llamosa-Rincón, Luis E; López-Isaza, Giovanni A; Villarreal-Castro, Milton F

2010-02-01

Analysing the fundamental methodological aspects which should be considered when drawing up calibration procedure for electro-medical equipment, thereby permitting international standard-based accreditation of electro-medical metrology laboratories in Colombia. NTC-ISO-IEC 17025:2005 and GTC-51-based procedures for calibrating electro-medical equipment were implemented and then used as patterns. The mathematical model for determining the estimated uncertainty value when calibrating electro-medical equipment for accreditation by the Electrical Variable Metrology Laboratory's Electro-medical Equipment Calibration Area accredited in compliance with Superintendence of Industry and Commerce Resolution 25771 May 26th 2009 consists of two equations depending on the case; they are: E = (Ai + sigmaAi) - (Ar + sigmaAr + deltaAr1) and E = (Ai + sigmaAi) - (Ar + sigmaA + deltaAr1). The mathematical modelling implemented for measuring uncertainty in the Universidad Tecnológica de Pereira's Electrical Variable Metrology Laboratory (Electro-medical Equipment Calibration Area) will become a good guide for calibration initiated in other laboratories in Colombia and Latin-America.

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR CALIBRATION AND OPERATION OF BALANCES (UA-L-1.2)

EPA Science Inventory

The purpose of this SOP is to describe the procedures used when calibrating and operating balances during the Arizona NHEXAS project and the "Border" study. Keywords: lab; equipment; balances.

The National Human Exposure Assessment Survey (NHEXAS) is a federal interagency rese...

Application of the Reference Method Isotope Dilution Gas Chromatography Mass Spectrometry (ID/GC/MS) to Establish Metrological Traceability for Calibration and Control of Blood Glucose Test Systems

PubMed Central

Andreis, Elisabeth; Küllmer, Kai

2014-01-01

Self-monitoring of blood glucose (BG) by means of handheld BG systems is a cornerstone in diabetes therapy. The aim of this article is to describe a procedure with proven traceability for calibration and evaluation of BG systems to guarantee reliable BG measurements. Isotope dilution gas chromatography mass spectrometry (ID/GC/MS) is a method that fulfills all requirements to be used in a higher-order reference measurement procedure. However, this method is not applicable for routine measurements because of the time-consuming sample preparation. A hexokinase method with perchloric acid (PCA) sample pretreatment is used in a measurement procedure for such purposes. This method is directly linked to the ID/GC/MS method by calibration with a glucose solution that has an ID/GC/MS-determined target value. BG systems are calibrated with whole blood samples. The glucose levels in such samples are analyzed by this ID/GC/MS-linked hexokinase method to establish traceability to higher-order reference material. For method comparison, the glucose concentrations in 577 whole blood samples were measured using the PCA-hexokinase method and the ID/GC/MS method; this resulted in a mean deviation of 0.1%. The mean deviation between BG levels measured in >500 valid whole blood samples with BG systems and the ID/GC/MS was 1.1%. BG systems allow a reliable glucose measurement if a true reference measurement procedure, with a noninterrupted traceability chain using ID/GC/MS linked hexokinase method for calibration of BG systems, is implemented. Systems should be calibrated by means of a traceable and defined measurement procedure to avoid bias. PMID:24876614

PSA discriminator influence on (222)Rn efficiency detection in waters by liquid scintillation counting.

PubMed

Stojković, Ivana; Todorović, Nataša; Nikolov, Jovana; Tenjović, Branislava

2016-06-01

A procedure for the (222)Rn determination in aqueous samples using liquid scintillation counting (LSC) was evaluated and optimized. Measurements were performed by ultra-low background spectrometer Quantulus 1220™ equipped with PSA (Pulse Shape Analysis) circuit which discriminates alpha/beta spectra. Since calibration procedure is carried out with (226)Ra standard, which has both alpha and beta progenies, it is clear that PSA discriminator has vital importance in order to provide precise spectra separation. Improvement of calibration procedure was done through investigation of PSA discriminator level and, consequentially, the activity of (226)Ra calibration standard influence on (222)Rn efficiency detection. Quench effects on generated spectra i.e. determination of radon efficiency detection were also investigated with quench calibration curve obtained. Radon determination in waters based on modified procedure according to the activity of (226)Ra standard used, dependent on PSA setup, was evaluated with prepared (226)Ra solution samples and drinking water samples with assessment of measurement uncertainty variation included. Copyright © 2016 Elsevier Ltd. All rights reserved.

Technical Note: Procedure for the calibration and validation of kilo-voltage cone-beam CT models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vilches-Freixas, Gloria; Létang, Jean Michel; Rit,

2016-09-15

Purpose: The aim of this work is to propose a general and simple procedure for the calibration and validation of kilo-voltage cone-beam CT (kV CBCT) models against experimental data. Methods: The calibration and validation of the CT model is a two-step procedure: the source model then the detector model. The source is described by the direction dependent photon energy spectrum at each voltage while the detector is described by the pixel intensity value as a function of the direction and the energy of incident photons. The measurements for the source consist of a series of dose measurements in air performedmore » at each voltage with varying filter thicknesses and materials in front of the x-ray tube. The measurements for the detector are acquisitions of projection images using the same filters and several tube voltages. The proposed procedure has been applied to calibrate and assess the accuracy of simple models of the source and the detector of three commercial kV CBCT units. If the CBCT system models had been calibrated differently, the current procedure would have been exclusively used to validate the models. Several high-purity attenuation filters of aluminum, copper, and silver combined with a dosimeter which is sensitive to the range of voltages of interest were used. A sensitivity analysis of the model has also been conducted for each parameter of the source and the detector models. Results: Average deviations between experimental and theoretical dose values are below 1.5% after calibration for the three x-ray sources. The predicted energy deposited in the detector agrees with experimental data within 4% for all imaging systems. Conclusions: The authors developed and applied an experimental procedure to calibrate and validate any model of the source and the detector of a CBCT unit. The present protocol has been successfully applied to three x-ray imaging systems. The minimum requirements in terms of material and equipment would make its implementation suitable in most clinical environments.« less

Force Measurement Services at Kebs: AN Overview of Equipment, Procedures and Uncertainty

NASA Astrophysics Data System (ADS)

Bangi, J. O.; Maranga, S. M.; Nganga, S. P.; Mutuli, S. M.

This paper describes the facilities, instrumentation and procedures currently used in the force laboratory at the Kenya Bureau of Standards (KEBS) for force measurement services. The laboratory uses the Force Calibration Machine (FCM) to calibrate force-measuring instruments. The FCM derives its traceability via comparisons using reference transfer force transducers calibrated by the Force Standard Machines (FSM) of a National Metrology Institute (NMI). The force laboratory is accredited to ISO/IEC 17025 by the Germany Accreditation Body (DAkkS). The accredited measurement scope of the laboratory is 1 MN to calibrate force transducers in both compression and tension modes. ISO 376 procedures are used while calibrating force transducers. The KEBS reference transfer standards have capacities of 10, 50, 300 and 1000 kN to cover the full range of the FCM. The uncertainty in the forces measured by the FCM were reviewed and determined in accordance to the new EURAMET calibration guide. The relative expanded uncertainty of force W realized by FCM was evaluated in a range from 10 kN-1 MN, and was found to be 5.0 × 10-4 with the coverage factor k being equal to 2. The overall normalized error (En) of the comparison results was also found to be less than 1. The accredited Calibration and Measurement Capability (CMC) of the KEBS force laboratory was based on the results of those intercomparisons. The FCM enables KEBS to provide traceability for the calibration of class ‘1’ force instruments as per the ISO 376.

40 CFR 92.121 - Oxides of nitrogen analyzer calibration and check.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Oxides of nitrogen analyzer calibration... Procedures § 92.121 Oxides of nitrogen analyzer calibration and check. (a) Quench checks; NO X analyzer. (1... performed in step in paragraph (a)(3)(i) this section. (b) Oxides of nitrogen analyzer calibration. (1...

Color measurement of plastics - From compounding via pelletizing, up to injection molding and extrusion

NASA Astrophysics Data System (ADS)

Botos, J.; Murail, N.; Heidemeyer, P.; Kretschmer, K.; Ulmer, B.; Zentgraf, T.; Bastian, M.; Hochrein, T.

2014-05-01

The typical offline color measurement on injection molded or pressed specimens is a very expensive and time-consuming process. In order to optimize the productivity and quality, it is desirable to measure the color already during the production. Therefore several systems have been developed to monitor the color e.g. on melts, strands, pellets, the extrudate or injection molded part already during the process. Different kinds of inline, online and atline methods with their respective advantages and disadvantages will be compared. The criteria are e.g. the testing time, which ranges from real-time to some minutes, the required calibration procedure, the spectral resolution and the final measuring precision. The latter ranges between 0.05 to 0.5 in the CIE L*a*b* system depending on the particular measurement system. Due to the high temperatures in typical plastics processes thermochromism of polymers and dyes has to be taken into account. This effect can influence the color value in the magnitude of some 10% and is barely understood so far. Different suitable methods to compensate thermochromic effects during compounding or injection molding by using calibration curves or artificial neural networks are presented. Furthermore it is even possible to control the color during extrusion and compounding almost in real-time. The goal is a specific developed software for adjusting the color recipe automatically with the final objective of a closed-loop control.

Characterization of the Exradin W1 scintillator for use in radiotherapy.

PubMed

Carrasco, P; Jornet, N; Jordi, O; Lizondo, M; Latorre-Musoll, A; Eudaldo, T; Ruiz, A; Ribas, M

2015-01-01

To evaluate the main characteristics of the Exradin W1 scintillator as a dosimeter and to estimate measurement uncertainties when used in radiotherapy. We studied the calibration procedure, energy and modality dependence, short-term repeatability, dose-response linearity, angular dependence, temperature dependence, time to reach thermal equilibrium, dose-rate dependence, water-equivalent depth of the effective measurement point, and long-term stability. An uncertainty budget was derived for relative and absolute dose measurements in photon and electron beams. Exradin W1 showed a temperature dependence of -0.225% °C(-1). The loss of sensitivity with accumulated dose decreased with use. The sensitivity of Exradin W1 was energy independent for high-energy photon and electron beams. All remaining dependencies of Exradin W1 were around or below 0.5%, leading to an uncertainty budget of about 1%. When a dual channel electrometer with automatic trigger was not used, timing effects became significant, increasing uncertainties by one order of magnitude. The Exradin W1 response is energy independent for high energy x-rays and electron beams, and only one calibration coefficient is needed. A temperature correction factor should be applied to keep uncertainties around 2% for absolute dose measurements and around 1% for relative measurements in high-energy photon and electron beams. The Exradin W1 scintillator is an excellent alternative to detectors such as diodes for relative dose measurements.

Mass measurement errors of Fourier-transform mass spectrometry (FTMS): distribution, recalibration, and application.

PubMed

Zhang, Jiyang; Ma, Jie; Dou, Lei; Wu, Songfeng; Qian, Xiaohong; Xie, Hongwei; Zhu, Yunping; He, Fuchu

2009-02-01

The hybrid linear trap quadrupole Fourier-transform (LTQ-FT) ion cyclotron resonance mass spectrometer, an instrument with high accuracy and resolution, is widely used in the identification and quantification of peptides and proteins. However, time-dependent errors in the system may lead to deterioration of the accuracy of these instruments, negatively influencing the determination of the mass error tolerance (MET) in database searches. Here, a comprehensive discussion of LTQ/FT precursor ion mass error is provided. On the basis of an investigation of the mass error distribution, we propose an improved recalibration formula and introduce a new tool, FTDR (Fourier-transform data recalibration), that employs a graphic user interface (GUI) for automatic calibration. It was found that the calibration could adjust the mass error distribution to more closely approximate a normal distribution and reduce the standard deviation (SD). Consequently, we present a new strategy, LDSF (Large MET database search and small MET filtration), for database search MET specification and validation of database search results. As the name implies, a large-MET database search is conducted and the search results are then filtered using the statistical MET estimated from high-confidence results. By applying this strategy to a standard protein data set and a complex data set, we demonstrate the LDSF can significantly improve the sensitivity of the result validation procedure.

The Gaia spectrophotometric standard stars survey: II. Instrumental effects of six ground-based observing campaigns

NASA Astrophysics Data System (ADS)

Altavilla, G.; Marinoni, S.; Pancino, E.; Galleti, S.; Ragaini, S.; Bellazzini, M.; Cocozza, G.; Bragaglia, A.; Carrasco, J. M.; Castro, A.; Di Fabrizio, L.; Federici, L.; Figueras, F.; Gebran, M.; Jordi, C.; Masana, E.; Schuster, W.; Valentini, G.; Voss, H.

2015-08-01

The Gaia SpectroPhotometric Standard Stars (SPSS) survey started in 2006, was awarded almost 450 observing nights and accumulated almost 100 000 raw data frames with both photometric and spectroscopic observations. Such large observational effort requires careful, homogeneous, and automatic data reduction and quality control procedures. In this paper, we quantitatively evaluate instrumental effects that might have a significant (i.e., ≥ 1 %) impact on the Gaia SPSS flux calibration. The measurements involve six different instruments, monitored over the eight years of observations dedicated to the Gaia flux standards campaigns: DOLORES@TNG in La Palma, EFOSC2@NTT and ROSS@REM in La Silla, CAFOS@2.2 m in Calar Alto, BFOSC@Cassini in Loiano, and LaRuca@1.5 m in San Pedro Mártir. We examine and quantitatively evaluate the following effects: CCD linearity and shutter times, calibration frames stability, lamp flexures, second order contamination, light polarization, and fringing. We present methods to correct for the relevant effects which can be applied to a wide range of observational projects at similar instruments. Based on data obtained with BFOSC@Cassini in Loiano, Italy; EFOSC2@NTT in La Silla, Chile; DOLORES@TNG in La Palma, Spain; CAFOS@2.2 m in Calar Alto, Spain; LaRuca@1.5 m in San Pedro Mártir, Mexico (see acknowledgements for more details).

Issues concerning international comparison of free-field calibrations of acoustical standards

NASA Astrophysics Data System (ADS)

Nedzelnitsky, Victor

2002-11-01

Primary free-field calibrations of laboratory standard microphones by the reciprocity method establish these microphones as reference standard devices for calibrating working standard microphones, other measuring microphones, and practical instruments such as sound level meters and personal sound exposure meters (noise dosimeters). These primary, secondary, and other calibrations are indispensable to the support of regulatory requirements, standards, and product characterization and quality control procedures important for industry, commerce, health, and safety. International Electrotechnical Commission (IEC) Technical Committee 29 Electroacoustics produces international documentary standards, including standards for primary and secondary free-field calibration and measurement procedures and their critically important application to practical instruments. This paper addresses some issues concerning calibrations, standards activities, and the international key comparison of primary free-field calibrations of IEC-type LS2 laboratory standard microphones that is being planned by the Consultative Committee for Acoustics, Ultrasound, and Vibration (CCAUV) of the International Committee for Weights and Measures (CIPM). This comparison will include free-field calibrations by the reciprocity method at participating major national metrology laboratories throughout the world.

Statistical photocalibration of photodetectors for radiometry without calibrated light sources

NASA Astrophysics Data System (ADS)

Yielding, Nicholas J.; Cain, Stephen C.; Seal, Michael D.

2018-01-01

Calibration of CCD arrays for identifying bad pixels and achieving nonuniformity correction is commonly accomplished using dark frames. This kind of calibration technique does not achieve radiometric calibration of the array since only the relative response of the detectors is computed. For this, a second calibration is sometimes utilized by looking at sources with known radiances. This process can be used to calibrate photodetectors as long as a calibration source is available and is well-characterized. A previous attempt at creating a procedure for calibrating a photodetector using the underlying Poisson nature of the photodetection required calculations of the skewness of the photodetector measurements. Reliance on the third moment of measurement meant that thousands of samples would be required in some cases to compute that moment. A photocalibration procedure is defined that requires only first and second moments of the measurements. The technique is applied to image data containing a known light source so that the accuracy of the technique can be surmised. It is shown that the algorithm can achieve accuracy of nearly 2.7% of the predicted number of photons using only 100 frames of image data.

Using genetic algorithms to achieve an automatic and global optimization of analogue methods for statistical downscaling of precipitation

NASA Astrophysics Data System (ADS)

Horton, Pascal; Weingartner, Rolf; Obled, Charles; Jaboyedoff, Michel

2017-04-01

Analogue methods (AMs) rely on the hypothesis that similar situations, in terms of atmospheric circulation, are likely to result in similar local or regional weather conditions. These methods consist of sampling a certain number of past situations, based on different synoptic-scale meteorological variables (predictors), in order to construct a probabilistic prediction for a local weather variable of interest (predictand). They are often used for daily precipitation prediction, either in the context of real-time forecasting, reconstruction of past weather conditions, or future climate impact studies. The relationship between predictors and predictands is defined by several parameters (predictor variable, spatial and temporal windows used for the comparison, analogy criteria, and number of analogues), which are often calibrated by means of a semi-automatic sequential procedure that has strong limitations. AMs may include several subsampling levels (e.g. first sorting a set of analogs in terms of circulation, then restricting to those with similar moisture status). The parameter space of the AMs can be very complex, with substantial co-dependencies between the parameters. Thus, global optimization techniques are likely to be necessary for calibrating most AM variants, as they can optimize all parameters of all analogy levels simultaneously. Genetic algorithms (GAs) were found to be successful in finding optimal values of AM parameters. They allow taking into account parameters inter-dependencies, and selecting objectively some parameters that were manually selected beforehand (such as the pressure levels and the temporal windows of the predictor variables), and thus obviate the need of assessing a high number of combinations. The performance scores of the optimized methods increased compared to reference methods, and this even to a greater extent for days with high precipitation totals. The resulting parameters were found to be relevant and spatially coherent. Moreover, they were obtained automatically and objectively, which reduces efforts invested in exploration attempts when adapting the method to a new region or for a new predictand. In addition, the approach allowed for new degrees of freedom, such as a weighting between the pressure levels, and non overlapping spatial windows. Genetic algorithms were then used further in order to automatically select predictor variables and analogy criteria. This resulted in interesting outputs, providing new predictor-criterion combinations. However, some limitations of the approach were encountered, and the need of the expert input is likely to remain necessary. Nevertheless, letting GAs exploring a dataset for the best predictor for a predictand of interest is certainly a useful tool, particularly when applied for a new predictand or a new region under different climatic characteristics.

A system for extracting 3-dimensional measurements from a stereo pair of TV cameras

NASA Technical Reports Server (NTRS)

Yakimovsky, Y.; Cunningham, R.

1976-01-01

Obtaining accurate three-dimensional (3-D) measurement from a stereo pair of TV cameras is a task requiring camera modeling, calibration, and the matching of the two images of a real 3-D point on the two TV pictures. A system which models and calibrates the cameras and pairs the two images of a real-world point in the two pictures, either manually or automatically, was implemented. This system is operating and provides three-dimensional measurements resolution of + or - mm at distances of about 2 m.

21 CFR 211.68 - Automatic, mechanical, and electronic equipment.

Code of Federal Regulations, 2010 CFR

2010-04-01

... SERVICES (CONTINUED) DRUGS: GENERAL CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS... satisfactorily, may be used in the manufacture, processing, packing, and holding of a drug product. If such... designed to assure proper performance. Written records of those calibration checks and inspections shall be...

Estimating Mutual Information for High-to-Low Calibration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michaud, Isaac James; Williams, Brian J.; Weaver, Brian Phillip

Presentation shows that KSG 2 is superior to KSG 1 because it scales locally automatically; KSG estimators are limited to a maximum MI due to sample size; LNC extends the capability of KSG without onerous assumptions; iLNC allows LNC to estimate information gain.

A stepwise, multi-objective, multi-variable parameter optimization method for the APEX model

USDA-ARS?s Scientific Manuscript database

Proper parameterization enables hydrological models to make reliable estimates of non-point source pollution for effective control measures. The automatic calibration of hydrologic models requires significant computational power limiting its application. The study objective was to develop and eval...

Comparison of automatic procedures in the selection of peaks over threshold in flood frequency analysis: A Canadian case study in the context of climate change

NASA Astrophysics Data System (ADS)

Durocher, M.; Mostofi Zadeh, S.; Burn, D. H.; Ashkar, F.

2017-12-01

Floods are one of the most costly hazards and frequency analysis of river discharges is an important part of the tools at our disposal to evaluate their inherent risks and to provide an adequate response. In comparison to the common examination of annual streamflow maximums, peaks over threshold (POT) is an interesting alternative that makes better use of the available information by including more than one flood event per year (on average). However, a major challenge is the selection of a satisfactory threshold above which peaks are assumed to respect certain conditions necessary for an adequate estimation of the risk. Additionally, studies have shown that POT is also a valuable approach to investigate the evolution of flood regimes in the context of climate change. Recently, automatic procedures for the selection of the threshold were suggested to guide that important choice, which otherwise rely on graphical tools and expert judgment. Furthermore, having an automatic procedure that is objective allows for quickly repeating the analysis on a large number of samples, which is useful in the context of large databases or for uncertainty analysis based on a resampling approach. This study investigates the impact of considering such procedures in a case study including many sites across Canada. A simulation study is conducted to evaluate the bias and predictive power of the automatic procedures in similar conditions as well as investigating the power of derived nonstationarity tests. The results obtained are also evaluated in the light of expert judgments established in a previous study. Ultimately, this study provides a thorough examination of the considerations that need to be addressed when conducting POT analysis using automatic threshold selection.

10 CFR 431.242 - Test Procedures [Reserved

Code of Federal Regulations, 2011 CFR

2011-01-01

... upstream of the draft control device of an individual, automatically operated, fossil fuel-fired appliance... intended for installation in the venting system of an individual, automatically operated, fossil fuel-fired...

10 CFR 431.242 - Test Procedures [Reserved

Code of Federal Regulations, 2010 CFR

2010-01-01

... upstream of the draft control device of an individual, automatically operated, fossil fuel-fired appliance... intended for installation in the venting system of an individual, automatically operated, fossil fuel-fired...

a Novel Approach to Camera Calibration Method for Smart Phones Under Road Environment

NASA Astrophysics Data System (ADS)

Lee, Bijun; Zhou, Jian; Ye, Maosheng; Guo, Yuan

2016-06-01

Monocular vision-based lane departure warning system has been increasingly used in advanced driver assistance systems (ADAS). By the use of the lane mark detection and identification, we proposed an automatic and efficient camera calibration method for smart phones. At first, we can detect the lane marker feature in a perspective space and calculate edges of lane markers in image sequences. Second, because of the width of lane marker and road lane is fixed under the standard structural road environment, we can automatically build a transformation matrix between perspective space and 3D space and get a local map in vehicle coordinate system. In order to verify the validity of this method, we installed a smart phone in the `Tuzhi' self-driving car of Wuhan University and recorded more than 100km image data on the road in Wuhan. According to the result, we can calculate the positions of lane markers which are accurate enough for the self-driving car to run smoothly on the road.

Calibration of Viking imaging system pointing, image extraction, and optical navigation measure

NASA Technical Reports Server (NTRS)

Breckenridge, W. G.; Fowler, J. W.; Morgan, E. M.

1977-01-01

Pointing control and knowledge accuracy of Viking Orbiter science instruments is controlled by the scan platform. Calibration of the scan platform and the imaging system was accomplished through mathematical models. The calibration procedure and results obtained for the two Viking spacecraft are described. Included are both ground and in-flight scan platform calibrations, and the additional calibrations unique to optical navigation.

Automatic processing influences free recall: converging evidence from the process dissociation procedure and remember-know judgments.

PubMed

McCabe, David P; Roediger, Henry L; Karpicke, Jeffrey D

2011-04-01

Dual-process theories of retrieval suggest that controlled and automatic processing contribute to memory performance. Free recall tests are often considered pure measures of recollection, assessing only the controlled process. We report two experiments demonstrating that automatic processes also influence free recall. Experiment 1 used inclusion and exclusion tasks to estimate recollection and automaticity in free recall, adopting a new variant of the process dissociation procedure. Dividing attention during study selectively reduced the recollection estimate but did not affect the automatic component. In Experiment 2, we replicated the results of Experiment 1, and subjects additionally reported remember-know-guess judgments during recall in the inclusion condition. In the latter task, dividing attention during study reduced remember judgments for studied items, but know responses were unaffected. Results from both methods indicated that free recall is partly driven by automatic processes. Thus, we conclude that retrieval in free recall tests is not driven solely by conscious recollection (or remembering) but also by automatic influences of the same sort believed to drive priming on implicit memory tests. Sometimes items come to mind without volition in free recall.

Shaping electromagnetic waves using software-automatically-designed metasurfaces.

PubMed

Zhang, Qian; Wan, Xiang; Liu, Shuo; Yuan Yin, Jia; Zhang, Lei; Jun Cui, Tie

2017-06-15

We present a fully digital procedure of designing reflective coding metasurfaces to shape reflected electromagnetic waves. The design procedure is completely automatic, controlled by a personal computer. In details, the macro coding units of metasurface are automatically divided into several types (e.g. two types for 1-bit coding, four types for 2-bit coding, etc.), and each type of the macro coding units is formed by discretely random arrangement of micro coding units. By combining an optimization algorithm and commercial electromagnetic software, the digital patterns of the macro coding units are optimized to possess constant phase difference for the reflected waves. The apertures of the designed reflective metasurfaces are formed by arranging the macro coding units with certain coding sequence. To experimentally verify the performance, a coding metasurface is fabricated by automatically designing two digital 1-bit unit cells, which are arranged in array to constitute a periodic coding metasurface to generate the required four-beam radiations with specific directions. Two complicated functional metasurfaces with circularly- and elliptically-shaped radiation beams are realized by automatically designing 4-bit macro coding units, showing excellent performance of the automatic designs by software. The proposed method provides a smart tool to realize various functional devices and systems automatically.

Calibration of Low Cost Digital Camera Using Data from Simultaneous LIDAR and Photogrammetric Surveys

NASA Astrophysics Data System (ADS)

Mitishita, E.; Debiasi, P.; Hainosz, F.; Centeno, J.

2012-07-01

Digital photogrammetric products from the integration of imagery and lidar datasets are a reality nowadays. When the imagery and lidar surveys are performed together and the camera is connected to the lidar system, a direct georeferencing can be applied to compute the exterior orientation parameters of the images. Direct georeferencing of the images requires accurate interior orientation parameters to perform photogrammetric application. Camera calibration is a procedure applied to compute the interior orientation parameters (IOPs). Calibration researches have established that to obtain accurate IOPs, the calibration must be performed with same or equal condition that the photogrammetric survey is done. This paper shows the methodology and experiments results from in situ self-calibration using a simultaneous images block and lidar dataset. The calibration results are analyzed and discussed. To perform this research a test field was fixed in an urban area. A set of signalized points was implanted on the test field to use as the check points or control points. The photogrammetric images and lidar dataset of the test field were taken simultaneously. Four strips of flight were used to obtain a cross layout. The strips were taken with opposite directions of flight (W-E, E-W, N-S and S-N). The Kodak DSC Pro SLR/c digital camera was connected to the lidar system. The coordinates of the exposition station were computed from the lidar trajectory. Different layouts of vertical control points were used in the calibration experiments. The experiments use vertical coordinates from precise differential GPS survey or computed by an interpolation procedure using the lidar dataset. The positions of the exposition stations are used as control points in the calibration procedure to eliminate the linear dependency of the group of interior and exterior orientation parameters. This linear dependency happens, in the calibration procedure, when the vertical images and flat test field are used. The mathematic correlation of the interior and exterior orientation parameters are analyzed and discussed. The accuracies of the calibration experiments are, as well, analyzed and discussed.

Peristaltic pump-based low range pressure sensor calibration system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vinayakumar, K. B.; Department of Electronic Systems Engineering, Indian Institute of Science, Bangalore 5600012; Naveen Kumar, G.

2015-11-15

Peristaltic pumps were normally used to pump liquids in several chemical and biological applications. In the present study, a peristaltic pump was used to pressurize the chamber (positive as well negative pressures) using atmospheric air. In the present paper, we discuss the development and performance study of an automatic pressurization system to calibrate low range (millibar) pressure sensors. The system includes a peristaltic pump, calibrated pressure sensor (master sensor), pressure chamber, and the control electronics. An in-house developed peristaltic pump was used to pressurize the chamber. A closed loop control system has been developed to detect and adjust the pressuremore » leaks in the chamber. The complete system has been integrated into a portable product. The system performance has been studied for a step response and steady state errors. The system is portable, free from oil contaminants, and consumes less power compared to existing pressure calibration systems. The veracity of the system was verified by calibrating an unknown diaphragm based pressure sensor and the results obtained were satisfactory.« less

Peristaltic pump-based low range pressure sensor calibration system

NASA Astrophysics Data System (ADS)

Vinayakumar, K. B.; Naveen Kumar, G.; Nayak, M. M.; Dinesh, N. S.; Rajanna, K.

2015-11-01

Peristaltic pumps were normally used to pump liquids in several chemical and biological applications. In the present study, a peristaltic pump was used to pressurize the chamber (positive as well negative pressures) using atmospheric air. In the present paper, we discuss the development and performance study of an automatic pressurization system to calibrate low range (millibar) pressure sensors. The system includes a peristaltic pump, calibrated pressure sensor (master sensor), pressure chamber, and the control electronics. An in-house developed peristaltic pump was used to pressurize the chamber. A closed loop control system has been developed to detect and adjust the pressure leaks in the chamber. The complete system has been integrated into a portable product. The system performance has been studied for a step response and steady state errors. The system is portable, free from oil contaminants, and consumes less power compared to existing pressure calibration systems. The veracity of the system was verified by calibrating an unknown diaphragm based pressure sensor and the results obtained were satisfactory.

Generation of synthetic influent data to perform (micro)pollutant wastewater treatment modelling studies.

PubMed

Snip, L J P; Flores-Alsina, X; Aymerich, I; Rodríguez-Mozaz, S; Barceló, D; Plósz, B G; Corominas, Ll; Rodriguez-Roda, I; Jeppsson, U; Gernaey, K V

2016-11-01

The use of process models to simulate the fate of micropollutants in wastewater treatment plants is constantly growing. However, due to the high workload and cost of measuring campaigns, many simulation studies lack sufficiently long time series representing realistic wastewater influent dynamics. In this paper, the feasibility of the Benchmark Simulation Model No. 2 (BSM2) influent generator is tested to create realistic dynamic influent (micro)pollutant disturbance scenarios. The presented set of models is adjusted to describe the occurrence of three pharmaceutical compounds and one of each of its metabolites with samples taken every 2-4h: the anti-inflammatory drug ibuprofen (IBU), the antibiotic sulfamethoxazole (SMX) and the psychoactive carbamazepine (CMZ). Information about type of excretion and total consumption rates forms the basis for creating the data-defined profiles used to generate the dynamic time series. In addition, the traditional influent characteristics such as flow rate, ammonium, particulate chemical oxygen demand and temperature are also modelled using the same framework with high frequency data. The calibration is performed semi-automatically with two different methods depending on data availability. The 'traditional' variables are calibrated with the Bootstrap method while the pharmaceutical loads are estimated with a least squares approach. The simulation results demonstrate that the BSM2 influent generator can describe the dynamics of both traditional variables and pharmaceuticals. Lastly, the study is complemented with: 1) the generation of longer time series for IBU following the same catchment principles; 2) the study of the impact of in-sewer SMX biotransformation when estimating the average daily load; and, 3) a critical discussion of the results, and the future opportunities of the presented approach balancing model structure/calibration procedure complexity versus predictive capabilities. Copyright © 2016. Published by Elsevier B.V.

The Comparison Of In-Flight Pitot Static Calibration Method By Using Radio Altimeter As Reference with GPS and Tower Fly By Methods On CN235-100 MPA

NASA Astrophysics Data System (ADS)

Derajat; Hariowibowo, Hindawan

2018-04-01

The new proposed In-Flight Pitot Static Calibration Method has been carried out during Development and Qualification of CN235-100 MPA (Military Patrol Aircraft). This method is expected to reduce flight hours, less human resources required, no additional special equipment, simple analysis calculation and finally by using this method it is expected to automatically minimized operational cost. At The Indonesian Aerospace (IAe) Flight Test Center Division, the development and updating of new flight test technique and data analysis method as specially for flight physics test subject are still continued to be developed as long as it safety for flight and give additional value for the industrial side. More than 30 years, Flight Test Data Engineers at The Flight Test center Division work together with the Air Crew (Test Pilots, Co-Pilots, and Flight Test Engineers) to execute the flight test activity with standard procedure for both the existance or development test techniques and test data analysis. In this paper the approximation of mathematical model, data reduction and flight test technique of The In-Flight Pitot Static Calibration by using Radio Altimeter as reference will be described and the test results had been compared with another methods ie. By using Global Position System (GPS) and the traditional method (Tower Fly By Method) which were used previously during this Flight Test Program (Ref. [10]). The flight test data case are using CN235-100 MPA flight test data during development and Qualification Flight Test Program at Cazaux Airport, France, in June-November 2009 (Ref. [2]).

U.K. National Radiological Protection Board Radon Calibration Procedures

PubMed Central

Cliff, K. D.

1990-01-01

A procedure for the calibration of instruments for the detection of 222Rn in air is described. The method is based on the alpha-spectrometric determination of the concentration in air of 218Po in the calibration chamber. The calibration chamber is described, together with the method of maintaining a high aerosol concentration. The 218Po concentration at steady state in the chamber is found to be 98% of the 222Rn concentration typically. An assessment of the sources of uncertainty in the method presented indicate that the 222Rn concentration in the chamber can be determined with an overall uncertainty of about 7% at the 95% confidence level. PMID:28179765

L5 TM radiometric recalibration procedure using the internal calibration trends from the NLAPS trending database

USGS Publications Warehouse

Chander, G.; Haque, Md. O.; Micijevic, E.; Barsi, J.A.

2008-01-01

From the Landsat program's inception in 1972 to the present, the earth science user community has benefited from a historical record of remotely sensed data. The multispectral data from the Landsat 5 (L5) Thematic Mapper (TM) sensor provide the backbone for this extensive archive. Historically, the radiometric calibration procedure for this imagery used the instrument's response to the Internal Calibrator (IC) on a scene-by-scene basis to determine the gain and offset for each detector. The IC system degraded with time causing radiometric calibration errors up to 20 percent. In May 2003 the National Landsat Archive Production System (NLAPS) was updated to use a gain model rather than the scene acquisition specific IC gains to calibrate TM data processed in the United States. Further modification of the gain model was performed in 2007. L5 TM data that were processed using IC prior to the calibration update do not benefit from the recent calibration revisions. A procedure has been developed to give users the ability to recalibrate their existing Level-1 products. The best recalibration results are obtained if the work order report that was originally included in the standard data product delivery is available. However, many users may not have the original work order report. In such cases, the IC gain look-up table that was generated using the radiometric gain trends recorded in the NLAPS database can be used for recalibration. This paper discusses the procedure to recalibrate L5 TM data when the work order report originally used in processing is not available. A companion paper discusses the generation of the NLAPS IC gain and bias look-up tables required to perform the recalibration.

Automatic Scoring of Paper-and-Pencil Figural Responses. Research Report.

ERIC Educational Resources Information Center

Martinez, Michael E.; And Others

Large-scale testing is dominated by the multiple-choice question format. Widespread use of the format is due, in part, to the ease with which multiple-choice items can be scored automatically. This paper examines automatic scoring procedures for an alternative item type: figural response. Figural response items call for the completion or…

Synthetic aperture imaging in ultrasound calibration

NASA Astrophysics Data System (ADS)

Ameri, Golafsoun; Baxter, John S. H.; McLeod, A. Jonathan; Jayaranthe, Uditha L.; Chen, Elvis C. S.; Peters, Terry M.

2014-03-01

Ultrasound calibration allows for ultrasound images to be incorporated into a variety of interventional applica­ tions. Traditional Z- bar calibration procedures rely on wired phantoms with an a priori known geometry. The line fiducials produce small, localized echoes which are then segmented from an array of ultrasound images from different tracked probe positions. In conventional B-mode ultrasound, the wires at greater depths appear blurred and are difficult to segment accurately, limiting the accuracy of ultrasound calibration. This paper presents a novel ultrasound calibration procedure that takes advantage of synthetic aperture imaging to reconstruct high resolution ultrasound images at arbitrary depths. In these images, line fiducials are much more readily and accu­ rately segmented, leading to decreased calibration error. The proposed calibration technique is compared to one based on B-mode ultrasound. The fiducial localization error was improved from 0.21mm in conventional B-mode images to 0.15mm in synthetic aperture images corresponding to an improvement of 29%. This resulted in an overall reduction of calibration error from a target registration error of 2.00mm to 1.78mm, an improvement of 11%. Synthetic aperture images display greatly improved segmentation capabilities due to their improved resolution and interpretability resulting in improved calibration.

Multi-objective vs. single-objective calibration of a hydrologic model using single- and multi-objective screening

NASA Astrophysics Data System (ADS)

Mai, Juliane; Cuntz, Matthias; Shafii, Mahyar; Zink, Matthias; Schäfer, David; Thober, Stephan; Samaniego, Luis; Tolson, Bryan

2016-04-01

Hydrologic models are traditionally calibrated against observed streamflow. Recent studies have shown however, that only a few global model parameters are constrained using this kind of integral signal. They can be identified using prior screening techniques. Since different objectives might constrain different parameters, it is advisable to use multiple information to calibrate those models. One common approach is to combine these multiple objectives (MO) into one single objective (SO) function and allow the use of a SO optimization algorithm. Another strategy is to consider the different objectives separately and apply a MO Pareto optimization algorithm. In this study, two major research questions will be addressed: 1) How do multi-objective calibrations compare with corresponding single-objective calibrations? 2) How much do calibration results deteriorate when the number of calibrated parameters is reduced by a prior screening technique? The hydrologic model employed in this study is a distributed hydrologic model (mHM) with 52 model parameters, i.e. transfer coefficients. The model uses grid cells as a primary hydrologic unit, and accounts for processes like snow accumulation and melting, soil moisture dynamics, infiltration, surface runoff, evapotranspiration, subsurface storage and discharge generation. The model is applied in three distinct catchments over Europe. The SO calibrations are performed using the Dynamically Dimensioned Search (DDS) algorithm with a fixed budget while the MO calibrations are achieved using the Pareto Dynamically Dimensioned Search (PA-DDS) algorithm allowing for the same budget. The two objectives used here are the Nash Sutcliffe Efficiency (NSE) of the simulated streamflow and the NSE of the logarithmic transformation. It is shown that the SO DDS results are located close to the edges of the Pareto fronts of the PA-DDS. The MO calibrations are hence preferable due to their supply of multiple equivalent solutions from which the user can choose at the end due to the specific needs. The sequential single-objective parameter screening was employed prior to the calibrations reducing the number of parameters by at least 50% in the different catchments and for the different single objectives. The single-objective calibrations led to a faster convergence of the objectives and are hence beneficial when using a DDS on single-objectives. The above mentioned parameter screening technique is generalized for multi-objectives and applied before calibration using the PA-DDS algorithm. Two different alternatives of this MO-screening are tested. The comparison of the calibration results using all parameters and using only screened parameters shows for both alternatives that the PA-DDS algorithm does not profit in terms of trade-off size and function evaluations required to achieve converged pareto fronts. This is because the PA-DDS algorithm automatically reduces search space with progress of the calibration run. This automatic reduction should be different for other search algorithms. It is therefore hypothesized that prior screening can but must not be beneficial for parameter estimation dependent on the chosen optimization algorithm.

40 CFR 1065.330 - Exhaust-flow calibration.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Section 1065.330 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calibrations and Verifications Flow-Related Measurements § 1065.330... ultrasonic flow meter for raw exhaust flow measurement, we recommend that you calibrate it as described in...

40 CFR 1066.130 - Measurement instrument calibrations and verifications.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Measurement instrument calibrations... (CONTINUED) AIR POLLUTION CONTROLS VEHICLE-TESTING PROCEDURES Equipment, Measurement Instruments, Fuel, and Analytical Gas Specifications § 1066.130 Measurement instrument calibrations and verifications. The...

US Army Test and Evaluation Command, Test Operations Procedure, Gamma Ray Source Calibration

DTIC Science & Technology

1980-03-28

SUPPLEMENTARY NOTES Safety, HTP 6-2-507 and AMCR-385-25. Related MTP’s: 8-3-171, AD 871790, 26 May 70 Radiation Detection Equipment 8-3-172, AD 728455, 1...perienced in Radiac calibration equipment and for that reason the procedures are not step-by-step but are planned to be interpreted by the operator in...is to be used by personnel trained and ex- perienced in the use of radiac calibration equipment and radiation prin- ciples. It ognnot be interpreted

Video camera system for locating bullet holes in targets at a ballistics tunnel

NASA Technical Reports Server (NTRS)

Burner, A. W.; Rummler, D. R.; Goad, W. K.

1990-01-01

A system consisting of a single charge coupled device (CCD) video camera, computer controlled video digitizer, and software to automate the measurement was developed to measure the location of bullet holes in targets at the International Shooters Development Fund (ISDF)/NASA Ballistics Tunnel. The camera/digitizer system is a crucial component of a highly instrumented indoor 50 meter rifle range which is being constructed to support development of wind resistant, ultra match ammunition. The system was designed to take data rapidly (10 sec between shoots) and automatically with little operator intervention. The system description, measurement concept, and procedure are presented along with laboratory tests of repeatability and bias error. The long term (1 hour) repeatability of the system was found to be 4 microns (one standard deviation) at the target and the bias error was found to be less than 50 microns. An analysis of potential errors and a technique for calibration of the system are presented.

Multimodal correlation and intraoperative matching of virtual models in neurosurgery

NASA Technical Reports Server (NTRS)

Ceresole, Enrico; Dalsasso, Michele; Rossi, Aldo

1994-01-01

The multimodal correlation between different diagnostic exams, the intraoperative calibration of pointing tools and the correlation of the patient's virtual models with the patient himself, are some examples, taken from the biomedical field, of a unique problem: determine the relationship linking representation of the same object in different reference frames. Several methods have been developed in order to determine this relationship, among them, the surface matching method is one that gives the patient minimum discomfort and the errors occurring are compatible with the required precision. The surface matching method has been successfully applied to the multimodal correlation of diagnostic exams such as CT, MR, PET and SPECT. Algorithms for automatic segmentation of diagnostic images have been developed to extract the reference surfaces from the diagnostic exams, whereas the surface of the patient's skull has been monitored, in our approach, by means of a laser sensor mounted on the end effector of an industrial robot. An integrated system for virtual planning and real time execution of surgical procedures has been realized.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schalkoff, R.J.

This report summarizes work after 4 years of a 3-year project (no-cost extension of the above-referenced project for a period of 12 months granted). The fourth generation of a vision sensing head for geometric and photometric scene sensing has been built and tested. Estimation algorithms for automatic sensor calibration updating under robot motion have been developed and tested. We have modified the geometry extraction component of the rendering pipeline. Laser scanning now produces highly accurate points on segmented curves. These point-curves are input to a NURBS (non-uniform rational B-spline) skinning procedure to produce interpolating surface segments. The NURBS formulation includesmore » quadrics as a sub-class, thus this formulation allows much greater flexibility without the attendant instability of generating an entire quadric surface. We have also implemented correction for diffuse lighting and specular effects. The QRobot joint level control was extended to a complete semi-autonomous robot control system for D and D operations. The imaging and VR subsystems have been integrated and tested.« less

Collaborated measurement of three-dimensional position and orientation errors of assembled miniature devices with two vision systems

NASA Astrophysics Data System (ADS)

Wang, Xiaodong; Zhang, Wei; Luo, Yi; Yang, Weimin; Chen, Liang

2013-01-01

In assembly of miniature devices, the position and orientation of the parts to be assembled should be guaranteed during or after assembly. In some cases, the relative position or orientation errors among the parts can not be measured from only one direction using visual method, because of visual occlusion or for the features of parts located in a three-dimensional way. An automatic assembly system for precise miniature devices is introduced. In the modular assembly system, two machine vision systems were employed for measurement of the three-dimensionally distributed assembly errors. High resolution CCD cameras and high position repeatability precision stages were integrated to realize high precision measurement in large work space. The two cameras worked in collaboration in measurement procedure to eliminate the influence of movement errors of the rotational or translational stages. A set of templates were designed for calibration of the vision systems and evaluation of the system's measurement accuracy.

A Low-Cost Device for Automatic Photometric Titrations

NASA Astrophysics Data System (ADS)

Rocha, Fábio R. P.; Reis, Boaventura F.

2000-02-01

Electronics is an important topic in chemistry courses. However, the introduction of basic concepts is often difficult and the lab instruments are frequently seen as "black boxes". To address this problem, we propose the construction of a simple, low-cost (about $150 U.S.) automatic photometric titrator employing a light-emitting diode (LED) and a phototransistor. The electronic circuit can be assembled by the students themselves. The device was employed to implement a common procedure in chemical labs, making feasible the introduction of concepts related to electronics in undergraduate chemistry courses. The titrator is able to work automatically, since a feedback system permits stopping the addition of titrant solution when the end-point is achieved. With this demonstration, it can be stressed that automatic procedures can be implemented without expensive instruments. Additionally, a classical procedure becomes more attractive to the students and its importance to chemical analysis can be emphasized. The feasibility of the titrator was demonstrated by acid-base titrations of HCl solutions with NaOH in the presence of phenolphthalein and by iodimetric determination of ascorbic acid in vitamin C tablets and lemon juice. Precise results (0.7% relative standard deviation, n = 10) in agreement at the 95% confidence level with those attained by a conventional procedure were obtained.

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR CALIBRATION AND OPERATION OF NHEXAS BALANCES (UA-L-1.2)

EPA Science Inventory

The purpose of this SOP is to describe the procedures used when calibrating and operating balances during the Arizona NHEXAS project and the Border study. Keywords: lab; equipment; balances.

The U.S.-Mexico Border Program is sponsored by the Environmental Health Workgroup of t...

Precise Haptic Device Co-Location for Visuo-Haptic Augmented Reality.

PubMed

Eck, Ulrich; Pankratz, Frieder; Sandor, Christian; Klinker, Gudrun; Laga, Hamid

2015-12-01

Visuo-haptic augmented reality systems enable users to see and touch digital information that is embedded in the real world. PHANToM haptic devices are often employed to provide haptic feedback. Precise co-location of computer-generated graphics and the haptic stylus is necessary to provide a realistic user experience. Previous work has focused on calibration procedures that compensate the non-linear position error caused by inaccuracies in the joint angle sensors. In this article we present a more complete procedure that additionally compensates for errors in the gimbal sensors and improves position calibration. The proposed procedure further includes software-based temporal alignment of sensor data and a method for the estimation of a reference for position calibration, resulting in increased robustness against haptic device initialization and external tracker noise. We designed our procedure to require minimal user input to maximize usability. We conducted an extensive evaluation with two different PHANToMs, two different optical trackers, and a mechanical tracker. Compared to state-of-the-art calibration procedures, our approach significantly improves the co-location of the haptic stylus. This results in higher fidelity visual and haptic augmentations, which are crucial for fine-motor tasks in areas such as medical training simulators, assembly planning tools, or rapid prototyping applications.

Automated Mounting Bias Calibration for Airborne LIDAR System

NASA Astrophysics Data System (ADS)

Zhang, J.; Jiang, W.; Jiang, S.

2012-07-01

Mounting bias is the major error source of Airborne LIDAR system. In this paper, an automated calibration method for estimating LIDAR system mounting parameters is introduced. LIDAR direct geo-referencing model is used to calculate systematic errors. Due to LIDAR footprints discretely sampled, the real corresponding laser points are hardly existence among different strips. The traditional corresponding point methodology does not seem to apply to LIDAR strip registration. We proposed a Virtual Corresponding Point Model to resolve the corresponding problem among discrete laser points. Each VCPM contains a corresponding point and three real laser footprints. Two rules are defined to calculate tie point coordinate from real laser footprints. The Scale Invariant Feature Transform (SIFT) is used to extract corresponding points in LIDAR strips, and the automatic flow of LIDAR system calibration based on VCPM is detailed described. The practical examples illustrate the feasibility and effectiveness of the proposed calibration method.

Objective Measurement of Erythema in Psoriasis using Digital Color Photography with Color Calibration

PubMed Central

Raina, Abhay; Hennessy, Ricky; Rains, Michael; Allred, James; Hirshburg, Jason M; Diven, Dayna; Markey, Mia K.

2016-01-01

Background Traditional metrics for evaluating the severity of psoriasis are subjective, which complicates efforts to measure effective treatments in clinical trials. Methods We collected images of psoriasis plaques and calibrated the coloration of the images according to an included color card. Features were extracted from the images and used to train a linear discriminant analysis classifier with cross-validation to automatically classify the degree of erythema. The results were tested against numerical scores obtained by a panel of dermatologists using a standard rating system. Results Quantitative measures of erythema based on the digital color images showed good agreement with subjective assessment of erythema severity (κ = 0.4203). The color calibration process improved the agreement from κ = 0.2364 to κ = 0.4203. Conclusions We propose a method for the objective measurement of the psoriasis severity parameter of erythema and show that the calibration process improved the results. PMID:26517973

In-flight photogrammetric camera calibration and validation via complementary lidar

NASA Astrophysics Data System (ADS)

Gneeniss, A. S.; Mills, J. P.; Miller, P. E.

2015-02-01

This research assumes lidar as a reference dataset against which in-flight camera system calibration and validation can be performed. The methodology utilises a robust least squares surface matching algorithm to align a dense network of photogrammetric points to the lidar reference surface, allowing for the automatic extraction of so-called lidar control points (LCPs). Adjustment of the photogrammetric data is then repeated using the extracted LCPs in a self-calibrating bundle adjustment with additional parameters. This methodology was tested using two different photogrammetric datasets, a Microsoft UltraCamX large format camera and an Applanix DSS322 medium format camera. Systematic sensitivity testing explored the influence of the number and weighting of LCPs. For both camera blocks it was found that when the number of control points increase, the accuracy improves regardless of point weighting. The calibration results were compared with those obtained using ground control points, with good agreement found between the two.

Multi-projector auto-calibration and placement optimization for non-planar surfaces

NASA Astrophysics Data System (ADS)

Li, Dong; Xie, Jinghui; Zhao, Lu; Zhou, Lijing; Weng, Dongdong

2015-10-01

Non-planar projection has been widely applied in virtual reality and digital entertainment and exhibitions because of its flexible layout and immersive display effects. Compared with planar projection, a non-planar projection is more difficult to achieve because projector calibration and image distortion correction are difficult processes. This paper uses a cylindrical screen as an example to present a new method for automatically calibrating a multi-projector system in a non-planar environment without using 3D reconstruction. This method corrects the geometric calibration error caused by the screen's manufactured imperfections, such as an undulating surface or a slant in the vertical plane. In addition, based on actual projection demand, this paper presents the overall performance evaluation criteria for the multi-projector system. According to these criteria, we determined the optimal placement for the projectors. This method also extends to surfaces that can be parameterized, such as spheres, ellipsoids, and paraboloids, and demonstrates a broad applicability.

Integrated calibration between digital camera and laser scanner from mobile mapping system for land vehicles

NASA Astrophysics Data System (ADS)

Zhao, Guihua; Chen, Hong; Li, Xingquan; Zou, Xiaoliang

The paper presents the concept of lever arm and boresight angle, the design requirements of calibration sites and the integrated calibration method of boresight angles of digital camera or laser scanner. Taking test data collected by Applanix's LandMark system as an example, the camera calibration method is introduced to be piling three consecutive stereo images and OTF-Calibration method using ground control points. The laser calibration of boresight angle is proposed to use a manual and automatic method with ground control points. Integrated calibration between digital camera and laser scanner is introduced to improve the systemic precision of two sensors. By analyzing the measurement value between ground control points and its corresponding image points in sequence images, a conclusion is that position objects between camera and images are within about 15cm in relative errors and 20cm in absolute errors. By comparing the difference value between ground control points and its corresponding laser point clouds, the errors is less than 20cm. From achieved results of these experiments in analysis, mobile mapping system is efficient and reliable system for generating high-accuracy and high-density road spatial data more rapidly.

Calibrating a tensor magnetic gradiometer using spin data

USGS Publications Warehouse

Bracken, Robert E.; Smith, David V.; Brown, Philip J.

2005-01-01

Scalar magnetic data are often acquired to discern characteristics of geologic source materials and buried objects. It is evident that a great deal can be done with scalar data, but there are significant advantages to direct measurement of the magnetic gradient tensor in applications with nearby sources, such as unexploded ordnance (UXO). To explore these advantages, we adapted a prototype tensor magnetic gradiometer system (TMGS) and successfully implemented a data-reduction procedure. One of several critical reduction issues is the precise determination of a large group of calibration coefficients for the sensors and sensor array. To resolve these coefficients, we devised a spin calibration method, after similar methods of calibrating space-based magnetometers (Snare, 2001). The spin calibration procedure consists of three parts: (1) collecting data by slowly revolving the sensor array in the Earth?s magnetic field, (2) deriving a comprehensive set of coefficients from the spin data, and (3) applying the coefficients to the survey data. To show that the TMGS functions as a tensor gradiometer, we conducted an experimental survey that verified that the reduction procedure was effective (Bracken and Brown, in press). Therefore, because it was an integral part of the reduction, it can be concluded that the spin calibration was correctly formulated with acceptably small errors.

Self-calibrating models for dynamic monitoring and diagnosis

NASA Technical Reports Server (NTRS)

Kuipers, Benjamin

1996-01-01

A method for automatically building qualitative and semi-quantitative models of dynamic systems, and using them for monitoring and fault diagnosis, is developed and demonstrated. The qualitative approach and semi-quantitative method are applied to monitoring observation streams, and to design of non-linear control systems.

Evaluation of a stepwise, multi-objective, multi-variable parameter optimization method for the APEX model

USDA-ARS?s Scientific Manuscript database

Hydrologic models are essential tools for environmental assessment of agricultural non-point source pollution. The automatic calibration of hydrologic models, though efficient, demands significant computational power, which can limit its application. The study objective was to investigate a cost e...

Calibration and evaluation of a dispersant application system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shum, J.S.

1987-05-01

The report presents recommended methods for calibrating and operating boat-mounted dispersant application systems. Calibration of one commercially-available system and several unusual problems encountered in calibration are described. Charts and procedures for selecting pump rates and other operating parameters in order to achieve a desired dosage are provided. The calibration was performed at the EPA's Oil and Hazardous Materials Simulated Environmental Test Tank (OHMSETT) facility in Leonardo, New Jersey.

Calibration procedure for Slocum glider deployed optical instruments.

PubMed

Cetinić, Ivona; Toro-Farmer, Gerardo; Ragan, Matthew; Oberg, Carl; Jones, Burton H

2009-08-31

Recent developments in the field of the autonomous underwater vehicles allow the wide usage of these platforms as part of scientific experiments, monitoring campaigns and more. The vehicles are often equipped with sensors measuring temperature, conductivity, chlorophyll a fluorescence (Chl a), colored dissolved organic matter (CDOM) fluorescence, phycoerithrin (PE) fluorescence and spectral volume scattering function at 117 degrees, providing users with high resolution, real time data. However, calibration of these instruments can be problematic. Most in situ calibrations are performed by deploying complementary instrument packages or water samplers in the proximity of the glider. Laboratory calibrations of the mounted sensors are difficult due to the placement of the instruments within the body of the vehicle. For the laboratory calibrations of the Slocum glider instruments we developed a small calibration chamber where we can perform precise calibrations of the optical instruments aboard our glider, as well as sensors from other deployment platforms. These procedures enable us to obtain pre- and post-deployment calibrations for optical fluorescence instruments, which may differ due to the biofouling and other physical damage that can occur during long-term glider deployments. We found that biofouling caused significant changes in the calibration scaling factors of fluorescent sensors, suggesting the need for consistent and repetitive calibrations for gliders as proposed in this paper.

Electronic test and calibration circuits, a compilation

NASA Technical Reports Server (NTRS)

1972-01-01

A wide variety of simple test calibration circuits are compiled for the engineer and laboratory technician. The majority of circuits were found inexpensive to assemble. Testing electronic devices and components, instrument and system test, calibration and reference circuits, and simple test procedures are presented.

An investigation of automatic exposure control calibration for chest imaging with a computed radiography system.

PubMed

Moore, C S; Wood, T J; Avery, G; Balcam, S; Needler, L; Beavis, A W; Saunderson, J R

2014-05-07

The purpose of this study was to examine the use of three physical image quality metrics in the calibration of an automatic exposure control (AEC) device for chest radiography with a computed radiography (CR) imaging system. The metrics assessed were signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and mean effective noise equivalent quanta (eNEQm), all measured using a uniform chest phantom. Subsequent calibration curves were derived to ensure each metric was held constant across the tube voltage range. Each curve was assessed for its clinical appropriateness by generating computer simulated chest images with correct detector air kermas for each tube voltage, and grading these against reference images which were reconstructed at detector air kermas correct for the constant detector dose indicator (DDI) curve currently programmed into the AEC device. All simulated chest images contained clinically realistic projected anatomy and anatomical noise and were scored by experienced image evaluators. Constant DDI and CNR curves do not appear to provide optimized performance across the diagnostic energy range. Conversely, constant eNEQm and SNR do appear to provide optimized performance, with the latter being the preferred calibration metric given as it is easier to measure in practice. Medical physicists may use the SNR image quality metric described here when setting up and optimizing AEC devices for chest radiography CR systems with a degree of confidence that resulting clinical image quality will be adequate for the required clinical task. However, this must be done with close cooperation of expert image evaluators, to ensure appropriate levels of detector air kerma.

An investigation of automatic exposure control calibration for chest imaging with a computed radiography system

NASA Astrophysics Data System (ADS)

Moore, C. S.; Wood, T. J.; Avery, G.; Balcam, S.; Needler, L.; Beavis, A. W.; Saunderson, J. R.

2014-05-01

The purpose of this study was to examine the use of three physical image quality metrics in the calibration of an automatic exposure control (AEC) device for chest radiography with a computed radiography (CR) imaging system. The metrics assessed were signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and mean effective noise equivalent quanta (eNEQm), all measured using a uniform chest phantom. Subsequent calibration curves were derived to ensure each metric was held constant across the tube voltage range. Each curve was assessed for its clinical appropriateness by generating computer simulated chest images with correct detector air kermas for each tube voltage, and grading these against reference images which were reconstructed at detector air kermas correct for the constant detector dose indicator (DDI) curve currently programmed into the AEC device. All simulated chest images contained clinically realistic projected anatomy and anatomical noise and were scored by experienced image evaluators. Constant DDI and CNR curves do not appear to provide optimized performance across the diagnostic energy range. Conversely, constant eNEQm and SNR do appear to provide optimized performance, with the latter being the preferred calibration metric given as it is easier to measure in practice. Medical physicists may use the SNR image quality metric described here when setting up and optimizing AEC devices for chest radiography CR systems with a degree of confidence that resulting clinical image quality will be adequate for the required clinical task. However, this must be done with close cooperation of expert image evaluators, to ensure appropriate levels of detector air kerma.

Ice Sheet Temperature Records - Satellite and In Situ Data from Antarctica and Greenland

NASA Astrophysics Data System (ADS)

Shuman, C. A.; Comiso, J. C.

2001-12-01

Recently completed decadal-length surface temperature records from Antarctica and Greenland are providing insights into the challenge of detecting climate change. Ice and snow cover at high latitudes influence the global climate system by reflecting much of the incoming solar energy back to space. An expected consequence of global warming is a decrease in area covered by snow and ice and an increase in Earth's absorption of solar radiation. Models have predicted that the effects of climate warming may be amplified at high latitudes; thinning of the Greenland ice sheet margins and the breakup of Antarctic Peninsula ice shelves suggest this process may have begun. Satellite data provide an excellent means of observing climate parameters across both long temporal and remote spatial domains but calibration and validation of their data remains a challenge. Infrared sensors can provide excellent temperature information but cloud cover and calibration remain as problems. Passive-microwave sensors can obtain data during the long polar night and through clouds but have calibration issues and a much lower spatial resolution. Automatic weather stations are generally spatially- and temporally-restricted and may have long gaps due to equipment failure. Stable isotopes of oxygen and hydrogen from ice sheet locations provide another means of determining temperature variations with time but are challenging to calibrate to observed temperatures and also represent restricted areas. This presentation will discuss these issues and elaborate on the development and limitations of composite satellite, automatic weather station, and proxy temperature data from selected sites in Antarctica and Greenland.

Evaluation on Radiometric Capability of Chinese Optical Satellite Sensors

PubMed Central

Yang, Aixia; Zhong, Bo; Wu, Shanlong; Liu, Qinhuo

2017-01-01

The radiometric capability of on-orbit sensors should be updated on time due to changes induced by space environmental factors and instrument aging. Some sensors, such as Moderate Resolution Imaging Spectroradiometer (MODIS), have onboard calibrators, which enable real-time calibration. However, most Chinese remote sensing satellite sensors lack onboard calibrators. Their radiometric calibrations have been updated once a year based on a vicarious calibration procedure, which has affected the applications of the data. Therefore, a full evaluation of the sensors’ radiometric capabilities is essential before quantitative applications can be made. In this study, a comprehensive procedure for evaluating the radiometric capability of several Chinese optical satellite sensors is proposed. In this procedure, long-term radiometric stability and radiometric accuracy are the two major indicators for radiometric evaluation. The radiometric temporal stability is analyzed by the tendency of long-term top-of-atmosphere (TOA) reflectance variation; the radiometric accuracy is determined by comparison with the TOA reflectance from MODIS after spectrally matching. Three Chinese sensors including the Charge-Coupled Device (CCD) camera onboard Huan Jing 1 satellite (HJ-1), as well as the Visible and Infrared Radiometer (VIRR) and Medium-Resolution Spectral Imager (MERSI) onboard the Feng Yun 3 satellite (FY-3) are evaluated in reflective bands based on this procedure. The results are reasonable, and thus can provide reliable reference for the sensors’ application, and as such will promote the development of Chinese satellite data. PMID:28117745

Evaluation on Radiometric Capability of Chinese Optical Satellite Sensors.

PubMed

Yang, Aixia; Zhong, Bo; Wu, Shanlong; Liu, Qinhuo

2017-01-22

The radiometric capability of on-orbit sensors should be updated on time due to changes induced by space environmental factors and instrument aging. Some sensors, such as Moderate Resolution Imaging Spectroradiometer (MODIS), have onboard calibrators, which enable real-time calibration. However, most Chinese remote sensing satellite sensors lack onboard calibrators. Their radiometric calibrations have been updated once a year based on a vicarious calibration procedure, which has affected the applications of the data. Therefore, a full evaluation of the sensors' radiometric capabilities is essential before quantitative applications can be made. In this study, a comprehensive procedure for evaluating the radiometric capability of several Chinese optical satellite sensors is proposed. In this procedure, long-term radiometric stability and radiometric accuracy are the two major indicators for radiometric evaluation. The radiometric temporal stability is analyzed by the tendency of long-term top-of-atmosphere (TOA) reflectance variation; the radiometric accuracy is determined by comparison with the TOA reflectance from MODIS after spectrally matching. Three Chinese sensors including the Charge-Coupled Device (CCD) camera onboard Huan Jing 1 satellite (HJ-1), as well as the Visible and Infrared Radiometer (VIRR) and Medium-Resolution Spectral Imager (MERSI) onboard the Feng Yun 3 satellite (FY-3) are evaluated in reflective bands based on this procedure. The results are reasonable, and thus can provide reliable reference for the sensors' application, and as such will promote the development of Chinese satellite data.

Automatic vehicle counting system for traffic monitoring

NASA Astrophysics Data System (ADS)

Crouzil, Alain; Khoudour, Louahdi; Valiere, Paul; Truong Cong, Dung Nghy

2016-09-01

The article is dedicated to the presentation of a vision-based system for road vehicle counting and classification. The system is able to achieve counting with a very good accuracy even in difficult scenarios linked to occlusions and/or presence of shadows. The principle of the system is to use already installed cameras in road networks without any additional calibration procedure. We propose a robust segmentation algorithm that detects foreground pixels corresponding to moving vehicles. First, the approach models each pixel of the background with an adaptive Gaussian distribution. This model is coupled with a motion detection procedure, which allows correctly location of moving vehicles in space and time. The nature of trials carried out, including peak periods and various vehicle types, leads to an increase of occlusions between cars and between cars and trucks. A specific method for severe occlusion detection, based on the notion of solidity, has been carried out and tested. Furthermore, the method developed in this work is capable of managing shadows with high resolution. The related algorithm has been tested and compared to a classical method. Experimental results based on four large datasets show that our method can count and classify vehicles in real time with a high level of performance (>98%) under different environmental situations, thus performing better than the conventional inductive loop detectors.

Polarimetric SAR calibration experiment using active radar calibrators

NASA Astrophysics Data System (ADS)

Freeman, Anthony; Shen, Yuhsyen; Werner, Charles L.

1990-03-01

Active radar calibrators are used to derive both the amplitude and phase characteristics of a multichannel polarimetric SAR from the complex image data. Results are presented from an experiment carried out using the NASA/JPL DC-8 aircraft SAR over a calibration site at Goldstone, California. As part of the experiment, polarimetric active radar calibrators (PARCs) with adjustable polarization signatures were deployed. Experimental results demonstrate that the PARCs can be used to calibrate polarimetric SAR images successfully. Restrictions on the application of the PARC calibration procedure are discussed.

Polarimetric SAR calibration experiment using active radar calibrators

NASA Technical Reports Server (NTRS)

Freeman, Anthony; Shen, Yuhsyen; Werner, Charles L.

1990-01-01

Active radar calibrators are used to derive both the amplitude and phase characteristics of a multichannel polarimetric SAR from the complex image data. Results are presented from an experiment carried out using the NASA/JPL DC-8 aircraft SAR over a calibration site at Goldstone, California. As part of the experiment, polarimetric active radar calibrators (PARCs) with adjustable polarization signatures were deployed. Experimental results demonstrate that the PARCs can be used to calibrate polarimetric SAR images successfully. Restrictions on the application of the PARC calibration procedure are discussed.

Generating Models of Surgical Procedures using UMLS Concepts and Multiple Sequence Alignment

PubMed Central

Meng, Frank; D’Avolio, Leonard W.; Chen, Andrew A.; Taira, Ricky K.; Kangarloo, Hooshang

2005-01-01

Surgical procedures can be viewed as a process composed of a sequence of steps performed on, by, or with the patient’s anatomy. This sequence is typically the pattern followed by surgeons when generating surgical report narratives for documenting surgical procedures. This paper describes a methodology for semi-automatically deriving a model of conducted surgeries, utilizing a sequence of derived Unified Medical Language System (UMLS) concepts for representing surgical procedures. A multiple sequence alignment was computed from a collection of such sequences and was used for generating the model. These models have the potential of being useful in a variety of informatics applications such as information retrieval and automatic document generation. PMID:16779094

Employing an Incentive Spirometer to Calibrate Tidal Volumes Estimated from a Smartphone Camera.

PubMed

Reyes, Bersain A; Reljin, Natasa; Kong, Youngsun; Nam, Yunyoung; Ha, Sangho; Chon, Ki H

2016-03-18

A smartphone-based tidal volume (V(T)) estimator was recently introduced by our research group, where an Android application provides a chest movement signal whose peak-to-peak amplitude is highly correlated with reference V(T) measured by a spirometer. We found a Normalized Root Mean Squared Error (NRMSE) of 14.998% ± 5.171% (mean ± SD) when the smartphone measures were calibrated using spirometer data. However, the availability of a spirometer device for calibration is not realistic outside clinical or research environments. In order to be used by the general population on a daily basis, a simple calibration procedure not relying on specialized devices is required. In this study, we propose taking advantage of the linear correlation between smartphone measurements and V(T) to obtain a calibration model using information computed while the subject breathes through a commercially-available incentive spirometer (IS). Experiments were performed on twelve (N = 12) healthy subjects. In addition to corroborating findings from our previous study using a spirometer for calibration, we found that the calibration procedure using an IS resulted in a fixed bias of -0.051 L and a RMSE of 0.189 ± 0.074 L corresponding to 18.559% ± 6.579% when normalized. Although it has a small underestimation and slightly increased error, the proposed calibration procedure using an IS has the advantages of being simple, fast, and affordable. This study supports the feasibility of developing a portable smartphone-based breathing status monitor that provides information about breathing depth, in addition to the more commonly estimated respiratory rate, on a daily basis.

Employing an Incentive Spirometer to Calibrate Tidal Volumes Estimated from a Smartphone Camera

PubMed Central

Reyes, Bersain A.; Reljin, Natasa; Kong, Youngsun; Nam, Yunyoung; Ha, Sangho; Chon, Ki H.

2016-01-01

A smartphone-based tidal volume (VT) estimator was recently introduced by our research group, where an Android application provides a chest movement signal whose peak-to-peak amplitude is highly correlated with reference VT measured by a spirometer. We found a Normalized Root Mean Squared Error (NRMSE) of 14.998% ± 5.171% (mean ± SD) when the smartphone measures were calibrated using spirometer data. However, the availability of a spirometer device for calibration is not realistic outside clinical or research environments. In order to be used by the general population on a daily basis, a simple calibration procedure not relying on specialized devices is required. In this study, we propose taking advantage of the linear correlation between smartphone measurements and VT to obtain a calibration model using information computed while the subject breathes through a commercially-available incentive spirometer (IS). Experiments were performed on twelve (N = 12) healthy subjects. In addition to corroborating findings from our previous study using a spirometer for calibration, we found that the calibration procedure using an IS resulted in a fixed bias of −0.051 L and a RMSE of 0.189 ± 0.074 L corresponding to 18.559% ± 6.579% when normalized. Although it has a small underestimation and slightly increased error, the proposed calibration procedure using an IS has the advantages of being simple, fast, and affordable. This study supports the feasibility of developing a portable smartphone-based breathing status monitor that provides information about breathing depth, in addition to the more commonly estimated respiratory rate, on a daily basis. PMID:26999152

An IMU-to-Body Alignment Method Applied to Human Gait Analysis.

PubMed

Vargas-Valencia, Laura Susana; Elias, Arlindo; Rocon, Eduardo; Bastos-Filho, Teodiano; Frizera, Anselmo

2016-12-10

This paper presents a novel calibration procedure as a simple, yet powerful, method to place and align inertial sensors with body segments. The calibration can be easily replicated without the need of any additional tools. The proposed method is validated in three different applications: a computer mathematical simulation; a simplified joint composed of two semi-spheres interconnected by a universal goniometer; and a real gait test with five able-bodied subjects. Simulation results demonstrate that, after the calibration method is applied, the joint angles are correctly measured independently of previous sensor placement on the joint, thus validating the proposed procedure. In the cases of a simplified joint and a real gait test with human volunteers, the method also performs correctly, although secondary plane errors appear when compared with the simulation results. We believe that such errors are caused by limitations of the current inertial measurement unit (IMU) technology and fusion algorithms. In conclusion, the presented calibration procedure is an interesting option to solve the alignment problem when using IMUs for gait analysis.

An experimental protocol for the definition of upper limb anatomical frames on children using magneto-inertial sensors.

PubMed

Ricci, L; Formica, D; Tamilia, E; Taffoni, F; Sparaci, L; Capirci, O; Guglielmelli, E

2013-01-01

Motion capture based on magneto-inertial sensors is a technology enabling data collection in unstructured environments, allowing "out of the lab" motion analysis. This technology is a good candidate for motion analysis of children thanks to the reduced weight and size as well as the use of wireless communication that has improved its wearability and reduced its obtrusivity. A key issue in the application of such technology for motion analysis is its calibration, i.e. a process that allows mapping orientation information from each sensor to a physiological reference frame. To date, even if there are several calibration procedures available for adults, no specific calibration procedures have been developed for children. This work addresses this specific issue presenting a calibration procedure for motion capture of thorax and upper limbs on healthy children. Reported results suggest comparable performance with similar studies on adults and emphasize some critical issues, opening the way to further improvements.

Multiple calibrator measurements improve accuracy and stability estimates of automated assays.

PubMed

Akbas, Neval; Budd, Jeffrey R; Klee, George G

2016-01-01

The effects of combining multiple calibrations on assay accuracy (bias) and measurement of calibration stability were investigated for total triiodothyronine (TT3), vitamin B12 and luteinizing hormone (LH) using Beckman Coulter's Access 2 analyzer. Three calibration procedures (CC1, CC2 and CC3) combined 12, 34 and 56 calibrator measurements over 1, 2, and 3 days. Bias was calculated between target values and average measured value over 3 consecutive days after calibration. Using regression analysis of calibrator measurements versus measurement date, calibration stability was determined as the maximum number of days before a calibrator measurement exceeded 5% tolerance limits. Competitive assays (TT3, vitamin B12) had positive time regression slopes, while sandwich assay (LH) had a negative slope. Bias values for TT3 were -2.49%, 1.49%, and -0.50% using CC1, CC2 and CC3 respectively, with calibrator stability of 32, 20, and 30 days. Bias values for vitamin B12 were 2.44%, 0.91%, and -0.50%, with calibrator stability of 4, 9, and 12 days. Bias values for LH were 2.26%, 1.44% and -0.29% with calibrator stability of >43, 39 and 36 days. Measured stability was more consistent across calibration procedures using percent change rather than difference from target: 26 days for TT3, 12 days for B12 and 31 days for LH. Averaging over multiple calibrations produced smaller bias, consistent with improved accuracy. Time regression slopes in percent change were unaffected by number of calibration measurements but calibrator stability measured from the target value was highly affected by the calibrator value at time zero.

40 CFR 1066.240 - Torque transducer verification and calibration.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) AIR POLLUTION CONTROLS VEHICLE-TESTING PROCEDURES Dynamometer Specifications § 1066.240 Torque transducer verification and calibration. Calibrate torque-measurement systems as described in 40 CFR 1065.310. ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Torque transducer verification and...

40 CFR 1066.240 - Torque transducer verification and calibration.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) AIR POLLUTION CONTROLS VEHICLE-TESTING PROCEDURES Dynamometer Specifications § 1066.240 Torque transducer verification and calibration. Calibrate torque-measurement systems as described in 40 CFR 1065.310. ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Torque transducer verification and...

Online C-arm calibration using a marked guide wire for 3D reconstruction of pulmonary arteries

NASA Astrophysics Data System (ADS)

Vachon, Étienne; Miró, Joaquim; Duong, Luc

2017-03-01

3D reconstruction of vessels from 2D X-ray angiography is highly relevant to improve the visualization and the assessment of vascular structures such as pulmonary arteries by interventional cardiologists. However, to ensure a robust and accurate reconstruction, C-arm gantry parameters must be properly calibrated to provide clinically acceptable results. Calibration procedures often rely on calibration objects and complex protocol which is not adapted to an intervention context. In this study, a novel calibration algorithm for C-arm gantry is presented using the instrumentation such as catheters and guide wire. This ensures the availability of a minimum set of correspondences and implies minimal changes to the clinical workflow. The method was evaluated on simulated data and on retrospective patient datasets. Experimental results on simulated datasets demonstrate a calibration that allows a 3D reconstruction of the guide wire up to a geometric transformation. Experiments with patients datasets show a significant decrease of the retro projection error to 0.17 mm 2D RMS. Consequently, such procedure might contribute to identify any calibration drift during the intervention.

Gaussian process based modeling and experimental design for sensor calibration in drifting environments

PubMed Central

Geng, Zongyu; Yang, Feng; Chen, Xi; Wu, Nianqiang

2016-01-01

It remains a challenge to accurately calibrate a sensor subject to environmental drift. The calibration task for such a sensor is to quantify the relationship between the sensor’s response and its exposure condition, which is specified by not only the analyte concentration but also the environmental factors such as temperature and humidity. This work developed a Gaussian Process (GP)-based procedure for the efficient calibration of sensors in drifting environments. Adopted as the calibration model, GP is not only able to capture the possibly nonlinear relationship between the sensor responses and the various exposure-condition factors, but also able to provide valid statistical inference for uncertainty quantification of the target estimates (e.g., the estimated analyte concentration of an unknown environment). Built on GP’s inference ability, an experimental design method was developed to achieve efficient sampling of calibration data in a batch sequential manner. The resulting calibration procedure, which integrates the GP-based modeling and experimental design, was applied on a simulated chemiresistor sensor to demonstrate its effectiveness and its efficiency over the traditional method. PMID:26924894

Assessment and certification of neonatal incubator sensors through an inferential neural network.

PubMed

de Araújo, José Medeiros; de Menezes, José Maria Pires; Moura de Albuquerque, Alberto Alexandre; da Mota Almeida, Otacílio; Ugulino de Araújo, Fábio Meneghetti

2013-11-15

Measurement and diagnostic systems based on electronic sensors have been increasingly essential in the standardization of hospital equipment. The technical standard IEC (International Electrotechnical Commission) 60601-2-19 establishes requirements for neonatal incubators and specifies the calibration procedure and validation tests for such devices using sensors systems. This paper proposes a new procedure based on an inferential neural network to evaluate and calibrate a neonatal incubator. The proposal presents significant advantages over the standard calibration process, i.e., the number of sensors is drastically reduced, and it runs with the incubator under operation. Since the sensors used in the new calibration process are already installed in the commercial incubator, no additional hardware is necessary; and the calibration necessity can be diagnosed in real time without the presence of technical professionals in the neonatal intensive care unit (NICU). Experimental tests involving the aforementioned calibration system are carried out in a commercial incubator in order to validate the proposal.

Assessment and Certification of Neonatal Incubator Sensors through an Inferential Neural Network

PubMed Central

de Araújo Júnior, José Medeiros; de Menezes Júnior, José Maria Pires; de Albuquerque, Alberto Alexandre Moura; Almeida, Otacílio da Mota; de Araújo, Fábio Meneghetti Ugulino

2013-01-01

Measurement and diagnostic systems based on electronic sensors have been increasingly essential in the standardization of hospital equipment. The technical standard IEC (International Electrotechnical Commission) 60601-2-19 establishes requirements for neonatal incubators and specifies the calibration procedure and validation tests for such devices using sensors systems. This paper proposes a new procedure based on an inferential neural network to evaluate and calibrate a neonatal incubator. The proposal presents significant advantages over the standard calibration process, i.e., the number of sensors is drastically reduced, and it runs with the incubator under operation. Since the sensors used in the new calibration process are already installed in the commercial incubator, no additional hardware is necessary; and the calibration necessity can be diagnosed in real time without the presence of technical professionals in the neonatal intensive care unit (NICU). Experimental tests involving the aforementioned calibration system are carried out in a commercial incubator in order to validate the proposal. PMID:24248278

Total reduction of distorted echelle spectrograms - An automatic procedure. [for computer controlled microdensitometer

NASA Technical Reports Server (NTRS)

Peterson, R. C.; Title, A. M.

1975-01-01

A total reduction procedure, notable for its use of a computer-controlled microdensitometer for semi-automatically tracing curved spectra, is applied to distorted high-dispersion echelle spectra recorded by an image tube. Microdensitometer specifications are presented and the FORTRAN, TRACEN and SPOTS programs are outlined. The intensity spectrum of the photographic or electrographic plate is plotted on a graphic display. The time requirements are discussed in detail.

Jeff Cheatham, senior metrologist

NASA Image and Video Library

2015-01-27

JEFF CHEATHAM, SENIOR METROLOGIST AT THE MARSHALL METROLOGY AND CALIBRATION LABORATORY, SPENT 12 YEARS DEVELOPING 2400 AUTOMATED SOFTWARE PROCEDURES USED FOR CALIBRATION AND TESTING SPACE VEHICLES AND EQUIPMENT

Ability Estimation and Item Calibration Using the One and Three Parameter Logistic Models: A Comparative Study. Research Report 77-1.

ERIC Educational Resources Information Center

Reckase, Mark D.

Latent trait model calibration procedures were used on data obtained from a group testing program. The one-parameter model of Wright and Panchapakesan and the three-parameter logistic model of Wingersky, Wood, and Lord were selected for comparison. These models and their corresponding estimation procedures were compared, using actual and simulated…

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR PREPARATION OF CALIBRATION AND SURROGATE RECOVERY SOLUTIONS FOR GC/MS ANALYSIS OF PESTICIDES (BCO-L-21.1)

EPA Science Inventory

The purpose of this SOP is to describe procedures for preparing calibration curve solutions used for gas chromatography/mass spectrometry (GC/MS) analysis of chlorpyrifos, diazinon, malathion, DDT, DDE, DDD, a-chlordane, and g-chlordane in dust, soil, air, and handwipe sample ext...

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION, CALIBRATION AND MAINTENANCE OF THE PERKIN-ELMER ZEEMAN/5000 SYSTEM ATOMIC ABSORPTION SPECTROMETER (BCO-L-6.0)

EPA Science Inventory

The purpose of this SOP is to outline the start-up, calibration, operation, and maintenance procedures for the Perkin-Elmer 5000 atomic absorption spectrophotometer (PE 5000 AA), and the Perkin Elmer 5000 Zeeman graphite furnace atomic absorption spectrophotometer (PE 5000Z GFAA)...

Improving Building Energy Simulation Programs Through Diagnostic Testing (Fact Sheet)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2012-02-01

New test procedure evaluates quality and accuracy of energy analysis tools for the residential building retrofit market. Reducing the energy use of existing homes in the United States offers significant energy-saving opportunities, which can be identified through building simulation software tools that calculate optimal packages of efficiency measures. To improve the accuracy of energy analysis for residential buildings, the National Renewable Energy Laboratory's (NREL) Buildings Research team developed the Building Energy Simulation Test for Existing Homes (BESTEST-EX), a method for diagnosing and correcting errors in building energy audit software and calibration procedures. BESTEST-EX consists of building physics and utility billmore » calibration test cases, which software developers can use to compare their tools simulation findings to reference results generated with state-of-the-art simulation tools. Overall, the BESTEST-EX methodology: (1) Tests software predictions of retrofit energy savings in existing homes; (2) Ensures building physics calculations and utility bill calibration procedures perform to a minimum standard; and (3) Quantifies impacts of uncertainties in input audit data and occupant behavior. BESTEST-EX is helping software developers identify and correct bugs in their software, as well as develop and test utility bill calibration procedures.« less

Metafitting: Weight optimization for least-squares fitting of PTTI data

NASA Technical Reports Server (NTRS)

Douglas, Rob J.; Boulanger, J.-S.

1995-01-01

For precise time intercomparisons between a master frequency standard and a slave time scale, we have found it useful to quantitatively compare different fitting strategies by examining the standard uncertainty in time or average frequency. It is particularly useful when designing procedures which use intermittent intercomparisons, with some parameterized fit used to interpolate or extrapolate from the calibrating intercomparisons. We use the term 'metafitting' for the choices that are made before a fitting procedure is operationally adopted. We present methods for calculating the standard uncertainty for general, weighted least-squares fits and a method for optimizing these weights for a general noise model suitable for many PTTI applications. We present the results of the metafitting of procedures for the use of a regular schedule of (hypothetical) high-accuracy frequency calibration of a maser time scale. We have identified a cumulative series of improvements that give a significant reduction of the expected standard uncertainty, compared to the simplest procedure of resetting the maser synthesizer after each calibration. The metafitting improvements presented include the optimum choice of weights for the calibration runs, optimized over a period of a week or 10 days.

10 CFR 431.135 - Units to be tested.

Code of Federal Regulations, 2011 CFR

2011-01-01

... EQUIPMENT Automatic Commercial Ice Makers Test Procedures § 431.135 Units to be tested. For each basic model of automatic commercial ice maker selected for testing, a sample of sufficient size shall be selected...

Enhanced Image-Aided Navigation Algorithm with Automatic Calibration and Affine Distortion Prediction

DTIC Science & Technology

2012-03-01

Lowe, David G. “Distinctive Image Features from Scale-Invariant Keypoints”. International Journal of Computer Vision, 2004. 13. Maybeck, Peter S...Fairfax Drive - 3rd Floor Arlington,VA 22203 Dr. Stefanie Tompkins ; (703)248–1540; Stefanie.Tompkins@darpa.mil DARPA Distribution A. Approved for Public

Automatic Web-based Calibration of Network-Capable Shipboard Sensors

DTIC Science & Technology

2007-09-01

Server, Java , Applet, and Servlet . 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18. SECURITY CLASSIFICATION OF THIS PAGE...49 b. Sensor Applet...........................................................................49 3. Java Servlet ...Table 1. Required System Environment Variables for Java Servlet Development. ......25 Table 2. Payload Data Format of the POST Requests from

Testing methods and techniques: Environmental testing: A compilation

NASA Technical Reports Server (NTRS)

1971-01-01

Various devices and techniques are described for testing hardware and components in four special environments: low temperature, high temperature, high pressure, and vibration. Items ranging from an automatic calibrator for pressure transducers to a fixture for testing the susceptibility of materials to ignition by electric spark are included.

7 CFR 802.1 - Qualified laboratories.

Code of Federal Regulations, 2010 CFR

2010-01-01

... certification program having auditing capability is automatically approved by the Service. (2) Any county or... calibration is approved by the Service. The State approval may be documented by a certificate or letter. The.... (Approved by the Office of Management and Budget under control number 0580-0011) [51 FR 7052, Feb. 28, 1986...

One-day offset in daily hydrologic modeling: An exploration of the issue in automatic model calibration

USDA-ARS?s Scientific Manuscript database

The literature of daily hydrologic modelling illustrates that daily simulation models are incapable of accurately representing hydrograph timing due to relationships between precipitation and watershed hydrologic response. For watersheds with a time of concentration less than 24 hrs and a late day p...

Calibration of automatic performance measures - speed and volume data : volume 1, evaluation of the accuracy of traffic volume counts collected by microwave sensors.

DOT National Transportation Integrated Search

2015-09-01

Over the past few years, the Utah Department of Transportation (UDOT) has developed a system called the : Signal Performance Metrics System (SPMS) to evaluate the performance of signalized intersections. This system : currently provides data summarie...

Neural changes associated to procedural learning and automatization process in Developmental Coordination Disorder and/or Developmental Dyslexia.

PubMed

Biotteau, Maëlle; Péran, Patrice; Vayssière, Nathalie; Tallet, Jessica; Albaret, Jean-Michel; Chaix, Yves

2017-03-01

Recent theories hypothesize that procedural learning may support the frequent overlap between neurodevelopmental disorders. The neural circuitry supporting procedural learning includes, among others, cortico-cerebellar and cortico-striatal loops. Alteration of these loops may account for the frequent comorbidity between Developmental Coordination Disorder (DCD) and Developmental Dyslexia (DD). The aim of our study was to investigate cerebral changes due to the learning and automatization of a sequence learning task in children with DD, or DCD, or both disorders. fMRI on 48 children (aged 8-12) with DD, DCD or DD + DCD was used to explore their brain activity during procedural tasks, performed either after two weeks of training or in the early stage of learning. Firstly, our results indicate that all children were able to perform the task with the same level of automaticity, but recruit different brain processes to achieve the same performance. Secondly, our fMRI results do not appear to confirm Nicolson and Fawcett's model. The neural correlates recruited for procedural learning by the DD and the comorbid groups are very close, while the DCD group presents distinct characteristics. This provide a promising direction on the neural mechanisms associated with procedural learning in neurodevelopmental disorders and for understanding comorbidity. Published by Elsevier Ltd.

Development of dynamic calibration methods for POGO pressure transducers. [for space shuttle

NASA Technical Reports Server (NTRS)

Hilten, J. S.; Lederer, P. S.; Vezzetti, C. F.; Mayo-Wells, J. F.

1976-01-01

Two dynamic pressure sources are described for the calibration of pogo pressure transducers used to measure oscillatory pressures generated in the propulsion system of the space shuttle. Rotation of a mercury-filled tube in a vertical plane at frequencies below 5 Hz generates sinusoidal pressures up to 48 kPa, peak-to-peak; vibrating the same mercury-filled tube sinusoidally in the vertical plane extends the frequency response from 5 Hz to 100 Hz at pressures up to 140 kPa, peak-to-peak. The sinusoidal pressure fluctuations can be generated by both methods in the presence of high pressures (bias) up to 55 MPa. Calibration procedures are given in detail for the use of both sources. The dynamic performance of selected transducers was evaluated using these procedures; the results of these calibrations are presented. Calibrations made with the two sources near 5 Hz agree to within 3% of each other.