Artificial Star Test for Crowded Field CCD Photometry

2015 ◽  
Vol 24 (3) ◽  
Author(s):  
R. Stonkutė ◽  
V. Vansevičius
Keyword(s):  
Error Estimates ◽  
Spatial Resolution ◽  
New Method ◽  
Ccd Photometry ◽  
Artificial Star ◽  
Star Test

AbstractA new method of performing an artificial star test (AST) for crowded field stellar CCD photometry is proposed. This AST method is superior in the cases when it is necessary to account for varying photometric quality across the study field, arising due to crowding variations. For this purpose, the color-magnitude diagrams (CMDs) of AST stars with statistically reliable error estimates, as well as completeness maps, can be generated at a required spatial resolution.

scholarly journals A New Method for Investigation of the Hair Shaft: Hard X-Ray Microscopy with a 90-nm Spatial Resolution

2008 ◽  
Vol 49 (2) ◽  
pp. 337 ◽  
Author(s):  
Soo-Young Jeon ◽  
Ja Woong Goo ◽  
Seung Phil Hong ◽  
Tak Heon Oh ◽  
Hwa Shik Youn ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Hair Shaft ◽  
New Method ◽  
X Ray

scholarly journals A new method for mapping spatial resolution in compound eyes suggests two visual streaks in fiddler crabs

2019 ◽  
Vol 223 (1) ◽  
pp. jeb210195 ◽  
Author(s):  
Zahra M. Bagheri ◽  
Anna-Lee Jessop ◽  
Susumu Kato ◽  
Julian C. Partridge ◽  
Jeremy Shaw ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
New Method ◽  
Compound Eyes ◽  
Fiddler Crabs

scholarly journals Generating Optimal Initial Conditions for Smoothed Particle Hydrodynamics Simulations

2015 ◽  
Vol 32 ◽  
Author(s):  
S. Diehl ◽  
G. Rockefeller ◽  
C. L. Fryer ◽  
D. Riethmiller ◽  
T. S. Statler
Keyword(s):  
Spatial Resolution ◽  
Smoothed Particle Hydrodynamics ◽  
Initial Conditions ◽  
New Method ◽  
Voronoi Tessellations ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Resolution Requirements

AbstractWe review existing smoothed particle hydrodynamics setup methods and outline their advantages, limitations, and drawbacks. We present a new method for constructing initial conditions for smoothed particle hydrodynamics simulations, which may also be of interest for N-body simulations, and demonstrate this method on a number of applications. This new method is inspired by adaptive binning techniques using weighted Voronoi tessellations. Particles are placed and iteratively moved based on their proximity to neighbouring particles and the desired spatial resolution. This new method can satisfy arbitrarily complex spatial resolution requirements.

Artificial star test by real-time video holography for the adjustment of high-numerical-aperture micro-objectives

2003 ◽  
Vol 42 (25) ◽  
pp. 5073 ◽  
Author(s):  
Joachim Heil ◽  
Joachim Wesner ◽  
Willi Müller ◽  
Thomas Sure
Keyword(s):  
Real Time ◽  
Numerical Aperture ◽  
High Numerical Aperture ◽  
Artificial Star ◽  
Star Test

scholarly journals RESEARCH ON HORIZONTAL ACCURACY METHOD OF HIGH SPATIAL RESOLUTION REMOTELY SENSED ORTHOPHOTO IMAGE

2018 ◽  
Vol XLII-3 ◽  
pp. 2005-2007
Author(s):  
Y. M. Xu ◽  
J. X. Zhang ◽  
F. Yu ◽  
S. Dong
Keyword(s):  
Remote Sensing ◽  
High Resolution ◽  
Spatial Resolution ◽  
Field Measurement ◽  
Reference Data ◽  
High Spatial Resolution ◽  
Remote Sensing Image ◽  
High Accuracy ◽  
New Method ◽  
Orthophoto Images

At present, in the inspection and acceptance of high spatial resolution remotly sensed orthophoto image, the horizontal accuracy detection is testing and evaluating the accuracy of images, which mostly based on a set of testing points with the same accuracy and reliability. However, it is difficult to get a set of testing points with the same accuracy and reliability in the areas where the field measurement is difficult and the reference data with high accuracy is not enough. So it is difficult to test and evaluate the horizontal accuracy of the orthophoto image. The uncertainty of the horizontal accuracy has become a bottleneck for the application of satellite borne high-resolution remote sensing image and the scope of service expansion. Therefore, this paper proposes a new method to test the horizontal accuracy of orthophoto image. This method using the testing points with different accuracy and reliability. These points’ source is high accuracy reference data and field measurement. The new method solves the horizontal accuracy detection of the orthophoto image in the difficult areas and provides the basis for providing reliable orthophoto images to the users.

Construction of passport static characteristics of the system using the interval approach

2021 ◽  
Vol 87 (1) ◽  
pp. 68-76
Author(s):  
N. V. Skibitskiy
Keyword(s):  
Error Estimates ◽  
Measurement System ◽  
Statistical Approach ◽  
Static Characteristic ◽  
New Method ◽  
Static Characteristics ◽  
Operating Range ◽  
Operation Conditions ◽  
Active Experiment ◽  
Interval Approach

An approach to constructing direct and inverse static characteristics of the system is considered proceeding from the experimental data obtained using a traditional «black box» concept, whereby the results of the experiment containing measured input and output values are used which, in practice, are determined with errors. The presence of various sources and trigger interference factors leads to a significant distortion of the error estimates and the formation of an inadequate conversion response. A crucially different character of the impact on the measurement results can be observed taking into account the type and sources of errors upon formation of the static characteristics and developing a model of noise arising upon measurements in actual operation conditions and during the experiment. However, analysis of the existing method based on a statistical approach and used for determining the error of the object model revealed a number of shortcomings: focusing mainly on the random components of errors and complexity of taking into account non-statistical information, including a priori information about the systematic errors, round-off and sampling errors, and the errors of the measurement system used in upon developing a model of the system. The statistical approach does not provide theoretical substantiation of the solution of the problem of the inverse static characteristic of the system which is relevant for many applications. Moreover, the fact that the interference models under experimental and real operation conditions have different sources and are generated by different factors is ignored in the framework of the statistical approach, which can lead to a significant distortion of the error estimates of the system model and to the formation of an inadequate direct and inverse transformation characteristics. We propose to eliminate the aforementioned shortcomings using the interval approach. The problem of developing a new method for constructing the passport characteristic of the inverse static function of a system is solved on the basis of a two-stage procedure of the experimental design. A new method based on the interval approach has been developed in which the problem of constructing the inverse static characteristic of the system and the problem of determining the error of the measurement system are solved separately using different types of active experiment. The boundaries of the uncertainty interval of the measurement system are defined in the general case by spline-functions. A concept of the operating range of the system, which does not coincide with the range of changes of the measured value in an active experiment, is introduced. It is shown that outside the operating range the system error sharply increases and becomes asymmetric with respect to the inverse static characteristic.

scholarly journals A new approach to accurate validation of remote sensing retrieval of evapotranspiration based on data fusion

2010 ◽  
Vol 7 (2) ◽  
pp. 1745-1784 ◽  
Author(s):  
C. Sun ◽  
D. Jiang ◽  
J. Wang ◽  
Y. Zhu
Keyword(s):  
Remote Sensing ◽  
Data Fusion ◽  
Spatial Resolution ◽  
Hydrological Model ◽  
Assessment Tool ◽  
High Spatial Resolution ◽  
Meteorological Data ◽  
New Method ◽  
Distributed Hydrological Model ◽  
New Approach

Abstract. The study presented a new method of validating the remote-sensing (RS) retrieval of evapotranspiration (ET) under the support of a distributed hydrological model: Soil and Water Assessment Tool (SWAT). In this method, the output runoff data based on a fusion of ET data, meteorological data and rainfall data, etc. were compared with the observed runoff data, so as to carry out validation analysis. A new pattern of validating the ET data obtained from RS retrieval, which was more appropriate than the conventional means of observing the ET at several limited stations based on eddy covariance, was proposed. It has integrated the advantage of high requirement of ET with high spatial resolution in the distributed hydrological model and that of the capacity of providing ET with high spatial resolution in RS methods. First, the ET data in five years (2000–2004) were retrieved with RS according to the principle of energy balance. The temporal/spatial ditribution of monthly ET data and related causes were analyzed in the year of 2000, and the monthly ET in the five years was calculated according to the PM model. Subsequently, the results of the RS retrieval of ET and the PM-based ET calculation were compared and validated. Finnaly, the ET data obtained from RS retrieval was evaluated with the new method, under the support of SWAT, meteorologic data, Digital Elevation Model (DEM), landuse data and soil data, etc. as the input, being compared with the PM-based ET. According to the ET data analysis, it can be inferred that the ET obtained from RS retrieval was more continuous and stable with less saltation, while the PM-based ET presented saltation, especially in the year of 2000 and 2001. The correlation coefficient between the monthly ET in two methods reaches 0.8914, which could be explained by the influence from clouds and the inadequate representativeness of the meteorologic stations. Moreover, the PM-based ET was smaller than the ET obtained from RS retrieval, which was in accordance with previous studies (Jamieson, 1982; Dugas and Ainsworth, 1985; Benson et al., 1992; Pereira and Nova, 1992). After the data fusion, the correlation (R2=0.8516) between the monthly runoff obtained from the simulation based on ET retrieval and the observed data was higher than that (R2=0.8411) between the data obtained from the PM-based ET simulation and the observed data. As for the RMSE, the result (RMSE=26.0860) between the simulated runoff based on ET retrieval and the observed data was also superior to the result (RMSE=35.71904) between the simulated runoff obtained with PM-based ET and the observed data. As for the MBE parameter, the result (MBE=−8.6578) for the RS retrieval method was obviously better than that (MBE=−22.7313) for the PM-based method. The comparison of them showed that the RS retrieval had better adaptivity and higher accuracy than the PM-based method, and the new approach based on data fusion and the distributed hydrological model was feasible, reliable and worth being studied further.

scholarly journals Innovations orthogonalization: a solution to the major pitfalls of EEG/MEG “leakage correction”

2017 ◽  
Author(s):  
Roberto D. Pascual-Marqui ◽  
Rolando J. Biscay ◽  
Jorge Bosch-Bayard ◽  
Pascal Faber ◽  
Toshihiko Kinoshita ◽  
...  
Keyword(s):  
Time Series ◽  
Spatial Resolution ◽  
Autoregressive Model ◽  
Cross Correlation ◽  
Effective Connectivity ◽  
Inverse Solution ◽  
New Method ◽  
Major Goal ◽  
Non Invasive ◽  
Multivariate Autoregression

1.AbstractThe problem of interest here is the study of brain functional and effective connectivity based non-invasive EEG-MEG inverse solution time series. These signals generally have low spatial resolution, such that an estimated signal at any one site is an instantaneous linear mixture of the true, actual, unobserved signals across all cortical sites. False connectivity can result from analysis of these low-resolution signals. Recent efforts toward “unmixing” have been developed, under the name of “leakage correction”. One recent noteworthy approach is that by Colclough et al (2015 NeuroImage, 117:439-448), which forces the inverse solution signals to have zero cross-correlation at lag zero. One goal is to show that Colclough’s method produces false human connectomes under very broad conditions. The second major goal is to develop a new solution, that appropriately “unmixes” the inverse solution signals, based on innovations orthogonalization. The new method first fits a multivariate autoregression to the inverse solution signals, giving the mixed innovations. Second, the mixed innovations are orthogonalized. Third, the mixed and orthogonalized innovations allow the estimation of the “unmixing” matrix, which is then finally used to “unmix” the inverse solution signals. It is shown that under very broad conditions, the new method produces proper human connectomes, even when the signals are not generated by an autoregressive model.

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