scholarly journals An accurate fingerprint reference point determination method based on curvature estimation of separated ridges

2018 ◽  
Vol 28 (1) ◽  
pp. 209-225 ◽  
Author(s):  
Rafal Doroz ◽  
Krzysztof Wrobel ◽  
Piotr Porwik
Keyword(s):  
Reference Point ◽  
Reference Points ◽  
Second Step ◽  
Multi Stage ◽  
Stage System ◽  
Series Of Experiments ◽  
Curvature Estimation ◽  
Point Determination ◽  
Point Detection

AbstractThis paper presents an effective method for the detection of a fingerprint’s reference point by analyzing fingerprint ridges’ curvatures. The proposed approach is a multi-stage system. The first step extracts the fingerprint ridges from an image and transforms them into chains of discrete points. In the second step, the obtained chains of points are processed by a dedicated algorithm to detect corners and other points of highest curvature on their planar surface. In a series of experiments we demonstrate that the proposed method based on this algorithm allows effective determination of fingerprint reference points. Furthermore, the proposed method is relatively simple and achieves better results when compared with the approaches known from the literature. The reference point detection experiments were conducted using publicly available fingerprint databases FVC2000, FVC2002, FVC2004 and NIST

A modified approach for automated reference point determination of SLR and VLBI telescopes

2018 ◽  
Vol 85 (10) ◽  
pp. 616-626 ◽  
Author(s):  
Michael Lösler ◽  
Cornelia Eschelbach ◽  
Stefan Riepl
Keyword(s):  
Reference Point ◽  
Terrestrial Reference Frame ◽  
Reference Points ◽  
Combination Process ◽  
Local Ties ◽  
Synchronization Errors ◽  
Space Geodetic Techniques ◽  
Point Determination ◽  
Technical Effort

AbstractThe International Terrestrial Reference Frame (ITRF) is derived by combining several space geodetic techniques. Basically, a meaningful combination of the geodesic space techniques is impossible without further geometrical information, i. e. local-ties. Local-tie vectors are defined between the geometrical reference points of space geodetic techniques at co-location stations. These local-ties are introduced during the inter-technique combination process, to overcome the weak physical connection between the space geodetic techniques. In particular, the determination of the reference point of radio telescopes or laser telescopes is a challenging task and requires indirect methods. Moreover, the Global Geodetic Observing System (GGOS) strives for an automated and continued reference point determination with sub-millimeter accuracy, because deviations in local-ties bias global results.This investigation presents a modified approach for automated reference point determination. The new approach extends the prior work of Lösler but evades the synchronization between the terrestrial instrument and the telescope. Thus, synchronization errors are omitted and the technical effort is reduced. A proof of concept was carried out at Geodetic Observatory Wettzell in 2018. Using a high-precision, mobile laser-tracker, the reference point of the Satellite Observing System Wettzell (SOS-W) was derived. An extended version of the in-house developed software package HEIMDALL was employed for a mostly automated data collection. To evaluate the estimated reference point, the derived results are compared with the results of two approved models.

scholarly journals ILRS Reference Point Determination Using Close Range Photogrammetry

2021 ◽  
Vol 11 (6) ◽  
pp. 2785
Author(s):  
Michael Lösler ◽  
Cornelia Eschelbach ◽  
Thomas Klügel ◽  
Stefan Riepl
Keyword(s):  
Reference Point ◽  
Reference Points ◽  
Geodetic Reference System ◽  
Unscented Transformation ◽  
Local Ties ◽  
Close Range Photogrammetry ◽  
Crucial Component ◽  
Space Geodetic Techniques ◽  
Close Range ◽  
Point Determination

A global geodetic reference system (GGRS) is realized by physical points on the Earth’s surface and is referred to as a global geodetic reference frame (GGRF). The GGRF is derived by combining several space geodetic techniques, and the reference points of these techniques are the physical points of such a realization. Due to the weak physical connection between the space geodetic techniques, so-called local ties are introduced to the combination procedure. A local tie is the spatial vector defined between the reference points of two space geodetic techniques. It is derivable by local measurements at multitechnique stations, which operate more than one space geodetic technique. Local ties are a crucial component within the intertechnique combination; therefore, erroneous or outdated vectors affect the global results. In order to reach the ambitious accuracy goal of 1 mm for a global position, the global geodetic observing system (GGOS) aims for strategies to improve local ties, and, thus, the reference point determination procedures. In this contribution, close range photogrammetry is applied for the first time to determine the reference point of a laser telescope used for satellite laser ranging (SLR) at Geodetic Observatory Wettzell (GOW). A measurement campaign using various configurations was performed at the Satellite Observing System Wettzell (SOS-W) to evaluate the achievable accuracy and the measurement effort. The bias of the estimates were studied using an unscented transformation. Biases occur if nonlinear functions are replaced and are solved by linear substitute problems. Moreover, the influence of the chosen stochastic model onto the estimates is studied by means of various dispersion matrices of the observations. It is shown that the resulting standard deviations are two to three times overestimated if stochastic dependencies are neglected.

A Comprehensive Algorithm for Detection, Identification of Naval Surface Forces and Target Allocation of Network-Centric Controlled Weapons

2020 ◽  
pp. 75-98
Author(s):  
E.M. Voronov ◽  
A.M. Kuslya ◽  
A.L. Repkin ◽  
S.I. Sychev ◽  
N.V. Khamaev ◽  
...  
Keyword(s):  
Surface Forces ◽  
Multi Stage ◽  
Detection And Identification ◽  
Statistical Series ◽  
Algorithm Operation ◽  
Main Target ◽  
Series Of Experiments ◽  
Target Allocation ◽  
High Degree

The purpose of the study was to examine and solve the problem of detecting and identifying the objects of naval surface forces by a group of controlled weapons within the group using coordinates and the type of such objects. The main target of naval surface forces was determined according to the parameters of the frequency of detection of the objects by the group of controlled weapons and the reliability of identification of the objects of naval surface forces. A matrix for detecting the objects of naval surface forces by the group of controlled weapons has been formed and analyzed. The introduction of restrictions on the tactics of actions of the group of controlled weapons and on the coefficient of convolution of criteria in the task of target allocation makes it possible to ensure almost complete absence of intersections of trajectories of controlled weapons. On the basis of statistical modeling of the configuration of the systems and the corresponding probabilities of detection and identification, the effectiveness of the developed algorithm is shown. An example of a multi-stage calculation of one variant from a statistical series of experiments is given, followed by a preliminary assessment of target allocation by the group of controlled weapons in accordance with the current configurations of the group of weapons and naval surface forces. The multivariate analysis of the efficiency of the algorithm operation on various configurations of the systems showed a high degree of identification of the objects of naval surface forces in comparison with the existing algorithms. A range of values for the probabilities of identifying the types of the objects of naval surface forces by the group of controlled weapons has been identified, which provides an almost unambiguous determination of the main target of naval surface forces

An Optimizing Method to Balance Aerodynamic Loading for Gas Turbine Engine Preliminary Design

2013 ◽  
Author(s):  
Qiuye Tu ◽  
Xianzhong Huang ◽  
Yang Shi ◽  
Kun Yang ◽  
Li Zhou
Keyword(s):  
Reference Point ◽  
Second Step ◽  
Preliminary Design ◽  
Aerodynamic Optimization ◽  
Turbine Engine ◽  
Axial Compressors ◽  
Aerodynamic Loading ◽  
Dimensional Parameters ◽  
Point Determination ◽  
Set Up

This paper presents a method to balance aerodynamic loading by optimizing the combined efficiencies of co-axial compressors and turbines for engine preliminary design. Relationships between the aerodynamic and dimensional parameters for co-axial compressors and turbines were set up by nonlinear equations. And the boundary conditions of the equations are thermodynamic parameters and Smith Charts of compressors and turbines. The process of the method includes the initial value guess, reference point determination and aerodynamic optimization. The first step solves approximate stage numbers for co-axial compressors and turbines, and other initial values used in the second step. In the second step, an appropriate solution of the equations determines a reference point on the Smith Chart. The first step is required for a better convergence in the second step due to the nature of the Newton-Raphson solver. In the third step, the combined efficiencies of co-axial compressors and turbines are optimized under the specified constraints. An optimizing tool was developed based on the proposed method. An example of a core engine was analyzed by using this tool. The results showed the reliability and high fidelity of the method.

A Rapid and Automatic Feature Extraction Method for Artificial Targets Used in Industrial Photogrammetry Applications

2012 ◽  
Vol 170-173 ◽  
pp. 2995-2998
Author(s):  
Jian Wei Liu ◽  
Zhi Qiang Jiang ◽  
Hao Hu ◽  
Xin Yin
Keyword(s):  
Feature Extraction ◽  
Reference Point ◽  
Extraction Method ◽  
Target Location ◽  
Reference Points ◽  
Improved Method ◽  
Feature Extraction Method ◽  
Automatic Feature Extraction ◽  
Centroid Algorithm ◽  
Point Detection

Distributing artificial targets on the object to be measured is a reliable and common method for achieving optimum target location and accurate correspondence among multi-view images, which are universally adopted in industrial photogrammetry applications. In this paper artificial circular un-coded targets and coded targets are used as reference points, an automatic and rapid algorithm for reference point detection is proposed. Targets are extracted from the images according to their size, shape, intensity , etc. An improved method to identify the ID of the coded target is proposed. The gray scale centroid algorithm is applied to get sub-pixel locations of both un-coded and coded targets. Practical examples show that the algorithm can identify and locate artificial targets in images quickly and accurately. It is robust to the change of projection angles and noise.

Cognitive Reflection Effects on Time Discounting

2018 ◽  
Vol 39 (2) ◽  
pp. 99-106 ◽  
Author(s):  
Michał Białek ◽  
Przemysław Sawicki
Keyword(s):  
Individual Differences ◽  
Individual Difference ◽  
Delay Discounting ◽  
Reference Point ◽  
Reference Points ◽  
Cognitive Reflection Test ◽  
Process Information ◽  
Time Discounting ◽  
Cognitive Reflection ◽  
The Way

Abstract. In this work, we investigated individual differences in cognitive reflection effects on delay discounting – a preference for smaller sooner over larger later payoff. People are claimed to prefer more these alternatives they considered first – so-called reference point – over the alternatives they considered later. Cognitive reflection affects the way individuals process information, with less reflective individuals relying predominantly on the first information they consider, thus, being more susceptible to reference points as compared to more reflective individuals. In Experiment 1, we confirmed that individuals who scored high on the Cognitive Reflection Test discount less strongly than less reflective individuals, but we also show that such individuals are less susceptible to imposed reference points. Experiment 2 replicated these findings additionally providing evidence that cognitive reflection predicts discounting strength and (in)dependency to reference points over and above individual difference in numeracy.

The Effect of Stress and Warfarin on the Adrenal Gland in Relation to Spontaneous Hemorrhage, as Judged by Measurement of Adrenal Ascorbic Acid and Serum Corticosterone

1971 ◽  
Vol 26 (02) ◽  
pp. 275-288 ◽  
Author(s):  
S Chattopadhyay ◽  
D. D Johnson ◽  
G. J Millar ◽  
L. B Jaques
Keyword(s):  
Ascorbic Acid ◽  
Acid Concentration ◽  
Ascorbic Acid Concentration ◽  
Corticosterone Concentration ◽  
Serum Corticosterone ◽  
Spontaneous Hemorrhage ◽  
Combined Action ◽  
Series Of Experiments ◽  
Pituitary Adrenal Axis

SummaryRats were subjected to the following procedures: No treatment, Stressor (10% NaCl i.p.), Warfarin for 7 days, Stressor followed by Warfarin; and groups were sacrificed at intervals for assessment of spontaneous hemorrhage and of adrenal ascorbic acid concentration. There was no hemorrhage in the no treatment and stressor groups; some hemorrhage in the warfarin group; profound hemorrhage with Warfarin + Stressor. The adrenal ascorbic acid concentration was found to be lower, 8 h and again 5 days after stress, and remained lower in the warfarin + stress animals. Warfarin had no effect on adrenal ascorbic acid level.In another series of experiments in which the stress consisted of an electric current to the cage floor for 6 sec over 15 min, rats were sacrificed daily for determination of serum corticosterone concentration and occurrence of spontaneous hemorrhage. There was a statistically significant increase of serum corticosterone concentration with stress, warfarin and combined warfarin and stress treatments (P< 0.001 for all three variables). There was a significant correlation (r = 0.96 and 0.89, P< 0.01) for serum corticosterone concentration with hemorrhage score and incidence of hemorrhage in stressed rats receiving warfarin, but not in those receiving only warfarin. The results indicate an activation, rather than an exhaustion, of the pituitary-adrenal axis during the combined action of anticoagulant and stress, which results in the development of spontaneous hemorrhage.

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