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Wyszukujesz frazę "Measurement" wg kryterium: Wszystkie pola


Tytuł:
Simultaneous measurement of refractive index and thickness for optically transparent object with a dual-wavelength quantitative technique
Autorzy:
Xu, X.
Wang, Y.
Xu, Y.
Jin, W.
Powiązania:
https://bibliotekanauki.pl/articles/174666.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
digital holography
phase measurement
cell measurement
red blood cell
Opis:
We present a new dual-wavelength quantitative measurement approach that can be employed for simultaneously measuring both the refractive index and the thickness of the homogenous specimen. This method is realized by dual-wavelength in-line phase-shifting digital holography, and then the phase images are obtained by using four-phase step algorithm for each wavelength separately. Based on computer simulation technology, the feasibility and the effectiveness of our proposed method are demonstrated by comparing our simulation results with the experimental results of the spherical silica bead and the red blood cell, respectively. Our work will provide some guidance in the experimental research for transparent phase objects.
Źródło:
Optica Applicata; 2016, 46, 4; 597-605
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Systematic Mapping Study on Software Measurement Programs in SMEs
Autorzy:
Tahir, T.
Rasool, G.
Noman, M.
Powiązania:
https://bibliotekanauki.pl/articles/384081.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
software measurement process
software measurement program
small enterprise (SME)
medium enterprise (SME)
software metrics
software measures
systematic mapping study
GQM
Opis:
Context: Software measurement programs are essential to understand, evaluate, improve and predict the software processes, products and resources. However, successful implementation of software measurement programs (MPs) in small and medium enterprises (SMEs) is challenging. Objective: To perform a detailed analysis of studies on MPs for highlighting the existing measurement models, tools, metrics selection methods and challenges for implementing MPs in SMEs. Methods: A Systematic Mapping Study (SMS) is conducted. Results: In total, 35 primary studies are comprehensively analyzed. We identified 29 software measurement models and 4 tools specifically designed for MPs in SMEs. Majority of the measurement models (51%) are built upon software process improvement approaches. With respect to measurement purposes of models, the distribution of MPs was identified as: characterization (63%), evaluation (83%), improvement (93%) and prediction (16%). Majority of primary studies discussed the use of measurement experts and experience (60%) followed by the use of measurement standards (40% and the use of automated tools (22%) for metrics selection in MPs. We found that the SMEs and large organization face different challenges as studies in SMEs report challenges that exist even before the implementation of MPs due to infrastructure and management processes of SMEs. The challenges reported by studies in large organizations are mostly related to the issues discovered while implementing MPs. Conclusion: The analysis of measurement models, tools, metrics selection methods and challenges of implementing MPs should help the SMEs to make a feasibility study before implementing a MP.
Źródło:
e-Informatica Software Engineering Journal; 2018, 12, 1; 133-165
1897-7979
Pojawia się w:
e-Informatica Software Engineering Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Precise sub-pixel size measurement with linear interpolation
Autorzy:
Yin, A
Yang, Z
Long, G
Powiązania:
https://bibliotekanauki.pl/articles/174568.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
geometry size measurement
linear image sensor
linear interpolation algorithm
Opis:
High precision automated size measurements are required during industrial and scientific applications. The principle of sub-pixel measuring is based on an intensity interpolation algorithm. Combined with the characteristics of light, a system with high precision, short measuring time and low cost was developed. The proposed system is then applied to the measurement of 5 cm objects and compared with traditional measuring techniques. The experiment demonstrates that the measuring accuracy can reach up to 0.012 μm, and that the measurement size of the system is practical and prompt. In addition, it is able to meet the requirement for industrial applications in a variety of settings with stable performance and high precision.
Źródło:
Optica Applicata; 2015, 45, 1; 113-123
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time Domain Measurement Representation in Computer System Diagnostics and Performance Analysis
Autorzy:
Wideł, S.
Flak, J.
Gaj, P.
Powiązania:
https://bibliotekanauki.pl/articles/384100.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
Time Domain Measurement Representation
Computer System Diagnostics
Opis:
Time analysis is a common approach for testing and detecting methods for the performance analysis of computer systems. In the article it is shown, that measuring and identifying performances based on a benchmark is not sufficient for the proper analysis of the computer systems behavior. The response time of the process is often composed of the execution of many subprocesses or many paths of execution. Under this assumption, it is presented, that both convolution and deconvolution methods can be helpful in obtaining time distributions and modeling of complex processes. In such a modeling the analysis of measurement errors is very important and was taken into consideration. The example of using the methods in buffering process is also discussed.
Źródło:
e-Informatica Software Engineering Journal; 2013, 7, 1; 53-64
1897-7979
Pojawia się w:
e-Informatica Software Engineering Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Moving-aperture-based three-dimensional micro-measurement system
Autorzy:
Fan, S.
Yu, M.
Jiang, G.
Wang, Y.
Wang, W.
Li, W.
Powiązania:
https://bibliotekanauki.pl/articles/174026.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
optical microscopy
computational photography
three-dimensional micro-measurement
moving aperture
Opis:
To overcome the depth-of-field limitation of an optical microscope image, a three-dimensional measurement method with a superior depth-of-field is proposed. In the proposed method, light-field information of different angles is obtained by moving the aperture and the three-dimensional scene is reconstructed by using a computational reconstruction technology. First, stereo matching of different aperture position images is performed to obtain the multi-aperture imaging deviation. The focal plane moving distance is thereby estimated. Then, the relational expression between the image coordinates and the focal plane moving distance is determined according to the image coordinates. Two dimensional coordinates of the space point are obtained by the expression coefficients. Finally, the depth coordinates are computed, and three-dimensional reconstruction of the spatial points is completed. Experiments of three-dimensional measurements of the calibration board with different angles and circuit boards are conducted. The results show that the maximum error of the distance measurement is controlled into 0.84%, and the maximum angle measurement error is controlled into 4.56%.
Źródło:
Optica Applicata; 2018, 48, 4; 533-547
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Neural network model for phase-height relationship of each image pixel in 3D shape measurement by machine vision
Autorzy:
Chung, B
Powiązania:
https://bibliotekanauki.pl/articles/173298.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
machine vision
shape measurement
fringe pattern projection
phase-height relationship
neural network
Opis:
In a three-dimensional measurement system based on a digital light processing projector and a camera, a height estimating function is very important. Sinusoidal fringe patterns of the projector are projected onto the object, and the phase of the measuring point is calculated from the camera image. Then, the height of the measuring point is inferred by the phase. The phase-to-height relationship is unique at each image point. However it is nonlinearly different according to the image coordinates. It is also difficult to obtain the geometrical model because of lens distortion. Even though some studies have been performed on neural network models to find the height from the phase and the related coordinates, the results are not good because of the complex relationship. Therefore, this paper proposes a hybrid method that combines a geometric analysis and a neural network model. The proposed method first finds the phase-to-height relationship from a geometric analysis for each image pixel, and then uses a neural network model to find the related parameters for the relationship. The experimental results show that the proposed method is superior to previous neural network methods.
Źródło:
Optica Applicata; 2014, 44, 4; 587-599
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low atmospheric density measurement based on Rayleigh scattering of an ultraviolet laser
Autorzy:
Wang, R
Yao, J.
Zhong, K.
Miao, Y.
Cui, H.
Zhao, X.
Zhang, C.
Powiązania:
https://bibliotekanauki.pl/articles/174910.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
atmospheric density measurement
Rayleigh scattering
ultraviolet laser
Opis:
The qualitative measurement of low atmospheric density in the air flow field has been investigated in this paper. The supersonic flow field with Mach number of 1.5 around the NACA0006 aerofoil has been numerically simulated and the transient slight pressure and low density atmosphere have been experimentally determined based on Rayleigh scattering of a 266 nm ultraviolet laser. The scattering patterns have been effectively captured under different atmospheric pressure of 4.5, 92, 470 and 710 Pa with laser energy of only 0.5 mJ. It has been demonstrated that in the pressure range from 4.5 to 1100 Pa, corresponding to the atmospheric density from 4.8105×10–5 kg/m3 to 1.279×10–2 kg/m3, the scattering intensity of an ultraviolet laser is linear to the pressure and density with the slope coefficient of 0.00968 a.u./Pa and 0.83226 a.u./(kg/m3×10–3). It has been proved that Rayleigh scattering is a promising technology for observation of instantaneous and multidimensional distribution of a supersonic flow field.
Źródło:
Optica Applicata; 2013, 43, 3; 597-605
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement of abdominal retractor loading and its effects on the surgeons arm
Autorzy:
Hučko, B.
Čekan, M.
Horvát, F.
Chlebo, O.
Bachraty, M.
Čambal, M.
Powiązania:
https://bibliotekanauki.pl/articles/1189968.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
hak chirurgiczny
pomiary
zmęczenie mięśni
abdominal retractor
measurement
muscle fatigue
Opis:
A load measuring apparatus integrated into an abdominal retractors and its methodology are presented. The measured forces offer new knowledge in the fields of surgery and may be useful in the design of new retractors and fixing frames as well as the investigation of tissue loading during surgical intervention. Effort required to hold the retractor is quantified for the surgeons forearm and the approximation of muscle fatigue can be evaluated with respect to the duration of surgical intervention.
Źródło:
Interdisciplinary Journal of Engineering Sciences; 2018, 6, 1; 60--63
2300-5874
Pojawia się w:
Interdisciplinary Journal of Engineering Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-uniform illumination correction based on the retinex theory in digital image correlation measurement method
Autorzy:
Gu, G.
She, B.
Xu, G.
Xu, X.
Powiązania:
https://bibliotekanauki.pl/articles/173506.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
digital image correlation (DIC)
non-uniform illumination correction
retinex theory
deformation measurement
Opis:
Digital image correlation is a well-known optical measurement method for full-field deformation and strain measurements. The quality of speckle images used in digital image correlation calculation can directly affect the measurement accuracy of digital image correlation. In most practical measurement circumstances, a uniform illumination environment is usually required to illuminate the detected object in order to capture speckle images upon different deformed states with uniform background intensity. However, the tested object becomes so large that the adopted light source cannot cover all the interested area with uniform illumination, and the speckle images acquired by CCD camera may have non-uniform background intensity distributions. In this paper, the influence of non-uniform illumination is first analyzed in detail by means of a comparison of experimental results of digital image correlation using speckle patterns with both uniform and non-uniform intensity distributions. Then, a new correctional method based on the combination of the basic retinex theory and the illumination formulae of a point light source is proposed. Finally, a real experiment with non-uniform illumination is implemented to verify the effectiveness of this method.
Źródło:
Optica Applicata; 2017, 47, 2; 199-208
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A super depth of field height measurement based on local disparity
Autorzy:
Cui, L.
Liu, Y.
Yu, M.
Jiang, G.
Fan, S.
Wang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/173522.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
microscopes
binocular vision
local disparity map
depth of field (DOF)
height measurement
Opis:
A super depth of field height measurement method is proposed to measure the object height with the optical stereoscopic microscope. The quasi-Euclidean epipolar rectification algorithm is utilized on the original stereoimage to obtain rectified stereoimages and calibrate two camera parameters. Then, feature points are obtained by the SURF (speed up robust feature) algorithm and their corresponding disparities are calculated. The disparity-depth of field curve is fitted by combining the step height values of a stepper motor. Moreover, through local disparity value got from feature points on the object, the relative shift height is calculated through regression analysis. Finally, according to binocular vision geometry, the thickness of the object can be calculated. Experimental results show that the measurement error in Z direction is from 1.51% to 7.71%, which indicates that the proposed method is able to measure the height of a microobject beyond depth of field within a tolerant error.
Źródło:
Optica Applicata; 2015, 45, 2; 205-214
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Method for improving sinusoidal quality of error diffusion binary encoded fringe used in phase measurement profilometry
Autorzy:
Tian, Z.
Chen, W.
Su, X.
Powiązania:
https://bibliotekanauki.pl/articles/174421.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
phase measurement profilometry
digital-light-processing projector
DLP projector
error diffusion algorithm
binary encoded grating
Opis:
Insufficient resolution of digital-light-processing projector will degrade the sinusoidal quality of the binary encoded fringe pattern because of less sampling points in a fringe period, which will degrade the measurement accuracy if it is used in phase measurement profilometry. Two resolutions are proposed in the paper. One is that a cylindrical lens is introduced in the projecting light path of the measurement system to improve sinusoidal quality of the binary encoded fringe by elliptical low-pass filtering of the system. The other one is that superposition of multi-frame binary encoded gratings with different microstructure is to reduce the binary image noise for improving the measurement accuracy. Simulations and experiments verify the validity of the above two methods.
Źródło:
Optica Applicata; 2016, 46, 2; 291-303
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Depth-resolved measurement of the compression displacement fields on the front and rear surfaces of an epoxy sample
Autorzy:
Zhang, W.
Dong, B.
He, Z.
Xie, S.
Zhou, Y.
Powiązania:
https://bibliotekanauki.pl/articles/174399.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
depth-resolved measurement
compression displacement field
wavenumber-scanning interferometry
epoxy
Opis:
Compression is one of the typical parameters measured in material mechanics. In this research, the compression displacement fields on the front and rear surfaces of an epoxy sample are measured by using a tilt depth-resolved wavenumber-scanning Michelson interferometer. The light source is a distributed feedback laser diode, the wavenumber of which can be modulated to about 1.017 × 104 m–1 by the temperature without mode hopping. A random-sampling Fourier transform is designed to evaluate the phase differences before and after the applied loads. Experimental results show that the depth-resolved measurement of the compression displacement field is of high accuracy. It can be used to analyze force propagation inside resin-based composites.
Źródło:
Optica Applicata; 2018, 48, 2; 311-323
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method for improving the precision of on-line phase measurement profilometry
Autorzy:
Mao, Z
Cao, Y
Zhong, L
Cao, S
Powiązania:
https://bibliotekanauki.pl/articles/174406.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
information optics
Stoilov's algorithm
phase measuring profilometry (PMP)
on-line phase measurement profilometry (OPMP)
phase-shifting
pixel matching
Opis:
An on-line phase measurement profilometry based on improved Stoilov’s algorithm is proposed to measure the 3D shape of moving object. While only one frame sinusoidal grating is projected on the moving object, the equal phase-shifting step deformed patterns modulated by profile of the measured object can be captured at every equivalent moving distance of the measured object instead of digital phase-shifting. Stoilov’s algorithm is an equal phase-shifting step algorithm at an arbitrary phase-shifting step, which is suitable for on-line phase measurement profilometry. However, the arbitrary phase-shifting step of Stoilov’s algorithm depends on the captured deformed patterns, in which the digitized errors of digital light projector or CCD camera, and the disturbance of surrounding light could be introduced, it will lead to some abnormities in wrapped phase, such as the denominator in Stoilov’s algorithm could be zero, which could cause the reconstructed 3D profile of the measured object appear burr, distortion or aberration, even could not be reconstructed. So an on-line phase measurement profilometry based on improved Stoilov’s algorithm is proposed. The arbitrary phase-shifting step is retrieved by both pixel matching and fringe cycle calibration rather than the captured deformed patterns. Experiments verify the feasibility and effectiveness of the proposed on-line phase measurement profilometry.
Źródło:
Optica Applicata; 2015, 45, 1; 51-61
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-parameter measurement under fiber bending based on directional resonance coupling in photonic crystal fibers
Autorzy:
Tan, C.
Wang, Q.
Ding, Y.
Li, H.-W.
Wang, M.
Liu, H.
Powiązania:
https://bibliotekanauki.pl/articles/174320.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fiber bending
multi-parameter measurement
photonic crystal fiber
fiber sensing
Opis:
A multi-parameter sensor with enhanced sensitivity based on magnetic fluids infiltrated photonic crystal fiber is proposed. The sensing performances are investigated using the mode coupling theory and finite element method. Four symmetrical defective channels are assembled into the photonic crystal fiber to produce two resonant transmission dips λCV and λCH in vertical and horizontal directions, respectively. Each dip can be split into two relatively shallow dips (λCV1, λCV2 or λCH1, λCH2) when the photonic crystal fiber is bent. Interestingly, the values of (λCH2 – λCH1) and (λCV2 – λCV1) are associated with corresponding bend-curvature but almost unaffected by external temperature or magnetic field. On the contrary, the values of (λCH2 + λCH1)/2 and (λCV2 + λCV1)/2 are sensitive to temperature or magnetic field regardless of the bending condition. Based on above characteristics and the dependence of the magnetic fluids refractive index on temperature and magnetic field, the proposed sensor can measure not only the bend-curvature and bend-direction, but also the temperature and magnetic field.
Źródło:
Optica Applicata; 2018, 48, 3; 449-462
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metrological requirements for measurements of circadian radiation
Autorzy:
Jakubowski, P.
Fryc, I.
Powiązania:
https://bibliotekanauki.pl/articles/174805.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
circadian radiation
optical measurement
LED lighting
Opis:
The article presents a definition of circadian radiation and its influence on human beings. Typical sources of this radiation have been discussed and compared. As the availability of devices designed for circadian radiation measurement is very limited, and their quality is rather poor, there is a need for the development of a new meter which would deliver precise data. The paper presents available methods of optical radiation measurement which can be used in a circadian radiation assessment. Advantages and disadvantages of presented methods have been discussed. A light path in typical measurement instruments has been analyzed, as well as the impact of each component on the final result (i.e. the influence of spatial correction, optical filters and detectors). Original results of authors’ research have been presented and the concept for decreasing the measurement error has been proposed.
Źródło:
Optica Applicata; 2018, 48, 4; 697-704
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł

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