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Tytuł:
Modeling and evaluation of performance of dual field-of-view common-aperture dual-band imaging system
Autorzy:
Wang, Qingsong
Gao, Ming
Powiązania:
https://bibliotekanauki.pl/articles/2172850.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
common aperture
dual-band
dual FOV
performance modeling
Opis:
For the modeling and evaluation of dual field-of-view (FOV) common-aperture dual-band imaging system performance, two factors must be considered at the same time. One is that the system must have a larger target acquisition range, and the other is that the detection range and recognition range of the system must be the same. In this paper, taking the dual FOV common-aperture visible/long-wave infrared (LWIR) imaging system as an example, the performance of the dual FOV common-aperture dual-band imaging system is modeled and evaluated using an imaging system performance model based on comprehensive resolution. Firstly, the target acquisition range of the dual FOV visible imaging system is analyzed, and the condition that the detection range is equal to the recognition range is obtained. Then, under the condition of common aperture, the target acquisition range and the relationship between detection range and recognition range of dual FOV LWIR imaging system are analyzed. The analysis results show that, under the condition of dual FOV and common aperture, when the detection and recognition ranges of the visible imaging system are equal, the detection and recognition ranges of the LWIR imaging system are not equal. When the detection and recognition ranges are close by reducing the comprehensive resolution, the target acquisition range of the dual FOV common-aperture dual-band imaging system will decrease.
Źródło:
Optica Applicata; 2022, 52, 4; 535--550
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A novel type of wearable dual-band antenna based on coplanar waveguide feeding for wearable wireless communications
Autorzy:
He, Zhengrui
Jin, Jie
Powiązania:
https://bibliotekanauki.pl/articles/1835773.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
wearable antenna
dual-band antenna
CPW-feed
metasurface
Opis:
A flexible and compact coplanar waveguide feed (CPW-fed) wearable antenna is introduced for wireless wearable communications applications at the industrial scientific medical (ISM) band. The proposed antenna consists of copper, which is used as the radiation patch and ground planes printed on the same side of polyimide flexible substrate. The overall size of the antenna is 30 mm × 28 mm × 0.08 mm, the results show that the antenna can transmit and receive signals in two frequency bands of 1.89–2.67 GHz and 3.02–3.23 GHz, in which radiating properties are characterized and agree well with the simulation results. The antenna is bent in different directions to further investigate the reflection coefficient and corresponding effect on the antenna under bending. The center frequency of the antenna is slightly shifted towards higher and lower frequencies when antenna is bent in X-axis and Y-axis, respectively. Furthermore, the wearability of the antenna is verified when the antenna is placed on different parts of the human body such as wrist and chest. Hence, the proposed flexible antenna is a suitable candidate for wearable wireless communication applications.
Źródło:
Optica Applicata; 2021, 51, 2; 159-170
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of dual-core photonic crystal fiber based temperature and pressure sensor for oceanic applications
Autorzy:
Jegadeesan, Subramani
Dhamodaran, Muneeswaran
Sri Shanmugapriya, Swaminathan
Powiązania:
https://bibliotekanauki.pl/articles/175134.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
dual core
photonic crystal fiber
birefringence
temperature sensor
pressure sensor
finite element method
Opis:
In this paper, a microstructured optical fiber with dual core was proposed which is known as photonic crystal fiber. Specific optical properties of a dual-core photonic crystal fiber were used to obtain high birefringence, small beat length, flattened dispersion, for different values of structural parameters varied over a wide range of wavelength and analyzed for application such as temperature and pressure sensors. The sensitivity of the temperature sensor is calculated as 20 pm/°C for 6 cm fiber, the sensitivity of the pressure sensor for a range from 0 to 1000 kPa is calculated as –10.5 nm/MPa.
Źródło:
Optica Applicata; 2019, 49, 2; 249-264
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two-step dual-wavelength interferometry for surface relief retrieval
Autorzy:
Kmet, Arkady B.
Muravsky, Leonid I.
Voronyak, Taras I.
Stasyshyn, Ihor V.
Powiązania:
https://bibliotekanauki.pl/articles/173569.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
dual-wavelength interferometry
two-step phase shifting interferometry
blind phase shift
surface relief retrieval
areal surface roughness
areal waviness
phase map
Opis:
The new two-step dual-wavelength interferometry method that uses only two pairs of interferograms for surface relief retrieval is proposed. In this method, two interferograms in each pair are differed only by an arbitrary phase shift of a reference wave. The method allows using only one out-of-plane shift of a reference wave to record each second interferogram in both pairs, since arbitrary phase shifts between interferograms in each pair can be defined by calculation of the correlation coefficient between two interferograms. This method can extract separately areal surface roughness and areal waviness phase maps from a phase map of the total surface relief and reduce errors produced during the surface relief retrieving. Computer simulation and experimental verification have confirmed the reliability of the proposed method.
Źródło:
Optica Applicata; 2019, 49, 2; 331-343
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of a visible dual broadband nearly perfect absorber
Autorzy:
Jia, Xiuli
Powiązania:
https://bibliotekanauki.pl/articles/174436.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
metamaterials
visible absorber
polarization-independent
nearly perfect absorption
Opis:
Many optical systems benefit from elements that can absorb a broad range of wavelengths over a wide range of angles, independent of polarization. In this paper, we present a nearly perfect absorber with dual broadband and polarization-independent in the visible regime that exploits strong symmetric and asymmetric resonance modes of electromagnetic dipoles. It makes use of a bilayer hollowed-out cross pattern structure which is simple, having five layers that include two stacks of metal film with hollowed-out ribbon in cross patterns, two dielectric spacers, and a metal reflecting layer. Simulations show that the design exhibits a significantly enhanced absorption property when compared to a device with a normal cross pattern structure. The nearly perfect absorption efficiency of the device is above 98.5% at two resonances regimes: from 5.57 × 1014to 6.08 × 1014Hz and from 6.75 × 1014to 7.05 × 1014Hz, and its stable absorption characteristics can be maintained over a wide range of polarizing angle – up to ±90°. This strategy can, in principle, be applied to other material systems and could be useful in diverse applications, including thermal emitters, photovoltaics, and photodetectors.
Źródło:
Optica Applicata; 2019, 49, 1; 115-124
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of a dual-slot waveguide for a refractive index biosensor
Autorzy:
Sahu, S.
Ali, J.
Singh, G.
Powiązania:
https://bibliotekanauki.pl/articles/173377.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
biosensor
evanescent field
eigenmode
dispersion
Opis:
The present article illustrates the modeling and optimization of a dual-slot waveguide for the application of a refractive index biosensor. The nanometer scale waveguide structure uses the silicon-on-insulator platform for the consideration of higher sensitivity and compactness of a resonator biosensor. The modal analysis is performed using the finite difference method based on full vector eigenmode calculation. The maximum field penetration in the lower index region is found for the quasi-TE mode. The sensitivity is maximized through the optimization of the waveguide dimension by relating effective refractive index with the dispersion of a waveguide. The biosensor showed the maximum calculated sensitivity of 461.327 nm/RIU and a limit-of-detection of 2.601 × 10–6 RIU (where RIU denotes refractive index unit).
Źródło:
Optica Applicata; 2018, 48, 1; 161-167
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fringe pattern inpainting based on dual-exposure fused fringe guiding CNN denoiser prior
Autorzy:
Peng, Guangze
Chen, Wenjing
Powiązania:
https://bibliotekanauki.pl/articles/2086757.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fringe projection profilometry
phase calculation
convolutional neural network
denoiser prior
Opis:
The intensity of some pixels of the captured fringe will be saturated when fringe projection profilometry is used to measure objects with high reflectivity, which will significantly affect the reconstruction of the measured object. In this paper, we propose a fringe pattern inpainting method based on the convolutional neural network (CNN) denoiser prior guided by additional information from a fringe captured in short exposure time. First, a binary mask obtained by Otsu algorithm from the modulation information of the short exposure fringe is used to detect the high-saturation region in the normal exposure fringe. Then, the corrected gray-scales of the region of the short exposure fringe selected by the mask are inserted in the saturated region of the normal fringe to form an initial fringe for iteration. At last, fringe pattern inpainting is achieved by using a CNN denoiser prior. The correct phase can be reconstructed from the inpainted fringes. The computer simulation and experiments verify the effectiveness of the proposed method.
Źródło:
Optica Applicata; 2022, 52, 2; 179--193
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The study of temperature measurement based on the transmission of fixed wavelengths for helical long-period grating
Autorzy:
Bai, Yunfeng
He, Zelong
Dang, Suihu
Powiązania:
https://bibliotekanauki.pl/articles/2060686.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
helical long-period grating
fixed wavelength
dual-wavelength ratio
temperature sensor
Opis:
This research involves a fixed wavelength and dual-wavelength ratio temperature measurement for helical long-period grating. There are two resonant dips near 1475 and 1520 nm, with the pitch length 782 μm. The temperature sensitivity of resonance wavelengths is about 0.06 nm/°C. Both theoretical simulation and experiment results show that the transmission of a fixed wavelength linearly changes with the temperature. It has a high application value for measuring temperature. Besides, the dual-wavelength ratio is studied to eliminate the influence of light source. The temperature sensitivity of transmission intensity ratio of I1469.6nm/I0 and I1469.6nm/I1526.5nm are about 1.0076/°C and 0.0155/°C, respectively, so the dual-wavelength ratio is more practical. And the 0.0155 times intensity change could be much more easily measured than the 0.06 nm wavelength change for each degree Celsius. So the dual-wavelength ratio of the helical long-period gratings is very suitable for temperature sensors.
Źródło:
Optica Applicata; 2022, 52, 1; 129--137
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Real time motion compensation technology based on least square support vector machine prediction
Autorzy:
Song, Zhehan
Feng, Huajun
Xu, Zhihai
Li, Qi
Powiązania:
https://bibliotekanauki.pl/articles/2086762.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
motion compensation
motion prediction
dual-resolution camera system
least square support vector machine
Opis:
When cameras are used in aerial photography, satellite imaging or other scenes, the motion of the observational target causes image blur. The corresponding motion compensation systems often present some response delay. Thus, we introduce effective and fast motion prediction for the target to achieve steady real-time motion compensation. We first analyze the target motion states to propose a fast and robust prediction method based on the least square support vector machine algorithm. Then, we evaluate the performance between ours and other state-of-the-art methods through experiments. Experimental results confirm that the proposed method provides a fast and robust prediction for target motion. At last, we embed our method with dual-resolution camera system to perform high-quality motion compensation effect in real time.
Źródło:
Optica Applicata; 2022, 52, 2; 259--272
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
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:
Polarity-reversed ultra-wideband monocycle pulse generation with dual-channel multicasting in a photonic crystal fiber
Autorzy:
Gong, J
Hui, Z
Powiązania:
https://bibliotekanauki.pl/articles/173791.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
nonlinear optics
cross-phase modulation (XPM)
radio frequency photonics
ultra-wideband (UWB)
photonic crystal fiber (PCF)
Opis:
This paper proposes and demonstrates a novel scheme of a two-channel-output ultra-wideband monocycle pulse generator consisting of a 100 m dispersion-flattened highly nonlinear photonic crystal fiber and two optical bandpass filters. Based on the cross-phase modulation effect in a dispersion-flattened highly nonlinear photonic crystal fiber, two polarity-reversed ultra-wideband monocycle pulses simultaneously output from two different channels are successfully achieved by appropriately locating the probe wavelength at the left linear slope and the right linear slope of the two optical bandpass filters transmission spectra, respectively. The full width at half-maximum and a fractional bandwidth of 24 ps and 260% for a positive pulse, 24 ps and 251% for a negative pulse are obtained. Moreover, the influences of input signal powers, the polarization misalignment between the data light and the continuous wave probe light, and probe wavelength variation on the double output ultra-wideband signals quality are also investigated. The results show that the system has some tolerance to both the input signal power fluctuation and the slight polarization mismatch and even can efficiently operate with a widely tunable wavelength range. This makes it very attractive for engineering applications in future multiuser ultra-wideband-over-fiber communication systems.
Źródło:
Optica Applicata; 2015, 45, 1; 25-39
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of dispersion order on optical millimetre-wave generation based on series optical external modulators without an optical filter
Autorzy:
Singh, M.
Raghuwanshi, S. K.
Powiązania:
https://bibliotekanauki.pl/articles/174512.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fiber chromatic dispersion
microwave photonics
radio-over-fiber
dual-drive Mach–Zehnder modulator
Opis:
The influence of higher order fiber dispersions (like chromatic dispersion and dispersion slope) on the optical millimeter-wave generation is studied. Optical sideband suppression ratio and radio frequency spurious suppression ratio are given and discussed. Moreover, the mathematical results of the proposed model are verified by experiments and numerical simulations.
Źródło:
Optica Applicata; 2015, 45, 2; 215-226
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Strain measurement based on fixed wavelength transmission of tapered long-period fiber grating
Autorzy:
Tang, Yong
Zhang, Hao
Zhang, Li
Yu, Xin Feng
Bai, Yun Feng
Powiązania:
https://bibliotekanauki.pl/articles/2172862.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
tapered fiber
long-period fiber
fiber grating
strain sensor
fixed dual-wavelength ratio
Opis:
This paper studies the relationship between transmission intensity and strain based on tapered long-period fiber grating at a fixed wavelength. In experiments, tapered long-period fiber grating was prepared by the electric melting method. Experimental results show that two resonance peaks appeared at 1482 and 1537 nm, respectively. Here is the elaboration of the relationship between the resonant wavelength and the strain, its wavelength-strain sensitivity is 20 pm/με, and the linearity was negative. Then our next study was about the relationship between transmission intensity and strain at a fixed wavelength. The results show that the transmission intensity at a fixed wavelength is related to the exponent with strain. The coupled-mode theory is applied to simulate the relationship between fixed wavelength and strain. The simulation results matched the experimental results. Two fixed wavelength transmission intensity ratio was used, and the ratio showed a linear relationship with the strain, and the slope is –0.018 dB/με. Therefore, within the 0.01% resolution of our detector, we could resolve a 0.16 με strain change. We can select the appropriate light source and detector to achieve higher measurement accuracy. Thus, there is a great potential in fiber grating strain sensors.
Źródło:
Optica Applicata; 2022, 52, 4; 511--519
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Robust dual color images watermarking scheme with hyperchaotic encryption based on quaternion DFrAT and genetic algorithm
Autorzy:
Luo, Hui-Xin
Gong, Li-Hua
Chen, Su-Hua
Powiązania:
https://bibliotekanauki.pl/articles/27310094.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
color image watermarking
hyperchaotic encryption
quaternion discrete fractional angular transform
quaternion singular value decomposition
genetic algorithm
Opis:
A robust dual color images watermarking algorithm is designed based on quaternion discrete fractional angular transform (QDFrAT) and genetic algorithm. To guarantee the watermark security, the original color watermark image is encrypted with a 4D hyperchaotic system. A pure quaternion matrix is acquired by performing the discrete wavelet transform (DWT), the block division and the discrete cosine transform on the original color cover image. The quaternion matrix is operated by the QDFrAT to improve the robustness and the security of the watermarking scheme with the optimal transform angle and the fractional order. Then the singular value matrix is obtained by the quaternion singular value decomposition (QSVD) to further enhance the scheme’s stability. The encryption watermark is also processed by DWT and QSVD. Afterward, the singular value matrix of the encryption watermark is embedded into the singular value matrix of the host image by the optimal scaling factor. Moreover, the values to balance imperceptibility and robustness are optimized with a genetic algorithm. It is shown that the proposed color image watermarking scheme performs well in imperceptibility, security, robustness and embedding capacity.
Źródło:
Optica Applicata; 2023, 53, 2; 261--280
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dual-parameter sensing characteristics of a single fiber Bragg grating half-pasted by 1C-LV epoxy under different curing
Autorzy:
Li, Hong
Zhang, Haoyue
Song, Yanming
Meng, Fanyong
Zhu, Lianqing
Powiązania:
https://bibliotekanauki.pl/articles/2033955.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fiber Bragg grating
cross-sensitivity
double peaks
surface pasting
curing
Opis:
A novel technology for the simultaneous and independent measurement of dual parameters is proposed and experimented. By using a single fiber Bragg grating half-pasted by 1C-LV epoxy under different curing conditions, the sensor structure is designed such that the reflective single-peak spectrum splits into a twin-peak spectrum, which makes the FBG spectrum form a natural spectral peak splitting bias. A measurement limitation exists in the FBG sensor packaging at room temperature, which can be solved by the high-temperature cured packaging method. To verify the validity of the theory and methodology, the experimental system is used. In the range from –1000 to +1000 με and from 35 to 75°C, the Bragg wavelength change is relative linear to the strain and temperature. The temperature and strain variations can be independently and simultaneously measured using the split peak, and the deviations of the FBG sensor are ±1°C and ±5 με, respectively. This single FBG sensor can realize dual-parameter measurement, which is valuable for narrow-space health monitoring.
Źródło:
Optica Applicata; 2021, 51, 3; 391-406
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł

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