Uncalibrated photometric stereo refined by polarization angle

2021 ◽  
Vol 28 (1) ◽  
pp. 119-133
Author(s):  
Daisuke Miyazaki ◽  
Shuhei Hashimoto
Keyword(s):  
Photometric Stereo ◽  
Polarization Angle

A fast LED calibration method under near field lighting based on photometric stereo

2021 ◽  
Vol 147 ◽  
pp. 106749
Author(s):  
Long Ma ◽  
Yuzhe Liu ◽  
Jirui Liu ◽  
Shengwei Guo ◽  
Xin Pei ◽  
...  
Keyword(s):  
Near Field ◽  
Calibration Method ◽  
Photometric Stereo

scholarly journals Photometric stereo-based high-speed inline battery electrode inspection

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Christian Kapeller ◽  
Ernst Bodenstorfer
Keyword(s):  
Quality Control ◽  
System Architecture ◽  
High Speed ◽  
Shape From Shading ◽  
Production Quality ◽  
Photometric Stereo ◽  
Inspection System ◽  
Coating Materials ◽  
Production Quality Control ◽  
Reconstruction Performance

Abstract Battery technology is a key component in current electric vehicle applications and an important building block for upcoming smart grid technologies. The performance of batteries depends largely on quality control during their production process. Defects introduced in the production of electrodes can lead to degraded performance and, more importantly, to short circuits in final cells, which is highly safety-critical. In this paper, we propose an inspection system architecture that can detect defects, such as missing coating, agglomerates, and pinholes on coated electrodes. Our system is able to acquire valuable production quality control metrics, like surface roughness. By employing photometric stereo techniques, a shape from shading algorithm, our system surmounts difficulties that arise while optically inspecting the black to dark gray battery coating materials. We present in detail the acquisition concept of the proposed system architecture, and analyze its acquisition-, as well as, its surface reconstruction performance in experiments. We carry these out utilizing two different implementations that can operate at a production speed of up to 2000 mm/s at a resolution of 50 µm per pixel. In this work we aim to provide a system architecture that can provide a reliable contribution to ensuring optimal performance of produced battery cells.

Mitigating the Effects of Non-Linear Distortion Using Polarizers in Microwave Photonic Link

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Sarika Singh ◽  
Sandeep K. Arya ◽  
Shelly Singla
Keyword(s):  
Dynamic Range ◽  
Extinction Ratio ◽  
Polarization Angle ◽  
Third Order ◽  
Microwave Photonic ◽  
Linear Behavior ◽  
Spurious Free Dynamic Range ◽  
Non Linear ◽  
Intermodulation Distortions ◽  
Insertion Losses

AbstractA scheme to suppress nonlinear intermodulation distortion in microwave photonic (MWP) link is proposed by using polarizers to compensate inherent non-linear behavior of dual-electrode Mach-Zehnder modulator (DE-MZM). Insertion losses and extinction ratio have also been considered. Simulation results depict that spurious free dynamic range (SFDR) of proposed link reaches to 130.743 dB.Hz2/3. A suppression of 41 dB in third order intermodulation distortions and an improvement of 15.3 dB is reported when compared with the conventional link. In addition, an electrical spectrum at different polarization angles is extracted and 79^\circ is found to be optimum value of polarization angle.

scholarly journals Single Day Outdoor Photometric Stereo

2020 ◽  
pp. 1-1 ◽  
Author(s):  
Yannick Hold-Geoffroy ◽  
Paulo Gotardo ◽  
Jean-Francois Lalonde
Keyword(s):  
Photometric Stereo

scholarly journals Predicting the broad-lines polarization emitted by supermassive binary black holes

2019 ◽  
Vol 623 ◽  
pp. A56 ◽  
Author(s):  
D. Savić ◽  
F. Marin ◽  
L. Č. Popović
Keyword(s):  
Black Holes ◽  
Emission Lines ◽  
Polarization Angle ◽  
Broad Line ◽  
Line Profiles ◽  
Binary Black Holes ◽  
True Nature ◽  
Line Shapes ◽  
Highly Sensitive ◽  
Balmer Lines

Context. Some Type-1 active galactic nuclei (AGN) show extremely asymmetric Balmer lines with the broad peak redshifted or blueshifted by thousands of km s−1. These AGN may be good candidates for supermassive binary black holes (SMBBHs). The complex line shapes can be due to the complex kinematics of the two broad line regions (BLRs). Therefore other methods should be applied to confirm the SMBBHs. One of them is spectropolarimetry. Aims. We rely on numerical modeling of the polarimetry of binary black holes systems, since polarimetry is highly sensitive to geometry, in order to find the specific influence of supermassive binary black hole (SMBBH) geometry and dynamics on polarized parameters across the broad line profiles. We apply our method to SMBBHs in which both components are assumed to be AGN with distances at the subparsec scale. Methods. We used a Monte Carlo radiative transfer code that simulates the geometry, dynamics, and emission pattern of a binary system where two black holes are getting increasingly close. Each gravitational well is accompanied by its own BLR and the whole system is surrounded by an accretion flow from the distant torus. We examined the emission line deformation and predicted the associated polarization that could be observed. Results. We modeled scattering-induced broad line polarization for various BLR geometries with complex kinematics. We find that the presence of SMBBHs can produce complex polarization angle profiles φ and strongly affect the polarized and unpolarized line profiles. Depending on the phase of the SMBBH, the resulting double-peaked emission lines either show red or blue peak dominance, or both the peaks can have the same intensity. In some cases, the whole line profile appears as a single Gaussian line, hiding the true nature of the source. Conclusions. Our results suggest that future observation with the high resolution spectropolarimetry of optical broad emission lines could play an important role in detecting subparsec SMBBHs.

A remote gain controlled and polarization angle tunable Doppler backward scattering reflectometer

2021 ◽  
Vol 92 (6) ◽  
pp. 063513
Author(s):  
J. Wen ◽  
Z. B. Shi ◽  
W. L. Zhong ◽  
Z. C. Yang ◽  
Z. J. Yang ◽  
...  
Keyword(s):  
Polarization Angle
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