Slope measurement of a phase object using a polarizing phase-shifting high-frequency Ronchi grating interferometer

2010 ◽  
Vol 49 (33) ◽  
pp. 6402 ◽  
Author(s):  
Noel-Ivan Toto-Arellano ◽  
Amalia Martínez-García ◽  
Gustavo Rodríguez-Zurita ◽  
Juan Antonio Rayas-Álvarez ◽  
Areli Montes-Perez
Keyword(s):  
High Frequency ◽  
Phase Shifting ◽  
Phase Object ◽  
Grating Interferometer

scholarly journals Spatial phase-shifting characteristic of double grating interferometer

2009 ◽  
Vol 17 (22) ◽  
pp. 20415 ◽  
Author(s):  
Yang Song ◽  
YunYun Chen ◽  
Anzhi He ◽  
Zhimin Zhao
Keyword(s):  
Phase Shifting ◽  
Spatial Phase ◽  
Grating Interferometer

scholarly journals STRUCTURED LIGHT BASED 3D SCANNING FOR SPECULAR SURFACE BY THE COMBINATION OF GRAY CODE AND PHASE SHIFTING

2016 ◽  
Vol XLI-B3 ◽  
pp. 137-142
Author(s):  
Yujia Zhang ◽  
Alper Yilmaz
Keyword(s):  
High Frequency ◽  
Structured Light ◽  
Gray Code ◽  
3D Scanning ◽  
Phase Shifting ◽  
Scanning System ◽  
High Quality ◽  
Specular Surface ◽  
Combination Technique ◽  
Indirect Illumination

Surface reconstruction using coded structured light is considered one of the most reliable techniques for high-quality 3D scanning. With a calibrated projector-camera stereo system, a light pattern is projected onto the scene and imaged by the camera. Correspondences between projected and recovered patterns are computed in the decoding process, which is used to generate 3D point cloud of the surface. However, the indirect illumination effects on the surface, such as subsurface scattering and interreflections, will raise the difficulties in reconstruction. In this paper, we apply maximum min-SW gray code to reduce the indirect illumination effects of the specular surface. We also analysis the errors when comparing the maximum min-SW gray code and the conventional gray code, which justifies that the maximum min-SW gray code has significant superiority to reduce the indirect illumination effects. To achieve sub-pixel accuracy, we project high frequency sinusoidal patterns onto the scene simultaneously. But for specular surface, the high frequency patterns are susceptible to decoding errors. Incorrect decoding of high frequency patterns will result in a loss of depth resolution. Our method to resolve this problem is combining the low frequency maximum min-SW gray code and the high frequency phase shifting code, which achieves dense 3D reconstruction for specular surface. Our contributions include: (i) A complete setup of the structured light based 3D scanning system; (ii) A novel combination technique of the maximum min-SW gray code and phase shifting code. First, phase shifting decoding with sub-pixel accuracy. Then, the maximum min-SW gray code is used to resolve the ambiguity resolution. According to the experimental results and data analysis, our structured light based 3D scanning system enables high quality dense reconstruction of scenes with a small number of images. Qualitative and quantitative comparisons are performed to extract the advantages of our new combined coding method.

Image reconstruction algorithm for recovering high-frequency information in parallel phase-shifting digital holography [Invited]

2012 ◽  
Vol 52 (1) ◽  
pp. A210 ◽  
Author(s):  
Peng Xia ◽  
Yuki Shimozato ◽  
Tatsuki Tahara ◽  
Takashi Kakue ◽  
Yasuhiro Awatsuji ◽  
...  
Keyword(s):  
Image Reconstruction ◽  
High Frequency ◽  
Digital Holography ◽  
Reconstruction Algorithm ◽  
Phase Shifting ◽  
Image Reconstruction Algorithm ◽  
Frequency Information

scholarly journals DC-link Current Harmonic Mitigation via Phase-shifting of Carrier Waves in Paralleled Inverter Systems

2021 ◽  
Author(s):  
Silpa Baburajan ◽  
Haoran Wang ◽  
Dinesh Kumar ◽  
Qian Wang ◽  
Frede Blaabjerg
Keyword(s):  
High Frequency ◽  
Cost Effective ◽  
Industrial Applications ◽  
Phase Shifting ◽  
Current Harmonics ◽  
Industrial Designers ◽  
Ripple Cancellation ◽  
High Frequency Harmonic ◽  
Current Ripple ◽  
Frequency Harmonic

DC-connected parallel inverter systems are gaining popularity in industrial applications. However, such parallel systems generate excess current ripple (harmonics) at the DC-link due to harmonic interactions between the inverters in addition to the harmonics from the PWM switching. These DC-link harmonics cause the failure of fragile components such as DC-link capacitors. This paper proposes an interleaving scheme to minimize the current harmonics induced in the DC-link of such a system. The results show that when the carrier waves of the two inverters are phase-shifted by 90° angle, the maximum high-frequency harmonic ripple cancellation occurs, which reduces the overall RMS value of the DC-capacitor current.The outcome of this proposed solution is a cost-effective DC-harmonics mitigating strategy for the industrial designers to practically configuring multi-inverter systems, even when most of the drives are not operating at rated power levels. Experimental and simulation results presented in this paper verify the effectiveness of the proposed carrier-based phase-shifting scheme for two different configurations of common DC connected multi-converter systems.

scholarly journals Single Input Single Output Two Level Isolated Dc-Dc Converter With Secondary Side Phase Shifting For Solar Applications

2021 ◽  
Vol 9 (2) ◽  
pp. 433-442
Author(s):  
K.Girinath Babu, Et. al.
Keyword(s):  
High Frequency ◽  
Power Loss ◽  
Short Circuit ◽  
Soft Switching ◽  
Phase Shifting ◽  
Single Input Single Output ◽  
Leakage Inductance ◽  
Circulating Current ◽  
High Frequency Transformer ◽  
Secondary Side

 The isolated dc–dc converters with primary-side phase shifting (PPS) provides severely narrow soft-switching range for main devices in the primary side leg of full bridge converter. The leakage inductance of the high frequency transformer should be large enough for providing the energy needed for soft switching operations and also the idling power loss due to circulating current in the converter legs under large phase-shift angle, which makes reduction of conversion efficiency and complicated in designing the parameters of transformer. Furthermore, the turn-off diode commutations in the output-side rectifier are performed by hard-switching mode. To overcome all these drawbacks, a secondary side phase shifting (SPS) technique has been developed for two-level isolated DC-DC converter. This scheme provides wider soft switching range and reduced power loss due to elimination of circulating current in the primary side of high frequency transformer. In addition, SPS control also provide no reverse recovery current in diodes and hence no power losses in the secondary rectifier circuit. The control switches operate under soft switching even under rated load and short circuit conditions.  

Performance Characterization of the Novel Topology for High-Frequency Isolation Bi-Directional DC/DC Converter

2013 ◽  
Vol 273 ◽  
pp. 305-309 ◽  
Author(s):  
Peng Hui Jing ◽  
Cong Wang ◽  
Jun Wang ◽  
Feng Zhao
Keyword(s):  
High Frequency ◽  
Power Flow ◽  
Control Strategies ◽  
High Reliability ◽  
Input Voltage ◽  
Phase Shifting ◽  
Matlab Simulation ◽  
High Input ◽  
The Cost ◽  
Bidirectional Power Flow

A novel topology of high-frequency isolation bi-directional DC/DC converter used in high-Input low-output system was proposed, which has not only the advantages, such as enabling bidirectional power flow, ease of realizing soft-switching control, galvanic isolation, high reliability and so on, but also can be used in high-input voltage application and apparently decreases the stress of the switches, which reduces the cost of the converter, improves power density and the efficiency of the converter. According to the different work condition, two control strategies are analyzed in this paper: the traditional phase shifting control (TPC) and PWM plus phase shifting control (PPC), which further improves the overall efficiency of the converter. The MATLAB simulation has been done to verify the feasibility of the proposed DC/DC converter and accuracy of the criterion.

Sign in / Sign up

Export Citation Format

Share Document