Low-cost automated system for phase-shifting and phase retrieval based on the tunability of a laser diode

2016 ◽  
Author(s):  
Uriel Rivera-Ortega ◽  
Joris Dirckx
Keyword(s):  
Laser Diode ◽  
Phase Retrieval ◽  
Low Cost ◽  
Phase Shifting ◽  
Automated System

Phase shifting and phase retrieval with a fully automated laser diode system

2015 ◽  
Vol 54 (33) ◽  
pp. 9896 ◽  
Author(s):  
Uriel Rivera-Ortega ◽  
Joris Dirckx ◽  
Cruz Meneses-Fabian
Keyword(s):  
Laser Diode ◽  
Phase Retrieval ◽  
Phase Shifting ◽  
Diode System

scholarly journals A Real-Time Automated System for Dual-Aperture Common-Path Interferometer Phase-Shifting

2021 ◽  
Vol 11 (16) ◽  
pp. 7438
Author(s):  
Antonio Barcelata-Pinzón ◽  
Ricardo Iván Álvarez-Tamayo ◽  
Patricia Prieto-Cortés
Keyword(s):  
Real Time ◽  
Phase Difference ◽  
Low Cost ◽  
Analytical Calculation ◽  
Ccd Camera ◽  
Phase Shifting ◽  
Automated System ◽  
Common Path ◽  
Interferometer Phase ◽  
Phase Differences

We report a novel fully real-time automatized optomechatronic dual-aperture common-path interferometer system for obtaining the phase difference between two interferograms by using the technique of phase-shifting interferometry. A motorized system is used to shift an additional phase transversally to the optical axis by ruling translation. For each high-resolution ruling displacement step of 0.793 μm, an interferogram is recorded by a CCD camera. The phase difference between the two successive recorded interferograms is then automatically calculated by computational self-calibrated algorithms. The proposed device provides more accurate measuring than typically used manual processes. Real-time phase differences are obtained from a robust low-cost optomechatronic system. Analytical calculation of the phase is performed automatically without the requirement of additional or external tools and processes, reducing the significant rework delay. A set of 47 interferograms were captured in real time then recorded and analyzed, obtaining an average phase shifting of 2.483 rad. Analytic explanation and experimental results are presented.

scholarly journals Simple concept for a wide-field lensless digital holographic microscope using a laser diode

2015 ◽  
Vol 1 (1) ◽  
pp. 261-264 ◽  
Author(s):  
A. Adinda-Ougba ◽  
N. Koukourakis ◽  
N. C. Gerhardt ◽  
M. R. Hofmann
Keyword(s):  
Laser Diode ◽  
Phase Retrieval ◽  
Low Cost ◽  
Angular Spectrum ◽  
Digital Holographic Microscopy ◽  
Retrieval Algorithm ◽  
Wide Field ◽  
Numerical Reconstruction ◽  
Phase Images ◽  
The Individual

AbstractWide-field, lensless digital holographic microscopy is a new microscopic imaging technique for telemedicine and for resource limited setting [1]. In this contribution we propose a very simple wide-field lensless digital holographic microscope using a laser diode. It is based on in-line digital holography which is capable to provide amplitude and phase images of a sample resulting from numerical reconstruction. The numerical reconstruction consists of the angular spectrum propagation method together with a phase retrieval algorithm. Amplitude and phase images of the sample with a resolution of ∽2 µm and with ∽24 mm2 field of view are obtained. We evaluate our setup by imaging first the 1951 USAF resolution test chart to verify the resolution. Second, we record holograms of blood smear and diatoms. The individual specimen can be easily identified after the numerical reconstruction. Our system is a very simple, compact and low-cost possibility of realizing a microscope capable of imaging biological samples. The availability of the phase provide topographic information of the sample extending the application of this system to be not only for biological sample but also for transparent microstructure. It is suitable for fault detection, shape and roughness measurements of these structures.

Phase-shifting digital holography with an unknown reference beam

2021 ◽  
Author(s):  
Roghayeh Yazdani ◽  
Hamidreza Fallah
Keyword(s):  
Digital Holography ◽  
Phase Retrieval ◽  
Reference Beam ◽  
Phase Shifting ◽  
Retrieval Algorithm ◽  
Reference Field ◽  
Digital Holograms ◽  
Noisy Conditions ◽  
Phase Retrieval Algorithm

In digital holography, errors of the reference field degrade the quality of the reconstructed object field. In this paper, we propose an effective method in phase-shifting digital holography in which the reference field does not need to be known and perfect. The unknown complex amplitudes of both reference and object fields are derived simultaneously. The method employs only five digital holograms and a single execution of a phase retrieval algorithm. So, the required measurements and algorithm executions in this method are fewer than those in other methods; it suggests a simpler and faster method. The effectiveness of the suggested method is indicated by simulation, under noise-free and noisy conditions. Moreover, the capability of the method to extract full information about the phase singularities in both fields is demonstrated.

Automated text messaging follow-up for patients who receive peripheral nerve blocks

2021 ◽  
pp. rapm-2021-102472
Author(s):  
Daniel Gessner ◽  
Oluwatobi O Hunter ◽  
Alex Kou ◽  
Edward R Mariano
Keyword(s):  
Regional Anesthesia ◽  
Nerve Block ◽  
Text Messaging ◽  
Low Cost ◽  
Automated System ◽  
Phone Call ◽  
Nerve Blocks ◽  
Patient Response ◽  
Patient Reported

BackgroundRoutine follow-up of patients who receive a nerve block for ambulatory surgery typically consists of a phone call from a regional anesthesia clinician. This process can be burdensome for both patients and clinicians but is necessary to assess the efficacy and complication rate of nerve blocks.MethodsWe present our experience developing an automated system for completing follow-up via short message service text messaging and our preliminary results using it at three clinical sites. The system is built on REDCap, a secure online research data capture platform developed by Vanderbilt University and currently available worldwide.ResultsOur automated system queried patients who received a variety of nerve block techniques, assessed patient-reported nerve block duration, and surveyed patients for potential complications. Patient response rate to text messaging averaged 91% (higher than our rates of daily phone contact reported previously) for patients aged 18 to 90 years.ConclusionsGiven the wide availability of REDCap, we believe this automated text messaging system can be implemented in a variety of health systems at low cost with minimal technical expertise and will improve both the consistency of patient follow-up and the service efficiency of regional anesthesia practices.

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