Difference between revisions of "Samuel Achamfuo-Yeboah"
From Applied Optics Wiki
(Created page, copy of Sam Achamfuo-Yeboah, will remove Sam Achamfuo-Yeboah) |
m |
||
| Line 49: | Line 49: | ||
<bibtex> | <bibtex> | ||
| − | @article{1742-6596-581-1-012009, author={ | + | @article{1742-6596-581-1-012009, author={Samuel Achamfuo-Yeboah and R A Light and S D Sharples}, title={Optical detection of ultrasound from optically rough surfaces using a custom CMOS sensor}, journal={Journal of Physics: Conference Series}, volume={581}, number={1}, pages={012009}, pdf = {http://iopscience.iop.org/article/10.1088/1742-6596/581/1/012009/pdf}, url={http://stacks.iop.org/1742-6596/581/i=1/a=012009}, year={2015}, abstract={The optical detection of ultrasound from optically rough surfaces is severely limited when using a conventional interferometric or optical beam deflection (OBD) setup because the detected light is speckled. This means that complicated and expensive setups are required to detect ultrasound optically on rough surfaces. We present a CMOS integrated circuit that can detect laser ultrasound in the presence of speckle. The detector circuit is based on the simple knife edge detector. It is self-adapting and is fast, inxepensive, compact and robust. The CMOS circuit is implemented as a widefield array of 32×32 pixels. At each pixel the received light is compared with an adjacent pixel in order to determine the local light gradient. The result of this comparison is stored and used to connect each pixel to the positive or negative gradient output as appropriate (similar to a balanced knife edge detector). The perturbation of the surface due to ultrasound preserves the speckle distribution whilst deflecting it. The spatial disturbance of the speckle pattern due to the ultrasound is detected by considering each pair of pixels as a knife edge detector. The sensor can adapt itself to match the received optical speckle pattern in less than 0.1 μs, and then detect the ultrasound within 0.5 μs of adaptation. This makes it possible to repeatedly detect ultrasound from optically rough surfaces very quickly. The detector is capable of independent operation controlled by a local microcontroller, or it may be connected to a computer for more sophisticated configuration and control. We present the theory of its operation and discuss results validating the concept and operation of the device. We also present preliminary results from an improved design which grants a higher bandwidth, allowing for optical detection of higher frequency ultrasound.} } |
</bibtex> | </bibtex> | ||
<bibtex> | <bibtex> | ||
| − | @article{1742-6596-520-1-012004, author={S D Sharpies and R A Light and | + | @article{1742-6596-520-1-012004, author={S D Sharpies and R A Light and Samuel Achamfuo-Yeboah and M Clark and M G Somekh}, title={The SKED: speckle knife edge detector}, journal={Journal of Physics: Conference Series}, volume={520}, number={1}, pages={012004}, pdf = {http://iopscience.iop.org/article/10.1088/1742-6596/520/1/012004/pdf}, url={http://stacks.iop.org/1742-6596/520/i=1/a=012004}, year={2014}, abstract={The knife edge detector—also known as optical beam deflection—is a simple and robust method of detecting ultrasonic waves using a laser. It is particularly suitable for detection of high frequency surface acoustic waves as the response is proportional to variation of the local tilt of the surface. In the case of a specular reflection of the incident laser beam from a smooth surface, any lateral movement of the reflected beam caused by the ultrasonic waves is easily detected by a pair of photodiodes. The major disadvantage of the knife edge detector is that it does not cope well with optically rough surfaces, those that give a speckled reflection. The optical speckles from a rough surface adversely affect the efficiency of the knife edge detector, because 'dark' speckles move synchronously with 'bright' speckles, and their contributions to the ultrasonic signal cancel each other out. We have developed a new self-adapting sensor which can cope with the optical speckles reflected from a rough surface. It is inelegantly called the SKED—speckle knife edge detector—and like its smooth surface namesake it is simple, cheap, compact, and robust. We describe the theory of its operation, and present preliminary experimental results validating the overall concept and the operation of the prototype device.} } |
</bibtex> | </bibtex> | ||
Revision as of 12:07, 11 January 2016
Samuel Osei Achamfuo-Yeboah
Micro-electronics research engineer with experience in design and test of full-custom CMOS integrated circuits, special interest in Optical Systems, Laser Ultrasound Systems
Current Research
I am currently working on a novel temporal pixel multiplexing camera. At the heart of it is a novel CMOS chip - the TPM. It offers a novel way of capturing images in low light a a very high frame rate, with user-customizable frame interleaving. The chip has been manufactured and is under rigorous characterization now. I'm working with Roger on this project.
I also work on the use of a novel laser ultrasound detector, the Speckle Knife Edge Detector (SKED). I recently spent a year characterizing it and investigating its feasibility for field work. The SKED is currently under test as a suitable detector in a SRAS system, especially for components with rough surfaces. I'm working with Rikesh, Roger and Steve on this project.
Location
B24 [IBIOS], Life Sciences Building, University Park
202/306 [AO], Electrical Systems and Optics, University Park
Phone
+44 (0)115 82-32322
samuel.achamfuo-yeboah
Education/Posts
2001-2005: BSc Electrical and Electronic Engineering (1st Class), Kwame Nkrumah University of Science and Technology
2006-2007: MSc Electronic Communications and Computer Engineering (1st Class), University of Nottingham
2007-2012: PhD Electrical and Electronic Engineering (Thesis), University of Nottingham
2012-present: Research Associate, University of Nottingham
PhD Research
Design and implementation of a full-custom Modulated Light Camera. My work focussed on the design of a CMOS MLC. It was manufactured and characterized successfully. (Thesis). I was supervised by Prof M Clark for this work.
Awards
- Standard Chartered Scholar Award, KNUST 2002-2005
- Deans Award, KNUST 2003-2005
- Tower Innovation Scholarship, University of Nottingham 2008 - 2010
Journal publications
Samuel Achamfuo-Yeboah, R A Light, S D Sharples - Optical detection of ultrasound from optically rough surfaces using a custom CMOS sensor
- Journal of Physics: Conference Series 581(1):012009,2015
- http://stacks.iop.org/1742-6596/581/i=1/a=012009
BibtexAuthor : Samuel Achamfuo-Yeboah, R A Light, S D Sharples
Title : Optical detection of ultrasound from optically rough surfaces using a custom CMOS sensor
In : Journal of Physics: Conference Series -
Address :
Date : 2015
S D Sharpies, R A Light, Samuel Achamfuo-Yeboah, M Clark, M G Somekh - The SKED: speckle knife edge detector
- Journal of Physics: Conference Series 520(1):012004,2014
- http://stacks.iop.org/1742-6596/520/i=1/a=012004
BibtexAuthor : S D Sharpies, R A Light, Samuel Achamfuo-Yeboah, M Clark, M G Somekh
Title : The SKED: speckle knife edge detector
In : Journal of Physics: Conference Series -
Address :
Date : 2014
Rikesh Patel, Samuel Achamfuo-Yeboah, Roger Light, Matt Clark - Widefield two laser interferometry
- Opt. Express 22(22):27094--27101, Nov 2014
- http://www.opticsexpress.org/abstract.cfm?URI=oe-22-22-27094
BibtexAuthor : Rikesh Patel, Samuel Achamfuo-Yeboah, Roger Light, Matt Clark
Title : Widefield two laser interferometry
In : Opt. Express -
Address :
Date : Nov 2014
Rikesh Patel, Samuel Achamfuo-Yeboah, Roger Light, Matt Clark - Ultrastable heterodyne interferometer system using a CMOS modulated light camera
- Opt. Express 20(16):17722--17733, Jul 2012
- http://www.opticsexpress.org/abstract.cfm?URI=oe-20-16-17722
BibtexAuthor : Rikesh Patel, Samuel Achamfuo-Yeboah, Roger Light, Matt Clark
Title : Ultrastable heterodyne interferometer system using a CMOS modulated light camera
In : Opt. Express -
Address :
Date : Jul 2012
Rikesh Patel, Samuel Achamfuo-Yeboah, Roger Light, Matt Clark - Widefield heterodyne interferometry using a custom CMOS modulated light camera
- Opt. Express 19(24):24546--24556, Nov 2011
- http://www.opticsexpress.org/abstract.cfm?URI=oe-19-24-24546
BibtexAuthor : Rikesh Patel, Samuel Achamfuo-Yeboah, Roger Light, Matt Clark
Title : Widefield heterodyne interferometry using a custom CMOS modulated light camera
In : Opt. Express -
Address :
Date : Nov 2011
David Summers, Matt Clark, Ian Stockford, Samuel Achamfuo-Yeboah, Joao Pereira Do Carmo - Modulated light camera for space applications and assessment via a test bench system
- Acta Astronautica 66(9–10):1399 - 1403,2010
- http://www.sciencedirect.com/science/article/pii/S0094576509005311
BibtexAuthor : David Summers, Matt Clark, Ian Stockford, Samuel Achamfuo-Yeboah, Joao Pereira Do Carmo
Title : Modulated light camera for space applications and assessment via a test bench system
In : Acta Astronautica -
Address :
Date : 2010
Conferences
- UON Institute of Aerospace exposition, Nottingham UK - 2010
- IOP Anglo-French physical acoustic conference AFPAC2014, London - 2014
- RCNDE Annual research review, Manchester UK - 2015
- International Symposium on Laser Ultrasonics LU2015, Evanston IL USA - 2015
