Proposed pixel for custom laser doppler vibrometry camera

Jackson, Stephen (2012) Proposed pixel for custom laser doppler vibrometry camera. PhD thesis, University of Nottingham.

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Non-destructive testing is an important field of research in many areas of industry and science. This field covers methods that test some property of an object while not impacting its future usefulness. This project is specifically interested in a method of NDE called Laser Doppler Vibrometry (LDV), which uses light to probe the motion of an object's surface.

This thesis presents research into the possibility of developing a full-field LDV camera capable of measuring the vibration at a number of points across an object simultaneously. The approach chosen was to develop a single processing element which contained a light detector as well as the processing required to produce an output signal proportional to the vibration of the surface imaged by the element. This processing element, or pixel, could then be used to produce a full-field LDV camera capable of imaging an object's surface to provide vibration amplitude and frequency for a number of points across the whole surface simultaneously

Some early work was carried out measuring the vibration of a piezoelectric target with a CMOS camera and the results were compared with theory. The method of processing chosen is called zero-crossing demodulation and a circuit was designed and simulated using this method. This circuit was then laid-out and a CMOS chip was fabricated with the pixel on it. The circuit was designed such that the different parts of it could be tested separately using electrical signals, and a number of electrical tests were performed to check how well the operation of the fabricated pixel compared with simulation. Using a laser interferometer the pixel was finally tested with real vibrating objects and compared with a commercial LDV.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Hayes-Gill, B.R.
Morgan, S.
Keywords: Nondestructive testing, vibration, measurement, instruments, demodulation (electronics), optoelectronic devices, design and construction
Subjects: T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK7800 Electronics > TK8300 Photoelectronic devices
Faculties/Schools: UK Campuses > Faculty of Engineering > Department of Electrical and Electronic Engineering
Item ID: 12975
Depositing User: EP, Services
Date Deposited: 20 Mar 2013 14:03
Last Modified: 18 Sep 2016 03:59

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