Synthetic aperture interferometry: High-resolution optical measurement over an exceptionally large field of view

This proposal is concerned with the development of synthetic aperture interferometry (SAI) for high resolution measurement of large scale, precision engineered parts (e.g. aerospace components and photovoltaic panels). SAI is a new way to link several small interferometers together to make one large interferometer with dramatically increased resolutution and/or field of view. In principle this is similar to the way that arrays of radio telescopes can be linked to provide the equivalent of a much larger telescope. For the case of surface metrology however, it is also important to consider the object illumination as this has an equally important effect on resolution.
In this work we propose to build a flexible system using an array of 15x15 5MP cameras and illumination at 3 separate laser wavelengths diverging from up to 225 fibre-optic sources. This is represents around 1TB of data and is at the limits of the processing capability of a high specification desktop computer. In this proposal, however, we will consider a hierachical approach to data analysis that will initially interogate a limited number of cameras and illumination conditions to indicate regions that may be out of tolerance. Subsequently, high resolution analysis will be used to measure the highlighted regions.
We will work closely with instrument manufacturers and end users to ensure that the technology is embedded within the UKs expanding high value manufacturing industry.

The idea that is central to the outline proposal will benefit our collaborators and the wider community as follows:

i) Manufacturing Industry.
Quality control is increasingly important in high-value manufacturing. Machine vision systems are integral to many
inspection processes (e.g. food packaging) but cannot work to the strict tolerances of large-scale, precision
engineering. At present quality control is limited to a few important contacting measurements and as such proof of
compliance is similarly limited. In the future, industries that can prove compliance are likely to succeed. We have received
cash support from several industries and are presently in discussion with others.

ii) Instrument Manufacturers.
The UK has a strong history of innovation in precision metrology and is a world leader in contacting measurements. The
idea in this proposal will bring precision metrology onto the production line and into the machine vision market that is
currently estimated to be worth over $3bn. We will work with instrument manufacturers to make this a reality.

iii) The Academic Community.
Our idea is generic since, in essence, optical metrology can only "illuminate and observe response". The flexible, multiple
illumination, multiple coherent observation instrument provides a platform that can emulate most optical instruments. It can
therefore be configured to optimise speed and resolution compromises. We are currently considering how to share this
capability with other academics through a suitable user engagement strategy.