DiscMatch Disc Authentication

The disc authentication system was designed to exploit naturally occurring production anomalies in the disc's inner ring to forensically identify optical discs. These anomalies, only visible using a high-powered microscope, effectively fingerprinted the pressing machines and the discs manufactured using them. Such anomalies are all but impossible to replicate artificially.

In order to capture manufacturing imperfections at the resolution required, several imaging options were researched. A darkfield microscope was decided upon as it met the necessary standard for the project.

Given the high resolution and consequent very small size of each individual image captured by the darkfield microscope, several thousand images of a disc's inner ring would need to be taken and then stitched together to allow for analysis and comparison with other discs. This necessitated the design and specification of associated control systems which could accurately position the microscope relative to the disc, capture and store an image, move the microscope, capture and store an image, and so on until the entire inner ring was imaged. A CNC table linked to a standard PC with bespoke control and image capture software was the chosen solution. The finished product automatically examines CDs/DVDs and has been deployed in the forensics department of a major multinational software organisation.