Did you know that all imaging system’s sensors e.g. cameras, scanners, smart phones leave a unique digital fingerprint that is retrievable from the image file produced by the system. This process involves the analysis of the sensor’s characteristic noise called the Photo Response Non Uniformity (PNRU).

Forensic analysis of a digital file’s PNRU in comparison with other photographs from the same camera can lead to the authentication and verification of the use of a specific camera and/or software editing application.

The same can also apply to editing applications such as Adobe Photoshop etc which also leave a specific characteristic structure in the processed image.

A camera’s sensor electrical responses to incoming light (photons) will occur in very specific and consistent ways.  This in conjunction with microscopic physical irregularities in the manufacturing processes produce measurable behavioural differences and sensor pattern noise. Examples include certain pixels being stuck on maximum or minimum brightness or some light overflow in sensor rows and/or columns.

There have been many studies that looked at the mobile phone camera market. These studies indicate that an image’s PRNU is likely to be unreliable in determining the source make/model of the camera without other provided images for comparison.