**2.2.1 Digital camera architectures**

Digital colour cameras capture colour images of real-life scenes electronically using an image sensor, usually a charge-coupled device (CCD), or complementary metal oxide semiconductor (CMOS), sensor, instead of the film used in the conventional analog cameras. Therefore, captured photos can be immediately viewed by the user on the digital camera's display, and immediately stored, processed, or transmitted without any doubt, this is one of the most attractive features of digital imaging (Lukac & Plataniotis, 2007).
