An image made up of pixels. Each pixel has numbers (digits) to describe its position and shade on the grey scale. The more shades available, described by the number of computer bits required to store the shade of grey, the more accurately the image represents the original tissue contrast. An 8-bit computer image shows 28 (256) possible shades of grey, close to the maximum the human eye can differentiate. 12-bit (4096 levels of grey) images are of much higher quality and take up more memory. They can be manipulated more easily by computer using image enhancement techniques. Compare analogue image.
Subjects: Medicine and Health — Science and Mathematics.