Should You be Aware of Scanning Images.
Scanners look and operate much like personal copiers and share much of the same technology.
Each cell produces an electrical signal proportional to the strength of the reflected light that hits it. The signal which represents one pixel in the original images is converted into a binary number and sent to the computer. Darker portions of the target reflect less light and are given lower numbers. Most scanners today can differentiate 256 shades of gray or levels of brightness. This is a fixed number based on the number of cells in the array and the total area scanned.