Where Do Pixels Come From?
and digital cameras use a lens to project an image onto an imaging
sensor. The sensor is either a
CCD ‘charged coupled device’ or a CMOS 'Complementary Metal-Oxide
Semiconductor'. A CCD or CMOS chip is made up of many small electrical
receptors that are in a continuous matrix. The matrix of receptors on the
camera's or scanner's image sensor converts the light
and colors from the projected image into a matrix of pixels in the digital image file.
A digital image constructed from a camera or scanner is called a BITMAPPED image because the digital image file contains a computer word (8 or 16 bits to the word) 'map' containing the color information for each pixel in the image. CCDs and CMOS sensors respond to the primary additive colors of RED, GREEN and BLUE.
Digital images made in DRAW and CAD programs are called VECTOR based digital images because the file contains color and shape information based on grid coordinates or intersecting line vectors within the basic square image.