Digital Image Fundamentals

We refer to definition as the number of points (pixels) constituting an image: it is the product of the number of columns multiplied by the number of rows in the image. An image with 10 columns and 11 rows will have a definition of 10 x 11.

The image is displayed on a screen (also called a monitor), which is an output device that provides a visual representation. This information comes from the computer but in an ”indirect” way.

The processor does not directly send information to the monitor; instead, it processes information from its random access memory (RAM) and then sends it to a graphics card responsible for converting the information into electrical impulses sent to the monitor.

To display these images, standard display formats have been defined based on the evolution of the hardware capabilities of graphics cards and screens. Here are the main ones:

• CGA (320 x 200) 4 colors.

• VGA (640 x 480) 16 colors.

• SVGA (800 x 600) 256 colors.

• XGA (1024 x 768) 256 colors.

• SXGA (1280 x 1024) in 16 million colors.

\[TotalNumberOfPixels = columns * rows\]

Example: 10 x 11 = 110 pixels in total for the above image.