Digital imaging devices highlight the number of pixels or megapixels as an important feature, especially digital cameras. The following guide helps you understand the terms "pixel" and "megapixel."
Understand a pixel. A digital image is constructed by many small dots, or squares. These equally spaced small dots are arranged as an array of rows and columns. These small dots are called pixels. The word "pixel" was derived from the two words "pix" from "pictures" and "el" from "element." As you can imagine, the overall quality of the image depends on arranging a sufficient number of dots closely.
You may find the term pixel in many contexts like printed pixels on a page, the pixels on a display device and pixels in a digital camera. In digital cameras, the pixels are image sensors elements (CCD), whereas the pixels are small display elements in display units.
Check the pixel count or resolution. The total number of pixels available in a display or image is mentioned by the resolution. In other words, resolution is the term used to specify the pixel count.
Understand the megapixels. If the pixel count or resolution is very small, the image quality is poor. Usually more pixels in the multiples of 1,000,000 are required to represent an image with clarity. Hence, instead of pixels, its larger unit "megapixels" is used to specify the total number of pixels or the resolution. One Megapixel means one million (1,000,000) pixels. Hence, 3.2 megapixels means 3,200,000 pixels (i.e., 3.2 x 1,000,000). Five megapixels means there are five million pixels.
Find hidden values of megapixels. Sometimes the resolution is mentioned as 800x600 or 800 by 600. As mentioned earlier, the pixels are arranged as rows and columns. Therefore, 800x600 means there are 800 pixels sideways and 600 from top to bottom (600 rows each having 800 pixels). You can find the total number of pixels by multiplying 800 and 600.
800 x 600 = 480,000 pixels. It is equal to 0.48 megapixels (480,000 / 1,000,000 = 0.48).
There is a standard way of representing the resolution. These standards are accepted worldwide. Some of the commonly used standards are EGA (640x350), VGA (640x480), SVGA (800x600), XGA ( 1024x768), SXGA (1,280x1,024), UXGA (1,600x1,200) etc. The value of resolution of these standards is given in the parenthesis.