There are many terms used in digital imaging, but the term "megapixels" is probably the most misunderstood of any of them. Maybe it's because megapixel is so misused in advertising campaigns, or maybe its because the word is the combination of two words, mega and pixel. Defining the term will help the reader to understand the basics of megapixels.
History Of The Pixel
In order to understand the word megapixel, knowing its etymology and where it originated from is useful. Megapixel is two words put together, mega and pixel. Pixel, or picture element, originates in the image processing and video coding field. The German word Bildpunkte, coined in the 1880's, translates into "picture points" and appears to be where the concept of picture elements came from. The term, picture element, was first used in an article in Wireless World magazine in 1927. The term pixel, a combining of pix (short for pictures) and el (short for elements), was first used in 1965.
Technical Function Of The Pixel
The picture elements or picture points being referred to are the smallest elements of information in a picture. The elements are placed within a 2-dimensional grid to recreate the original image. The more pixels contained in an image, the more closely the image represents the original. Often they are represented by dots, but they can also be represented as squares or rectangles and other shapes. The variation of shape depends on the device the image is viewed on.
Megapixel Size
Megapixel (mp) translates to 1 million pixels, or 1 million picture elements or points -- 1 million image sensor elements. Counting pixels is expressed in several ways, by a single digit or a pair of digits. So a 3.1mp camera is also shown as 2048 x 1536, and an 8mp is 3264 x 2448. Figuring mp's is just like figuring square footage, as long as the room being measured is rectangular in shape.
Important Information About Megapixels
Context is important when using the term megapixel. When acquiring an image on one device and displaying the image on a different type of device, or converting images from one format to another, understanding the changes taking place, and the differences between the use of pixel, and megapixel, between the devices is important in retaining the original image and viewing quality. Pixels can be arranged differently from one device to another, meaning they are not referenced on a two-dimensional grid but referenced in some other pattern. If this is so, the image will be re-sampled and thereby resized, which can stretch or distort the image.
Misconceptions About Megapixels
The megapixel (mp) is a term that is often misused, especially in advertising digital cameras. Although typically it refers to the ability to print in large scale (think 12 x16 or 16 x 20) --- the larger the number of mp's the sharper the print size capability --- not everyone agrees about this. It is also thought that the size of the digital sensor area (where the pixels are stored) is part of the equation for sharp pictures in digital cameras.
Tags: picture elements, About Megapixels, digital cameras, first used, image more, mega pixel
