Pixels and image resolution

Pixels
Pixels per inch or pixel density. The word pixel comes from picture and element. A pixel is the smallest thing in a digital image. We create pixels using different software such as photoshop or paint. It can be presented on a television such as a LCD screen. Pictures can be took using a camera or a scanner and it contains pixels. Digital images are always rectangles or squares. They are constructed of pixels. There's a horizontal and vertical number of pixel size of an image. A million pixels is called a megapixel. E.g 1920 x1080 has 2,073,600 pixels which is 2.07 megapixels.There are two types of images which is screen and print. Screen is the pixels on the monitor and the resolution is 72ppi (pixels per inch). A print is a image which is printed off and has 300dpi (dots per inch) which is basically the same thing. When people are making games for phones they have to consider the ppi of the phone. Such as the iPhone 3gs has 165ppi.

Image Resolution
The image resolution is a term that descrives the detail the image hold. This term applist to digital images , film images and other type of images. The resolution can be lines per mm (LP/mm) or lines per inch (LP/Inch). A resolution can consist of loads of different amount of pixels. For example HD us 1280x720 pixels. Whereas full HD is either 1440x1080 or 1920x1080 depending of the input.

Bit is conflation of 2 words - Binary and digit. Origin of the word is attributed to John W Tukey who first written on Bell Labs memo on 9th of January 1947 in contracted "binary digit" to simplify "bit"

In computing a bit can only have 2 possible values 0 or 1 , yes or no , true or false , + or - etc.

A byte is a group of 8 bits. Bytes or multiples thereof, are almost always used to speicfy the sizes of computing files and the capacity of storage uinits. Most modern compiter and peripheral devices are designed to manipulate data whole bytes or groups of bytes rather than individual bits.A nibble is 4 bits or half a byte. 2 to the power of 8 is 256 bits. Bit depth specifies how much each pixel is an image. The more bits of information per pixel , the more available colours and more accuraate colour representaion.

An image with 1 pixel has 2 values black and white. An image with a bit depth of 8 has 2(8) or 256 possible values grayscale mode images with bit depth of 8 have 256 possibe gray values.

RGB images ae made of three colour channels. An 8 bit per pixel RGB image has 256 possible values fir each channel which means it has over 16 million pissible colour values. RGB images with 8 bits per channel (bpc) are sometimes called 24 bit images (8 bits x 3 channels = 24 bits of date for each pixel).