Human being has desire to keep things that exist in their lives. As a result, human invented camera, and as a medium that stores those images, computer was invented. At first, people used film camera that when used, it saves on the film. After computer being invented, people developed digital store method using computer. Now, most of images are on the computer with digital store method. Digital store method includes Bitmap image expression method and Vector graphic expression method. Computer being developed, the images are not just to be what these are; people adjust the images into their characteristic through image processing.
Bitmap images expression method is that the images are stored through small units called pixel. Generally, it is known that materials are consists with the atoms regarded as smallest unit. In bitmap images expression, the materials are the images and the pixels are the atoms. Mainly Square shape of pixel makes whole digital images with raster. Raster constitutes images with 2-D array form of pixel and expressing a picture with certain pixel interval. Extensions of bitmap are GIF, JPEG, PNG, and BMP and so on. Merit of Bitmap image is easy to handle, and efficient except for the large scale of data for high-revolution.
Vector is mathematical way of expressing coordinate of dots, which has both scale and direction. In computer, vector is used as vector graphics which express graphics on the screen by moving electric beam continuously along the lines on graphic screen. Through series of instruction word and mathematical expression, vector graphic makes digital images for placing given lines or shapes 2-D or 3-D space. That is to say, graphic files that are results of creative activity are expressed and kept as a form of series of vector sentences. Since vector graphic file keeps position of dots, it takes lower data than bitmap file. The merits of vector graphic are easy to handling printing that is made of lines, and are high-revolution.
Anyway, the saved images are often arbitrarily changed through image processing. Generally, it point out all form of information processing that input and output are images. Most of it processes image and video. The methods of image processing are Euclidean geometrical change like expansion, reduction and rotation, color compensation, composition, restoration of raw images through interpolation and undressing mosaic and so on. If image processing is applied, computer vision, augmented reality, face detection and etc. can be made. Computer vision plays a role of eyes for mechanics so that mechanic recognizes objects and patterns, learns something and so on. Augmented reality is a mixed reality that virtual reality is overlapped. In the augmented reality, computer graphic provides tagged information about reality that position, phone number of store etc. Face detection is technic that informs position of the faces.
Images were just stored in the computer through image expression methods. Using them, and changing them, human gets information about near environments so that those have been developed into our lives again, in the other ways.