Acquisition
An image is a planar representation of a scene or object located in a three- dimensional space (plus the temporal dimension). The acquisition, processing, and rendering of an image resemble a processing chain (signal processing) with all its issues, notably the sensors: sensors (digitizer).
A digital image consists of a rectangular sampling grid whose components are pixels carrying information about the light intensity in different locations within the image.
Thus, a digital image is represented by a two-dimensional matrix, with its elements being natural numbers corresponding to quantization levels in the scale of light intensity.
Initially, an input image is captured by a television camera in (2D) and digitized, described by an image function f(x, y) whose value is the light intensity as a function of two parameters x, y, representing the coordinates of the location in the image.
An image is merely an imperfect representation of a scene, and creating an image involves the intention to present an entity observable by the human eye.