ABSTRACT
All optical systems can perform mapping, or transformation of images from the input plane to the output plane. However, the processing and analysing of information of two dimensional (2D) images are usually done by converting the image into electronic domain by photonic hardware and then by using image processing software, where such an image is described by a 2D function I = f(x, y), x and y being the spatial coordinates. Amplitude of f at any pair of coordinates (x, y) is the intensity I and is expressed by gray values for gray images. When spatial coordinates and amplitude values are all finite and discrete, the image is called the digital image. Common processing of such images is carried out mostly in the spatial domain by various methods. The term spatial domain refers to the aggregate of pixels composing an image, and spatial domain methods operate directly on these pixels to yield processed output g(x, y) = T[f(x, y)], where T is an operator on the image f defined over a neighbourhood square area centred around (x, y).
