Image is a non verbal representation of object in 2D. If an image needs to be processed it has to be converted into digital form by sampling and quantization first. To process an image by means of a digital computer is called digital image processing.
Image processing is a technique to translate an image into digital form and executing various operations on it, to attain an enhanced image or to extract some useful information from it. It is a type of signal dispensation in which input is image, like video frame or photograph and output may be image or characteristics associated with that image.