Algorithmic techniques used to extract useful information from digital images and video. Initially, image processing techniques are used to improve the image quality with respect to the features of interest. Then some form of feature matching is applied in order to establish the presence of the desired information, which can be extracted with further analysis. Computer-vision systems are becoming ubiquitous, with applications ranging from number-plate recognition, surveying, and face recognition. The use of similar techniques for quality control in an industrial or manufacturing context is referred to as machine vision.