Digital imaging or digital image acquisition is the creation of a representation of the visual characteristics of an object, such as a physical scene or the interior structure of an object. The term is often assumed to imply or include the processing, compression, storage, printing, and display of such images. Digital imaging can be classified by the type of electromagnetic radiation or other waves whose variable attenuation, as they pass through or reflect off objects, conveys the information that constitutes the image. In all classes of digital imaging, the information is converted by image sensors into digital signals that are processed by a computer and outputted as a visible-light image. For example, the medium of visible light allows digital photography with various kinds of digital cameras. X-rays allow digital X-ray imaging, and gamma rays allow digital gamma ray imaging. Sound allows ultrasonography and sonar, and radio waves allow radar. Digital imaging lends itself well to image analysis by software, as well as to image editing.