Lisbon (/ˈlɪzbən/, LIZ-bən; Portuguese: Lisboa, IPA: [liʒˈboɐ] or [liʒˈβoɐ]) is the capital city and largest city of Portugal with a population of 547,631 within its administrative limits on a land area of 84.8 km2 (33 sq mi). The urban area of Lisbon extends beyond the administrative city limits with a population of over 3 million on an area of 958 km2 (370 sq mi), making it the 11th most populous urban area in the European Union. About 3,035,000 people live in the Lisbon Metropolitan Area (which represents approximately 27% of the population of the country). Lisbon is the westernmost large city located in Europe, as well as its westernmost capital city and the only one along the Atlantic coast. It lies in the western Iberian Peninsula on the Atlantic Ocean and the Tagus River.
In photography and computing, a grayscale or greyscaledigital image is an image in which the value of each pixel is a single sample, that is, it carries only intensity information. Images of this sort, also known as black-and-white, are composed exclusively of shades of gray, varying from black at the weakest intensity to white at the strongest.
Grayscale images are distinct from one-bit bi-tonal black-and-white images, which in the context of computer imaging are images with only the two colors, black, and white (also called bilevel or binary images). Grayscale images have many shades of gray in between. Grayscale images are also called monochromatic, denoting the presence of only one (mono) color (chrome).
Grayscale images are often the result of measuring the intensity of light at each pixel in a single band of the electromagnetic spectrum (e.g. infrared, visible light, ultraviolet, etc.), and in such cases they are monochromatic proper when only a given frequency is captured. But also they can be synthesized from a full color image; see the section about converting to grayscale.