Contrast is the difference in
luminance or
colour that makes an object (or its representation in an image or display) distinguishable. In
visual perception of the real world, contrast is determined by the difference in the
color and
brightness of the object and other objects within the same
field of view. The human visual system is more sensitive to contrast than absolute
luminance, we can perceive the world similarly regardless of the huge changes in illumination over the day or from place to place. The maximum
contrast of an image is the
contrast ratio or
dynamic range.