A method and
system of verifying display of primary visual information on a screen of an
electronic visual display device. Primary visual information is combined with visual
verification information to create combined primary and
verification visual information in a computer-
usable format. The combined primary and
verification visual information is rendered on the screen of the visual
display device. The screen is monitored using an
optical detector to detect display of the visual verification information on the screen thereby verifying display of the primary visual information. Preferably, wherein said combining involves creating a
computer file containing data representing said combined primary and verification visual information. Preferably the data is rendered on the screen a media player. Preferably, said rendering involves rendering said primary visual information using a
visual media editor. The invention relates to verifying that adverts have been displayed on an electronic display as scheduled. Preferably quality of the visual information is assessed based on a comparison of a measured visual characteristic with a corresponding desired visual characteristic. The visual characteristic may be one or more of
illuminance, luminance, brightness and / or colour.