US Patent 7420649 Theater identification system utilizing identifiers projected through a screen

A method and a system for identifying a copy of an image sequence which is presented on a screen. At least one identifier distinct from the image sequence can be projected through the screen such that the identifier is displayed using visible light along with the image sequence. The identifier can be presented at periodic intervals and can define a theater location, a date and/or a time. A color and/or an illumination of at least a portion of the image sequence presentation can be measured. Based on the measured illumination and/or color, a projection brightness and/or color can be determined for the identifier. Also, a location on the screen through which the identifier should be projected can be determined.