To provide a coded pattern applied to an object to be accurately identified when the object is placed on the display of an interactive display unit.

The coded pattern is detected within the image on the output display by an infrared (IR) video camera disposed on the display, opposite to the object, responding to the IR light reflected from the coded pattern. The coded patterns are as follows: circle, linear, matrix, variable bit length matrix, multi level matrix, black and white (binary) and gray scale pattern. The coded pattern is used as an object identifier and includes a code part disposed at a cue component and the defined position of the cue component. The boundary area encloses the cue component and code part, and masks unwanted noise which can interfere decoding of the code part.