Patent ID: 7356159

Claim:
An apparatus for embedding imperceptible codes into digital image data comprising: a data divider to divide, per frame, digital image data into an â€œNâ€ number of fields wherein â€œNâ€ being an integer of 2 or more; a code producer to produce an â€œmâ€ number of combinations of imperceptible codes, each combination having a first imperceptible code and a second imperceptible code, the first imperceptible code being one of the â€œmâ€ number of first imperceptible codes, the second imperceptible code being one of the â€œmâ€ number of second imperceptible codes given by a specific function with each first imperceptible code and a specific identification code as variables, in which the specific identification code is given by the specific function with the first and second imperceptible codes of each combination as variables wherein â€œmâ€ being an integer of 2 or more and given by dividing â€œNâ€ by an integer; and a code embeder to embed the first and second imperceptible codes of each combination into image data of each of the divided fields according to a specific rule of positional correspondence that defines a positional relationship between the first and second imperceptible codes of each combination when embedded in each field of one frame.