US 4,528,588 AGranted

Method and apparatus for marking the information content of an information carrying signal

OwnerBo Lofberginventor

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Abstract

An information signal (INF) which is transmitted in coded form (CINF) from a signal source (RC) to a signal receiver (4,5) is decoded at the receiver and at the same time marked (MINF) by the introduction of an identification information (ID) which is characteristic of the receiver or its possessor. The signal from a video disc (RC) carrying a coded programme is decoded and marked before it is supplied to a television set (6). Via said identification information a so-called pirate copy is directly traceable to its originator. Thereby a protection against such copying is obtained. A device for the playback of a video disc of this type comprises a decoding and modification unit to which the necessary decoding information and identification information may be supplied from a personal data carrier (ID).

Claims17

Dependent claims

A method for processing a coded video information signal, which coded information signal is transmitted from a signal source to a signal receiver, in order to mark the information content of the information signal and thereby to permit tracing of unauthorized copying of said information signal, the method comprising:

decoding the video information signal at a signal receiver during reception;
obtaining an identification information and unique modification information from a data carrier, said identification information comprising personal identification information in the form of a personal code comprising a bit sequence of a given number of bits;
modifying the decoded information signal at said signal receiver by introducing said obtained identification information into the decoded information signal by a repeated bit-by-bit introduction of said personal identification bit sequence into said decoded information signal;
said identification information being a characteristic of at least one of said signal receiver and its possessor;
and
said identification information being introduced into at least one of time and frequency spaces of the decoded information signal such that the information content of said information signal is essentially unchanged;
said modifying step comprising introducing at least one bit of said bit-by-bit personal identification bit sequence within one line interval of each field of said video signal, and wherein said interval is randomly selected for each field as a function of said modification information obtained from said data carrier.

4 more elements

Apparatus for processing a coded video information signal, which coded information signal is transmitted from a signal source to a signal receiver in order to mark the information content of the information signal and thereby to permit tracing of unauthorized copying of said information signal, comprising:

means for decoding the information signal at a signal receiver during reception;
modifying means coupled to said decoding means for modifying the decoded information signal at said signal receiver by introducing into the decoded information signal an identification information, said identification information being a personal code in the form of a bit sequence having a given number of bits;
a source of modification information comprising a bit sequence of a predetermined length;
means at said receiver for generating said identification information as a characteristic of at least one of said signal receiver and its possessor;
said modifying means being coupled to said identification information means for introducing said identification information into at least one of time and frequency spaces of the decoded information signal such that the information content of said information signal is essentially unchanged;
and
said modifying means comprising means for selecting randomly one line per field of the video signal;
and means for introducing at least one bit of said personal code bit sequence into the line interval of each line which is selected.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/385,374Filed 18 May 1982
Priority: SE 800677226 Sep 1980
Granted: 9 Jul 1985
Term ends: Not estimatedThe source records don’t support an estimate.

Classification18 codes

H04N 7/162
Analogue secrecy systems; Analogue subscription systems: authorising the user terminal, e.g. by paying; Registering the use of a subscription…
G06F 21/16
Protecting distributed programs or content, e.g. vending or licensing of copyrighted material ; Digital rights management [DRM]: program or…
G06Q 20/346
Using cards, e.g. integrated circuit [IC] cards or magnetic cards: cards serving only as information carrier of service
G07C 9/23
In combination with an identity check of the pass holder: by means of a password