Watermark generator, watermark decoder, method for providing a watermark signal in dependence on binary message data, method for providing binary message data in dependence on a watermarked signal and computer program using a two-dimensional bit spreading

A watermark decoder for providing binary message data in dependence on a watermarked signal, the watermark decoder comprising:

• a time-frequency-domain representation provider configured to provide a time-frequency-domain representation of the watermarked signal;
• a synchronization determinator comprising a despreader including one or more despreader blocks, wherein the despreader is configured to perform a 2-dimensional despreading in order to acquire a synchronization information in dependence on a 2-dimensional portion of the time-frequency-domain representation;
• and
• a watermark extractor configured to extract the binary message data from the time-frequency-domain representation of the watermarked signal using the synchronization information;
• wherein the despreader is configured to acquire a set of temporally despread values, wherein the despreader is configured to multiply a plurality of values of the time-frequency-domain representation with values of a temporal despread sequence, and to add results of the multiplications in order to acquire one of the temporally despread values, and
• wherein the despreader is configured to multiply the temporally despread values with values of a frequency despread sequence in an element-wise manner, and to add results of the multiplications to acquire a 2-dimensionally despread value;
• wherein the despreader is configured to multiply subsequent sets of temporally despread values with values of different frequency despread sequences in an element-wise manner, such that a first set of the temporally despread values is effectively multiplied, in an element-wise manner and in a one-step or multi-step multiplication, with a first combined frequency despread sequence, which is a product of a common frequency despread sequence and a first overlay despread sequence, and such that a second set of the temporally despread values is effectively multiplied, in an element-wise manner and in a one-step or multi-step multiplication, with a second combined frequency despread sequence, which is a product of the common frequency despread sequence and a second overlay despread sequence, which is different from the first overlay frequency despread sequence,
• wherein the first overlay despread sequence and the second overlay despread sequence are orthogonal.

A watermark decoder for providing binary message data in dependence on a watermarked signal, the watermark decoder comprising:

• a time-frequency-domain representation provider configured to provide a time-frequency-domain representation of the watermarked signal;
• and
• a watermark extractor comprising a despreader including one or more despreader blocks, wherein the despreader is configured to perform a 2-dimensional despreading in order to acquire a bit of the binary message data in dependence on a 2-dimensional portion of the time-frequency-domain representation;
• wherein the despreader is configured to acquire a set of temporally despread values, wherein the despreader is configured to multiply a plurality of values of the time-frequency-domain representation with values of a temporal despread sequence, and to add results of the multiplications in order to acquire one of the temporally despread values, and
• wherein the despreader is configured to multiply the temporally despread values with values of a frequency despread sequence in an element-wise manner, and to add results of the multiplications to acquire a 2-dimensionally despread value;
• wherein the despreader is configured to multiply subsequent sets of temporally despread values with values of different frequency despread sequences in an element-wise manner, such that a first set of the temporally despread values is effectively multiplied, in an element-wise manner and in a one-step or multi-step multiplication, with a first combined frequency despread sequence, which is a product of a common frequency despread sequence and a first overlay despread sequence, and such that a second set of the temporally despread values is effectively multiplied, in an element-wise manner and in a one-step or multi-step multiplication, with a second combined frequency despread sequence, which is a product of the common frequency despread sequence and a second overlay despread sequence, which is different from the first overlay frequency despread sequence,
• wherein the first overlay despread sequence and the second overlay despread sequence are orthogonal.

A method for providing a watermark signal in dependence on binary message data, the method comprising:

• Providing, in dependence on a single message bit of the binary message data, a 2-dimensional spread information representing the message bit in the form of a set of time-frequency-domain values;
• and
• providing the watermark signal on the basis of the 2-dimensional spread information;
• wherein a first message bit is spread in a first spreading direction using a first spread sequence and a second message bit is spread in the first spreading direction using the first spread sequence, in order to acquire an intermediate information representation, and wherein the intermediate information representation is combined with an overlay information representation, in order to acquire a combined information representation, and wherein the combined information representation is spread in a second direction using a second spread sequence, in order to acquire the 2-dimensional spread information,
• wherein the intermediate information representation is combined with an overlay information representation, which is spread in the first spreading direction using a plurality of overlay information spreading sequences, such that the first spread message bit is multiplied with a first overlay information spread sequence, and such that the second spread message bit is multiplied with a second overlay information spread sequence,
• wherein the first overlay information spread sequence and the second overlay information spread sequence are orthogonal.

A method for providing binary message data in dependence on a watermarked signal, the method comprising:

• providing a time-frequency-domain representation of the watermarked signal;
• and
• performing a 2-dimensional despreading in order to acquire a bit of the binary message data or a synchronization information used to extract the binary message data from the time-frequency-domain representation of the watermark signal in dependence on a 2-dimensional portion of the time-frequency-domain representation;
• wherein a set of temporally despread values is acquired, wherein a plurality of values of the time-frequency-domain representation is multiplied with values of a temporal despread sequence, and wherein results of the multiplications are added in order to acquire one of the temporally despread values, and
• wherein the temporally despread values are multiplied with values of a frequency despread sequence in an element-wise manner, and wherein results of the multiplications are added to acquire a 2-dimensionally despread value;
• wherein subsequent sets of temporally despread values are multiplied with values of different frequency despread sequences in an element-wise manner, such that a first set of the temporally despread values is effectively multiplied, in an element-wise manner and in a one-step or multi-step multiplication, with a first combined frequency despread sequence, which is a product of a common frequency despread sequence and a first overlay despread sequence, and such that a second set of the temporally despread values is effectively multiplied, in an element-wise manner and in a one-step or multi-step multiplication, with a second combined frequency despread sequence, which is a product of the common frequency despread sequence and a second overlay despread sequence, which is different from the first overlay frequency despread sequence,
• wherein the first overlay despread sequence and the second overlay despread sequence are orthogonal

A non-transitory computer readable medium including a computer program for performing, when the computer program runs on a computer, a method for providing a watermark signal in dependence on binary message data, the method comprising:

• providing, in dependence on a single message bit of the binary message data, a 2-dimensional spread information representing the message bit in the form of a set of time-frequency-domain values;
• and
• providing the watermark signal on the basis of the 2-dimensional spread information;
• wherein a first message bit is spread in a first spreading direction using a first spread sequence and a second message bit is spread in the first spreading direction using the first spread sequence, in order to acquire an intermediate information representation, and wherein the intermediate information representation is combined with an overlay information representation, in order to acquire a combined information representation, and wherein the combined information representation is spread in a second direction using a second spread sequence, in order to acquire the 2-dimensional spread information,
• wherein the intermediate information representation is combined with an overlay information representation, which is spread in the first spreading direction using a plurality of overlay information spreading sequences, such that the first spread message bit is multiplied with a first overlay information spread sequence, and such that the second spread message bit is multiplied with a second overlay information spread sequence,
• wherein the first overlay information spread sequence and the second overlay information spread sequence are orthogonal.

A non-transitory computer readable medium including a computer program for performing, when the computer program runs on a computer, a method for providing binary message data in dependence on a watermarked signal, the method comprising:

• providing a time-frequency-domain representation of the watermarked signal;
• and
• performing a 2-dimensional despreading in order to acquire a bit of the binary message data or a synchronization information used to extract the binary message data from the time-frequency-domain representation of the watermark signal in dependence on a 2-dimensional portion of the time-frequency-domain representation;
• wherein a set of temporally despread values is acquired, wherein a plurality of values of the time-frequency-domain representation is multiplied with values of a temporal despread sequence, and wherein results of the multiplications are added in order to acquire one of the temporally despread values, and
• wherein the temporally despread values are multiplied with values of a frequency despread sequence in an element-wise manner, and wherein results of the multiplications are added to acquire a 2-dimensionally despread value;
• wherein subsequent sets of temporally despread values are multiplied with values of different frequency despread sequences in an element-wise manner, such that a first set of the temporally despread values is effectively multiplied, in an element-wise manner and in a one-step or multi-step multiplication, with a first combined frequency despread sequence, which is a product of a common frequency despread sequence and a first overlay despread sequence, and such that a second set of the temporally despread values is effectively multiplied, in an element-wise manner and in a one-step or multi-step multiplication, with a second combined frequency despread sequence, which is a product of the common frequency despread sequence and a second overlay despread sequence, which is different from the first overlay frequency despread sequence,
• wherein the first overlay despread sequence and the second overlay despread sequence are orthogonal.