Embedding supplementary data in an information signal

• US 20050025314A1
• Filed: 10/24/2002
• Published: 02/03/2005
• Est. Priority Date: 11/16/2001
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Bruekers, Alphons Antonius Maria Lambertus, Van Der Veen, Minne
• Granted Patent: US 7,561,688 B2
• Time in Patent Office: Days
• US Class Current: 380/254
• CPC Class Codes: G10L 19/018 Audio watermarking, i.e. embedding inaudible data in the audio signal
• CPC Class Codes: G10L 19/02 using spectral analysis, e.g. transform vocoders or subband vocoders
• CPC Class Codes: G11B 20/00891 embedded in audio data

Abstract

Disclosed is a method of adjusting a supplementary data signal (wm(n)) to be embedded in an information signal (x(n)), for example an audio signal. The method comprises the steps of determining (107) a relative magnitude (g(n)) of a first property function (M_x(n)) of the information signal averaged over a region of a predetermined size and a second property function (M_wm(n)) of the supplementary data signal averaged over said region; and adjusting (407) the supplementary data signal according to the determined relative magnitude.

Claims

1. A method of adjusting a supplementary data signal (wm(n)) to be embedded in an information signal (x(n)), the method comprising the steps of

determining a relative magnitude (g(n)) of a first property function (M_x(n)) of the information signal averaged over a region of a predetermined size (N) and a second property function (M_wm(n)) of the supplementary data signal averaged over said region;

adjusting the supplementary data signal according to the determined relative magnitude.

2. A method according to claim 1, wherein the first property function is a local energy function of the information signal and the second property function is a local energy function of the supplementary data signal.

3. A method according to claim 1, wherein the first property function is a local magnitude of the information signal and the second property function is a local magnitude of the supplementary data signal.

4. A method according to claim 1, wherein the step of adjusting the supplementary data signal according to the determined relative magnitude further comprises the step of regularising the determined relative magnitude.

5. A method according to claim 4, wherein the step of regularising comprises the step of limiting the amplitude of the relative magnitude to a predetermined maximum value.

6. A method according to claim 4, wherein the step of regularising comprises the step of applying a low pass filter to the determined relative magnitude.

7. A method according to claim 1, wherein the step of adjusting the supplementary data signal according to the determined relative magnitude comprises the steps of

delaying the supplementary data signal by a predetermined delay;

and

adjusting the delayed supplementary data signal according to the determined relative magnitude.

8. A method according to claim 7, wherein the predetermined delay corresponds to the size of the region.

9. A method according to claim 1, wherein the step of adjusting the supplementary data signal according to the determined relative magnitude comprises the steps of

delaying the supplementary data signal by a delay corresponding to the size of the region resulting in a delayed signal;

adjusting the delayed signal according to the determined relative magnitude, resulting in a first delayed adjusted signal;

adjusting the supplementary data signal according to the determined relative magnitude resulting in an adjusted signal;

delaying the adjusted signal by a delay corresponding to the size of the region, resulting in a second delayed adjusted signal; and

combining the first and second delayed adjusted signals.

10. A method according to claim 1, wherein the step of determining a relative magnitude (g(n)) further comprises the steps of

calculating a third property function;

delaying the third property function to obtain a delayed property function; and

combining the third property function with the delayed property function to obtain the second property function.

11. A method according to claim 1, wherein the information signal comprises a digital audio signal.

12. An arrangement for adjusting a supplementary data signal (wm(n)) to be embedded in an information signal (x(n)), the arrangement comprising

means (107) for determining a relative magnitude (g(n)) of a first property function (M_x(n)) of the information signal averaged over a region of a predetermined size (N) and a second property function (M_wm(n)) of the supplementary data signal averaged over said region;

and

means (407) for adjusting the supplementary data signal according to the determined relative magnitude.

13. A device for embedding a supplementary data signal (wm(n)) in an information signal (x(n)), the device comprising an arrangement for adjusting the supplementary data signal to be embedded in the information signal, the arrangement comprising

means (107) for determining a relative magnitude (g(n)) of a first property function (M_x(n)) of the information signal averaged over a region of a predetermined size (N) and a second property function (M_wm(n)) of the supplementary data signal averaged over said region;

and

means (407) for adjusting the supplementary data signal according to the determined relative magnitude.

14. An information signal (y(n)) having embedded therein a supplementary data signal (wm(n)), wherein the supplementary data signal has been adjusted by a method comprising the steps of

determining a relative magnitude (g(n)) of a first property function (M_x(n)) of the information signal averaged over a region of a predetermined size (N) and a second property function (M_wm(n)) of the supplementary data signal averaged over said region;

adjusting the supplementary data signal according to the determined relative magnitude.

15. A storage medium having recorded thereon an information signal according to claim 14.