Reducing watermark perceptibility and extending detection distortion tolerances
The present disclosures relates generally to digital watermarking and data hiding. One claim recites a smartphone comprising: a camera to capture video of a display that is rendering video, in which the video comprises a first watermark signal embedded in a first portion of the data, a second watermark signal embedded in a second portion of the data, and a third watermark signal embedded in a third portion of the data, in which at least two of the first watermark signal, second watermark signal and third watermark signal are inversely related to one another; electronic memory for buffering data representing captured video; one or more electronic processors programmed for: applying a first perspective distortion to the data representing the captured video to yield first perspective distorted video; and analyzing the first perspective distorted video to detect digital watermarking, in which a second perspective distortion is applied to the data representing the captured video to yield second perspective distorted video when the analyzing does not detect digital watermarking, and then performing analyzing the second perspective distorted video to detect digital watermarking. Of course, other claims are provided too.
1. A method comprising:
obtaining data representing video depicting people or objects;
using one or more electronic processors, determining a first change to the data that represents a first watermark signal, the first watermark signal to be embedded in a first portion of the data, the first watermark signal comprising a first signal polarity;
using one or more electronic processors, determining a second change to the data that represents a second watermark signal, the second watermark signal to be embedded in a second portion of the data, the second watermark signal comprising a second signal polarity that is inversely related to the first signal polarity;
determining whether the first portion or the second portion corresponds to a clipped or saturated threshold;
upon a condition in which the first portion or the second portion corresponds to a clipped or saturated threshold, calculating a first scaling factor for the first change and a second scaling factor for the second change, and applying the lower of the first scaling factor and the second scaling factor to each of the first change and the second change.
2. The method of claim 1 in which said calculating utilizes an absolute magnitude of color values associated with the first portion of the data and the second portion of the data.
3. A smartphone comprising:
a camera to capture video of a display that is rendering video, in which the video comprises a first watermark signal embedded in a first portion of the data, a second watermark signal embedded in a second portion of the data, and a third watermark signal embedded in a third portion of the data, in which at least two of the first watermark signal, second watermark signal and third watermark signal are inversely related to one another;
electronic memory for buffering data representing captured video;
one or more electronic processors programmed for:
applying a first perspective distortion to the data representing the captured video to yield first perspective distorted video; and
analyzing the first perspective distorted video to detect digital watermarking, in which a second perspective distortion is applied to the data representing the captured video to yield second perspective distorted video when the analyzing does not detect digital watermarking, and then performing analyzing the second perspective distorted video to detect digital watermarking.
4. The smartphone of claim 3 in which the one or more electronic processors are programmed for applying a plurality of different perspective distortions to the data until digital watermark can be detected from such.
5. The method of claim 1 further comprising: upon the condition in which the first portion or the second portion corresponds to a clipped or saturated threshold, transforming the data representing video with the first change and the second change, each of first change and the second change having been altered with the lower of the first scaling factor and the second scaling factor.
6. The method of claim 1 further comprising: transforming the data representing video with the first change and the second change.
7. An apparatus comprising:
input means for obtaining data representing video depicting people or objects;
means for determining a first change to the data that represents a first watermark signal, the first watermark signal to be embedded in a first portion of the data, the first watermark signal comprising a first signal polarity;
means for determining a second change to the data that represents a second watermark signal, the second watermark signal to be embedded in a second portion of the data, the second watermark signal comprising a second signal polarity that is inversely related to the first signal polarity;
means for determining whether the first portion or the second portion corresponds to a clipped or saturated threshold; and
means for, upon a condition in which the first portion or the second portion corresponds to a clipped or saturated threshold, calculating a first scaling factor for the first change and a second scaling factor for the second change, and for applying the lower of the first scaling factor and the second scaling factor to each of the first change and the second change.
8. The apparatus of claim 7 further comprising: embedding means for, upon the condition in which the first portion or the second portion corresponds to a clipped or saturated threshold, transforming the data representing video with the first change and the second change, each of first change and the second change having been altered with the lower of the first scaling factor and the second scaling factor.
9. The apparatus of claim 7 further comprising: embedding means for transforming the data representing video with the first change and the second change.
10. A smartphone comprising:
means for capturing video of a display that is rendering video, in which the video comprises a first watermark signal embedded in a first portion of the data, a second watermark signal embedded in a second portion of the data, and a third watermark signal embedded in a third portion of the data, in which at least two of the first watermark signal, second watermark signal and third watermark signal are inversely related to one another;
means for buffering data representing captured video;
means for applying a first perspective distortion to the data representing the captured video to yield first perspective distorted video; and
means for analyzing the first perspective distorted video to detect digital watermarking, in which a second perspective distortion is applied to the data representing the captured video to yield second perspective distorted video when the analyzing does not detect digital watermarking, and for performing analyzing the second perspective distorted video to detect digital watermarking.
11. The smartphone of claim 10 including means for applying a plurality of different perspective distortions to the data until digital watermark can be detected from such.