Another measure is the extent to which the known signature matches a signature computed from the suspect signal. A variety of correlation methods may be employed, including, for example general matched filtering. We cannot provide any kind of advice, explanation, opinion, or recommendation about possible legal rights, remedies, defenses, options, selection of forms or strategies. The detector may also quantify the extent of watermark degradation. In this example, the detector correlates the calibration signal or attributes of it with the suspect signal 200, 202. Apart from these restrictions, care has been taken to keep the presentation as rigorous as possible: the topics addressed are dealt with quantitatively, the results are given in mathematical form, and the interested reader should be able to fol low the algebra all the way through. The detector may compute different measures of correlation in each stage and evaluate a metric that combines information from these correlation measures to get improved rejection of unmarked signals.
The watermarks may be viewed with software and can reveal either a unique identification code that can be traced to the copyright owner or specific information about the copyright owner. The synchronization process varies depending on the type of host and watermark signal. . Also, each portion may represent different orientations of the suspect signal, or a component of the signal. They have removable subtitles, and the quality is usually better than the silvers. In addition to certain guarantees provided by law, LegalZoom guarantees your satisfaction with our services and support.
In this case, the calibration signal corresponds to the orientation signal. Therefore the resulting detection value is low. This correlation can be computed in the spatial domain, the Fourier magnitude domain, or some other transform domain. Next, the detector computes relative detection values based on the detection values calculated previously from the suspect signal 206. Since visual watermarks change the look of an image or video, they are effective in eliminating potential commercial value for Internet pirates. If the detection value fails to exceed T 1, the suspect image is labeled an unmarked image and further processing ceases. One advantage of using both absolute and relative detection values is that they usually contain complementary information.
As a result, the mean performance times are reduced. The detector performs correlation between an orientation signal and the suspect signal. In one implementation, the result of filtering at each impulse function location in the Fourier magnitude domain is added to compute a measure of correlation. For example, if the detection value falls below a limit either predetermined or adapted based on the suspect signal , then the detector may conclude that the associated signal is unmarked. The dot product is computed between the two signals after transforming the orientation signal to a candidate orientation e.
Furthermore, the watermark can be customized in terms of what it shows and where on the screen. The following points can be made about this two stage screening: 1 There are two screening stages to reject unmarked images. Ideally, the initial detection stage should allow all watermarked images to proceed to later detection stages but reject all unmarked images. Based on the measure of correlation, the detector determines whether to reject the suspect signal. Based on the watermark strength, the detector can assess whether a suspect signal has a valid watermark, and the extent to which a signal has been transformed. One such filtering operation is to divide the sample in the suspect signal at the impulse location by an average of neighboring samples. One example is a thresholding process that subtracts a first constant from each filtered result, and then clips values greater than a second constant to that constant value.
Another action is to use the detection values to direct further actions of the detector. The method of claim 1 where the detection values have corresponding orientation parameters; and wherein the orientation parameters approximate a spatial or temporal transform that at least a portion of the suspect signal has undergone subsequent to being embedded with an auxiliary signal. Next, it determines how to direct further detector actions based on the detection values 106. There is no method a scrubber could use to identify the presense or absense of one of these bits, if the three copies they have all happen to store the same piece of data. Fragile watermarks are commonly used for tamper detection integrity proof. In many watermark systems, a key specifies where a watermark is located in an un-modified watermarked signal.
Both absolute and relative detection values may be evaluated relative to desired limits or thresholds to determine an appropriate action. I am not referring to prints. We are not a law firm or a substitute for an attorney or law firm. In a particular implementation in the cited application, an initial detection stage decides whether a watermark is present in a suspect image and, if so, provides estimates of orientation parameters to later detection stages. In other words, the initial detection stage acts as a classifier that discriminates between marked and unmarked images. There are two ballots: a nominating ballot and a final ballot for the Academy Awards themselves.
Another aspect of the invention is a method for using two or more detection metrics to control the detection process. There are many possible modifications, for example, lossy compression of the data in which resolution is diminished , cropping an image or video, or intentionally adding noise. One way to compute the correlation strength in this context is to compute the dot product of the impulse functions of the orientation signal and the suspect signal in the Fourier Magnitude domain. In particular, the relative detection value is computed as a ratio of a top correlation value to one or more lesser correlation values or combination of lesser correlation values e. A watermark is embedded into a digital signal at each point of distribution. The marks often were created by a wire sewn onto the paper mold. One such measure is a correlation value that quantifies the correlation between the calibration signal and a portion of the suspect signal.
This would make the images acceptable for legal purposes. The goal is to minimize both the false positives and the false negatives. One action is to reject the candidate signal associated with the detection value as being unmarked. The method of claim 1 wherein the attributes comprise impulse functions in a transform domain. Also, the apparent absence of a watermark may trigger some action or prevent an action such as providing output indicating that the signal has been tampered with or controlling processing of the signal e.