Patent application number | Description | Published |
20090187765 | Method and apparatus for determining whether or not a reference pattern is present in a received and possibly watermarked signal - Many watermarking systems make use of correlation for calculating a detection metric, which means that several reference patterns are generated at encoder side and one or more of them are embedded inside the content signal, dependent on the message to be embedded. To decode the embedded message, it is necessary to discover which reference pattern was embedded at encoder side. This is determined by correlating the known reference patterns with the content signal. A watermark detector decides, depending on the size of the correlation result values, whether or not a given pseudo-random sequence was embedded. However, this does not provide correct decisions if watermarked audio is emitted by a loudspeaker and then captured with a microphone. According to the invention, it is taken advantage of the received signal echoes instead of treating them as noise. The watermark detection result is improved by integrating the correlation values resulting from echoes into the main correlation peak, thereby using correlation result amplitude values located within a predetermined neighborhood of a correlation result peak amplitude value and exceeding a predetermined threshold. | 07-23-2009 |
20090193255 | Method and apparatus for determining and using the sampling frequency for decoding watermark information embedded in a received signal sampled with an original sampling frequency at encoder side - Many watermarking systems make use of correlation for calculating a detection metric, which means that reference patterns are generated at encoder side and are embedded inside the audio or video signal, dependent on the message to be embedded. The same reference patterns are generated at decoder side. The embedded message is decoded by correlating the reference patterns with the watermarked signal. The watermark detector decides, depending on the size of the correlation result values, whether or not a given reference pattern was embedded. However, decoding watermarked audio or video signals is difficult if the link between the watermark encoder and the watermark decoder is not a digital one, for example an acoustic path. According to the invention, a re-sampler control unit controls the sampling frequency of a re-sampler, in connection with a watermark decoder that outputs, in addition to the watermark information bits, a corresponding confidence value that is derived from the correlation result and that is used for synchronizing the re-sampler sampling frequency with the original sampling frequency of the watermarked signal. The synchronization processing includes a search mode and a synchronized mode. | 07-30-2009 |
20090323725 | Data transmission method and device for carrying out the method - The invention relates to the technical field of data transmission via a transmission link according to the TDM method, corresponding to time division multiplex. Such a method is used in an audio mixing console in order to transport the sample words of a plurality of audio channels jointly to an audio DSP processor and, after processing, to transmit them back from said processor to an output processor. Since the data output process is performed in an automated manner with the aid of a DMA unit, severe interfering noise can occur in cases of error, said noise also being output via the loudspeakers. The invention is based on the aim of avoiding such interfering effects. An error detection method based on the marking of data frames is used for this. For this purpose, a number of marking bits of the time slot of the data frame are set, the bit pattern of the marking bits being alternated in a defined sequence. Upon error detection, the outputting of the data via the loudspeakers is prevented, such that no interfering noise arises. | 12-31-2009 |
20130070960 | PROVIDING A WATERMARKED DECODED AUDIO OR VIDEO SIGNAL DERIVED FROM A WATERMARKED AUDIO OR VIDEO SIGNAL THAT WAS LOW BIT RATE ENCODED AND DECODED - Various audio signal watermarking systems are known, which are also applied to digitally encoded audio signals. However, in current audio signal watermarking systems the watermark signal and its watermark payload do not survive very low bit rate audio coding, in particular parametric coding. According to the invention, a watermarked uncompressed audio signal bit-stream is low-bit rate compressed, but the water-marking is removed and the watermark's payload only is transmitted together with the compressed audio signal bit-stream. At decoder side, the received audio signal bit stream is de-compressed and water-marked again using the transmitted watermark payload. Advantageously, it does not matter that the compressed bitstream is not watermarked because the compressed bitstream can be encrypted prior to transmission. | 03-21-2013 |
20130073065 | METHOD AND APPARATUS FOR DETECTING WHICH ONE OF SYMBOLS OF WATERMARK DATA IS EMBEDDED IN A RECEIVED SIGNAL - Watermark symbol detection requires a detection metric for deciding at decoder side which candidate symbol is embedded inside the audio or video signal content. The invention provides an improved detection metric processing that achieves a reliable detection of watermarks in the presence of additional noise and echoes, and that is adaptive to signal reception conditions and requires a decreased computational power. This is performed by taking into account the information contained in the echoes of the received audio signal in the decision metric and comparing it with the corresponding metric obtained from decoding a non-marked audio signal, based on recursive calculation of false positive detection rates of Correlations for all REFP Reference Pattern peaks in correlation result values. The watermark symbol corresponding to the reference sequence having the lowest false positive error is selected as the embedded one. | 03-21-2013 |
20130132729 | METHOD AND SYSTEM FOR PROTECTING BY WATERMARKING AGAINST NON-AUTHORISED USE ORIGINAL AUDIO OR VIDEO DATA WHICH ARE TO BE PRESENTED - For protecting by watermarking against non-authorised use, e.g. non-authorised recording or copying, original audio or video data which are to be presented in a digital cinema, a sender site generates from the original signal at least two differently pre-watermarked versions for successive blocks or frames of the signal, wherein these versions are derived by applying a repeated watermark symbol value to a version and different watermark symbol values to the different versions. The pre-watermarked signal versions are encrypted and transferred e.g. as data files to a digital cinema unit in which they are decrypted. According to the values of a desired watermark information word, corresponding frames or blocks from said decrypted and pre-watermarked versions are assembled in a successive manner, so as to provide and present a watermarked version of said original audio or video signal that carries said watermark information word. | 05-23-2013 |
20140006790 | METHOD AND APPARATUS FOR WATERMARKING AN AC-3 ENCODED BIT STREAM | 01-02-2014 |