# US 12,112,763 B2 · Methods and apparatus to identify signals using a low power watermark > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,112,763 B2 - Document ID: US12112763B2 - Status: Granted - Kind: B2 - Application number: 17/148,302 - Filed: 2021-01-13 - Published: 2021-05-06 - Granted: 2024-10-08 - Earliest claimed: 2018-03-21 - Assignees: The Nielsen Company (US), LLC - Applicants: The Nielsen Company (US), LLC - Inventors: Timothy Christian; Javon Lee - Web page: https://patentgrep.com/patent/US12112763B2 ## CPC - G10L 19/018: Audio watermarking, i.e. embedding inaudible data in the audio signal - H04N 21/233: Processing of audio elementary streams {(monitoring, identification or recognition of audio in broadcast systems H04H60/58)} - H04N 21/23892: {involving embedding information at multiplex stream level, e.g. embedding a watermark at packet level} - H04N 21/8358: involving watermark {(protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467)} - G10L: SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Methods, apparatus, systems and articles of manufacture are disclosed for signal identification using a low power watermark. Example apparatus for media identification based on watermarks includes a first processor to determine, in response to receiving a signal, if a first watermark is present in the signal using a first processing technique. The example first processor is further to provoke, in response to the first watermark being present in the signal, a second processing technique on a signal processor. The signal processor is to extract a second watermark in the signal using the second processing technique. ## Claims ### Claim 1 A computing system for watermark encoding, the computing system comprising: a processor; and a non-transitory computer-readable storage medium, having stored thereon program instructions that, upon execution by the processor, cause performance of a set of operations comprising: determining a set of characteristics of a first watermark, wherein the set of characteristics of the first watermark comprise at least one of a frequency, an amplitude, or a phase characteristic; determining a set of characteristics of a second watermark, wherein the determining the set of characteristics of the second watermark comprises ensuring that the set of characteristics of the first watermark is different from the set of characteristics of the second watermark; adding the first watermark, based on the set of characteristics of the first watermark, to a media signal; and adding the second watermark to the media signal; wherein the set of characteristics of the second watermark is different than the set of characteristics of the first watermark; wherein the set of characteristics of the second watermark comprises repeatable audio characteristics; wherein the repeatable audio characteristics comprise a first frequency and a second frequency, distinct from the first frequency; and wherein the first frequency and the second frequency alternate. ### Claim 2 (depends on 1) The computing system of claim 1, wherein the second watermark is optimized to maximize a watermark amplitude while maintaining audibility. ### Claim 3 (depends on 1) The computing system of claim 1, wherein the set of characteristics of the first watermark comprises a third frequency at which the first watermark is added. ### Claim 4 (depends on 3) The computing system of claim 3, wherein the third frequency at which the first watermark is added is different than the first frequency and the second frequency. ### Claim 5 (depends on 1) The computing system of claim 1, wherein the second watermark is added to the media signal at a beginning of the first watermark. ### Claim 6 (depends on 1) The computing system of claim 1, wherein the second watermark indicates a presence of the first watermark in the media signal; and wherein the first watermark comprises media identification information. ### Claim 7 (depends on 1) The computing system of claim 1, wherein a length of the second watermark equals a length of the first watermark. ### Claim 8 (depends on 7) The computing system of claim 7, wherein the second watermark is encoded at a beginning of the media signal. ### Claim 9 A non-transitory computer-readable storage medium, having stored thereon program instructions that, upon execution by a processor, cause performance of a set of operations comprising: determining a set of characteristics of a first watermark, wherein the set of characteristics of the first watermark comprise at least one of a frequency, an amplitude, or a phase characteristic; determining a set of characteristics of a second watermark, wherein the determining the set of characteristics of the second watermark comprises ensuring that the set of characteristics of the first watermark is different from the set of characteristics of the second watermark; adding the first watermark, based on the set of characteristics of the first watermark, to a media signal; and adding the second watermark to the media signal, wherein the set of characteristics of the second watermark is different than the set of characteristics of the first watermark; wherein the set of characteristics of the second watermark comprises repeatable audio characteristics; wherein the repeatable audio characteristics comprise a first frequency and a second frequency, distinct from the first frequency; and wherein the first frequency and the second frequency alternate. ### Claim 10 (depends on 9) The non-transitory computer-readable storage medium of claim 9, wherein the second watermark is optimized to maximize a watermark amplitude while maintaining audibility. ### Claim 11 (depends on 9) The non-transitory computer-readable storage medium of claim 9, wherein the set of characteristics of the first watermark comprises a third frequency at which the first watermark is added. ### Claim 12 (depends on 11) The non-transitory computer-readable storage medium of claim 11, wherein the third frequency at which the first watermark is added is different than the first frequency and the second frequency. ### Claim 13 (depends on 9) The non-transitory computer-readable storage medium of claim 9, wherein the second watermark is added to the media signal at a beginning of the first watermark. ### Claim 14 (depends on 9) The non-transitory computer-readable storage medium of claim 9, wherein the second watermark indicates a presence of the first watermark in the media signal; and wherein the first watermark comprises media identification information. ### Claim 15 A method for watermark encoding, the method comprising: determining a set of characteristics of a first watermark, wherein the set of characteristics of the first watermark comprise at least one of a frequency, an amplitude, or a phase characteristic; determining a set of characteristics of a second watermark, wherein the determining the set of characteristics of the second watermark comprises ensuring that the set of characteristics of the first watermark is different from the set of characteristics of the second watermark; adding the first watermark, based on the set of characteristics of the first watermark, to a media signal; and adding the second watermark to the media signal, wherein the set of characteristics of the second watermark is different than the set of characteristics of the first watermark; wherein the set of characteristics of the second watermark comprises repeatable audio characteristics; wherein the repeatable audio characteristics comprise a first frequency and a second frequency, distinct from the first frequency; and wherein the first frequency and the second frequency alternate. ### Claim 16 (depends on 15) The method of claim 15, wherein the second watermark is optimized to maximize a watermark amplitude while maintaining audibility. ### Claim 17 (depends on 15) The method of claim 15, wherein the set of characteristics of the first watermark comprises a third frequency at which the first watermark is added. ### Claim 18 (depends on 17) The method of claim 17, wherein the third frequency at which the first watermark is added is different than the first frequency and the second frequency. ### Claim 19 (depends on 15) The method of claim 15, wherein the second watermark is added to the media signal at a beginning of the first watermark. ### Claim 20 (depends on 15) The method of claim 15, wherein ensuring the second watermark indicates a presence of the first watermark in the media signal; and wherein the first watermark comprises media identification information.