Patent Description:
Audience measurement systems typically include one or more site meters to monitor the media presented by one or more media devices located at a monitored site. Many such audience measurement systems also include one or more people meters to obtain information characterizing the composition(s) of the audience(s) in the vicinity of the media device(s) being monitored. An exemplary audience measurement approach for jointly identifying media of a media presentation device and members of the audience of the presentation is disclosed in <CIT>. In prior audience measurement systems, the people meters typically are separate from the site meters, or employ different signal processing technology than that employed by the site meters. For example, the site meters may be configured to process media signals captured from the monitored media devices to detect watermarks embedded in the media signals, whereas the people meters may be configured to capture and process images of an audience, and/or process input commands entered by members of the audience.

Wherever possible, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts, elements, etc..

Methods, apparatus, systems and articles of manufacture (e.g., physical storage media) to utilize audio watermarking for people monitoring are disclosed herein. The invention is defined by an audience measurement meter according to claim <NUM>, a people monitoring method according to claim <NUM> and a tangible computer readable medium according to claim <NUM>. Some example
people monitoring methods disclosed herein include determining, at a user device, whether a first trigger condition for emitting an audio watermark identifying at least one of the user device or a user of the user device is satisfied. Such disclosed example methods also include, in response to determining that the first trigger condition is satisfied, providing a first audio signal including the audio watermark to an audio circuit that is to output an acoustic signal from the user device.

In some such examples, the first trigger condition is satisfied when an input audio signal sensed at the user device satisfies an audio threshold.

Some such disclosed example methods further include downloading a software application to the user device. In such examples, the software application determines whether the first trigger condition is satisfied and provides the first audio signal to the audio circuit.

In some such disclosed example methods, the first audio signal includes only the audio watermark, whereas in other disclosed example methods, the first audio signal includes the audio watermark combined with a second signal.

Some such disclosed example methods further include determining a level of an input audio signal, and adjusting a level of the first audio signal based on the level of the input audio signal. For example, adjusting the level of the first audio signal may include adjusting the level of the first audio signal to cause the first audio signal to be substantially masked by a source of the input audio signal when the acoustic signal is output from the user device.

In some such disclosed example methods, the audio watermark is a first audio watermark conveyed in a first range of frequencies different from a second range of frequencies used to convey a second audio watermark included in an input audio signal sensed by the user device.

Some such disclosed example methods further include determining, at the user device, whether a second trigger condition is satisfied, and in response to determining that the first trigger condition and the second trigger condition are satisfied, but not if either the first trigger condition or the second trigger condition is not satisfied, providing the first audio signal including the audio watermark to the audio circuit. In some such examples, the second trigger condition is satisfied when a location of the user device is determined to correspond to a first geographical area including a monitored media device. In some such examples, the second trigger condition is satisfied when a current time at the user device corresponds to a first time period. In some such examples, the second trigger condition is satisfied when a second audio signal is being provided to the audio circuit.

Some example people monitoring methods disclosed herein include detecting, with a processor (e.g., such as a site meter), a first watermark in a first audio signal obtained from an acoustic sensor. In such examples, the first watermark identifies media presented by a monitored media device, and the acoustic sensor is to sense audio in a vicinity of the monitored media device. Such disclosed example methods also include processing, with the processor, the first audio signal obtained from the acoustic sensor to determine whether a second watermark, different from the first watermark, is embedded in the first audio signal. In such examples, the second watermark identifies at least one of a user device or a user of the user device. Such disclosed example methods further include, when the second watermark is determined to be embedded in the first audio signal, reporting at least one of the second watermark or information decoded from the second watermark to identify at least one of the user device or the user of the user device as being exposed to the media presented by the monitored media device.

In some such disclosed example methods, the first watermark is conveyed in a first range of frequencies different from a second range of frequencies used to convey the second watermark.

In some such disclosed example methods, the first watermark is substantially inaudible to the user of the user device and the second watermark is substantially inaudible to the user of the user device, whereas in other such disclosed example methods, the first watermark is substantially inaudible to the user of the user device and the second watermark is substantially audible to the user of the user device.

In some such disclosed example methods, the first watermark is included in a media signal output from the monitored media device, and the second watermark is output from the user device.

These and other example methods, apparatus, systems and articles of manufacture (e.g., physical storage media) to utilize audio watermarking for people detection are disclosed in further detail below.

As mentioned above, in prior audience measurement systems, the people meters used to obtain information characterizing audience composition typically are separate from the site meters used to monitor the media presented by one or more media devices located at a monitored site, or employ signal processing technology different than that employed by the site meters. Unlike such prior systems, example audience measurement systems implementing audio watermarking for people monitoring as disclosed herein are able to reuse the processing technology and capabilities of the site meters to also perform people monitoring. For example, some example audience measurement systems disclosed herein utilize people monitoring watermarks embedded in an acoustic signal output from a user device, such as the user's mobile phone, to identify the user device and/or the user as being in the vicinity of a monitored media device. In such examples, the site meter that is detecting media watermarks embedded in the media presented by the media device is also able to detect the people monitoring watermarks output from the user device.

In some disclosed examples, the people monitoring watermarks output from the user device are caused to be output by a software application downloaded to the user device, and/or are embedded in ringtones and/or other audio signals to be output by the user device during normal operation. In examples in which the people monitoring watermarks are caused to be output by a software application, the software application may evaluate one or more trigger conditions to optimize when to output the people monitoring watermarks, as disclosed in further detail below. In such examples, the site meter can correlate detection of the people monitoring watermarks with one or more of those trigger conditions. In examples in which the people monitoring watermarks are embedded in ringtones and/or other audio signals to be output by the user device during normal operation, the site meter may rely on opportunistic detection of the people monitoring watermarks to identify the user device and/or the user as being exposed to the media presented by the monitored media device.

In the context of media monitoring, watermarks may be transmitted within media signals. For example, watermarks can be used to transmit data (e.g., such as identification codes, ancillary codes, etc.) with media (e.g., inserted into the audio, video, or metadata stream of media) to uniquely identify broadcasters and/or media (e.g., content or advertisements), and/or to convey other information. Watermarks are typically extracted using a decoding operation.

In contrast, signatures are a representation of some characteristic of the media signal (e.g., a characteristic of the frequency spectrum of the signal). Signatures can be thought of as fingerprints. Signatures are typically not dependent upon insertion of identification codes (e.g., watermarks) in the media, but instead preferably reflect an inherent characteristic of the media and/or the signal transporting the media. Systems to utilize codes (e.g., watermarks) and/or signatures for media monitoring are long known. See, for example, <CIT>.

Turning to the figures, a block diagram of an example audience metering system <NUM> employing audio watermarking for people monitoring as disclosed herein is illustrated in <FIG>. The example audience measurement system <NUM> supports monitoring of audience exposure to media presented at one or more monitored sites, such as the example monitored site <NUM> illustrated in <FIG>. The monitored site <NUM> includes an example media presentation device <NUM>. Although the example of <FIG> illustrates one monitored site <NUM>, audio watermarking for people monitoring as disclosed herein can be used in audience measurement systems <NUM> supporting any number of monitored sites <NUM>.

The audience measurement system <NUM> of the illustrated example includes an example site meter <NUM>, also referred to as a site unit <NUM>, a home unit <NUM>, an audience measurement meter <NUM>, etc., to monitor media presented by the media presentation device <NUM>. In the illustrated example, the site meter <NUM> includes an example acoustic sensor <NUM>, such as, but not limited to, a microphone, to sense acoustic signals <NUM> output (e.g., emitted) by the media presentation device <NUM>. The site meter <NUM> of the illustrated example processes the resulting audio signals obtained from the acoustic sensor <NUM> to monitor the media presented by the media presentation device <NUM>.

Additionally, the example site meter <NUM> of <FIG> supports audio watermarking for people monitoring as disclosed herein, which enables the site meter <NUM> to monitor people present in the vicinity (e.g., in the presentation area) of the media presentation device <NUM>, such as the example person <NUM> of the illustrated example. For example, and as disclosed in further detail below, the acoustic sensor <NUM> of the site meter <NUM> is able to sense example acoustic signals <NUM> output (e.g., emitted) by an example user device <NUM>. The acoustic signals <NUM> include one or more audio watermarks capable of, for example, identifying the user device <NUM> and/or the user <NUM> of the user device <NUM>. In the illustrated example of <FIG>, the site meter <NUM> processes the resulting audio signals obtained from the acoustic sensor <NUM> to not only monitor the media being presented by the media presentation device <NUM>, but to also detect people monitoring audio watermarks conveyed by acoustic signals output by user devices, such as the audio watermark(s) conveyed by the example acoustic signal <NUM> output by the example user device <NUM>. Such audio watermarks are also referred to herein as people monitoring audio watermarks, people monitoring watermarks, etc., to distinguish them from media watermarks conveyed in the media presented by the media devices, such as the example media presentation device <NUM>. As disclosed in further detail below, in some examples, the people monitoring watermarks enable determination of other characteristics, in addition to the identity of the user <NUM> and/or the identity of the user device <NUM>, related to the exposure of the user <NUM> (or the user device <NUM>) to the media presented by media presentation device <NUM>.

In some examples, the audience measurement system <NUM> further includes an example people meter <NUM> to capture information about the audience exposed to media presented by the media presentation device <NUM>. For example, the people meter <NUM> may be configured to receive information via an input device having a set of input keys, each assigned to represent a single audience member. In such examples, the people meter <NUM> prompts the audience members to indicate their presence by pressing the appropriate input key on the input device of the people meter <NUM>. The people meter <NUM> of the illustrated example may also receive information from the site meter <NUM> to determine times at which to prompt the audience members to enter information on people meter <NUM>.

In the illustrated example of <FIG>, the site meter <NUM> determines audience measurement data characterizing media exposure at the monitored site <NUM> by combining device metering data (also referred to as media data, tuning data, etc.), which is determined by monitoring the media presentation device <NUM>, with audience identification data (also referred to as demographic data, people monitoring data, etc.), which is determined from the people monitoring watermarks detected by the site meter <NUM>, as well as from data provided by the people meter <NUM>, if present. The site meter <NUM> then stores and reports this audience measurement data via an example network <NUM> to an example data processing facility <NUM>. The data processing facility <NUM> performs any appropriate post-processing of the audience measurement data to, for example, determine audience ratings information, identify targeted advertising to be provided to the monitored site <NUM>, etc. In the illustrated example, the network <NUM> can correspond to any type(s) and/or number of wired and/or wireless data networks, or any combination thereof.

In the illustrated example, the media presentation device <NUM> monitored by the site meter <NUM> can correspond to any type of audio, video and/or multimedia presentation device capable of presenting media content audibly and/or visually. For example, the media presentation device <NUM> can correspond to a television and/or display device that supports the National Television Standards Committee (NTSC) standard, the Phase Alternating Line (PAL) standard, the Système Électronique pour Couleur avec Mémoire (SECAM) standard, a standard developed by the Advanced Television Systems Committee (ATSC), such as high definition television (HDTV), a standard developed by the Digital Video Broadcasting (DVB) Project, etc. As another example, the media presentation device <NUM> can correspond to a multimedia computer system, a personal digital assistant, a cellular/mobile smartphone, a radio, etc..

In the illustrated example, the user device <NUM> can correspond to any type of user device capable of emitting audio/acoustic signals. In some examples, the user device <NUM> is implemented by a portable device of the user, such as, but not limited to, a mobile phone or smartphone, a tablet (e.g., such as an iPad™), a personal digital assistant (PDA), a portable gaming device, etc., adapted to support audio watermarking for people monitoring in addition to its native functionality. In some examples, the user device <NUM> is implemented by a portable device dedicated to people monitoring, such as a portable people meter (PPM) to be carried the audience member <NUM>. Also, although only one user device <NUM> is depicted in the example illustrated in <FIG>, the example audience measurement system <NUM> can support any number and/or type(s) of user devices <NUM>.

The site meter <NUM> included in the audience measurement system <NUM> of the illustrated example can correspond to any type of metering device capable of monitoring media presented by the media presentation device <NUM>. In the illustrated example, the site meter <NUM> employs non-invasive monitoring not involving any physical connection to the media presentation device <NUM>. For example, the site meter <NUM> processes audio signals obtained from the media presentation device <NUM> via the acoustic sensor <NUM> (e.g., a microphone) to detect media and/or source identifying audio watermarks embedded in audio portion(s) of the media presented by the media presentation device <NUM>, to detect people monitoring audio watermarks embedded in the audio signals (e.g., acoustic signals) emitted by user devices, such as the acoustic signals <NUM> emitted by the user device <NUM>, etc. In some examples, the site meter <NUM> may additionally utilize invasive monitoring involving one or more physical connections to the media presentation device <NUM>. In such examples, the site meter <NUM> may additionally process audio signals obtained from the media presentation device <NUM> via a direct cable connection to detect media and/or source identifying audio watermarks embedded in such audio signals. In some examples, the site meter <NUM> may process video signals obtained from the media presentation device <NUM> via a camera and/or a direct cable connection to detect media and/or source identifying video watermarks embedded in video portion(s) of the media presented by the media presentation device <NUM>. In some examples, the site meter <NUM> may process the aforementioned audio signals and/or video signals to generate respective audio and/or video signatures from the media presented by the media presentation device <NUM>, which can be compared to reference signatures to perform source and/or content identification. Any other type(s) and/or number of media monitoring techniques can be supported by the site meter <NUM>.

<FIG> illustrates example user devices 140A-B that may be used to implement the example user device <NUM> included in or otherwise operable with the example audience measurement system of <FIG>. <FIG> also illustrates an example implementation of the example data processing facility <NUM> included in the example audience measurement system of <FIG>. In the illustrated example of <FIG>, the example data processing facility <NUM> includes an example people monitor downloader <NUM> to facilitate download of an example people monitoring watermarker <NUM> to a user device, such as the example user device 140A. For example, the people monitoring watermarker <NUM> can be implemented by one or more applications (apps) capable of being downloaded to and executed by the example user device 140A. In such examples, the people monitor downloader <NUM> stores the application(s) implementing the people monitoring watermarker <NUM>, and may store different versions of the applications tailored for different types of user devices 140A. In the illustrated example, the people monitor downloader <NUM> receives a request via the network <NUM> from the user device 140A to download the people monitoring watermarker <NUM>. The example people monitor downloader <NUM> then responds to the request by sending, via the network <NUM>, the application(s) implementing the people monitoring watermarker <NUM> to the requesting user device 140A. The user device 140A then installs and executes the application(s) implementing the people monitoring watermarker <NUM>.

As disclosed in further detail below, the people monitoring watermarker <NUM> causes the user device 140A to emit acoustic signals, such as the acoustic signal <NUM>, which include one or more people monitoring audio watermarks. As described above, the people monitoring audio watermark(s) identify the user device 140A and/or a user (e.g., the user <NUM>) operating or otherwise associated with the user device 140A. In some examples, the people monitoring watermarker <NUM> evaluates one or more trigger conditions that condition when the people monitoring watermarker <NUM> is to cause the people monitoring audio watermarks to be output by the user device 140A. For example, and as disclosed in further detail below, such trigger conditions can be based on an input audio level measured by the people monitoring watermarker <NUM>, a time of day, a geographic location, an operating state of the user device 140A, etc. In such examples, detection of a people monitoring audio watermark (e.g., by the site meter <NUM>) can be correlated to the trigger condition(s) that would trigger the people monitoring watermarker <NUM> to cause the people monitoring audio watermarks to be output by the user device 140A. An example implementation of the people monitoring watermarker <NUM> is illustrated in <FIG>, which is described in further detail below.

In the illustrated example of <FIG>, the example data processing facility <NUM> additionally or alternatively includes an example watermarked audio downloader <NUM> to downloaded watermark audio data to a user device, such as the example user device 140B. In the illustrated example, the watermarked audio data includes, for example, any audio data, such as ringtones, audible alerts, audio tracks, movies, etc., capable of being presented (e.g., output) by the user device 140B. The watermarked audio data provided by the watermarked audio downloader <NUM> includes people monitoring audio watermark(s) embedded in or otherwise combined with the audio data. In the illustrated example, the watermarked audio downloader <NUM> receives a request via the network <NUM> from the user device 140B to download audio data. The example watermarked audio downloader <NUM> then responds to the request by sending, via the network <NUM>, the requested audio data, which contains or is otherwise combined with the people monitoring watermark(s), to the requesting user device 140B. The user device 140B then stores the watermarked audio data in an example audio data store <NUM> for subsequent use. The example audio data store <NUM> can correspond to any type of memory, storage, data structure, database, etc., capable of storing audio data for subsequent retrieval.

In some examples, the user device 140B outputs (e.g., emits) people monitoring watermark(s) whenever the user device 140B presents (e.g., outputs, plays, etc.) the downloaded audio data containing the people monitoring watermark(s). For example, when the watermarked audio data downloaded from the watermarked audio downloader <NUM> corresponds to a ringtone or audible alert, the user device 140B outputs (e.g., emits) people monitoring watermark(s) whenever the user device 140B plays the ringtone, outputs the audio alert, etc. Similarly, when the watermarked audio data downloaded from the watermarked audio downloader <NUM> corresponds an audio track, movie, etc., the user device 140B outputs (e.g., emits) people monitoring watermark(s) whenever the user device 140B presents the audio track, movie, etc..

A block diagram of an example implementation of the people monitoring watermarker <NUM> of <FIG> is illustrated in <FIG>. In some examples, the people monitoring watermarker <NUM> is implemented by one or more applications downloaded to a user device, such as the user devices <NUM> and/or 140A. In some examples, the people monitoring watermarker <NUM> is implemented by a combination of hardware and/or software included in the user device (e.g., the user devices <NUM> and/or 140A), and one or more applications downloaded to the user device. In some examples, the people monitoring watermarker <NUM> is implemented by a combination of hardware and/or software included in the user device (e.g., the user devices <NUM> and/or 140A) before the user device is provided to a user, such as the user <NUM>. Other approaches for implementing the people monitoring watermarker <NUM> can also be used.

In the illustrated example of <FIG>, the people monitoring watermarker <NUM> includes an example audio watermarker <NUM> to generate or otherwise obtain people monitoring watermark(s) that convey digital information <NUM> identifying one or more of (<NUM>) the user device (e.g., the user devices <NUM> and/or 140A) implementing or otherwise including the people monitoring watermarker <NUM>, (<NUM>) a user of the user device, (<NUM>) an operating state of the user device, etc., and/or any other information related to people monitoring. As such, in some examples, the digital information <NUM> conveyed by the people monitoring watermark(s) generated by the example audio watermarker <NUM> can be static information that does not change over time, dynamic information that changes over time, or a combination thereof. In some examples, the audio watermarker <NUM> generates the watermark to be a frequency domain watermark capable of conveying this digital information <NUM> in frequency domain components of an acoustic signal, such as the acoustic signal <NUM>. Example watermark generation techniques that can be implemented by the audio watermarker <NUM> to generate such frequency domain watermarks include, but are not limited to, the examples disclosed in <CIT>, <CIT>, and <CIT>. <CIT>, <CIT> and <CIT> describe example watermarking systems in which a watermark is embedded in an audio signal by manipulating a set of frequencies of the audio signal.

In some examples, the audio watermarker <NUM> generates the watermark signal to be a time domain watermark capable of conveying digital information in time domain components of an acoustic signal, such as the acoustic signal <NUM>. In such examples, audio watermarker <NUM> may generate a watermark signal that is to modulate the amplitude and/or phase of an audio signal in the time domain. Example watermark generation techniques that can be implemented by the audio watermarker <NUM> to generate such time domain watermarks include, but are not limited to, generating a spread spectrum time domain signal modulated by the digital information, which is to then be embedded in (e.g., added to) the audio signal used to generate the acoustic signal <NUM>.

In some examples, the people monitoring watermark(s) generated or otherwise obtained by audio watermarker <NUM> reside in the audible frequency range (e.g., the range of frequencies generally within the range of human hearing. ) In some examples, the people monitoring watermark(s) generated or otherwise obtained by audio watermarker <NUM> reside outside (e.g., above and/or below) the audible frequency range. In some examples, the people monitoring watermark(s) generated or otherwise obtained by audio watermarker <NUM> have one or more characteristics that differentiate the people monitoring watermark(s) from other types of audio watermarks, such as audio watermarks embedded in the media presented by the media presentation device <NUM>. For example, if the audio watermarks used for monitoring media (e.g., which are embedded in the media presented by the media presentation device <NUM>) reside in a first range of frequencies (e.g., a first frequency band or set of bands), then the people monitoring watermark(s) may reside in a second range of frequencies (e.g., a second frequency band or set of bands) different from the first range of frequencies.

In some examples, the audio watermarker <NUM> embeds the people monitoring watermark(s) in another audio signal generated by the audio watermarker <NUM> or obtained from an example audio data store <NUM>. For example, this other audio signal may be a pseudo-noise audio signal generated by the audio watermarker <NUM> or obtained from an example audio data store <NUM> to mask the people monitoring watermark(s). In other examples, the other audio signal in which the people monitoring watermark(s) is/are to be embedded may be a tone or melodic audio signal generated by the audio watermarker <NUM> or obtained from an example audio data store <NUM>. In either of these examples, the audio watermarker <NUM> applies the audio signal embedded with the people monitoring watermark(s) to example audio circuitry <NUM> of the user device. The audio circuitry <NUM> of the illustrated examples processes the watermarked audio signal to generate and emit an acoustic signal, such as the acoustic signal <NUM>, via one or more example speakers <NUM>. The example audio circuitry <NUM> can be implemented by any existing and/or novel audio circuit technology capable of receiving an audio signal and emitting an appropriate acoustic signal <NUM> (e.g., such as one that meets one or more design specifications, etc.).

In some examples, the audio watermarker <NUM> provides the people monitoring watermark(s) to the audio circuitry <NUM> without embedding the watermark(s) in another audio signal. In such examples, the acoustic signal <NUM> output from the audio circuitry <NUM> and speaker(s) <NUM> may correspond to just the people monitoring watermark(s). In some examples, the audio circuitry <NUM> may combine the people monitoring watermark(s) provided by the audio watermarker <NUM> with other audio signals already being output by the user device, such as a ringtone, an audible alert, an audio track, a movie, etc. In some examples, the audio watermarker <NUM> obtains one or more of the people monitoring watermark(s) from the example audio data store <NUM> in addition to, or as an alternative to, generating the people monitoring watermark(s). The audio data store <NUM> can correspond to any type of memory, storage, data structure, database, etc., capable of storing audio data for subsequent retrieval. The audio data store <NUM> can be the same as, or different from, the audio data store <NUM>.

The example people monitoring watermarker <NUM> of <FIG> also includes an example trigger condition evaluator <NUM> to evaluate one or more trigger conditions that condition when the example audio watermarker <NUM> is to provide the people monitoring audio watermark(s) to the example audio circuitry <NUM>. In the illustrated example, the trigger condition evaluator <NUM> determines whether a trigger condition for emitting the people monitoring watermark(s) has been satisfied. Then, in response to determining that the trigger condition has been satisfied, the trigger condition evaluator <NUM> causes (e.g., via a signal, a function call, etc.) the audio watermarker <NUM> to provide an audio signal including the people monitoring watermark(s) to the audio circuitry <NUM>. As described above, this audio signal may include just the people monitoring watermark(s), or may be a combination of the people monitoring audio watermark(s) and another audio signal.

In some examples, the trigger condition evaluator <NUM> determines whether multiple trigger conditions for emitting the people monitoring watermark(s) have been satisfied. In some such examples, the trigger condition evaluator <NUM> causes the audio watermarker <NUM> to provide the audio signal including the people monitoring watermark(s) to the audio circuitry <NUM> in response to determining that all trigger conditions have been satisfied, but not otherwise. In some examples, the trigger condition evaluator <NUM> causes the audio watermarker <NUM> to provide the audio signal including the people monitoring watermark(s) to the audio circuitry <NUM> in response to determining that at least one trigger condition has been satisfied. In some examples, the trigger condition evaluator <NUM> causes the audio watermarker <NUM> to provide the audio signal including the people monitoring watermark(s) to the audio circuitry <NUM> in response to determining that a combination (e.g., a majority) of the trigger conditions have been satisfied, but not otherwise.

The example people monitoring watermarker <NUM> of <FIG> includes one or more of an example input audio evaluator <NUM>, an example clock <NUM>, an example location determiner <NUM> and an example device state evaluator <NUM> to provide trigger condition information to the trigger condition evaluator <NUM> for evaluation. The input audio evaluator <NUM> of the illustrated example obtains input audio data corresponding to an input audio signal sensed by an example acoustic sensor <NUM>. For example, the acoustic sensor <NUM> can be a microphone and/or other acoustic sensor of the user device (e.g., the user device <NUM> or 140A) implementing or otherwise including the example people monitoring watermarker <NUM>. The example input audio evaluator <NUM> processes the input audio data to determine a level (e.g., amplitude level, power level, etc.) of the input audio signal, whether the input audio data includes watermarks, such as media identification watermarks, etc. The trigger condition evaluator <NUM> of the illustrated example uses the input audio level determined by the input audio evaluator <NUM> to evaluate one or more audio-related trigger conditions. For example, the trigger condition evaluator <NUM> can determine that an audio level trigger condition is satisfied when the input audio level determined by the input audio evaluator <NUM> satisfies (e.g., equals or exceeds) an audio threshold. The audio level trigger condition enables the trigger condition evaluator <NUM> to limit output (e.g., emission) of people monitoring watermark(s) to situations in which the ambient audio is strong enough to be indicative of media being presented by the media presentation device <NUM>. In this way, the trigger condition evaluator <NUM> can be used to trigger emission of the people monitoring watermark(s) to occur under conditions in which the people monitoring watermark(s) is/are likely to be masked by the media being presented by the media presentation device <NUM>. Additionally or alternatively, the trigger condition evaluator <NUM> can determine that an watermarked audio trigger condition is satisfied when the input audio evaluator <NUM> detects a watermark in the input audio data (which may indicate an increased likelihood that a meter, such as the site meter <NUM>, capable of detecting watermark(s) to be emitted by the people monitoring watermarker <NUM> is nearby).

In some examples, the audio watermarker <NUM> employs psychoacoustic masking to increase the likelihood that the source of the input audio signal processed by the input audio evaluator <NUM> (e.g., the audio in the vicinity of the user device, which may correspond to the media presented by the media presentation device <NUM>) will be able to mask the people monitoring watermark(s) emitted by the user device. In some such examples, the audio watermarker <NUM> uses the input audio level determined by the input audio evaluator <NUM> to adjust a level of the audio signal, which includes the people monitoring watermark(s), that the audio watermarker <NUM> is to provide to the audio circuitry <NUM>. For example, the audio watermarker <NUM> may adjust a level of the audio signal including the people monitoring watermark(s) by applying a gain factor or attenuation factor that causes the level of the audio signal including the people monitoring watermark(s) to be less than or equal to (or a fraction of, etc.) the input audio level determined by the input audio evaluator <NUM> for the input audio signal. In this way, the people monitoring watermark(s) may reside in the audible frequency range, but may be masked by (e.g., inaudible over) the ambient audio in the vicinity of the media presentation device <NUM>.

The clock <NUM> of the illustrated example provides clock information (e.g., day and time information) to the trigger condition evaluator <NUM>. The trigger condition evaluator <NUM> uses the clock information provided by the clock <NUM> to evaluate one or more clock trigger conditions. For example, the trigger condition evaluator <NUM> can determine that a clock trigger condition is satisfied when the clock information provided by the clock <NUM> indicates that the current time (e.g., as determined by the clock <NUM>) is within a specified time period or set of time periods. For example, the trigger condition evaluator <NUM> may be configured with one or more time periods during which the output (e.g., emission) of people monitoring watermark(s) is or is not permitted. The trigger condition evaluator <NUM> can then limit emission of people monitoring watermark(s) to the permitted time period(s). For example, the trigger condition evaluator <NUM> can use the clock information provided by the clock <NUM> to limit emission of people monitoring watermark(s) to daytime hours when people are not expected to be at work, and not permit people monitoring watermark(s) to be emitted at nighttime (e.g., when people are expected to be asleep), during normal business hours (e.g., when people are expected to be at work), etc..

The location determiner <NUM> of the illustrated example provides location information (e.g., geographic positioning system (GPS) data and/or other location data, etc.) to the trigger condition evaluator <NUM>. The trigger condition evaluator <NUM> uses the location information provided by the location determiner <NUM> to evaluate one or more location trigger conditions. For example, the trigger condition evaluator <NUM> can determine that a location trigger condition is satisfied when the location information provided by the location determiner <NUM> indicates that the current location of the user device (e.g., as specified by the location information) is within a specified geographic area or set of geographic areas. For example, the trigger condition evaluator <NUM> may be configured with one or more geographic areas within which the output (e.g., emission) of people monitoring watermark(s) is or is not permitted. The trigger condition evaluator <NUM> can then limit emission of people monitoring watermark(s) to occur when the user device is located within the permitted geographic area(s). For example, the trigger condition evaluator <NUM> can use the location information provided by the location determiner <NUM> to limit emission of people monitoring watermark(s) to occur when the user device is located at the monitored site <NUM>, and not permit people monitoring watermark(s) to be emitted when the user device is not located at the monitored site <NUM>.

The device state evaluator <NUM> of the illustrated example provides device state information to the trigger condition evaluator <NUM>. The trigger condition evaluator <NUM> uses the device state information provided by the location determiner <NUM> to evaluate one or more device state trigger conditions. For example, the trigger condition evaluator <NUM> can determine that a device state trigger condition is satisfied when the device state information provided by the device state evaluator <NUM> indicates that the user device currently has a given operating state. For example, the trigger condition evaluator <NUM> may be configured with one or more user device operating states during which the output (e.g., emission) of people monitoring watermark(s) is or is not permitted. The trigger condition evaluator <NUM> can then limit emission of people monitoring watermark(s) to occur when the user device is operating in one or more of the permitted operating states. For example, the trigger condition evaluator <NUM> can use the device state information provided by the device state evaluator <NUM> to limit emission of people monitoring watermark(s) to occur when the user device is already outputting another audio signal (e.g., to permit the audio circuitry <NUM> to combine the watermark(s) with this audio signal), and not permit people monitoring watermark(s) to be emitted when the user device is not already outputting another audio signal. As another example, the trigger condition evaluator <NUM> can use the device state information provided by the device state evaluator <NUM> to limit emission of people monitoring watermark(s) to occur when the user device is in an idle operating state, and not permit people monitoring watermark(s) to be emitted when the user device is performing a native operation, such as making a phone call, etc..

A block diagram of an example implementation of the site meter <NUM> of <FIG> is illustrated in <FIG>. The example site meter <NUM> of <FIG> includes an example sensor interface <NUM> to obtain audio data from one or more of the example acoustic sensors <NUM> included in and/or in communication with the site meter <NUM>. In the illustrated example, the acoustic sensor(s) <NUM> may include one or more microphones, audio transducers, etc., capable of sensing acoustic signals, such as the example acoustic signals <NUM> and/or <NUM>. The sensor interface <NUM> of the illustrated example includes any appropriate sensor interface technology (e.g., such as an audio gain control stage, an analog-to-digital conversion stage, etc.) to process the output(s) of the acoustic sensor(s) <NUM> to determine audio data, which may be representative of the sensed acoustic signals <NUM> and/or <NUM>.

The example site meter <NUM> of <FIG> also includes an example watermark detector <NUM> to detect watermark(s) embedded in the audio data obtained from the sensor interface <NUM>. In some examples, the watermark(s) is/are embedded in the frequency domain of the audio data. In such examples, the watermark detector <NUM> employs frequency domain processing to detect whether a valid watermark is embedded in the frequency domain of the audio data obtained from the sensor interface <NUM>. Example watermark detection techniques that can be implemented by the watermark detector <NUM> to detect watermarks embedded in the frequency domain of audio data include, but are not limited to, examples disclosed in <CIT>, <CIT> and <CIT>, which are described in further detail above. In some examples, the watermark(s) is/are embedded in the time domain of the audio data. In such examples, the watermark detector <NUM> employs time domain processing, such as amplitude demodulation, phase demodulation, spread spectrum detection, etc., to detect whether a valid watermark is embedded in the time domain of the audio data obtained from the sensor interface <NUM>.

The example site meter <NUM> of <FIG> further includes an example watermark classifier <NUM> to classify the watermark(s) detected by the watermark detector <NUM> in the audio data obtained from the sensor interface <NUM>. For example, the acoustic signal <NUM> may include media watermark(s) embedded in the media presented by the media presentation device <NUM>, whereas the acoustic signal <NUM> emitted by the user device <NUM> may include people monitoring watermark(s). The media watermark(s) may convey digital information identifying the media (e.g., a name of the media), a source of the media, etc., whereas the people monitoring watermark(s) may convey digital information identifying the user device <NUM> and/or the user <NUM> of the user device <NUM>, etc. In such examples, the watermark classifier <NUM> examines characteristics of the detected watermark(s) to determine, for example, whether a detected watermark is a media watermark or a people monitoring watermark. In some such examples, the watermark classifier <NUM> examines the data conveyed by the detected watermark to classify the detected watermark as a media watermark or a people monitoring watermark. Additionally or alternatively, the watermark classifier <NUM> examines signal characteristics of the watermarks, such as the frequency band(s) in which the watermark was detected, to classify the detected watermark as a media watermark or a people monitoring watermark. For example, and as described above, the media watermark(s) may reside in a first range of frequencies (e.g., a first frequency band or set of bands), and the people monitoring watermark(s) may reside in a second range of frequencies (e.g., a second frequency band or set of bands) different from the first range of frequencies. In such examples, the watermark classifier <NUM> may classify a detected watermark as a media watermark if the watermark was detected in the first range of frequencies, and may classify a detected watermark as a people monitoring watermark if the watermark was detected in the second range of frequencies. In some examples, if the watermark classifier <NUM> classifies a detected watermark as a people monitoring watermark, the watermark classifier <NUM> associates information with the detected watermark that indicates the trigger condition(s) that would have triggered emission of the people monitoring watermark.

The example site meter <NUM> of <FIG> includes an example data reporter <NUM> to report the watermark information decoded by the example watermark detector <NUM> and any watermark classifications made by the watermark classifier <NUM> to, for example, the data processing facility <NUM> via the network <NUM>. For example, the data reporter <NUM> can implement any wireless (e.g., WiFi, cellular data, etc.) and/or wired (e.g., USB, Ethernet, etc.) digital data interface capable of sending digital information over a network, such as the network <NUM>, to a receiving device, such as the data processing facility <NUM>.

While example manners of implementing the audience metering system <NUM> are illustrated in <FIG>, one or more of the elements, processes and/or devices illustrated in <FIG> may be combined, divided, re-arranged, omitted, eliminated and/or implemented in any other way. Further, the example site meter <NUM>, the example acoustic sensor <NUM>, the example user devices <NUM>, 140A and/or 140B, the example people meter <NUM>, the example network <NUM>, the example data processing facility <NUM>, the example people monitor downloader <NUM>, the example people monitoring watermarker <NUM>, the example watermarked audio downloader <NUM>, the example audio data store <NUM>, the example audio watermarker <NUM>, the example audio data store <NUM>, the example audio circuitry <NUM>, the example speaker(s) <NUM>, the example trigger condition evaluator <NUM>, the example input audio evaluator <NUM>, the example clock <NUM>, the example location determiner <NUM>, the example device state evaluator <NUM>, the example acoustic sensor <NUM>, the example sensor interface <NUM>, the example watermark detector <NUM>, the example watermark classifier <NUM>, the example data reporter <NUM> and/or, more generally, the example audience metering system <NUM> of <FIG> may be implemented by hardware, software, firmware and/or any combination of hardware, software and/or firmware. Thus, for example, any of the example site meter <NUM>, the example acoustic sensor <NUM>, the example user devices <NUM>, 140A and/or 140B, the example people meter <NUM>, the example network <NUM>, the example data processing facility <NUM>, the example people monitor downloader <NUM>, the example people monitoring watermarker <NUM>, the example watermarked audio downloader <NUM>, the example audio data store <NUM>, the example audio watermarker <NUM>, the example audio data store <NUM>, the example audio circuitry <NUM>, the example speaker(s) <NUM>, the example trigger condition evaluator <NUM>, the example input audio evaluator <NUM>, the example clock <NUM>, the example location determiner <NUM>, the example device state evaluator <NUM>, the example acoustic sensor <NUM>, the example sensor interface <NUM>, the example watermark detector <NUM>, the example watermark classifier <NUM>, the example data reporter <NUM> and/or, more generally, the example audience metering system <NUM> could be implemented by one or more analog or digital circuit(s), logic circuits, programmable processor(s), application specific integrated circuit(s) (ASIC(s)), programmable logic device(s) (PLD(s)) and/or field programmable logic device(s) (FPLD(s)). When reading any of the apparatus or system claims of this patent to cover a purely software and/or firmware implementation, at least one of the example audience metering system <NUM>, the example site meter <NUM>, the example acoustic sensor <NUM>, the example user devices <NUM>, 140A and/or 140B, the example people meter <NUM>, the example network <NUM>, the example data processing facility <NUM>, the example people monitor downloader <NUM>, the example people monitoring watermarker <NUM>, the example watermarked audio downloader <NUM>, the example audio data store <NUM>, the example audio watermarker <NUM>, the example audio data store <NUM>, the example audio circuitry <NUM>, the example speaker(s) <NUM>, the example trigger condition evaluator <NUM>, the example input audio evaluator <NUM>, the example clock <NUM>, the example location determiner <NUM>, the example device state evaluator <NUM>, the example acoustic sensor <NUM>, the example sensor interface <NUM>, the example watermark detector <NUM>, the example watermark classifier <NUM> and/or the example data reporter <NUM> is/are hereby expressly defined to include a tangible computer readable storage device or storage disk such as a memory, a digital versatile disk (DVD), a compact disk (CD), a Blu-ray disk, etc. storing the software and/or firmware. Further still, the example audience metering system <NUM> of <FIG> may include one or more elements, processes and/or devices in addition to, or instead of, those illustrated in <FIG>, and/or may include more than one of any or all of the illustrated elements, processes and devices.

Flowcharts representative of example machine readable instructions for implementing the example audience metering system <NUM>, the example site meter <NUM>, the example acoustic sensor <NUM>, the example user devices <NUM>, 140A and/or 140B, the example people meter <NUM>, the example network <NUM>, the example data processing facility <NUM>, the example people monitor downloader <NUM>, the example people monitoring watermarker <NUM>, the example watermarked audio downloader <NUM>, the example audio data store <NUM>, the example audio watermarker <NUM>, the example audio data store <NUM>, the example audio circuitry <NUM>, the example speaker(s) <NUM>, the example trigger condition evaluator <NUM>, the example input audio evaluator <NUM>, the example clock <NUM>, the example location determiner <NUM>, the example device state evaluator <NUM>, the example acoustic sensor <NUM>, the example sensor interface <NUM>, the example watermark detector <NUM>, the example watermark classifier <NUM> and/or the example data reporter <NUM> are shown in <FIG>. In these examples, the machine readable instructions comprise one or more programs for execution by a processor, such as the processor <NUM> shown in the example processor platform <NUM> discussed below in connection with <FIG>. The one or more programs, or portion(s) thereof, may be embodied in software stored on a tangible computer readable storage medium such as a CD-ROM, a floppy disk, a hard drive, a digital versatile disk (DVD), a Blu-ray disk™, or a memory associated with the processor <NUM>, but the entire program or programs and/or portions thereof could alternatively be executed by a device other than the processor <NUM> and/or embodied in firmware or dedicated hardware (e.g., implemented by an ASIC, a PLD, an FPLD, discrete logic, etc.). Further, although the example program(s) is(are) described with reference to the flowcharts illustrated in <FIG>, many other methods of implementing the example audience metering system <NUM>, the example site meter <NUM>, the example acoustic sensor <NUM>, the example user devices <NUM>, 140A and/or 140B, the example people meter <NUM>, the example network <NUM>, the example data processing facility <NUM>, the example people monitor downloader <NUM>, the example people monitoring watermarker <NUM>, the example watermarked audio downloader <NUM>, the example audio data store <NUM>, the example audio watermarker <NUM>, the example audio data store <NUM>, the example audio circuitry <NUM>, the example speaker(s) <NUM>, the example trigger condition evaluator <NUM>, the example input audio evaluator <NUM>, the example clock <NUM>, the example location determiner <NUM>, the example device state evaluator <NUM>, the example acoustic sensor <NUM>, the example sensor interface <NUM>, the example watermark detector <NUM>, the example watermark classifier <NUM> and/or the example data reporter <NUM> may alternatively be used. For example, with reference to the flowcharts illustrated in <FIG>, the order of execution of the blocks may be changed, and/or some of the blocks described may be changed, eliminated, combined and/or subdivided into multiple blocks.

As mentioned above, the example processes of <FIG> may be implemented using coded instructions (e.g., computer and/or machine readable instructions) stored on a tangible computer readable storage medium such as a hard disk drive, a flash memory, a read-only memory (ROM), a compact disk (CD), a digital versatile disk (DVD), a cache, a random-access memory (RAM) and/or any other storage device or storage disk in which information is stored for any duration (e.g., for extended time periods, permanently, for brief instances, for temporarily buffering, and/or for caching of the information). As used herein, the term tangible computer readable storage medium is expressly defined to include any type of computer readable storage device and/or storage disk and to exclude propagating signals and to exclude transmission media. As used herein, "tangible computer readable storage medium" and "tangible machine readable storage medium" are used interchangeably. Additionally or alternatively, the example processes of <FIG> may be implemented using coded instructions (e.g., computer and/or machine readable instructions) stored on a non-transitory computer and/or machine readable medium such as a hard disk drive, a flash memory, a ROM, a CD, a DVD, a cache, a RAM and/or any other storage device or storage disk in which information is stored for any duration (e.g., for extended time periods, permanently, for brief instances, for temporarily buffering, and/or for caching of the information). As used herein, the term non-transitory computer readable medium is expressly defined to include any type of computer readable storage device and/or storage disk and to exclude propagating signals and to exclude transmission media. As used herein, when the phrase "at least" is used as the transition term in a preamble of a claim, it is open-ended in the same manner as the term "comprising" is open ended. Also, as used herein, the terms "computer readable" and "machine readable" are considered equivalent unless indicated otherwise.

An example program <NUM> that may be executed by the example user devices <NUM> and/or 140A of <FIG> and/or <NUM> to download the example people monitoring watermarker <NUM> is represented by the flowchart shown in <FIG>. For convenience and without loss of generality, the example program <NUM> is described in the context of being executed by the example user device 140A. With reference to the preceding figures and associated written descriptions, the example program <NUM> of <FIG> begins execution at block <NUM> at which the user device 140A downloads the people monitoring watermarker <NUM> from the example data processing facility <NUM> via the example network <NUM>, as described above. At block <NUM>, the user device 140A installs and activates the people monitoring watermarker <NUM>, as described above.

An example program <NUM> that may be executed by the example data processing facility <NUM> of <FIG> and/or <NUM> to provide the example people monitoring watermarker <NUM> to user devices, such as the example user devices <NUM> and/or 140A, is represented by the flowchart shown in <FIG>. With reference to the preceding figures and associated written descriptions, the example program <NUM> of <FIG> begins execution at block <NUM> at which the example people monitor downloader <NUM> of the data processing facility <NUM> receives a request via the network <NUM> from a user device, such as the user device <NUM> or 140A, to download the people monitoring watermarker <NUM>, as described above. At block <NUM>, the people monitor downloader <NUM> sends the people monitoring watermarker <NUM> to the requesting user device, as described above.

An example program <NUM> that may be executed by the example user devices <NUM> and/or 140B of <FIG> and/or <NUM> to download audio data watermarked with people monitoring watermarks is represented by the flowchart shown in <FIG>. For convenience and without loss of generality, the example program <NUM> is described in the context of being executed by the example user device 140B. With reference to the preceding figures and associated written descriptions, the example program <NUM> of <FIG> begins execution at block <NUM> at which the user device 140B requests watermarked audio data from the example data processing facility <NUM> via the example network <NUM>, as described above. At block <NUM>, the user device 140B downloads and stores the requested watermarked audio data for output during use of the user device 140B, as described above.

An example program <NUM> that may be executed by the example data processing facility <NUM> of <FIG> and/or <NUM> to provide audio data watermarked with people monitoring watermarks to user devices, such as the example user devices <NUM> and/or 140B, is represented by the flowchart shown in <FIG>. With reference to the preceding figures and associated written descriptions, the example program <NUM> of <FIG> begins execution at block <NUM> at which the example watermarked audio downloader <NUM> of the data processing facility <NUM> receives a request via the network <NUM> from a user device, such as the user device <NUM> or 140B, to download watermarked audio data, as described above. At block <NUM>, the watermarked audio downloader <NUM> sends the requested watermarked audio data to the requesting user device, as described above.

A first example program <NUM> that may be executed to implement the example people monitoring watermarker <NUM> of <FIG> and/or <NUM> in the example user device <NUM> and/or 140A of <FIG> and/or <NUM> is illustrated in <FIG>. The example program <NUM> may be executed at predetermined intervals, based on an occurrence of a predetermined event, etc., or any combination thereof. With reference to the preceding figures and associated written descriptions, the example program <NUM> of <FIG> begins execution at block <NUM> at which example trigger condition evaluator <NUM> of the people monitoring watermarker <NUM> evaluates, as described above, one or more trigger conditions for outputting an audio signal (e.g., emitting an acoustic signal) including one or more people monitoring watermarks. Example machine readable instructions that may be executed to implement the processing at block <NUM> are illustrated in <FIG>, which is described in detail below.

At block <NUM>, the trigger condition evaluator <NUM> determines whether the trigger condition(s) evaluated at block <NUM> have been satisfied. If the trigger condition(s) have been satisfied (block <NUM>), then at block <NUM> the trigger condition evaluator <NUM> causes the example audio watermarker <NUM> of the people monitoring watermarker <NUM> to provide an audio signal including the people monitoring watermark(s) to the example audio circuitry <NUM>, as described above. As also described above, the audio circuitry <NUM> is to process the audio signal provided by the audio watermarker <NUM> to generate and output (e.g., emit), from the user device <NUM>/140A, a corresponding acoustic signal conveying the people monitoring watermark(s).

At block <NUM>, the people monitoring watermarker <NUM> determines whether people monitoring is complete. If people monitoring is not complete (block <NUM>), processing returns to block <NUM> and blocks subsequent thereto to enable the people monitoring watermarker <NUM> to cause people monitoring watermark(s) to continue to be output by (e.g., emitted from) the user device <NUM>/140A. Otherwise, execution of the example program <NUM> ends.

A second example program <NUM> that may be executed to implement the example people monitoring watermarker <NUM> of <FIG> and/or <NUM> in the example user device <NUM> and/or 140A of <FIG> and/or <NUM> is illustrated in <FIG>. The example program <NUM> may be executed at predetermined intervals, based on an occurrence of a predetermined event, etc., or any combination thereof. Similar blocks in <FIG> and <FIG> are labelled with the same reference numerals. With reference to the preceding figures and associated written descriptions, the example program <NUM> of <FIG> begins execution at blocks <NUM> and <NUM> at which the example trigger condition evaluator <NUM> of the people monitoring watermarker <NUM> evaluates, as described above, one or more trigger conditions for outputting an audio signal (e.g., emitting an acoustic signal) including one or more people monitoring watermarks. Example machine readable instructions that may be executed to implement the processing at block <NUM> are illustrated in <FIG>, which is described in detail below.

At block <NUM>, the trigger condition evaluator <NUM> determines whether the trigger condition(s) evaluated at block <NUM> have been satisfied. If the trigger condition(s) have been satisfied (block <NUM>), then at block <NUM> the trigger condition evaluator <NUM> causes the example audio watermarker <NUM> of the people monitoring watermarker <NUM> to generate or retrieve an audio signal including people monitoring watermark(s), as described above. At block <NUM>, the audio watermarker <NUM> adjusts, as described above, the level of the watermarked audio signal obtained at block <NUM> based on an input audio signal level determined by the input audio evaluator <NUM>. For example, and as described in detail above, at block <NUM> the audio watermarker <NUM> may apply a gain factor or attenuation factor that causes the level of the audio signal obtained at block <NUM>, which includes the people monitoring watermark(s), to be less than or equal to (or a fraction of, etc.) the input audio level determined by the input audio evaluator <NUM> for the input audio signal. Such adjustments can increase the likelihood that the people monitoring watermark(s) is/are masked by the ambient audio. At block <NUM>, the audio watermarker <NUM> provides the adjusted audio signal, which includes the people monitoring watermark(s), to the example audio circuitry <NUM>, as described above.

An example program 905P that may be executed to implement the example trigger condition evaluator <NUM> of the example people monitoring watermarker <NUM> of <FIG>, and/or that may be used to implement the processing at block <NUM> of <FIG> and/or <NUM>, is illustrated in <FIG>. With reference to the preceding figures and associated written descriptions, the example program 905P of <FIG> begins execution at block <NUM> at which the trigger condition evaluator <NUM> indicates that an audio level trigger condition for emitting people monitoring watermark(s) is satisfied if an input audio level determined by the example input audio evaluator <NUM> of the people monitoring watermarker <NUM> meets a threshold audio level, as described above. At block <NUM>, the trigger condition evaluator <NUM> indicates that a clock (or day/time) trigger condition for emitting people monitoring watermark(s) is satisfied if the current time, as determined from clock information provided by the example clock <NUM> of the people monitoring watermarker <NUM>, is within one of the time period(s) (or window(s)) specified for people monitoring, as described above. At block <NUM>, the trigger condition evaluator <NUM> indicates that a location trigger condition for emitting people monitoring watermark(s) is satisfied if the current location of the user device, as determined from location information provided by the example location determiner <NUM> of the people monitoring watermarker <NUM>, is within one of the geographic area(s) specified for people monitoring, as described above. At block <NUM>, the trigger condition evaluator <NUM> indicates that a device state trigger condition for emitting people monitoring watermark(s) is satisfied if the example device state evaluator <NUM> of the people monitoring watermarker <NUM> indicates that the user device is already outputting an audio signal, such as a ringtone, an audible alert, an audio track, a movie, etc. (or is otherwise in a permitted operating state), as described above.

An example program <NUM> that may be executed to implement the example site meter <NUM> of <FIG> is illustrated in <FIG>. The example program <NUM> may be executed at predetermined intervals, based on an occurrence of a predetermined event, etc., or any combination thereof. With reference to the preceding figures and associated written descriptions, the example program <NUM> of <FIG> begins execution at block <NUM> at which the example sensor interface <NUM> of the site meter <NUM> samples or otherwise obtains audio data from the example acoustic sensor(s) <NUM>, as described above. At block <NUM>, the example watermark detector <NUM> of the site meter <NUM> performs watermark detection, as described above, to detect watermark(s) included in the audio data obtained at block <NUM>. At block <NUM>, the example watermark classifier <NUM> of the site meter <NUM> classifies the watermark(s) detected at block <NUM>. For example, and as described above, the watermark classifier <NUM> may classify the detected watermark(s) as media watermark(s), people monitoring watermark(s), etc. At block <NUM>, the example data reporter <NUM> of the site meter <NUM> reports the information decoded by the example watermark detector <NUM>, the watermark classifications made by the watermark classifier <NUM>, and/or any other data to the data processing facility <NUM>, as described above.

At block <NUM>, the site meter <NUM> determines whether monitoring is complete. If monitoring is not complete (block <NUM>), processing returns to block <NUM> and blocks subsequent thereto to enable the site meter <NUM> to continue monitoring. Otherwise, execution of the example program <NUM> ends.

<FIG> is a block diagram of an example processor platform <NUM> capable of executing the instructions of <FIG> to implement the example audience metering system <NUM>, the example site meter <NUM>, the example acoustic sensor <NUM>, the example user devices <NUM>, 140A and/or 140B, the example people meter <NUM>, the example network <NUM>, the example data processing facility <NUM>, the example people monitor downloader <NUM>, the example people monitoring watermarker <NUM>, the example watermarked audio downloader <NUM>, the example audio data store <NUM>, the example audio watermarker <NUM>, the example audio data store <NUM>, the example audio circuitry <NUM>, the example speaker(s) <NUM>, the example trigger condition evaluator <NUM>, the example input audio evaluator <NUM>, the example clock <NUM>, the example location determiner <NUM>, the example device state evaluator <NUM>, the example acoustic sensor <NUM>, the example sensor interface <NUM>, the example watermark detector <NUM>, the example watermark classifier <NUM> and/or the example data reporter <NUM> of <FIG>. The processor platform <NUM> can be, for example, a server, a personal computer, a mobile device (e.g., a cell phone, a smart phone, a tablet such as an iPad™), a personal digital assistant (PDA), an Internet appliance, a DVD player, a CD player, a digital video recorder, a Blu-ray player, a gaming console, a personal video recorder, a set top box a digital camera, or any other type of computing device.

The processor <NUM> of the illustrated example is in communication with a main memory including a volatile memory <NUM> and a non-volatile memory <NUM> via a link <NUM>. The link <NUM> may be implemented by a bus, one or more point-to-point connections, etc., or a combination thereof.

The input device(s) <NUM> permit(s) a user to enter data and commands into the processor <NUM>. The input device(s) can be implemented by, for example, an audio sensor, a microphone, a camera (still or video), a keyboard, a button, a mouse, a touchscreen, a track-pad, a trackball, a trackbar (such as an isopoint), a voice recognition system and/or any other human-machine interface. Also, many systems, such as the processor platform <NUM>, can allow the user to control the computer system and provide data to the computer using physical gestures, such as, but not limited to, hand or body movements, facial expressions, and face recognition.

The output devices <NUM> can be implemented, for example, by display devices (e.g., a light emitting diode (LED), an organic light emitting diode (OLED), a liquid crystal display, a cathode ray tube display (CRT), a touchscreen, a tactile output device, a printer and/or speakers). The interface circuit <NUM> of the illustrated example, thus, typically includes a graphics driver card, a graphics driver chip or a graphics driver processor.

Examples of such mass storage devices <NUM> include floppy disk drives, hard drive disks, compact disk drives, Blu-ray disk drives, RAID (redundant array of independent disks) systems, and digital versatile disk (DVD) drives.

Coded instructions <NUM> corresponding to the instructions of <FIG> may be stored in the mass storage device <NUM>, in the volatile memory <NUM>, in the non-volatile memory <NUM>, in the local memory <NUM> and/or on a removable tangible computer readable storage medium, such as a CD or DVD <NUM>.

Claim 1:
An audience measurement meter comprising:
an acoustic sensor configured to sense audio in a vicinity of a monitored media device;
a watermark detector configured to:
detect a first watermark in a first audio signal obtained from the acoustic sensor, the first watermark identifying media presented by the monitored media device; and
process the first audio signal obtained from the acoustic sensor to detect a second watermark, different from the first watermark, embedded in the first audio signal;
a watermark classifier configured to classify the second watermark into a media watermark classification or a people monitoring watermark classification based on examination of characteristics of the second watermark, the characteristics including signal characteristics of the second watermark; and
a data reporter configured to report, in response to classification of the second watermark into the people monitoring watermark classification, at least one of the second watermark or information decoded from the second watermark to identify at least one of a user device or a user of the user device as being exposed to the media presented by the monitored media device.