Methods and apparatus for identifying media content using temporal signal characteristics
Methods and apparatus to identify media content using temporal signal characteristics are disclosed. An example method includes generating a reference signature based on a reference signal corresponding to known media, generating sums based on peaks in a media signal corresponding to media, identifying signal peaks based on the generated sums, generating a second signature based on normalized curve features, wherein the normalized curve features respectively correspond to the identified signal peaks at a corresponding temporal locations of the corresponding signal peak, and determining whether the media signal corresponds to the reference signal based on a comparison of the reference signature and the second signature.
1. An apparatus comprising:
means for detecting peaks of a sensed media signal during time intervals, the means for detecting the peaks to output absolute values of the peaks;
means for generating interval sums respective to the time intervals, the means for generating the interval sums to generate the interval sums based on the absolute values;
means for identifying second peaks based on the interval sums; and
means for generating a signature representative of the media signal, the signature including normalized curve features located at temporal locations of the second peaks, the means for generating the signature to output the signature.
2. The apparatus of claim 1 , wherein the signature is a first signature, and further including means for generating an index based on a comparison of the first signature representative of the media signal to a second signature representative of a reference media signal.
3. The apparatus of claim 2 , further including means for determining whether the media signal matches the reference media signal based on a comparison of the index to a threshold.
4. The apparatus of claim 1 , further including means for smoothing the interval sums.
5. The apparatus of claim 1 , further including means for detecting zero crossings of the media signal.
6. The apparatus of claim 5 , wherein the means for detecting the peaks is to detect the peaks based on the zero crossings.
7. The apparatus of claim 1 , wherein the signature has a substantially zero value except at temporal locations corresponding to the normalized curve features.
8. The apparatus of claim 1 , wherein the normalized curve features have equal heights.
9. The apparatus of claim 8 , wherein the normalized curve features have equal widths.
10. A method comprising:
detecting, by executing one or more instructions with a processor, peaks in time intervals of a sensed media signal;
generating, by executing one or more instructions with the processor, interval sums respective to the time intervals based on absolute values of the detected peaks;
identify, by executing one or more instructions with the processor, second peaks based on the interval sums; and
generating, by executing one or more instructions with the processor, a signature including normalized curve features at respective temporal locations of the second peaks, each one of the curve features including a respective shape having a respective height, a respective width, and a respective center location at the respective temporal location corresponding to the temporal location of a corresponding one of the second peaks, and at least one of the respective height or the respective width being equal or proportional to at least one of a height or the temporal location of the corresponding one of the second peaks.
11. The method of claim 10 , wherein the signature has a substantially zero value except at the normalized curve features.
12. The method of claim 10 , wherein the signature is a first signature, and further including determining whether the media signal corresponds to a reference media signal based on a comparison of the first signature and a reference signature.
13. The method of claim 12 , further including generating an index value based on the comparison, wherein the determining of whether the media signal corresponds to the reference media signal includes determining whether the index value satisfies a threshold.
14. The method of claim 10 , further including smoothing the interval sums.
15. The method of claim 10 , wherein the media signal includes at least one of an audio signal or a video signal.
16. A computer readable storage device or storage disk comprising instructions that, when executed, cause at least one processor to at least:
identify peaks in time intervals of a sensed media signal;
determine interval sums respective to the time intervals based on absolute values of the peaks occurring in the time intervals;
identify second peaks based on the interval sums; and
generate a waveform signature to identify the media signal, the waveform signature including normalized curve features based on the second peaks.
17. The computer readable storage device or storage disk of claim 16 , wherein the instructions, when executed, further cause the at least one processor to generate an index based on a comparison of the waveform signature generated to identify the media signal and a reference waveform signature associated with a reference media signal.
18. The computer readable storage device or storage disk of claim 17 , wherein the instructions, when executed, further cause the at least one processor to identify the media signal based on whether the index satisfies a threshold.
19. The computer readable storage device or storage disk of claim 16 , wherein the instructions, when executed, further cause the at least one processor to smooth the interval sums prior to identification of the second peaks.
20. The computer readable storage device or storage disk of claim 16 , wherein the media signal is associated with at least one of a broadcast program or a local media source.