Reducing signature matching uncertainty in media monitoring systems
Methods, apparatus, systems and articles of manufacture to reduce signature matching uncertainty in media monitoring systems are disclosed. Disclosed example apparatus are to compare first neighborhoods of monitored signatures representative of monitored media with second neighborhoods of reference signatures representative of respective reference media to determine a first sequence of matching results for an observation period, the first and second neighborhoods to have respective sizes that span a first number of signatures. Disclosed example apparatus are also to select whether to output the first or a second sequence of matching results for the observation period based on whether a discontinuity is detected in the first sequence of matching results, the second sequence of matching results to be determined from comparisons of third neighborhoods of monitored signatures with fourth neighborhoods of reference signatures, the third and fourth neighborhoods to have respective sizes that span a second larger number of signatures.
1. An apparatus to perform signature comparison, the apparatus comprising:
memory including computer readable instructions; and
a process to execute the instructions to at least:
compare first neighborhoods of monitored signatures representative of monitored media with second neighborhoods of reference signatures representative of respective reference media to determine a first sequence of signature matching results for an observation period, the first neighborhoods and the second neighborhoods to have respective neighborhood sizes that span a first number of signatures; and
select whether to output the first sequence of signature matching results or a second sequence of signature matching results for the observation period based on whether a discontinuity is detected in the first sequence of signature matching results, the second sequence of signature matching results to be determined from comparisons of third neighborhoods of monitored signatures with fourth neighborhoods of reference signatures, the third neighborhoods and fourth neighborhoods to have respective neighborhood sizes that span a second number of signatures larger than the first number of signatures.
2. The apparatus of claim 1 , wherein the processor is to detect the discontinuity based on whether discontinuous timestamps are included in the first sequence of signature matching results.
3. The apparatus of claim 2 , wherein respective ones of the signature matching results in the first sequence of signature matching results include respective timestamps, and the processor is to determine that discontinuous timestamps are included in the first sequence of signature matching results when successive ones of the timestamps in the first sequence of signature matching results do not increment relative to preceding ones of the timestamps in the first sequence of signature matching results by amounts within a range based on a time resolution.
4. The apparatus of claim 1 , wherein the processor is to detect the discontinuity based on whether at least one of the first sequence of signature matching results indicates no match was found.
5. The apparatus of claim 1 , wherein the processor is to detect the discontinuity based on whether at least a portion of the first sequence of signature matching results oscillates between at least two different reference media identifiers.
6. The apparatus of claim 1 , wherein the processor is to compare the third neighborhoods of monitored signatures with the fourth neighborhoods of reference signatures to determine the second sequence of signature matching results before the processor is to select whether to output the first sequence of signature matching results or the second sequence of signature matching results.
7. The apparatus of claim 1 , wherein the processor is to compare the third neighborhoods of monitored signatures with the fourth neighborhoods of reference signatures to determine the second sequence of signature matching results after the processor is to select whether to output the first sequence of signature matching results or the second sequence of signature matching results.
8. A system to perform signature comparison, the system comprising:
means for comparing first neighborhoods of monitored signatures representative of monitored media with second neighborhoods of reference signatures representative of respective reference media to determine a first sequence of signature matching results for an observation period, the first neighborhoods and the second neighborhoods to have respective neighborhood sizes that span a first number of signatures; and
means for selecting whether to output the first sequence of signature matching results or a second sequence of signature matching results for the observation period based on whether a discontinuity is detected in the first sequence of signature matching results, the second sequence of signature matching results to be determined from comparisons of third neighborhoods of monitored signatures with fourth neighborhoods of reference signatures, the third neighborhoods and fourth neighborhoods to have respective neighborhood sizes that span a second number of signatures larger than the first number of signatures.
9. The system of claim 8 , wherein the means for selecting is to detect the discontinuity based on whether discontinuous timestamps are included in the first sequence of signature matching results.
10. The system of claim 9 , wherein respective ones of the signature matching results in the first sequence of signature matching results include respective timestamps, and the means for selecting is to determine that discontinuous timestamps are included in the first sequence of signature matching results when successive ones of the timestamps in the first sequence of signature matching results do not increment relative to preceding ones of the timestamps in the first sequence of signature matching results by amounts within a range based on a time resolution.
11. The system of claim 8 , wherein the means for selecting is to detect the discontinuity based on whether at least one of the first sequence of signature matching results indicates no match was found.
12. The system of claim 8 , wherein the means for selecting is to detect the discontinuity based on whether at least a portion of the first sequence of signature matching results oscillates between at least two different reference media identifiers.
13. The system of claim 8 , wherein the means for comparing is first means for comparing, and further including second means for comparing the third neighborhoods of monitored signatures with the fourth neighborhoods of reference signatures to determine the second sequence of signature matching results before the means for selecting is to select whether to output the first sequence of signature matching results or the second sequence of signature matching results.
14. The system of claim 8 , wherein the means for comparing is to compare the third neighborhoods of monitored signatures with the fourth neighborhoods of reference signatures to determine the second sequence of signature matching results after the means for selecting is to select whether to output the first sequence of signature matching results or the second sequence of signature matching results.
15. A non-transitory computer readable medium comprising computer readable instructions that, when executed, cause a processor to at least:
compare first neighborhoods of monitored signatures representative of monitored media with second neighborhoods of reference signatures representative of respective reference media to determine a first sequence of signature matching results for an observation period, the first neighborhoods and the second neighborhoods to have respective neighborhood sizes that span a first number of signatures; and
select whether to output the first sequence of signature matching results or a second sequence of signature matching results for the observation period based on whether a discontinuity is detected in the first sequence of signature matching results, the second sequence of signature matching results to be determined from comparisons of third neighborhoods of monitored signatures with fourth neighborhoods of reference signatures, the third neighborhoods and fourth neighborhoods to have respective neighborhood sizes that span a second number of signatures larger than the first number of signatures.
16. The non-transitory computer readable medium of claim 15 , wherein the instructions, when executed, cause the processor to detect the discontinuity based on whether discontinuous timestamps are included in the first sequence of signature matching results.
17. The non-transitory computer readable medium of claim 15 , wherein the instructions, when executed, cause the processor to detect the discontinuity based on whether at least one of the first sequence of signature matching results indicates no match was found.
18. The non-transitory computer readable medium of claim 15 , wherein the instructions, when executed, cause the processor to detect the discontinuity based on whether at least a portion of the first sequence of signature matching results oscillates between at least two different reference media identifiers.
19. The non-transitory computer readable medium of claim 15 , wherein the instructions, when executed, cause the processor to compare the third neighborhoods of monitored signatures with the fourth neighborhoods of reference signatures to determine the second sequence of signature matching results before the processor is to select whether to output the first sequence of signature matching results or the second sequence of signature matching results.
20. The non-transitory computer readable medium of claim 15 , wherein the instructions, when executed, cause the processor to compare the third neighborhoods of monitored signatures with the fourth neighborhoods of reference signatures to determine the second sequence of signature matching results after the processor is to select whether to output the first sequence of signature matching results or the second sequence of signature matching results.