Methods and apparatus to optimize reference signature matching using watermark matching

A non-transitory computer readable storage medium having stored thereon program instructions that, upon execution by a processor, cause performance of operations comprising:

• obtaining, via a network interface, monitoring data associated with a time period of a media event, wherein the monitoring data of the media event includes a first segment and a second segment, the first segment including one or more detected watermarks and the second segment including a monitored signature;
• comparing a primary unhashed reference signature with a monitored signature of the second segment, wherein the primary unhashed reference signature is selected based on determining that the one or more detected watermarks of the first segment match one or more respective reference watermarks stored in a reference watermark database;
• determining that the monitoring data comprises unidentified media events based on comparing the primary unhashed reference signature with the monitored signature of the second segment;
• selecting one or more secondary unhashed reference signatures corresponding to adjacent media events of one or more media events associated with the primary unhashed reference signature;
• and
• crediting media exposure as having occurred during the second segment based on a comparison of the one or more secondary unhashed reference signatures and the monitored signature.

A method comprising:

• obtaining, via a network interface, monitoring data associated with a time period of a media event, wherein the monitoring data of the media event includes a first segment and a second segment, the first segment including one or more detected watermarks and the second segment including a monitored signature;
• comparing a primary unhashed reference signature with a monitored signature of the second segment, wherein the primary unhashed reference signature is selected based on determining that the one or more detected watermarks of the first segment match one or more respective reference watermarks stored in a reference watermark database;
• determining that the monitoring data comprises unidentified media events based on comparing the primary unhashed reference signature with the monitored signature of the second segment;
• selecting one or more secondary unhashed reference signatures corresponding to adjacent media events of one or more media events associated with the primary unhashed reference signature;
• and
• crediting media exposure as having occurred during the second segment based on a comparison of the one or more secondary unhashed reference signatures and the monitored signature.