Methods and systems for automatic discovery of fraudulent calls using speaker recognition

A computer-implemented method for identifying a voice associated with undesirable activity, comprising:

• obtaining voiceprint data that includes vector representations of voices from a plurality of audio recordings;
• performing a nearest-neighbor analysis on the vector representations to identify one or more vector representations having a similarity below a predetermined threshold;
• generating a sub-set of vector representations by discarding the one or more identified vector representations;
• grouping the sub-set of vector representations into a plurality of clusters by performing a clustering operation:
• identifying one or more spurious clusters by performing a filtering operation on the plurality of clusters, wherein the one or more clusters are identified as spurious based on one or more of cluster size, cluster coherence, number of voices represented by vectors within a same cluster, or number of accounts associated with vector representations within a same cluster;
• and
• forming a voiceprint library for identifying a voice associated with undesirable activity by discarding the one or more spurious clusters from the plurality of clusters.

A computer-implemented method for identifying a voice associated with undesirable activity, comprising:

• obtaining voiceprint data that includes vector representations of voices from a plurality of audio recordings;
• identifying one or more vector representations that are unlikely to cluster with others of the vector representations by performing a nearest-neighbor analysis on the vector representations to identify one or more vector representations having a similarity below a predetermined threshold;
• generating a sub-set of vector representations by discarding the one or more identified vector representations that are unlikely to cluster with others of the vector representations;
• grouping the sub-set of vector representations into a plurality of clusters by performing a clustering operation, wherein the clustering operation includes iteratively, until no grouping of one or more vector representations has a similarity above a predetermined threshold, performing the operations of:
• determining a similarity between each grouping and one or more neighboring groupings;
• and
• merging groupings that have a similarity above the predetermined threshold:
• identifying one or more spurious clusters by performing a filtering operation on the plurality of clusters, wherein a spurious cluster is a cluster that one or more of:
• (i) includes vector representations of more than one voice;
• (ii) includes vector representations that were clustered together due to common background noise or interference in corresponding audio recordings;
• (iii) has a cluster coherence below a predetermined threshold;
• (iv) includes less than a threshold number of vector representations;
• or
• (v) includes vector representations associated with only one account;
• forming a voiceprint library for identifying a voice associated with undesirable activity by discarding the one or more spurious clusters from the plurality of clusters;
• and
• configuring the voiceprint library as a blacklist, such that a future audio recording is compared against each cluster in the voiceprint library, the voiceprint library configured to blacklist the future audio recording upon a similarity between the audio recording and at least one of the clusters being above a predetermined similarity threshold.