"Other patent filings have recently become public, suggesting Google has been working all along to apply visual query technology to searching for faces," it writes.
Meanwhile, Google's recent patent filing for User Interface for Presenting Search Results for Multiple Regions of a Visual Query suggests that Google's visual search for smartphones may be evolving.
Last year, Google acquired Like.com which is a visual search engine currently used for shopping, but was previously a visual search service called Riya which used facial recognition technology to search images that users had uploaded and tagged.