14. The method of claim 13 , wherein deriving text from the one or more video frames comprises detecting entity text from the text that describes an entity.
14. The method of claim 13 , wherein deriving text from the one or more video frames comprises detecting entity text from the text that describes an entity. 16. The method of claim 14 , wherein generating a modified query based on the query and the entity text describing the entity comprises: determining a similarity of the text of the query and the entity text to each of a plurality of prior queries stored in a query log; and selecting, form the query log, prior queries for which the similarity measure meets a threshold similarity value.