Real-time Lexicon-free Scene Text Retrieval

•Improved method that achieves state of the art performance in image-based text retrieval.•Results on different CNN backbones modified to predict a PHOC of detected textual instances are presented.•Effect of different PHOC dimensions is explored and analyzed.•PHOC embedding allows retrieving out-of-vocabulary words unseen at training time.•Proposed method achieves state of the art in multilingual dataset of unseen samples at training time.•Method is faster than state of the art, allowing real-time retrieval in videos.