This specification describes technologies relating to recognition of text in various media. In general, one aspect of the subject matter described in this specification can be embodied in methods that include receiving an input signal including data representing one or more words and passing the input signal to a text recognition system that generates a recognized text string based on the input signal. The methods may further include receiving the recognized text string from the text recognition system. The methods may further include presenting the recognized text string to a user and receiving a corrected text string based on input from the user. The methods may further include checking if an edit distance between the corrected text string and the recognized text string is below a threshold. If the edit distance is below the threshold, the corrected text string may be passed to the text recognition system for training purposes.