Bidirectional extraction and recognition of scene text with layout consistency

Text recognition in natural scene images is a challenging task that has recently been garnering increased research attention. In this paper, we propose a method for recognizing text by utilizing the layout consistency of a text string. We estimate the layout (four lines of a text string) using initial character extraction and recognition result. On the basis of the layout consistency across a word, we perform character extraction and recognition again using four lines, which is more accurate than the first process. Our layout estimation method is different from previous methods in terms of exploiting character recognition results and its use of a class-conditional layout model. More accurate and robust estimation is achieved, and it can be used to refine character extraction and recognition. We call this two-way process--from extraction and recognition to layout, and from layout to extraction and recognition--"bidirectional" to discriminate it from previous feedback refinement approaches. Experimental results demonstrate that our bidirectional processes provide a boost to the performance of word recognition.