Document images captured by a mobile phone camera often have perspective distortions. Efficiency and accuracy are two important issues in designing a rectification system for such perspective documents. In this paper, we propose a new perspective rectification system based on vanishing point detection. This system achieves both the desired efficiency and accuracy using a multi-stage strategy: at the first stage, document boundaries and straight lines are used to compute vanishing points; at the second stage, text baselines and block aligns are utilized; and at the last stage, character tilt orientations are voted for the vertical vanishing point. A profit function is introduced to evaluate the reliability of detected vanishing points at each stage. If vanishing points at one stage are reliable, then rectification is ended at that stage. Otherwise, our method continues to seek more reliable vanishing points in the next stage. We have tested this method with more than 400 images including paper documents, signboards and posters. The image acceptance rate is more than 98.5% with an average speed of only about 60ms.
In this paper we propose a new method of extracting a character string from images with a background design. In Japanese newspaper headlines, it is common for character components to be placed independent of background components. In view of this, we represent a character string candidate as a consistent combination of connected components, and we calculate its character string resemblance value. In this case, a character string resemblance value of a combination of connected components depends upon its character recognition result and the area of the rectangular area occupied by it. We then extract the combination of connected components that has the maximum character string resemblance value. We applied this method to 142 headline images. The results show that the method accurately extracted a character string from various kinds of images with a background design and the method has a favorable processing speed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.