Document image recognition based on template matching of component block projections

Document Image Recognition (DIR), a very useful technique in office automation and digital library applications, is to find the most similar template for any input document image in a prestored template document image data set. Existing methods use both local features and global layout information. In this paper, we propose a novel algorithm based on the global matching of Component Block Projections (CBP), which are the concatenated directional projection vectors of the component blocks of a document image. Compared to those existing methods, CBP-based template-matching methods possess two major advantages: 1) The spatial relationship among the component blocks of a document image is better represented, hence a very high matching accuracy can be obtained even for a large template set and seriously distorted input images; and 2) the effective matching distance of each template and the triangle inequality are proposed to significantly reduce the computational cost. Our experimental results confirm these advantages and show that the CBP-based template-matching methods are very suitable for DIR applications.