A multiple-label guided clustering algorithm for historical document dating and localization

It is of essential importance for historians to know the date and place of origin of the documents they study. It would be a huge advancement for historical scholars if it would be possible to automatically estimate the geographical and temporal provenance of a handwritten document by inferring them from the handwriting style of such a document. We propose a multiple-label guided clustering algorithm to discover the correlations between the concrete low-level visual elements in historical documents and abstract labels, such as date and location. Firstly, a novel descriptor, called Histogram of Orientations of Handwritten Strokes (HOHS or H2OS), is proposed to extract and describe the visual elements, which is built on a scale-invariant polar-feature space. In addition, the Multi-Label Self-Organizing Map (MLSOM) is proposed to discover the correlations between the low-level visual elements and their labels in a single framework. Our proposed MLSOM can be used to predict the labels directly. Moreover, the MLSOM can also be considered as a pre-structured clustering method to build a codebook, which contains more discriminative information on date and geography. Experimental results on the Medieval Paleographic Scale (MPS) data set demonstrate that our method achieves state-of-the-art results