PT Journal
AU Partha Pratim Roy
   Umapada Pal
   Josep Llados
TI Document Seal Detection Using Ght and Character Proximity Graphs
SO Pattern Recognition
JI PR
PY 2011
BP 1282
EP 1295
VL 44
IS 6
DI http://dx.doi.org/10.1016/j.patcog.2010.12.004
DE Seal recognition; Graphical symbol spotting; Generalized Hough transform; Multi-oriented character recognition
AB This paper deals with automatic detection of seal (stamp) from documents with cluttered background. Seal detection involves a difficult challenge due to its multi-oriented nature, arbitrary shape, overlapping of its part with signature, noise, etc. Here, a seal object is characterized by scale and rotation invariant spatial feature descriptors computed from recognition result of individual connected components (characters). Scale and rotation invariant features are used in a Support Vector Machine (SVM) classifier to recognize multi-scale and multi-oriented text characters. The concept of generalized Hough transform (GHT) is used to detect the seal and a voting scheme is designed for finding possible location of the seal in a document based on the spatial feature descriptor of neighboring component pairs. The peak of votes in GHT accumulator validates the hypothesis to locate the seal in a document. Experiment is performed in an archive of historical documents of handwritten/printed English text. Experimental results show that the method is robust in locating seal instances of arbitrary shape and orientation in documents, and also efficient in indexing a collection of documents for retrieval purposes.
ER