Hybrid Mathematical Symbol Recognition Using Support Vector Machines

Recognition of mathematical symbols is a challenging task, with a large set with many similar symbols. We present a support vector machine based hybrid recognition system that uses both online and offline information for classification. Probabilistic outputs from the two support vector machine based multi-class classifiers running in parallel are combined by taking a weighted sum. Results from the experiments show that giving slightly higher weight to the on-line information produces better results. The overall error rate of the hybrid system is lower than that of both the online and offline recognition systems when used in isolation.

[1]  Chih-Jen Lin,et al.  A comparison of methods for multiclass support vector machines , 2002, IEEE Trans. Neural Networks.

[2]  Alexander H. Waibel,et al.  Combining bitmaps with dynamic writing information for on-line handwriting recognition , 1994, Proceedings of the 12th IAPR International Conference on Pattern Recognition, Vol. 3 - Conference C: Signal Processing (Cat. No.94CH3440-5).

[3]  Michael Perrone,et al.  Combining online and offline handwriting recognition , 2003, Seventh International Conference on Document Analysis and Recognition, 2003. Proceedings..

[4]  K. Ishigaki,et al.  Hybrid pen-input character recognition system based on integration of online-offline recognition , 1999, Proceedings of the Fifth International Conference on Document Analysis and Recognition. ICDAR '99 (Cat. No.PR00318).

[5]  Chih-Jen Lin,et al.  Probability Estimates for Multi-class Classification by Pairwise Coupling , 2003, J. Mach. Learn. Res..

[6]  Eugene H. Ratzlaff Methods, reports and survey for the comparison of diverse isolated character recognition results on the UNIPEN database , 2003, Seventh International Conference on Document Analysis and Recognition, 2003. Proceedings..

[7]  Jiri Matas,et al.  On Combining Classifiers , 1998, IEEE Trans. Pattern Anal. Mach. Intell..

[8]  Raúl Rojas,et al.  Recognition of on-line handwritten mathematical expressions in the E-Chalk system - an extension , 2005, Eighth International Conference on Document Analysis and Recognition (ICDAR'05).

[9]  John Platt,et al.  Probabilistic Outputs for Support vector Machines and Comparisons to Regularized Likelihood Methods , 1999 .

[10]  Maurice Milgram,et al.  Constraint tangent distance for on-line character recognition , 1996, Proceedings of 13th International Conference on Pattern Recognition.

[11]  Christian Viard-Gaudin,et al.  From Off-line to On-line Handwriting Recognition , 2004 .

[12]  Vladimir Vapnik,et al.  Statistical learning theory , 1998 .