A new hierarchical structure of the Self-Organizing Map (SOM) with dynamic growth is presented and applied to codebook design in vector quantization (VQ) and image compression. The tree-structured approach for codebook design is motivated for reducing the high computational efforts in the training and image coding phases in traditional VQ algorithms. The DHSOM has the ability to self determine the structure of the network through heuristically rules, and its final structure reflects the variability of the data (image blocks). It is shown that training and coding times obtained with DHSOM algorithm are faster than conventional SOM and LBG algorithms, while the qualitative results are equivalent.1753758Erickson, D.S., Thyagarajan, K.S., A neural network approach to image compression, Circuits and Systems (1992) ISCAS '92. Proceedings., IEEE International Symposium on, 6, pp. 2921-2924. , 10-13 May, vol.6Linde, Y., Buzo, A., Gray, R.M., An Algorithm for Vector Quantization Design (1980) IEEE Trans. Commun., 28, pp. 84-95Setiono, R., Guojun, L., Image compression using a feedforward neural network (1994) Neural Networks, 1994. IEEE World Congress on Computational Intelligence, 7, pp. 4761-4765. , 27 Jun-2 Jul, vol.7Qiu, G., Varley, M.R., Terrell, T.J., Variable bit rate block truncation coding for image compression using Hopfield neural networks (1993) Artificial Neural Networks, 1993., Third International Conference on, pp. 233-237. , 25-27 MayBarbalho, J.M., Neto, A.D., Costa, J.A.F., Netto, M.L., Hierarchical SOM applied to image compression (2001) IJCNNGray, R.M., Neuhoff, D.L., Quantization (1998) IEEE Trans. on Information Theory, 44, pp. 2325-2383Kohonen, T., (1997) "Self-organizing Maps," 2nd Ed., , Springer-Verlag: BerlimNasrabadi, N.M., King, Y., Vector Quantization of Images Based upon the Kohonen Self-Organizing Feature Maps (1988) Proc. IEEE Int. Conf. Neural NetwoksCosta, J.A.F., (1999) Automatic Classification and Data Analysis by Self-Organizing Neural Networks, , Dr. Eng. Thesis, State Univ. of Campinas, São Paulo, Brazil (In Portuguese)Koikkalainen, P., Progress with the Tree-Structured Self-Organizing Map (1994) Proc. of the 11 th European Conference on Artificial Intelligence, pp. 211-215Lampinen, J., Oja, E., Clustering properties of hierarchical self-organizing maps (1992) Journal of Mathematical Imaging and Vision, 2, pp. 261-272(2000) SOM Toolbox, , http;/www.cis.hut.fi/projects/somtoolbox
