Vector quantization & LBG

Question

Hi there,

In the purpose of vector quantization, I'm using the linde-buzo-gray (LBG) algorithm to generate the codebook.

To generate 256 codewords in this codebook, I'm using 256 000 training vectors (all of 128 dimensions).

This codebook is initialized with a vector and than split until obtaining 256 codewords.

My problem is : at the end of the LBG process, I don't have 256 codewords but only near 50. It seems the algorithm converge before generating 256 elements.

In other words, are these 50 vectors really representing 256 000 vectors ?

Why can't I obtain 256 elements ? (I tried with different values of threshold but none worked).

I'm really stuck, Thanks a lot.