矢量量化的编码过程计算复杂性极高，为了减少编码时大量的矢量间距离计算，许多文献提出利用不等式关系以较少的计算量来估算距离的方法。在Chang等人提出的利用双限制三角不等式的快速搜索算法基础上，通过改进参考矢量的选取方法，有效提高了码字搜索的效率。实验结果表明，改进算法的码字排除率可以提高3.735%9.976%，编码时间可以减少6.03%35.25%。

The encoding process of vector quantization (VQ) is computational expensive. To reduce the distance computations between vectors， many methods use inequality relations to make distance estimations with less computational cost. This paper aims at extending the method using two-bounds triangle inequality proposed by Chang C C et al by improving reference the vector selection. The experimental results show that our proposed method can increase the ratio of codeword rejection by 3.735%9.976%， and reduce the encoding time by 6.03%35.25%.