嵌入容量是衡量信息隐藏方法的重要指标之一。为了提高嵌入容量，提出一种面向矢量量化索引图邻块编码的信息隐藏改进算法，利用当前块的四邻块的空间相对位置关系和邻块与当前块索引差值的数值范围进行信息隐藏。实验结果表明，改进后的算法能够显著提高嵌入容量，在比特率仅增加5.13%13.10%的情况下可将嵌入容量提高到Chang方法容量的2.113.16倍，嵌入效率由原来平均0.10提高到了0.26。

Embedding capacity is one of the important factors that affect the information hiding perfomance.An improved information hiding scheme for VQ-compressed index map images based-on joint neighboring coding(JNC)technique is proposed to increase the embedding capacity.The proposed method embeds secret data by using the difference values ranging between the current VQ-compressed index and its four neighboring indices.Experimental results show that the proposed method increases the embedding capacity significantly compared with Chang’s and Yang’s method.The proposed method obtains 2.11 to 3.16 times embedding capacity compared to Chang’s method with only a 5.13%to 13.10%increas of the bit rate.As a result，the value of embedding-efficiency is increased on average from 0.10 in Chang’s method to 0.26 in the proposed method.