基于三维Saab变换的高光谱图像压缩方法

Hyperspectral image compression method based on 3D Saab transform

高光谱图像中存储了丰富的光谱信息,具有极大的应用价值,但现有大部分高光谱图像压缩方法难以同时兼顾图像中的空间冗余与谱间冗余,导致压缩性能受到局限。针对该问题,提出了一种基于三维修正偏置的子空间(Saab)变换的高光谱图像压缩方法。采用三维Saab变换对高光谱图像的分块进行空间光谱信息融合的降维操作,同时去除谱间冗余和局部空间冗余;利用高效率视频编码(HEVC)中的帧内编码模块进一步去除空间冗余和统计冗余;实现低失真、高比率的高光谱图像压缩。在多个高光谱图像数据集上的实验结果表明,所提方法在同码率下重建图像的信噪比(SNR)比采用主成分分析(PCA)降维的方法至少提高0.62 dB,在高码率的情况下性能优于张量分解的压缩方法。同时,验证了不同降维方法对分类任务的性能影响,结果表明,所提方法更好地保留了图像中的重要特征,在低码率的情况下仍可以保持较高的分类精度。

Hyperspectral images contain rich and valuable spectral information,which brings great challenges to storage and transmission.However,most current hyperspectral image compression methods cannot consider spatial and spectral redundancy simultaneously,resulting in limited compression performance.We present a hyperspectral image compression method based on 3D subspace approximation with adjusted bias(Saab)transform.3D Saab transform is firstly applied to hyperspectral image blocks,which performs spatial-spectral fusion and dimensionality reduction on blocks to remove spectral redundancy and local spatial redundancy simultaneously.Then,we use intra mode of high efficiency video coding(HEVC)to further remove spatial and statistical redundancy.Experimental results demonstrate that the proposed method can improve the signal-to-noise ratio(SNR)by at least 0.62 dB as compared with principle component analysis(PCA)based algorithm.At a high bit rate,the proposed method outperforms the state-of-art tensor decomposition compression method.We also evaluate the impact of different dimensionality reduction methods on classification,which demonstrates that the proposed method can better retain important features,with improved classification accuracy at a low bit rate.