实用型模块化成像光谱仪多光谱图像的信噪比估算及压缩方法研究

采用局部标准差法和去相关法对实用型模块化成像光谱仪多光谱图像的信噪比进行估算。这两种方法已将地物变化的影响降低到很低的程度。这样在大气订正后，图像的信噪比性能充分反映出遥感仪器的信噪比性能。针对图像压缩，提出控制各波段恢复图像的峰值信噪比刚好大于原始图像的信噪比，使由压缩算法本身所带来的噪声限制在原始图像的噪声范围之内。结合这种压缩思想，用基于离散余弦变换和基于离散小波变换的压缩算法，对实用型模块化成像光谱仪多光谱图像进行压缩。实验表明，利用这种方法，对于高信噪比的波段，图像信息得到了保真；对低信噪比的波段，压缩倍数提高迅速且恢复图像视觉无失真，对整幅成像光谱图像，压缩性能提升显著——当压缩比等于37．95倍时，峰值信噪比等于45．86dB。

Study on Signal-to-Noise Ratio Estimation and Compression Method of Operational Modular Imaging Spectrometer Multi-Spectral Images

The text adopts two methods named local standard deviation and de-correlation to estimate the signal-to-noise ratio of operational modular imaging spectrometer(OMIS) multi-spectral images. The methods have reduced the influence of object texture change to a very low extent. In this way, after atmosphere correction the signal-to-noise ratio characteristic of OMIS images can reflect that of the OMIS instrument sufficiently. With regard to the image compression, the text proposes to control the peak signal-to-noise ratio of resumed image of each band exactly bigger than the signal-to-noise ratio of original image of the same band, which limits the noise brought by the compression algorithm of self within the noise of original images. Combining the thought dimensioned above, with discrete cosine transform-based and DWT-based compression algorithms, the OMIS multi-spectral images are compressed. The results indicate that the resumed image information is almost lossless in the bands of high signal-to-noise ratio is 45.86 dB.