基于DCT分层结构的遥感图像分级多描述编码算法

Multiple description scalable coding algorithm of remote sensing image based on DCT layered structure

多媒体及网络技术的快速发展使遥感图像的实时传输成为可能。近年来,多描述编码机制作为一种有效克服不可靠信道传输时遥感图像降质的可选方案而受到关注。本文将多描述编码与图像质量可分级编码机制相结合,提出一种基于DCT分层结构的遥感图像分级多描述编码方案,将包含图像细节信息的增强层通过下采样形成多个描述,并将包含图像关键信息的基本层作为冗余引入到每个描述中,保证了在解码端获取遥感图像基本层信息的最大可能性。此外,方案中对描述中的基本层信息进行了独立嵌入式编码,可方便对其进行有效的信道传输保护,提高传输码流的稳健性。本文编码方案具有计算复杂度低、描述间的冗余度方便控制和编码码流具有嵌入式等特性。实验结果验证了方案的有效性。

The rapid development of multimedia and Internet technology enables real-time remote sensing image and video transmission.In recent years,multiple description coding has attracted considerable attention as an optional solution to remote sensing image degradation problem caused by unreliable channel＇s transmission.Combining multiple description coding with quality scalable coding mechanism,this paper proposes a layered multiple description scalable remote sensing image coding algorithm based on discrete cosine transform （DCT）.The algorithm first divides DCT coefficients into a base layer and an enhancement layer by quantization.The enhancement layer is then subsample to form multiple descriptions,while the base layer is encoded into every description as a redundancy.Since base layer contains significant information of original remote sensing image,the above strategy ensures that each description obtains as much base layer information as possible when decoding.Moreover,the base layer in each description is coded independently in an embedded manner.This can facilitate an effective protection against channel transmission errors so as to improve robustness of coded bitstream.The layered structure realizes low computational complexity,easy redundancy control,and embedded bitstream.Experimental results validate the effectiveness of the proposed algorithm.