摘要
针对基于KL(Karhunen-Loeve)变换和JPEG-LS编码的多光谱图像压缩系统中码率控制不准确以及码率分配效果差的问题,提出了一种联合码率分配—码率控制方法。首先分析了重构波段失真相当的条件下各变换分量量化步长之间的关系,根据该关系对各分量统一调整量化步长以控制码率,使码率分配和码率控制有效统一起来。为了更精确的控制码率,满足图像通信中有限带宽的要求,还提出了基于二次迭代调整的码率控制方法,使得实际码率在小于目标码率的前提下尽可能的接近目标码率。实验结果表明本文算法控制码率精确,计算复杂度低,整体重构质量明显优于其它码率分配方法,而且各波段重构质量非常稳定。
A joint rate allocation-control approach is proposed tor multispeetral image compression based on KI, （Karhunen-Loeve） transform and JPEG-LS. Firstly the relation of quantization steps for each transfurmed component is analyzed under the condition of comparable reconstruction quality. Based on the analysis, the proposed method adjusts the quantization steps of each component in a unified way to control the rate, thus the rate allocation and rate control are joinl efficiently. In addition, a rate control method based on twice-iterated adjustment is proposed to control rate accurately. Our proposed rate control method can achieve the targeted rate as close as possible and would not exceed the targeted rate to meet the demand of limited bandwidth in image communication. Experimental results show that our proposed method could control rate precisely with low complexity; besides, the overall reconstruction quality obviously outperforms other rate allocation methods and the reconstruction quality of each band is very stable.
出处
《宇航学报》
EI
CAS
CSCD
北大核心
2014年第2期220-226,共7页
Journal of Astronautics
基金
国家自然科学基金(61301291
61305109)
中央高校基本科研业务费专项资金(K5051323004
K5051301015)
