【摘要】 根据合成孔径雷达(SAR)原始数据经离散余弦变换(DCT)后的系数特性,分析了在DCT域按各子带能量分布作变比特块自适应量化的算法DCT域块自适应量化(DCT-BAQ),并将该方法与时域BAQ算法作了比较。结合一组实测SAR原始数据,用两种算法分别进行了压缩和解压缩,并计算了数据域及图像域信噪比,给出了两种压缩算法所成的图像。实验证明,在相同的比特率下,DCT-BAQ算法的数据域和图像域信噪比均比时域BAQ算法高。数据域信噪比增加1.38～1.94dB,图像域信噪比增加1.56～1.91dB。加之DCT变换是实数运算、有快速算法,所以将它用于SAR原始数据压缩有一定的优越性。更多还原

【Abstract】 According to the characteristics of SAR raw data coefficients in DCT transform domain, an algorithm of variable bit rate allocation according to energey distribution of every subband in DCT transform domain-Block Adaptive Quantization in DCT domain (DCT-BAQ) is analyzed. The comparison between DCT-BAQ and time domain BAQ is analysed. By using a real SAR raw data, compression and decompression are performed respectively. The SQNR and SDNR are achieved. The images correspond to the two algorithms are gained. The experiments manifest that with same bit rate, SQNR and SDNR of DCT-BAQ surpass that of time domain BAQ. In addition, as DCT transform has the characteristics of real number operation and fast speed algorithm, therefore, DCT-BAQ has some advantage in the domain of SAR raw data compression.更多还原