CAJ | 학술논문

为了提高离散余弦变换(DCT)域隐写的嵌入容量，提出一种基于菱形编码和修改量化表的DCT域图像隐写。首先将载体图像进行8×8的DCT变换后，对变换得到的DCT系数采用修改的8×8量化表进行量化，从而提高了嵌入容量和载密图像的视觉质量。同时通过改进的菱形编码将8进制的秘密信息嵌入到载体图像量化 DCT 系数的中频部分，从而进一步提高了嵌入容量。实验结果表明：该隐写算法不但与JPEG压缩标准兼容，而且有效地提高了嵌入容量。
위료제고리산여현변환(DCT)역은사적감입용량，제출일충기우릉형편마화수개양화표적DCT역도상은사。수선장재체도상진행8×8적DCT변환후，대변환득도적DCT계수채용수개적8×8양화표진행양화，종이제고료감입용량화재밀도상적시각질량。동시통과개진적릉형편마장8진제적비밀신식감입도재체도상양화 DCT 계수적중빈부분，종이진일보제고료감입용량。실험결과표명：해은사산법불단여JPEG압축표준겸용，이차유효지제고료감입용량。
In order to improve embedding capacity of steganography in discrete cosine transform (DCT) Domain, a new image steganography is proposed based on the diamond encoding and quantization table modification. Firstly, the carrier image is transformed by 8×8 block DCT, then the DCT coefficients are quantized using the modified 8×8 quantification table, which increases the embedding capacity and steno-image visual quality. The 8-ary secret image data are embedded in the middle-band of frequency of the carrier image’s DCT coefficients using the modified diamond encoding, then the embedding capacity can thus be further improved. The experimental results show that the proposed method not only maintains good imperceptibility of image after embedding large amount of secret message, but also effectively improves the embedding capacity as well.