隐写容量是信息隐藏的4项性能指标之一,目前,相关科研工作者对其他3项指标,即鲁棒性、透明性和计算复杂性进行过大量的研究,但隐写容量方面的研究却很少。该研究有力地完善了信息隐藏的理论体系,根据JPEG2000压缩标准以及人眼对小波系数改变的敏感程度,借助小波系数的失真代价函数,区分出小波系数的承载秘密信息能力:失真代价函数值越小,该小波系数承载能力就越强;反之,该小波系数承载能力就越弱。当失真代价函数值大于1时,该系数不具有承载信息的能力,即为湿系数。通过最大隐写容量估算实验以及位满嵌入、过位嵌入和湿嵌入等评估实验,验证了所提方法的有效性。
Steganography payload is one of the four key performance indicators for information hiding. Previous research on information hiding has mainly focused on the other three performance indicators, namely, the robustness, transparency and computational complexity, with very few work being carried out regarding to the steganography payload. This research aims to effectively improve the theoretical system of information hiding. According to the JPEG2000 compression standard and the human eye sensitivity of changing wavelet coefficients, along with the aid of distortion cost function, the study discriminates the wavelet coefficients’ carrying capacity of secret information: The smaller the distortion cost function value, the stronger the wavelet coefficients’ carrying capacity. Conversely, the larger distortion cost function value, the weaker the wavelet coefficients’ carrying capacity. When the distortion cost function value is greater than one, the coefficient will not have enough capacity to carry information, i.e., wet coefficients. By means of the maximum steganography payload experiments along with the bit full embedding, over bits embedding and wet embedding experiments, the effectiveness of the proposed estimation method in this work is verified.