  It is widely recognized that the image format is crucial to steganography for
that each individual format has its unique properities. Nowadays, the most
famous approach of digital image steganography is to combine a well-defined
distortion function with efficient practical codes such as STC. And numerous
researches are concentrated on spatial domain and jpeg domain. However, whether
in spatial domain or jpeg domain, high payload (e.g., 0.5 bit per pixel) is not
secure enough. In this paper, we propose a novel adaptive steganography scheme
based on 32-bit HDR (High dynamic range) format and Norm IEEE 754. Experiments
show that the steganographic method can achieve satisfactory security under
payload from 0.3bpp to 0.5bpp.
