A Novel Data Hiding Algorithm for High Dynamic Range Images
In this paper, we propose a novel data hiding algorithm for high dynamic range (HDR) images encoded by the OpenEXR file format. The proposed algorithm exploits each of three 10-bit mantissa fields as an embedding unit in order to conceal k bits of a secret message using an optimal base which produces the least pixel variation. An aggressive bit encoding and decomposition scheme is recommended, which offers a high probability to convey (k+1) bits without increasing pixel variation caused by message concealment. In addition, we present a bit inversion embedding strategy to further increase the capacities when the probability of appearance of secret bit “1” is greater than 0.5. Furthermore, we introduce an adaptive data hiding approach for concealing more secret messages in pixels with low luminance, exploiting the features of the human visual system to achieve luminance-aware adaptive data hiding. The stego HDR images produced by our algorithm coincide with the high dynamic range image file format, causing no suspicion from malicious eavesdroppers. The generated stego HDR images and their tone-mapped low dynamic range (LDR) images reveal no perceptual differences when subjected to quantitative testing by Visual Difference Predictor. Our algorithm can resist steganalytic attacks from the HDR and LDR RS and SPAM steganalyzers. We present the first data hiding algorithm for OpenEXR HDR images offering a high embedding rate and producing high visual quality of the stego images. Our algorithm outperforms the current state-of-the-art works.
- In existing systems, author proposed a distortion-free data embedding scheme for HDR images. Their scheme takes advantage of the Cartesian product of all of the HDR pixels, thus exploiting all of the homogeneous representations.
- Their method provides an average embedding rate of 0.1355 bpp. And also introduced a new homogeneity index table for homogeneity values of N=3, 5, 6, 7, which efficiently exploits all homogeneous representations of each pixel.
- Their scheme offers an average embedding rate of 0.1445 bpp.
DISADVANTAGES OF EXISTING SYSTEM:
There are three drawbacks in the existing data hiding algorithm for HDR images.
- First, while most algorithms target the 32-bit radiance RGBE or 48-bit TIFF format, none of them is developed for the OpenEXR format.
- Second, while works reported byconstantly increase the embedding capacity, a stego HDR image generated by these algorithms does not preserve the radiance RGBE encoding format, thus becoming perceptible to eavesdroppers and vulnerable to steganalytic attack.
- Third, most algorithms do not consider how to minimize pixel distortion incurred from message concealment, thus producing a tone-mapped stego image with a moderate image quality. This paper presents a novel data hiding algorithm for HDR images which is detailed in the next section.
- This paper presents a novel data hiding algorithm using optimal base, abbreviated as DHOB, which employs an optimal base to conceal a serial secret bit stream with least distortion in a high dynamic range image encoded by 48-bit OpenEXR file format. This type of HDR image consists of three 16-bit floating-point values in the red, green and blue channels, all of them being “half” data types with 1-bit sign, 5-bit exponent and 10-bit mantissa field.
- Considering a variety of luminance levels in an HDR image, we propose an adaptive data hiding scheme using optimal base, abbreviated as ADHOB, which supports luminance-aware message embedding, where more secret messages are carried on pixels with low luminance, and vice versa. This scheme exploits the feature of the human visual system since human beings are less sensitive to luminance variation when a pixel has low luminance.
ADVANTAGES OF PROPOSED SYSTEM:
- The proposed algorithm takes advantage of 10-bit mantissa fields to convey secret messages, while leaving intact the sign and exponent fields.
- The proposed algorithm in HDR images encoded by the OpenEXR format capable of providing a variety of capacities and producing high quality stego images feasible for real applications.
- System : Pentium Dual Core.
- Hard Disk : 120 GB.
- Monitor : 15’’ LED
- Input Devices : Keyboard, Mouse
- Ram : 1 GB
- Operating system : Windows 7.
- Coding Language : NET,C#.NET
- Tool : Visual Studio 2008
- Database : SQL SERVER 2005
Yun-Te Lin, Chung-Ming Wang*, Member, IEEE, Wei-Sung Chen, Fang-Pang Lin, and Woei Lin, Member, IEEE, “A Novel Data Hiding Algorithm for High Dynamic Range Images”, IEEE Transactions on Multimedia, 2017.