Image Steganography Method Based on PVD and Modulus Function
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The document presents an improved image steganography method that utilizes both pixel value differencing (PVD) and modulus function, addressing limitations of traditional PVD by embedding information in both horizontal and vertical pixel directions. By dividing cover images into 2×2 blocks and applying innovative calculations, the method enhances stego-image quality and embedding capacity while ensuring resistance to common attacks. Experimental results confirm the effectiveness of this approach, showcasing significant improvements over existing methods.
Image Steganography Method Based on PVD and Modulus Function
- 1. Image Steganography Method Based on PVD and Modulus Function Image Processing Project
- 2. Abstract ● The traditional steganography methods with Pixel Value Differencing usually only deal with the PVD in the horizontal direction but ignore the vertical one. ● In this paper, the cover image is divided into 2×2 non overlapping blocks, then the modulus function method is used in horizontal direction and the simple PVD method is used in vertical direction for steganography. ● In addition, the falling-off-boundary problem is solved. ● Experimental results show that the proposed approach provides higher stego-image quality, larger embedding capacity, and can against common attacks.
- 3. The problem ● PVD (Pixel Value Differencing), uses the difference value of two adjacent pixels of cover image to determine the number of bits that could embed into the cover image ● This method has low embedding capacity, poor stego image quality and also low security.
- 4. The solution STEGANOGRAPHY METHOD BASED ON PVD AND MODULUS FUNCTION
- 5. ● Existing Methods Original Method of PVD ● The cover image is divided into non- overlapping blocks. ● Denote the pixel pair in some block as P i and P j ˈthe difference d is calculated as d=P j − P i ● This range is divided into r sub-regions R k (k=1,2,..,r), the width of each sub-region are power of 2. The number of bits embedding in the region of R k is n = log 2 ( w k ) , where w k is the width of the k-th sub-region. A method of PVD based on modulus function Improved PVD method based on horizontal and vertical direction ● The cover image is divided into non- overlapping blocks, b is the decimal value of secret information, calculate: ● F rem = ( p i + p j ) mod(2 ) ● When extract the secret information, first of all , calculate the number of bits each pixel can be embedded ● n = log 2 ( w k ) , then using equation (1) to calculate the decimal value of the embedded information, and finally change the decimal value F rem to n bits secret message. ● 2 × 2 pixel blocks, two pairs of horizontal direction’s pixels and a pair of vertical direction’s pixels. ● In order to extract the secret information correctly, a modification to another pair of vertical direction’s pixels is needed; if there has falling-oơ-boundary problems, the value of pixels will have to be adjusted.
- 6. Embedding Process Let the original cover image from left to right, from top to bottom into non- overlapping blocks with 2 × 2 pixels. For an image with M×N (length and width), we can get blocks nblocks = M/2 X N/2 blocks. Then a series of steps occurs to embed the hidden image into the original image The Extraction process work exactly opposite to the embedding process to obtain the original image.
- 9. Conclusion This paper presents an image steganography method which utilize horizontal pixels and vertical pixel difference, in the horizontal direction we use high-quality model function method for two pairs of pixels to embed message and in the vertical direction we select one pair of pixels to embed message with the common PVD methods. Experiments show that this scheme has not only improved the embedding capacity, stego image quality, but also achieved high security such as resistance to common attacks and RS histogram attack