A novel steganographic method using 8-neighboring PVD (8nPVD) and LSB substitution

Abstract

This paper presents a novel steganographic method based on Least Significant Bit (LSB) substitution and 8-neighboring Pixel Value Differencing (8nPVD) for gray scale image in order to improve the embedding capacity with an imperceptible stego image. The proposed method partitions the cover image into some 3×3 non-overlapping pixel blocks in row major order. k-bits of the secret bit stream are embedded in the center pixel of the block using modified LSB substitution. The difference between the center pixel and 8-neighboring pixels are employed to find out the number of bits that can be embedded in the difference value. The method divides the gray levels [0-255] into five different continuous ranges. The number of bits to be embedded is calculated from the range table. The experimental results show that the proposed method has a higher embedding capacity and Peak Signal to Noise Ratio (PSNR) value of the stego image against the cover image. This work also presents a comparison of the embedding capacity and PSNR value of the proposed method with the existing scheme [5], [7].