Pixel value differencing steganography using correlation of target pixel with neighboring pixels

This paper presents a steganograhpic technique based on the correlation of a target pixel with its neighboring pixels. There are four schemes; (i) five neighbor correlation, (ii) six neighbor correlation, (iii) seven neighbor correlation, and (iv) eight neighbor correlation. In five neighbor correlation scheme the difference between the target pixel value and the average of the five neighboring pixel values is calculated to estimate the number of bits that can be embedded in the target pixel. Similarly, in six, seven, and eight neighbor correlation schemes the difference between the target pixel value and the average of the six, seven and eight neighboring pixel values respectively is calculated to estimate the number of bits that can be embedded in the target pixel. The experimental results reveal that no visual marks can be observed at the stego-images. The estimated peak signal-to-noise ratio values in the stego-images are higher as compared to that of the existing two, three, and four sided side match schemes. The extraction procedure is very simple and does not require the original image to retrieve the message from the stego-image.