زيادة سعة إخفاء البيانات في الصورة الرقمية الرمادية باستخدام خوارزمية خانة الإشارة المعدلة MSD

In this paper, an experimental analysis and study of the Modified Signed-Digit (MSD) method was conducted, which aims to hide a quantity of secret data represented in a grayscale image of size 512 × 512 in a set of cover images. Some quality metrics such as signal-to-noise ratio (PSNR), mean squared error (MSE), and embedding capacity (BPP) were measured. As well as calculating, the optimal number of cover images, the time taken in the hiding process, and the consumed memory. The experiments were conducted two different sizes of cover images, where the number of cover images required for the secret image is determined according to some inputs such as the number of pixels n in each group of the cover image and the number of bits in each block of the secret image L=n+1. Also, four different values of n, (2, 3, 4, 5). We tried to find the best value for the number of bits in each block L of the secret image and in each case of n to achieve the best case for image quality PSNR, MSE for both cover image sizes, and on the other hand, less time memory consumption. By using the Matlab program, we compared the results at different cover image sizes, we found that as the larger size used, the fewer cover images are needed and less time consumption. On the other hand, more memory consumption. For the other metrics, PSNR, MSE and BPP, close results were obtained. Finally, the best choice remains related to the user and the type of application or the required performance, whether in image quality or in less memory and time consumption with a larger embedding capacity. Keywords: MSD algorithm, Signal-to-noise ratio (PSNR), Mean square error (MSE), Bit-per-pixel (BPP), Memory consumption, Time consumption.