I'm working on face region encryption. The task is to detect the face, encrypt the face region and embed the coordinates of face in the image. Now I have three different images,
image1 - is the original image,
image2 - is the image with face region encryption,
image3 - is the image with face region encryption with coordinates embed in the image using LSB technique.
Now I have calculated PSNR value between image3 and image1.
As per theory, high PSNR value indicates lower variation between images ; this result suits for steganography only. But for encryption, the PSNR value is expected to be low to indicate high variation between the images.
But in my case, I have used both encryption and steganography and I got the value of 18.4134. I want to know how good this value is?