how to make the letter mapping / simple matrix patrren ?

I want to make the letter mapping which called simple matrix pattern as below

I want to make a constant mapping table for 32 characters including 26 lower case alphabets and six nonalphanumeric symbols, which replace pixel values of the cover image by constant values of the table.

And instead of hiding the bit stream of the secret message in the least significant bits, i want to generate 49 unique matrix patterns from the texture of each block for 49 characters. After that, I want to use the 4th to 7th bit layers of the cover image for hiding the secret message.

These 49 matrix patterns are then assigned to 49 characters including 26 English characters, 10 digit numbers, 12 keyboard nonalphanumeric symbols, and one end of message character.

Answer 1

[Image Analyst]

There is nothing like that built-in so you'll have to write it yourself. The best I can do is to offer a similar thing that allows you to hide text in the pixels, or watermark the image into a given bit plane. Demos are attached. Again, they do what they do, NOT what you're asking for.

I have no idea what the "49 unique matrix patterns" are, or how to generate them. It sounds like you're following a paper you've seen. We do not have that paper

Altering the most significant several bits (4-7) would, I think, create a noticeable variation from the normal, unaltered scene. In other words I think you'd notice something was wrong with that image, but I don't know the details of your algorithm so perhaps it is not noticeable.

And if you have 26 English characters then you need to decide if you're going to deal with only lower case or only upper case characters.