how can i embedding secret image into transformed (integer wavelet ) cover image.

I use lwt2(image,'haar') to decompose an image to approximation matrix and detail coefficients. values in detail coefficients are integer(negative and positive).

I use dec2bin(d,n) function to convert a integer to binary, but detail coefficients values are negative and positive, so this function release an error for negative numbers.

how i can decompose an image to positive matrices or how i convert a negative number to binary? i do this work for a course project for steganography.

thanks.

Answer 1

[Walter Roberson]

d_int = int16(d);
d_uint = typecast(d_int, 'uint16');
Now do your bitsets or dec2bin or whatever, altering d_uint. Then
d_int = typecast(d_uint, 'int16');
d = double(d_int);