RONI Based Secured and Authenticated Indexing of Lung CT Images

Algorithm 3

Secured watermark embedding algorithm.

Input: Lung CT image, index position of RONI, secret key and the watermark image

Output: Watermark embedded image

begin

  crop and save host image from input image using index position of RONI

  verify whether the host image can accommodate the watermark image.

  convert host image and watermark image into single column vector

  start inserting header to the host image

      convert the bit position of the host image with respect to the secret key

  end header

  calculate the indices for the next pseudo-random pixels

  start inserting actual watermark image

      calculate the linear index of the pixel to be changed

      alter the least significant bit of the pseudo random index

  end insertion

end