Steganography Algorithm Based on the Nonlocal Maximum Likelihood Noise Estimation for Mobile Applications

Algorithm 2

Image recovery.

1: Preprocessing: RGB stego-image is separated in its respective layers.

2: for each layer do

3:Stego layer decomposition: The discrete wavelet transformation or Haar is applied to stego layer.

Where denotes the desomposition, is the cover layer and

4: Extraction process: Using a 3x3 Kernel as reconstruct detector is applied to the sub-band (Map)

5:if The element in the Kernel meet the condition   then

6:Calculate the confirmation element as

7:else

8:Calculate the confirmation element as

9:end if

10:if    then

11:Abstract the element of the sub-band to the recover sub-band

12:end if

13:Adjust information of sub-band: An adjust operation is applied to the information in the recover sub-band

14:Generate recover layer: Is applied the inverse discrete wavelet transform or Daubechis 4 to the recover sub-bands to form

the recover sub-band , also is applied the inverse discrete wavelet transform Haar to the recover sub-band and sub-bands

to form the recover layer

Where denotes the , is the recover sub-band and

Where denotes the , is the recover layer and

15: end for

16: Generate Recover Image: The resulting layers are combined to obtain a RGB image