| 1: Preprocessing: RGB cover image and image to be hidden are separated in their respective layers. Each layer is an 8-bit grayscale |
| image. |
| 2: for each layer do |
| 3:Cover layer decomposition: The discrete wavelet transformation or Haar is applied to cover layer. |
|
| Where denotes the desomposition, is the cover layer and |
| 4:Hidden layer decomposition: The discrete wavelet transformation or Haar and Daubechis 4 are applied to the |
| layer to be hidden. |
|
| Where denotes the desomposition, is the layer to be hidden and |
|
| Where denotes the desomposition, is the approximation sub-band of first level of decomposition and , |
| |
| 5:Adjust information of sub-band: An adjust operation is applied to the sub-band |
|
| 6:Noise detection: Using a 3x3 Kernel as noise detection mechanism based on the local máximum likelihood is determited |
| the umbral of change |
|
| 7:if The element of the kernel meet the condition then |
| 8:Do the change in the sub-band for the element in the sub-band |
|
| 9:Do the change in the subband for the element in the sub-band |
|
| 10:if The element changed in the sub-band meet the condition then |
| 11:Change the element in the sub-band according to |
|
| 12: else |
| 13:Change the element in the sub-band according to |
|
| 14:end if |
| 15:end if |
| 16:Generate Stego layer: Obtain modified sub-bands coefficients and apply inverse discrete wavelet transform or Haar |
| to form the stego layer |
|
| Where denotes the inverse discrete wavelete transform, and the stego layer |
| 17: end for |
| 19: Generate Stego Image: The resulting layers are combined to obtain a RGB image. |
