A Recursive Algorithm to Hide Three Secret Images In One Image Using Wavelet Transform | ||
| Engineering and Technology Journal | ||
| Article 1, Volume 30, Issue 2, January 2012, Pages 238-260 PDF (766.94 K) | ||
| DOI: 10.30684/etj.30.2.5 | ||
| Author | ||
| Yasmin Muwafaq kassim | ||
| Abstract | ||
| This paper presents an algorithm based on wavelet transform to hide three secret colored or gray-scale images with different sizes in one colored cover image. The algorithm takes level1 wavelet transformation for the cover image and level2 wavelet transformation for the coefficients resultant from level1. The algorithm begins to divide and transpose the secret images into multiple sub bands, then imbedding them into the coefficient parts resulting from level2. The embedding depends upon a variable threshold which begins with a very small value. Here the algorithm ensures the embedding of all the pixels values of the sub band, if it is not, the operation will be repeated with a larger threshold value until all the pixels are embedded. Also the pixel's value will not be embedded directly, the difference between the cover and the secret pixel value will be embedded instead of it after some manipulation (mathematical operations). All of these factors (divide and transpose the secret images, the variable threshold for each sub band and changes on the embedded pixels) increase the robustness and quality of the algorithm. The resultant stego image and the extracted secret images are very close to the original one with high PSNR, high Correlation, low Normal Absolute Error and low Maximum Difference. | ||
| Keywords | ||
| Image Steganography; Discrete Wavelet Transform; Stego Image; Threshold; PSNR | ||
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