Error Filtering Schemes for Color Images in Visual Cryptography

The color visual cryptography methods are free from the limitations of randomness on color images. The two basic ideas used are error diffusion and pixel synchronization. Error diffusion is a simple method, in which the quantization error at each pixel level is filtered and fed as the input to the next pixel. In this way low frequency that is obtained between the input and output image is minimized which in turn give quality images. Degradation of colors are avoided with the help of pixel synchronization. The proposal of this work presents an efficient color image visual cryptic filtering scheme to improve the image quality on restored original image from visual cryptic shares. The proposed color image visual cryptic filtering scheme presents a deblurring effect on the non-uniform distribution of visual cryptic share pixels. After eliminating blurring effects on the pixels, Fourier transformation is applied to normalize the unevenly transformed share pixels on the original restored image. This in turn improves the quality of restored visual cryptographic image to its optimality. In addition the overlapping portions of the two or multiple visual cryptic shares are filtered out with homogeneity of pixel texture property on the restored original image. Experimentation are conducted with standard synthetic and real data set images, which shows better performance of proposed color image visual cryptic filtering scheme measured in terms of PSNR value (improved to 3 times) and share pixel error rate (reduced to nearly 11%) with existing grey visual cryptic filters. The results showed that the noise effects such as blurring on the restoration of original image are removed completely.

@article{F.R2011,
  title     = {Error Filtering Schemes for Color Images in Visual Cryptography},
  journal   = {International Journal of Advanced Computer Science and Applications},
  volume    = {2},
  number    = {11},
  year      = {2011},
  publisher = {The Science and Information Organization},
  author    = {Shiny Malar F.R and Jeya Kumar M.K},
  doi       = {10.14569/IJACSA.2011.021112},
  url       = {https://doi.org/10.14569/IJACSA.2011.021112}
}