Visual cryptography for gray-level images by dithering techniques
Pattern Recognition Letters
Hi-index | 0.00 |
This paper proposed a new visual cryptography scheme with the stereoscopic display which showed and accurately decrypted the hidden information for gray images. Results indicated that contrast ratio and pixel disparity of the decrypted stereo-image were key problems that would impact on the perceived quality of the decrypted image. Next, this research performed a subjective experiment of shifting pixels between both of left and right images to investigate the disparity effects of decrypted information on a full HD stereo-display with film-pattern-retarder technology. In addition, the effects of font size and contrast ratio were addressed as well. Results revealed that the thresholds of pixel disparity were between 2 and 7 pixels. To alphabets, the font size of 50 points was lower boundary to show the decrypted information. To numeric, the font size of 45 points was lower boundary over different contrast ratios.