Analysis and combination of positive aspects of threshold RG based VSS schemes

Conventional VSS schemes had drawbacks of pixel expansion and need of codebook design and poor visual quality. RG based VSS schemes are alternative to conventional VSS schemes but they still have problem of poor visual quality when there are extensive number of shares. Stacking of more shares results in poor visual quality of reconstructed image. But if decryption is done by XOR operation this drawback is also removed. In this paper, all existing Threshold RG based VSS schemes are discussed and compared. Also schemes with better contrast are suggested which have ability of OR as well as XOR decryption. Experimental results are illustrated which show that competitive visual quality is obtained.