Hybrid (2, n) Visual Secret Sharing Scheme for Color Images

In several recent decades, many secret sharing schemes for digital images have been developed. At the beginning stage, traditional schemes typically must deal with the problem of computational complexity. Later, other visual secret sharing schemes come with either higher storage cost or low accuracy problems. In this paper, a new (2, n) secret sharing scheme for color images is proposed with hybrid techniques: the gradual search algorithm for a single bitmap BTC (GSBTC), the discrete wavelet transform (DWT), and the vector quantization (VQ) technique. Experimental results confirm that our proposed scheme not only generates a high reconstructed secret color image quality but also provides a set of noise-like grayscale shadows which are much smaller than these in existing schemes.