In this paper we discuss construction of the visual secret sharing scheme for plural secret images. We first consider generation of n shares for given two secret image SI_1 and SI_2. For i = 1,2, while no information of SI_1 is revealed from any less than n - 2+i shares, SI_1 is visually recovered by the superimposition of arbitrary n - 2+i shares. We define a new class of basis matrices used for generation of the n shares and give a simple construction of such basis matrices. In addition, a fundamental bound on the contrasts of SI_1 and SI_2 is established. These results are extended to the case where we have more than two secret images.
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