Existing Extended Progressive Visual Cryptography scheme (EPVCS) suffers from the problem of pixel expansion, poor quality of reconstructed image and residual trace of cover images in the reconstructed image. Hence in this paper, Two in One Image secret sharing scheme for EPVCS is proposed which decodes the encrypted image in two stages. The proposed scheme provides $\left(k,n\right)$ threshold construction using meaningful shares without pixel expansion and demonstrates that the reconstructed image has improved quality compared to the existing schemes. To reduce the computational complexity, the proposed scheme uses simple Modular Arithmetic operations instead of Galois field. The proposed scheme has the additional advantages of supporting any value of k and n, no overhead in resizing the secret image and no residual trace of cover image. Simulation results and performance analysis show the effectiveness of proposed scheme with improved contrast, 99% Structural Similarity of the reconstructed image and good progressive reconstruction.

现有的扩展渐进视觉密码方案（EPVCS）存在像素扩展，重构图像质量差以及重构图像中覆盖图像残留痕迹的问题。因此，本文提出了一种用于EPVCS的二合一图像秘密共享方案，该方案分两个阶段对加密图像进行解码。拟议方案提供$\left(ķ，ñ\right)$使用有意义的份额进行阈值构造而没有像素扩展，并证明了与现有方案相比，重建图像的质量有所提高。为了降低计算复杂度，所提出的方案使用简单的模块化算术运算而不是Galois字段。所提出的方案具有支持k和n的任何值的额外优点，在调整秘密图像大小时没有开销，并且没有覆盖图像的残留痕迹。仿真结果和性能分析表明，该方案具有良好的对比度，重建图像的99％结构相似度和良好的渐进重建效果。