  Two novel visual cryptography (VC) schemes are proposed by combining VC with
single-pixel imaging (SPI) for the first time. It is pointed out that the
overlapping of visual key images in VC is similar to the superposition of pixel
intensities by a single-pixel detector in SPI. In the first scheme, QR-code VC
is designed by using opaque sheets instead of transparent sheets. The secret
image can be recovered when identical illumination patterns are projected onto
multiple visual key images and a single detector is used to record the total
light intensities. In the second scheme, the secret image is shared by multiple
illumination pattern sequences and it can be recovered when the visual key
patterns are projected onto identical items. The application of VC can be
extended to more diversified scenarios by our proposed schemes.
