Visual Two-Layer QR Code

QR codes have become a popular contactless interface for delivering information. A standard QR code encodes a string of text which can be scanned by using the smartphone camera within a QR code app. The widespread adoption of QR codes has sparked significant research interest, particularly in enhancing their visual appeal and augmenting their data capacity. This paper presents a novel QR code scheme that integrates three layers of information into a single QR code. Each QR code displays an image, while two distinct public messages can be retrieved using standard QR code applications—one when scanned from a close range and another from a distance. The trade-off between the robustness of the decoding process for the two messages and the visual quality of the displayed image is examined, and experiments are conducted to demonstrate the feasibility of the proposed method.